EP4695631A1 - Probe for radiation detection - Google Patents

Probe for radiation detection

Info

Publication number
EP4695631A1
EP4695631A1 EP24704900.0A EP24704900A EP4695631A1 EP 4695631 A1 EP4695631 A1 EP 4695631A1 EP 24704900 A EP24704900 A EP 24704900A EP 4695631 A1 EP4695631 A1 EP 4695631A1
Authority
EP
European Patent Office
Prior art keywords
probe
signal
detector apparatus
detector
tracks
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24704900.0A
Other languages
German (de)
French (fr)
Inventor
Angelo RIVETTI
Manuel ROLO
Lucio Pancheri
Marco Petasecca
Silvia Tedesco
Raffaele A. GIAMPAOLO
Edoardo BIANCO
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Wollongong
Universita Di Trento
Instituto Nazionale di Fisica Nucleare INFN
Politecnico di Torino
Original Assignee
University of Wollongong
Universita Di Trento
Instituto Nazionale di Fisica Nucleare INFN
Politecnico di Torino
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Wollongong, Universita Di Trento, Instituto Nazionale di Fisica Nucleare INFN, Politecnico di Torino filed Critical University of Wollongong
Publication of EP4695631A1 publication Critical patent/EP4695631A1/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/02—Dosimeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T7/00—Details of radiation-measuring instruments

Definitions

  • the present invention relates to the field of medical instrumentation.
  • the present invention concerns a probe for detecting ionizing radiation during radiotherapy procedures.
  • Cancer treatment is largely based on the use of sources of ionizing radiation, mainly particles, which are employed to irradiate a tumoral mass in order to kill the cells composing it.
  • brachytherapy requires an accurate planning of the distribution of one or more radiation sources to be implanted in the patient.
  • monitoring the emitted radiation is difficult and inaccurates.
  • the verification technique used for LDR in the state of the art adopts radiography equipment to create two or more projections of the implanted sources are created. This technique allows counting of the implanted sources, but not checking their actual position relative to the tumor.
  • Other techniques require the use of an ultrasonic rectal probe showing the position of the tumor, but not the position of the implanted sources. Correlating such data in order to fully verify the quality of treatment is often impossible.
  • Such techniques require the use of complex calculations to provide arather imprecise and unreliable estimate of the dose accumulated at a point of the tumor or neighboring healthy tissues.
  • a further purposeof the present invention is to provide a system for monitoring the radiation dosage within a narrow space, such as the urethra of a human being.
  • conditioning a signal refers to a signal processing operation designed to modify the sensor signal so as to ensure optimal processing by elements connected to the probe's processing module.
  • signal conditioningcarried out by the processing module comprises one or more of filtering or amplifying operations on the signal provided by the sensor.
  • Similar definitions of the expression “conditioning a signal” or “signal conditioning” can be found in R. Pallas-Areny, J.G. Webster: “Sensors and Signal Conditioning", ch. 1.1.3, 2nd ed., Wiley Interscience, 2000, and in John Dempster: "Biological Techniques Series, The Laboratory Computer” , Academic Press, 2001, ch. 4, pp. 74-100.
  • the detector apparatus generates and transmits to the processing device, through at least one of the conductive tracks, an output signal indicative of the intensity of the radiations hitting it.
  • the preamplifier circuit and the amplifier circuit are located close to, more preferably at, the sensor, it is possible to effectively and efficiently amplify the signal generated by the sensor.
  • the output signal generated by the probe is robust with respect tonoise and/or interference and can be transferred over distances in the order of meters without the information contained therein undergoing any significant degradation.
  • the detector apparatus is a monolithic device, in which the sensor and the processing module are integrated in the same substrate of semiconductor material.
  • the probe according to the invention is suitable for sliding in catheters having an internal diameter between 1.6 mm and 2.5 mm - i.e., from 4 to 10 units of the French (or Charriere) scale.
  • the preamplifier circuit comprises a programmable filter.
  • the detector apparatus comprises a programming terminal connected to a respective programming track for receiving a programming signal from the processing device.
  • the transfer function of the preamplifier circuit can be adjusted based on the programming signal.
  • the amplifier circuit comprises a programmable gain block.
  • the detector apparatus comprises a gain programming terminal connected to a respective gain programming track to receive a gain programming signal from the processing device.
  • the amplifier circuit can also adjust the gain with which the signal is to be amplified based on the programming signal.
  • the possibility of programming the filter cut-off frequency and the gains allow the probe suitable for measuring radiations of different intensity and type and/ or adapts the output signal to different electromagnetic noise conditions.
  • the probe thus conceived is highly versatile. For example, by adjusting the programmable elements it is possible to monitor radiotherapy dosages having substantially different specifications.
  • the probe comprises a plurality of detector apparatuses.
  • the detector apparatuses are arranged sequentially along a main extension direction of the flexible support.
  • the detector apparatuses are spaced apart from each other by a distance of between 1 cm and 1.5 cm.
  • the probe can provide measured radiation information with higher resolution, without substantially reducing the probe's flexibility or complicating the probe production process.
  • the plurality of tracks of the flexible support comprises a power supply track, a reference track, a bias track, and a plurality of signal tracks.
  • the power supply track, the reference track and the bias track are connected to respective power supply, reference and bias terminals of each detector apparatus of the probe, so that each one of the detector apparatuses will receive the same supply voltage, the same reference voltage and the same bias voltage.
  • each signal track is connected to a respective output terminal of the detector apparatuses, so that the detector apparatuses will transmit the respective output signal in parallel.
  • This track arrangement allows the number of side-by-side tracks, and hence the total width of the probe, to be kept small.
  • the maximum number of side- by-side tracks is limited to NA+3 tracks (where NA is the number of detector apparatuses of the probe), for non-programmable conditioning and amplification circuits, or NA+5 tracks, for programmable filtering and amplification circuits.
  • the flexible support is a multilayer tape comprising at least one pair of external insulating layers, one pair of conductive layers, wherein the tracks are formed, and one internal insulating layer placed between said pair of conductive layers.
  • the tracks have a maximum width of 50 pm to 150 pm, e.g., approx. 100 pm. Even more preferably, the tracks formed in the same layer are spaced apart by a maximum distance ranging between 50 pm and 150 pm, e.g., approx. 100 pm.
  • the multilayer structure and the track arrangement according to the invention allow to keep the dimensions of the flexible support small.
  • the width can be limited to a value of approx. 0.8 mm for a single detector apparatus, or approx. 1.6 mm for a probe comprising four (non-programmable) detector apparatuses, with 100pm wide tracks spaced apart by 100 pm.
  • the probe comprises a protective container for each detector apparatus.
  • the protective container encloses the respective detector apparatus of the probe, so as to protect it from the external environment.
  • the protective container is transparent to ionizing radiation.
  • the container allows the probe apparatuses to be protected from foreign bodies and electromagnetic radiation in the visible spectrum, without however impairing neither the flexibility nor the versatility of the probe.
  • the protective container is made from epoxy resin opaque to electromagnetic radiation in the visible spectrum.
  • the protective container has a substantially cylindrical shape and a diameter between 1.2 mm and 1.5 mm.
  • the protective container with such features can be easily manufactured and allows effective protection of the respective detector apparatus.
  • suitably shaped container e.g., a container having a rounded shape or just rounded edges - will facilitate the sliding action of the probe through catheters and other similar spaces.
  • a different aspect of the present invention concerns a system for monitoring the dosage of ionizing radiation - e.g., in radiotherapy treatments - comprising the probe according to any one of the above-described embodiments and a processing device to which the probe is connected through a connector provided at one end of the flexible support, opposite to the end whereto one or more detector apparatuses are connected.
  • the system thus assembled allows reliable and accurate monitoring of radiation dosage within an area of interest.
  • Figure 1 is a schematic side view of a system for monitoring the dosage of radiation according to an embodiment of the present invention
  • Figure 2 is a schematic side sectional view of a portion of the flexible support used in the probe according to an embodiment of the invention, comprised in the system of Figure 1;
  • Figure 3 is a block diagram of the system of Figure 1, showing the components of a detector apparatus used in the probe according to the present invention;
  • Figure 4 is a principle circuit diagram of a detector apparatus according to a first embodiment of the present invention.
  • Figure 5 is a bottom view of the detector apparatus of Figure 4, showing the connection terminals of the same;
  • Figure 6 is a schematic view of two conductive layers of the flexible support of the probe according to a first embodiment of the invention, highlighting a plurality of conductive tracks;
  • Figure 7 is a schematic top view of a probe according to a second embodiment of the present invention, showing the conductive tracks of the flexible support of the probe;
  • Figure 8 is a schematic side view of the probe of Figure 7;
  • Figure 9 is a principle circuit diagram of an alternative detector apparatus according to a third embodiment of the present invention.
  • Figure 10 is a bottom view of the detector apparatus of Figure 9, showing the connection terminals of the same;
  • Figure 11 is a schematic top view of a probe according to the third embodiment of the present invention, which uses the detector apparatus of Figures 8 and 9, highlighting the conductive tracks of the flexible support of the probe, and
  • Figure 12 is a principle circuit diagram of an alternative detector apparatus according to a fourth embodiment of the present invention.
  • a probe 1 for detecting radiotherapy radiation comprises a flexible support 10, at least one detector apparatus 20 and, preferably, a casing 30.
  • the flexible support 10 is a multilayer tape.
  • the detector apparatus 20 is mechanically and electrically coupled to a first end 11 of the flexible support 10, while at a second end of the flexible support 10 there is a connector 12 that can be connected to a processing device 40 - e.g., a general-purpose computer - suitable for supplying power to the detector apparatus and for executing a software application controlling the acquisition and, preferably, the processing of the signals supplied by the detector apparatus 20 of the probe 1.
  • the probe 1 and the processing device 40 form a system for monitoring ionizing radiation, e.g., a dosimeter for monitoring the radiation dose administered by radiotherapy in a desired region.
  • the flexible support 10 is a tape comprising a plurality of layers, which in the example of Figure 2, two external insulating layers 13a and 13b, two conductive layers 14a and 14b, two coating layers 15a and 15b of conductive material, and an internal insulating layer 16.
  • Each one of the external insulating layers 13a and 13b is coupled to a respective internal coating layer 15a and 15b by means of a layer of adhesive material 17a and 17b.
  • the coating layers 15a and 15b are coupled to the conductive layers 14a and 14b, respectively, by lamination.
  • the conductive layers 14a and 14b are coupled to the internal insulating layer 16 by means of a pair of internal adhesive layers 18a and 18b.
  • the conductive layers 14a and 14b are, preferably, made of copper and comprise conductive tracks (not shown in Figure 2, but described in the following) for suitably connecting terminals of the detector apparatus 20 to corresponding terminals of the processing device 40 as will be described hereinafter.
  • the coating layers 15a and 15b are, preferably, made of copper and are used in order to create lines 15c for mutually connecting tracks formed in the conductive layers 14a and 14b, or to create an electric connection line that, from the external insulating layer 13a, leads to the layer 14b.
  • the insulating layers 13a, 13b and 16 are, preferably, made of polyimide.
  • the flexible support 10 has a thickness - i.e., the dimension across the above-described layers - ranging between 0.4 mm and 0.7 mm; preferably, the flexible support 10 has a thickness of 0.5 mm.
  • the detector apparatus 20 comprises at least one ionizing radiation sensor, hereafter simply referred to as sensor 21, and a signal processing module 22.
  • the detector apparatus 20 is a monolithic device, i.e., the sensor 21 and the signal processing module 22 are integrated into the same semiconductor material substrate.
  • a suitable detector apparatus 20 is described in Italian patent no. 102017000122669 entitled “Sensore integrato di radiazione ionizzante e di particelle ionizzanti" ("Integrated sensor of ionizing radiation and ionizing particles”), incorporated herein as a reference.
  • the processing module 22 comprises a preamplifier circuit 221 for processing the signal generated by the sensor 21 and an amplifier circuit 222 connected in series with the preamplifier circuit 221 for amplifying an output signal thereof.
  • the preamplifier circuit 221 comprises an amplifier OA1, a capacitor CF and a resistor RF; the capacitor CF and the resistor RF are connected in parallel with each other and connected in feedback relation with the amplifier OA1 - i.e., connected to an input terminal and to the output terminal of the amplifier OA1.
  • the capacitor CF and the resistor RF define the cut-off frequency of the preamplifier circuit.
  • the capacitor CF and the resistor RF are elements that define the signal transfer function that characterizes the preamplifier circuit 221.
  • the amplifier circuit 222 comprises an amplifier OA2 and a gain block G - e.g., an impedance - connected in feedback relation with the amplifier OA2.
  • the detector apparatus 20 receives from the processing device 40 a bias voltage VB (e.g., ranging between 10 V and 30 V, e.g., 20V) suitable to keep the detector 21 in an operative condition, in which condition it can detect interaction with particles, in particular associated with ionizing radiation.
  • VB bias voltage
  • the detector apparatus 20 receives from the processing device 40 a supply voltage VDD suitable to power the preamplifier circuit 221 and the amplifier circuit 222.
  • the detector apparatus 20 comprises four terminals that are connected to the processing device 40 by means of as many conductive tracks formed in the conductive layers 14a and 14b of the flexible support 10.
  • the detector 20 is an integrated device encapsulated into a flip-chip packaging.
  • the packaging is made of insulating material, typically polymeric material, and generally has a parallelepiped shape comprising two main surfaces separated by four side surfaces.
  • a power supply terminal 24a on a (coupling) main surface 23 of the detector apparatus 20, four terminals, or pads, are provided: a power supply terminal 24a, a reference terminal 24b, a bias terminal 24c, and an output terminal 24d.
  • the terminals 24a-24d are electrically coupled to respective tracks 19a-19d formed on the flexible support 10, schematically shown in Figure 6.
  • the power supply terminal 24a is connected to a power supply track 19a
  • the reference terminal 24b is connected to a ground track or plane 19b
  • the bias terminal 24c is connected to a bias track 19c
  • the output terminal 24d is connected to a signal track 19d.
  • All tracks 19a-d are formed in one of the conductive layers 14a, 14b of the flexible support.
  • the tracks 19a, 19c and 19d are formed in the first conductive layer 14a of the flexible support 10, while the ground track 19b is formed in the second conductive layer 14b of the flexible support, and a line 15c connects it to the reference terminal 24b.
  • all tracks 19a-19d of the flexible support 10 are coupled to a corresponding terminal of the connector 12 to provide an electrical and mechanical connection with a corresponding terminal (not shown) of the processing device 40, so that the latter can supply the corresponding power, reference and bias voltage, and receive an output signal So from the detector apparatus 20.
  • the minimum width Wmin of the flexible support is:
  • the electric signal SR is indicative of an intensity of the ionizing radiation hitting the detector apparatus 20. More generally, the electric signal SR is indicative of a measurement of energetic particles/ electromagnetic radiations within a predetermined range of energy/ frequency that are hitting the probe 1.
  • the electric signal SR is first integrated by the preamplifier circuit 221 and then amplified by the amplifier circuit 222.
  • the output signal So is supplied to the output terminal 24d of the detector apparatus 20 and propagates through the output track 19d up to the processing device 40.
  • the output signal So is a signal obtained by conditioning the signal SR generated by the sensor 21.
  • the preamplifier circuit 221 is adapted to receive the signal SR from the sensor 21 and process it in order to adapt the sensor's signal to optimal levels (e.g., voltage and current values, signal-to- noise (SNR) ratio, etc.) for the operation of the amplifier circuit 222.
  • the amplifier circuit 222 amplifies the preamplified signal SR to generate the output signal So.
  • the detector apparatus 20 is enclosed in the container 30.
  • the container 30 is suitable to protect the detector apparatus 20 against foreign bodies, mechanical forces, and light.
  • the container 30 fully envelops the detector apparatus 20 and covers a surface of the flexible support 10 near the position where the detector apparatus 20 is mounted.
  • the container 30 has a substantially cylindrical shape, with a diameter ranging between 1.2 mm and 2.5 mm, e.g., 1.8 mm. Even more preferably, the container 30 has rounded edges and/ or a rounded shape to facilitate the sliding action thereof through a catheter.
  • the container 30 is made from an epoxy polymer, preferably black in color, suitable to protect the detector apparatus 20 against foreign bodies, mechanical forces, and electromagnetic radiation in the visible spectrum.
  • the probe la comprises more than one detector apparatus 20.
  • the probe la is designed to monitor the progress of brachytherapy for prostate cancer treatment.
  • the probe la comprises four detector apparatuses 20 arranged in series starting from the free end 11 of the flexible support 10.
  • the detector apparatuses 20 are mutually spaced apart along the support 10 by a distance ranging between 1 cm and 1.5 cm, preferably 1 cm.
  • each detector apparatus 20 is enclosed in a respective container 30 having substantially the same characteristics as already described above.
  • the detector apparatuses can thus be protected against foreign bodies and, at the same time, the probe la can remain flexible.
  • the power supply track 19a, the ground track 19b and the bias track 19c are connected to the various power supply terminals 24a, reference terminals 24b and bias terminals 24c of each one of the four detector apparatuses 20.
  • the output terminals 24d of the four detector apparatuses 20 are connected to respective signal tracks 19d.
  • the total number of tracks Np g is:
  • N P NA+3, (2) where NA is the number of detector apparatuses 20.
  • the probe lb comprises four programmable detector apparatuses 20a.
  • the capacitor CF and the resistor RF of the preamplifier circuit 221 are of the programmable type; likewise, the gain block G of the gain circuit 222 is also of the programmable type.
  • the capacitor CF, the resistor RF and the gain block G have a known structure, which will not be described any further herein for brevity's sake.
  • the resistor RF is made by means of a transconductor.
  • the detector apparatus 20a also comprises, in addition to the above-described terminals 24a-24d, two programming terminals: a conditioning programming terminal 24e and a gain programming terminal 24f, as shown in Figure 10.
  • the processing device 40 is suitable for transmitting to the detector apparatus 20a a conditioning configuration signal PF and a gain configuration signal PG through corresponding programming tracks 19e and 19f.
  • the programming tracks 19e and 19f are formed, for example, in the conductive layer 14a, as shown in Figure 11, and are connected to the terminals 24e and 24f, respectively.
  • the processing device 40 can be configured to set and/ or adjust the conditioning configuration signal PF and the gain configuration signal PG - such signals being, for example, both analog ones - based on a specific application, on the source type used for generating the ionizing radiation to be detected, etc., in order to obtain, from each detector apparatus 20a of the probe lb, an optimal output signal So that can be processed correctly.
  • the transfer function of the preamplifier circuit 221 can be adjusted by means of the conditioning configuration signal PF, allowing the cutoff frequency and/ or the gain of the transfer function of the preamplifier circuit 221.
  • the gain configuration signal PG makes it possible to adjust the amplification of the signal SR produced by the preamplifier circuit 221, to be provided by the gain circuit 222 that transmits the output signal So on the respective signal track 19d.
  • an alternative detector apparatus 20b is provided, as illustrated in Figure 12.
  • the detector apparatus 20b is equipped with an analog- to-digital converter ADC connected in series with the amplifier circuit 222.
  • the analog-to-digital converter ADC receives the output signal So from the amplifier circuit 222 and converts it into a digital signal SD.
  • the digital signal SD is serially supplied to the processing device 40 through a single signal track 19d.
  • the bias, power and programming voltages are supplied by an apparatus other than the processing device that processes the signals.
  • a signal preprocessing apparatus may be provided, separate from the above-described processing device, and adapted to execute additional steps of conditioning, filtering, amplifying and/ or digitalizing the signals outputted by the detection apparatus(es).
  • programming the capacitor and the resistor of the preamplifier circuit and/or programming the gain block of the amplifier circuit may involve the serial transfer of a bit word from the processing device to the one or more detector apparatuses.
  • each apparatus will comprise a decoding circuit converting the serially received bit word into a respective programming command for the capacitor or the resistor of the preamplifier circuit and/ or for the gain block of the amplifier circuit.
  • the power supply voltage may be varied dynamically to modify the conditioning and/ or the amplification effected by the processing module of the one or more detector apparatuses.
  • all tracks are formed on a single conductive layer.
  • the width of the tracks may differ from the width of the spaces between adjacent tracks.
  • the width of the tracks is selected to avoid track damage and exceeding a predetermined maximum operating temperature when the tracks are crossed by electric signals having a predetermined power level.
  • the width of the spaces between the tracks is so selected as to cancel, or even just limit, any electromagnetic interference between the tracks.
  • the programmable detector apparatus comprises only either the capacitor or the resistor is of the programmable type. Moreover, nothing prevents from creating a programmable detector apparatus wherein only the gain element of the amplifier circuit is programmable. Also, nothing prevents alternative embodiments from comprising any combination of such programmable and non-programmable elements. Furthermore, in more complex embodiments (not shown), each detector apparatus, or each group of detector apparatuses, receives different programming signals for one or more programmable elements of the circuits comprised in the processing module.
  • the processing module is configured to condition the signal received from the sensor with which it is integrated into the detector apparatus.
  • signal conditioning is a signal processing step aimed at modifying the sensor's signal to guarantee optimal processing by elements connected to the probe's processing module, thus ensuring robustness to interference and attenuation as the signal is transmitted on the track that connects the detector apparatus to the processing device.
  • the signal conditioning provided by the processing module comprises one or more steps of filtering, amplifying, limiting and linearizing the signal supplied by the sensor.
  • the processing module may comprise circuits, and a number thereof, which are different from those described with reference to the exemplary embodiment.
  • the processing module may comprise one or more filtering circuits in addition and/or as an alternative to the preamplifier circuit and the amplifier circuit. Of course, all details may be replaced with other technically equivalent elements.
  • the packaging of the detector apparatuses may have ball grid array (BGA) or flat no-leads (FN) terminals, or other equivalent types of terminals.
  • BGA ball grid array
  • FN flat no-leads

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Measurement Of Radiation (AREA)
  • Radiation-Therapy Devices (AREA)

Abstract

The present invention relates to a probe (1; 1a; 1b) for detecting ionizing radiation. The probe (1; 1a; 1b) comprises an elongated flexible support (10) and a detector apparatus (20; 20a; 20b), which is coupled to the flexible support (10) near one end (11) thereof. The flexible support (10) comprises a plurality of electrically conductive tracks (19a-f) coupled to corresponding electrical terminals (24a-f) of the detector apparatus (20; 20a; 20b) to allow the exchange of electrical signals between the apparatus and a processing device (40). Advantageously, the detector apparatus (20; 20a; 20b) comprises a sensor (21) adapted to generate a signal indicative of an intensity of ionizing radiations hitting the detector apparatus (20; 20a; 20b), and a processing module (22) adapted to condition the signal generated by the sensor (21).

Description

PROBE FOR RADIATION DETECTION
DESCRIPTION
TECHNICAL FIELD
The present invention relates to the field of medical instrumentation. In more detail, the present invention concerns a probe for detecting ionizing radiation during radiotherapy procedures.
BACKGROUND ART
Cancer treatment is largely based on the use of sources of ionizing radiation, mainly particles, which are employed to irradiate a tumoral mass in order to kill the cells composing it.
Several radiotherapy treatments have been developed in the art both for general use and for use in treating specific tumor forms. Whatever the type of radiotherapy treatment, the quantity, or dose, of radiation administered to a patient must be accurately selected and monitored to avoid damaging the tissues adjoining the tumor mass to be treated.
In particular, in case of brachytherapy - or internal radiotherapy - the radiation source is placed inside or near a tumor mass to be treated. It is complex to obtain a direct measurement of the radiation dose irradiated on a tumor mass or, more generally, a precise value of the radiation emitted over time by the radiation source at the target. Brachytherapy is mainly used for treating tumors growing in the prostate, in the uterine cervix, in the brain, in the lumen of a hollow organ (e.g., the trachea or the esophagus), in blood vessels, etc.
Two types of brachytherapy can be distinguished:: a) Low-Dose Rate (LDR), wherein a certain number of sources are permanently implanted in the tumor and the dose is released at a low rate for many days; and b) High-Dose Rate (HDR), wherein a single source is temporarily inserted in the tumor for a certain time and then removed.
In order to achieve adequate treatments, brachytherapy requires an accurate planning of the distribution of one or more radiation sources to be implanted in the patient. However, once the radiation sources have been implanted in the patient, monitoring the emitted radiation is difficult and inaccurates. The verification technique used for LDR in the state of the art adopts radiography equipment to create two or more projections of the implanted sources are created. This technique allows counting of the implanted sources, but not checking their actual position relative to the tumor. Other techniques require the use of an ultrasonic rectal probe showing the position of the tumor, but not the position of the implanted sources. Correlating such data in order to fully verify the quality of treatment is often impossible. Such techniques require the use of complex calculations to provide arather imprecise and unreliable estimate of the dose accumulated at a point of the tumor or neighboring healthy tissues.
For HDR brachytherapy, there are no state-of-the-art techniques or clinical instruments for verifying in-vivo treatment. Everything relies on planning calculations and precision of the catheter implantation for the movementof the radioactive source.
Therefore, there is a need in this field for instruments and procedures for accurately monitoring the emitted radiation dose, during short-term treatments, or the state of decay of the radiation sources, during long-term treatments.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention aims at overcoming the drawbacks of the prior art.
In particular, it is one object of the present invention to provide a probe that is capable of accurately measuring the dose of radiation hitting it, and which permits generating a reliable measurement signal.
A further purposeof the present invention is to provide a probe for radiation measurement with an adequate resolution to accurately and reliably monitor a radiotherapy treatment, in particular brachytherapy.
It is a further object of the present invention to provide a probe for radiation measurement which is compact and easy to handle.
A further purposeof the present invention is to provide a system for monitoring the radiation dosage within a narrow space, such as the urethra of a human being.
These and other purpose of the present invention are achieved by means of a system incorporating the features set out in the appended claims, which form an integral part of the present description.
According to a first aspect, the present invention relates a probe for detecting ionizing radiation. The probe comprises an elongated flexible support and a detector apparatus, which is coupled to the flexible support near one end thereof. The flexible support comprises a plurality of electrically conductive tracks coupled to corresponding electrical terminals of the detector apparatus to allow the exchange of electrical signals between the apparatus and a processing device. Advantageously, the detector apparatus comprises a sensor, suitable forgenerating a signal indicative of an intensity of ionizing radiations hitting the detector apparatus, and a processing module. In particular, the processing module is suitable for conditioning the signal provided by the sensor and transferring it through at least one track of the plurality of tracks.
In particular, expressions like "conditioning a signal" or "signal conditioning" refer to a signal processing operation designed to modify the sensor signal so as to ensure optimal processing by elements connected to the probe's processing module. For example, signal conditioningcarried out by the processing module comprises one or more of filtering or amplifying operations on the signal provided by the sensor. Similar definitions of the expression "conditioning a signal" or "signal conditioning" can be found in R. Pallas-Areny, J.G. Webster: "Sensors and Signal Conditioning", ch. 1.1.3, 2nd ed., Wiley Interscience, 2000, and in John Dempster: "Biological Techniques Series, The Laboratory Computer" , Academic Press, 2001, ch. 4, pp. 74-100.
The probe according to the present invention provides a stable output signal against electromagnetic interference. Accordingly, the flexible support can be long enough to allow insertion into different ducts and cavities ,for example, a male urethral catheter is about 30-40cm long, while a female one is from 7 cm and 20 cm in length, until it reach a region where it is desired to measure radiation intensity without suffering any significant deformation of the signal provided at the output, thus ensuring greater accuracy and reliability of the information resulting from the processing of the signals received by the probe, e.g. the evaluation of a dosage of radiation administered in proximity to the probe.
In one embodiment, the processing module comprises a preamplifier circuit suitable for processingthe signal provided by the sensor, and an amplifier circuit suitable for amplifying the processed signal. In particular, the preamplifier circuit is suitable for receiving the signal from the sensor and submitting it to processing it in order to adapt the sensor's signal to optimal levels (e.g., voltage and current values, signal-to-noise (SNR) ratio, etc.) for the operation of the amplifier circuit.
Preferably, the amplifier transmits the conditioned and amplified signal on at least one conductive track.
Thus, the detector apparatus generates and transmits to the processing device, through at least one of the conductive tracks, an output signal indicative of the intensity of the radiations hitting it.
Since the preamplifier circuit and the amplifier circuit are located close to, more preferably at, the sensor, it is possible to effectively and efficiently amplify the signal generated by the sensor. As a consequence, the output signal generated by the probe is robust with respect tonoise and/or interference and can be transferred over distances in the order of meters without the information contained therein undergoing any significant degradation.
Preferably, the detector apparatus is a monolithic device, in which the sensor and the processing module are integrated in the same substrate of semiconductor material.
Even more preferably, the detector apparatus is a flip-chip technology device.
These features of the detector apparatus allow the probe to be made very small, thus increasing the versatility thereof. For example, the probe according to the invention is suitable for sliding in catheters having an internal diameter between 1.6 mm and 2.5 mm - i.e., from 4 to 10 units of the French (or Charriere) scale.
In one embodiment, the preamplifier circuit comprises a programmable filter. In such a case, the detector apparatus comprises a programming terminal connected to a respective programming track for receiving a programming signal from the processing device. Thus, the transfer function of the preamplifier circuit can be adjusted based on the programming signal.
Preferably, the programmable filter of the preamplifier circuit comprises a programmable resistor and a programmable capacitor. In this case, the preamplifier circuit can adjust the resistance value of the programmable resistor and the capacitance value of the programmable capacitor as a function of the programming signal.
In other words, through the programming signal it is possible to adjust the cutoff frequency and/ or the gain of the transfer function of the preamplifier circuit.
As an alternative or in addition, the amplifier circuit comprises a programmable gain block. In such a case, the detector apparatus comprises a gain programming terminal connected to a respective gain programming track to receive a gain programming signal from the processing device. Thus, the amplifier circuit can also adjust the gain with which the signal is to be amplified based on the programming signal.
The possibility of programming the filter cut-off frequency and the gains allow the probe suitable for measuring radiations of different intensity and type and/ or adapts the output signal to different electromagnetic noise conditions. As a result, the probe thus conceived is highly versatile. For example, by adjusting the programmable elements it is possible to monitor radiotherapy dosages having substantially different specifications.
In one embodiment, the probe comprises a plurality of detector apparatuses. Advantageously, the detector apparatuses are arranged sequentially along a main extension direction of the flexible support. Preferably, the detector apparatuses are spaced apart from each other by a distance of between 1 cm and 1.5 cm.
With such a structure, the probe can provide measured radiation information with higher resolution, without substantially reducing the probe's flexibility or complicating the probe production process.
In one embodiment, the plurality of tracks of the flexible support comprises a power supply track, a reference track, a bias track, and a plurality of signal tracks. In this case, the power supply track, the reference track and the bias track are connected to respective power supply, reference and bias terminals of each detector apparatus of the probe, so that each one of the detector apparatuses will receive the same supply voltage, the same reference voltage and the same bias voltage. Moreover, each signal track is connected to a respective output terminal of the detector apparatuses, so that the detector apparatuses will transmit the respective output signal in parallel.
This track arrangement allows the number of side-by-side tracks, and hence the total width of the probe, to be kept small. In fact, the maximum number of side- by-side tracks is limited to NA+3 tracks (where NA is the number of detector apparatuses of the probe), for non-programmable conditioning and amplification circuits, or NA+5 tracks, for programmable filtering and amplification circuits.
In one embodiment, the flexible support is a multilayer tape comprising at least one pair of external insulating layers, one pair of conductive layers, wherein the tracks are formed, and one internal insulating layer placed between said pair of conductive layers. Preferably, the tracks have a maximum width of 50 pm to 150 pm, e.g., approx. 100 pm. Even more preferably, the tracks formed in the same layer are spaced apart by a maximum distance ranging between 50 pm and 150 pm, e.g., approx. 100 pm.
The multilayer structure and the track arrangement according to the invention allow to keep the dimensions of the flexible support small. For example, the width can be limited to a value of approx. 0.8 mm for a single detector apparatus, or approx. 1.6 mm for a probe comprising four (non-programmable) detector apparatuses, with 100pm wide tracks spaced apart by 100 pm.
In one embodiment, the probe comprises a protective container for each detector apparatus. The protective container encloses the respective detector apparatus of the probe, so as to protect it from the external environment. Advantageously, the protective container is transparent to ionizing radiation.
The container allows the probe apparatuses to be protected from foreign bodies and electromagnetic radiation in the visible spectrum, without however impairing neither the flexibility nor the versatility of the probe.
Preferably, the protective container is made from epoxy resin opaque to electromagnetic radiation in the visible spectrum.
Even more preferably, the protective container has a substantially cylindrical shape and a diameter between 1.2 mm and 1.5 mm.
The protective container with such features can be easily manufactured and allows effective protection of the respective detector apparatus.
In addition, the suitably shaped container - e.g., a container having a rounded shape or just rounded edges - will facilitate the sliding action of the probe through catheters and other similar spaces.
A different aspect of the present invention concerns a system for monitoring the dosage of ionizing radiation - e.g., in radiotherapy treatments - comprising the probe according to any one of the above-described embodiments and a processing device to which the probe is connected through a connector provided at one end of the flexible support, opposite to the end whereto one or more detector apparatuses are connected.
The system thus assembled allows reliable and accurate monitoring of radiation dosage within an area of interest.
Further features and objects of the present invention will become clearer from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described below with reference to some non-limiting explanatory examples illustrated in the accompanying drawings. Such drawings illustrate different aspects and embodiments of the present invention and, wherever appropriate, any similar structures, components, materials and/or elements in the various drawings are designated by similar reference numbers.
Figure 1 is a schematic side view of a system for monitoring the dosage of radiation according to an embodiment of the present invention;
Figure 2 is a schematic side sectional view of a portion of the flexible support used in the probe according to an embodiment of the invention, comprised in the system of Figure 1; Figure 3 is a block diagram of the system of Figure 1, showing the components of a detector apparatus used in the probe according to the present invention;
Figure 4 is a principle circuit diagram of a detector apparatus according to a first embodiment of the present invention;
Figure 5 is a bottom view of the detector apparatus of Figure 4, showing the connection terminals of the same;
Figure 6 is a schematic view of two conductive layers of the flexible support of the probe according to a first embodiment of the invention, highlighting a plurality of conductive tracks;
Figure 7 is a schematic top view of a probe according to a second embodiment of the present invention, showing the conductive tracks of the flexible support of the probe;
Figure 8 is a schematic side view of the probe of Figure 7;
Figure 9 is a principle circuit diagram of an alternative detector apparatus according to a third embodiment of the present invention;
Figure 10 is a bottom view of the detector apparatus of Figure 9, showing the connection terminals of the same;
Figure 11 is a schematic top view of a probe according to the third embodiment of the present invention, which uses the detector apparatus of Figures 8 and 9, highlighting the conductive tracks of the flexible support of the probe, and
Figure 12 is a principle circuit diagram of an alternative detector apparatus according to a fourth embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
While the invention is susceptible of several modifications and alternative constructions, the drawings show some preferred embodiments that will be described in detail below. It should be understood, however, that there is no intention to limit the invention to the specific embodiments illustrated herein, since the invention shall also cover any such modifications, alternative constructions and equivalents falling within the scope of the invention as defined in the claims.
Unless otherwise specified, "for example", "etc.", "or" indicate non-exclusive and non-limiting alternatives. Unless otherwise specified, "includes" means "includes, without being limited to,".
Referring to Figure 1, a probe 1 for detecting radiotherapy radiation according to an embodiment of the present invention comprises a flexible support 10, at least one detector apparatus 20 and, preferably, a casing 30.
The flexible support 10 is a multilayer tape. The detector apparatus 20 is mechanically and electrically coupled to a first end 11 of the flexible support 10, while at a second end of the flexible support 10 there is a connector 12 that can be connected to a processing device 40 - e.g., a general-purpose computer - suitable for supplying power to the detector apparatus and for executing a software application controlling the acquisition and, preferably, the processing of the signals supplied by the detector apparatus 20 of the probe 1. The probe 1 and the processing device 40 form a system for monitoring ionizing radiation, e.g., a dosimeter for monitoring the radiation dose administered by radiotherapy in a desired region.
The flexible support 10 is a tape comprising a plurality of layers, which in the example of Figure 2, two external insulating layers 13a and 13b, two conductive layers 14a and 14b, two coating layers 15a and 15b of conductive material, and an internal insulating layer 16. Each one of the external insulating layers 13a and 13b is coupled to a respective internal coating layer 15a and 15b by means of a layer of adhesive material 17a and 17b. The coating layers 15a and 15b are coupled to the conductive layers 14a and 14b, respectively, by lamination. Lastly, the conductive layers 14a and 14b are coupled to the internal insulating layer 16 by means of a pair of internal adhesive layers 18a and 18b.
In more detail, the conductive layers 14a and 14b are, preferably, made of copper and comprise conductive tracks (not shown in Figure 2, but described in the following) for suitably connecting terminals of the detector apparatus 20 to corresponding terminals of the processing device 40 as will be described hereinafter. The coating layers 15a and 15b are, preferably, made of copper and are used in order to create lines 15c for mutually connecting tracks formed in the conductive layers 14a and 14b, or to create an electric connection line that, from the external insulating layer 13a, leads to the layer 14b. The insulating layers 13a, 13b and 16 are, preferably, made of polyimide.
In the embodiments of the present invention, the flexible support 10 has a thickness - i.e., the dimension across the above-described layers - ranging between 0.4 mm and 0.7 mm; preferably, the flexible support 10 has a thickness of 0.5 mm.
As shown in the block diagram of Figure 3, the detector apparatus 20 comprises at least one ionizing radiation sensor, hereafter simply referred to as sensor 21, and a signal processing module 22. Advantageously, the detector apparatus 20 is a monolithic device, i.e., the sensor 21 and the signal processing module 22 are integrated into the same semiconductor material substrate. One example of a suitable detector apparatus 20 is described in Italian patent no. 102017000122669 entitled "Sensore integrato di radiazione ionizzante e di particelle ionizzanti" ("Integrated sensor of ionizing radiation and ionizing particles"), incorporated herein as a reference.
As illustrated in the circuit diagram of Figure 4, the processing module 22 comprises a preamplifier circuit 221 for processing the signal generated by the sensor 21 and an amplifier circuit 222 connected in series with the preamplifier circuit 221 for amplifying an output signal thereof. The preamplifier circuit 221 comprises an amplifier OA1, a capacitor CF and a resistor RF; the capacitor CF and the resistor RF are connected in parallel with each other and connected in feedback relation with the amplifier OA1 - i.e., connected to an input terminal and to the output terminal of the amplifier OA1. As a result, the capacitor CF and the resistor RF define the cut-off frequency of the preamplifier circuit. In other words, the capacitor CF and the resistor RF are elements that define the signal transfer function that characterizes the preamplifier circuit 221. The amplifier circuit 222 comprises an amplifier OA2 and a gain block G - e.g., an impedance - connected in feedback relation with the amplifier OA2.
In particular, the detector apparatus 20 receives from the processing device 40 a bias voltage VB (e.g., ranging between 10 V and 30 V, e.g., 20V) suitable to keep the detector 21 in an operative condition, in which condition it can detect interaction with particles, in particular associated with ionizing radiation. Moreover, the detector apparatus 20 receives from the processing device 40 a supply voltage VDD suitable to power the preamplifier circuit 221 and the amplifier circuit 222.
As a result, the detector apparatus 20 comprises four terminals that are connected to the processing device 40 by means of as many conductive tracks formed in the conductive layers 14a and 14b of the flexible support 10. In a preferred embodiment, the detector 20 is an integrated device encapsulated into a flip-chip packaging. The packaging is made of insulating material, typically polymeric material, and generally has a parallelepiped shape comprising two main surfaces separated by four side surfaces.
In the example of Figure 5, on a (coupling) main surface 23 of the detector apparatus 20, four terminals, or pads, are provided: a power supply terminal 24a, a reference terminal 24b, a bias terminal 24c, and an output terminal 24d. The terminals 24a-24d are electrically coupled to respective tracks 19a-19d formed on the flexible support 10, schematically shown in Figure 6. In particular, the power supply terminal 24a is connected to a power supply track 19a, the reference terminal 24b is connected to a ground track or plane 19b, the bias terminal 24c is connected to a bias track 19c, and the output terminal 24d is connected to a signal track 19d. All tracks 19a-d are formed in one of the conductive layers 14a, 14b of the flexible support. In the example shown in Figure 6, the tracks 19a, 19c and 19d are formed in the first conductive layer 14a of the flexible support 10, while the ground track 19b is formed in the second conductive layer 14b of the flexible support, and a line 15c connects it to the reference terminal 24b. Finally, all tracks 19a-19d of the flexible support 10 are coupled to a corresponding terminal of the connector 12 to provide an electrical and mechanical connection with a corresponding terminal (not shown) of the processing device 40, so that the latter can supply the corresponding power, reference and bias voltage, and receive an output signal So from the detector apparatus 20.
Therefore, considering a minimum width of the tracks 19a-d ranging between 50 pm and 150 pm, preferably approx. 100 pm, and a minimum distance between the tracks 19a-d ranging between 50 pm and 150 pm, preferably approx. 100 pm, the minimum width Wmin of the flexible support 10 can be calculated - considering a minimum distance d between the tracks and the edges of the flexible support 10 ranging between 50 pm and 150 pm, preferably approx. 100 pm - as follows: where Npg is the number of tracks Np, excluding the track 19b connected to the reference terminal 24b (i.e., Npg = Np - 1).
In the case considered herein with four tracks 19a-d Npg = 3), the minimum width Wmin of the flexible support is:
Wmin = 0.7 mm.
In operation, when a radiation hits the sensor 21, the latter will generate an electric signal SR indicative of an intensity of the ionizing radiation hitting the detector apparatus 20. More generally, the electric signal SR is indicative of a measurement of energetic particles/ electromagnetic radiations within a predetermined range of energy/ frequency that are hitting the probe 1. The electric signal SR is first integrated by the preamplifier circuit 221 and then amplified by the amplifier circuit 222. The output signal So is supplied to the output terminal 24d of the detector apparatus 20 and propagates through the output track 19d up to the processing device 40.
In other words, the output signal So is a signal obtained by conditioning the signal SR generated by the sensor 21. In particular, the preamplifier circuit 221 is adapted to receive the signal SR from the sensor 21 and process it in order to adapt the sensor's signal to optimal levels (e.g., voltage and current values, signal-to- noise (SNR) ratio, etc.) for the operation of the amplifier circuit 222. The amplifier circuit 222 amplifies the preamplified signal SR to generate the output signal So.
The detector apparatus 20 is enclosed in the container 30. The container 30 is suitable to protect the detector apparatus 20 against foreign bodies, mechanical forces, and light. In the example shown in Figure 1, the container 30 fully envelops the detector apparatus 20 and covers a surface of the flexible support 10 near the position where the detector apparatus 20 is mounted.
Preferably, the container 30 has a substantially cylindrical shape, with a diameter ranging between 1.2 mm and 2.5 mm, e.g., 1.8 mm. Even more preferably, the container 30 has rounded edges and/ or a rounded shape to facilitate the sliding action thereof through a catheter.
For example, the container 30 is made from an epoxy polymer, preferably black in color, suitable to protect the detector apparatus 20 against foreign bodies, mechanical forces, and electromagnetic radiation in the visible spectrum.
In an alternative embodiment, schematically illustrated in Figures 7 and 8, the probe la comprises more than one detector apparatus 20.
The probe la is designed to monitor the progress of brachytherapy for prostate cancer treatment. In this example, the probe la comprises four detector apparatuses 20 arranged in series starting from the free end 11 of the flexible support 10. In the case of a probe to be used for monitoring radiation emission during brachytherapy for prostate cancer treatment, the detector apparatuses 20 are mutually spaced apart along the support 10 by a distance ranging between 1 cm and 1.5 cm, preferably 1 cm. Thus, by inserting the probe la into the patient's urethra it is possible to monitor the radiation intensity throughout the length of the patient's prostate gland, without the probe la having to be greater in size than the probe 1.
Preferably, each detector apparatus 20 is enclosed in a respective container 30 having substantially the same characteristics as already described above. The detector apparatuses can thus be protected against foreign bodies and, at the same time, the probe la can remain flexible. In this embodiment, the power supply track 19a, the ground track 19b and the bias track 19c are connected to the various power supply terminals 24a, reference terminals 24b and bias terminals 24c of each one of the four detector apparatuses 20. On the contrary, the output terminals 24d of the four detector apparatuses 20 are connected to respective signal tracks 19d. In other words, the total number of tracks Npg is:
NP = NA+3, (2) where NA is the number of detector apparatuses 20. In the case of the probe la considered herein, Npg=7, and the minimum width Wmm of the flexible support 10 is:
Wmin | Npg=7 — 1.5 mm.
In an alternative embodiment, shown in Figures 9 - 11, the probe lb comprises four programmable detector apparatuses 20a.
In particular, in the alternative programmable detector apparatus 20a of Figure 9 the capacitor CF and the resistor RF of the preamplifier circuit 221 are of the programmable type; likewise, the gain block G of the gain circuit 222 is also of the programmable type. In general, the capacitor CF, the resistor RF and the gain block G have a known structure, which will not be described any further herein for brevity's sake. Preferably, the resistor RF is made by means of a transconductor. In order to allow programming these circuit elements CF, RF and G, the detector apparatus 20a also comprises, in addition to the above-described terminals 24a-24d, two programming terminals: a conditioning programming terminal 24e and a gain programming terminal 24f, as shown in Figure 10.
In this case, the processing device 40 is suitable for transmitting to the detector apparatus 20a a conditioning configuration signal PF and a gain configuration signal PG through corresponding programming tracks 19e and 19f. The programming tracks 19e and 19f are formed, for example, in the conductive layer 14a, as shown in Figure 11, and are connected to the terminals 24e and 24f, respectively.
When in use, the processing device 40 can be configured to set and/ or adjust the conditioning configuration signal PF and the gain configuration signal PG - such signals being, for example, both analog ones - based on a specific application, on the source type used for generating the ionizing radiation to be detected, etc., in order to obtain, from each detector apparatus 20a of the probe lb, an optimal output signal So that can be processed correctly. As a consequence, the transfer function of the preamplifier circuit 221 can be adjusted by means of the conditioning configuration signal PF, allowing the cutoff frequency and/ or the gain of the transfer function of the preamplifier circuit 221. Likewise, the gain configuration signal PG makes it possible to adjust the amplification of the signal SR produced by the preamplifier circuit 221, to be provided by the gain circuit 222 that transmits the output signal So on the respective signal track 19d.
In a different embodiment an alternative detector apparatus 20b is provided, as illustrated in Figure 12. The detector apparatus 20b is equipped with an analog- to-digital converter ADC connected in series with the amplifier circuit 222. The analog-to-digital converter ADC receives the output signal So from the amplifier circuit 222 and converts it into a digital signal SD. For example, the digital signal SD is serially supplied to the processing device 40 through a single signal track 19d.
It is however clear that the above-described examples should not be deemed as limiting, and that the invention thus conceived is susceptible of numerous modifications and variations.
For example, in one embodiment (not shown) the bias, power and programming voltages are supplied by an apparatus other than the processing device that processes the signals.
As an alternative or in addition, a signal preprocessing apparatus (not shown) may be provided, separate from the above-described processing device, and adapted to execute additional steps of conditioning, filtering, amplifying and/ or digitalizing the signals outputted by the detection apparatus(es).
Also, programming the capacitor and the resistor of the preamplifier circuit and/or programming the gain block of the amplifier circuit may involve the serial transfer of a bit word from the processing device to the one or more detector apparatuses. In such a case, each apparatus will comprise a decoding circuit converting the serially received bit word into a respective programming command for the capacitor or the resistor of the preamplifier circuit and/ or for the gain block of the amplifier circuit.
In addition, or as an alternative, the power supply voltage may be varied dynamically to modify the conditioning and/ or the amplification effected by the processing module of the one or more detector apparatuses.
In an alternative embodiment (not shown), all tracks are formed on a single conductive layer. In this case, the thickness of the support will be defined by the following formula: min = (2 X Np + 1) X 100/ .m, )
In other embodiments (not shown), the width of the tracks may differ from the width of the spaces between adjacent tracks. In general, the width of the tracks is selected to avoid track damage and exceeding a predetermined maximum operating temperature when the tracks are crossed by electric signals having a predetermined power level. Likewise, the width of the spaces between the tracks is so selected as to cancel, or even just limit, any electromagnetic interference between the tracks.
Furthermore, in different embodiments nothing prevents from of realisation in which the tracks are drawn in non-rectilinear patterns - e.g., zigzag patterns - in order to increase the deformability of the flexible support and reduce the risk of track damage - e.g., formation of cracks - while using the probe.
In alternative embodiments (not shown), the programmable detector apparatus comprises only either the capacitor or the resistor is of the programmable type. Moreover, nothing prevents from creating a programmable detector apparatus wherein only the gain element of the amplifier circuit is programmable. Also, nothing prevents alternative embodiments from comprising any combination of such programmable and non-programmable elements. Furthermore, in more complex embodiments (not shown), each detector apparatus, or each group of detector apparatuses, receives different programming signals for one or more programmable elements of the circuits comprised in the processing module.
It will be clear to a person skilled in the art that, in general, the processing module is configured to condition the signal received from the sensor with which it is integrated into the detector apparatus. In particular, signal conditioning is a signal processing step aimed at modifying the sensor's signal to guarantee optimal processing by elements connected to the probe's processing module, thus ensuring robustness to interference and attenuation as the signal is transmitted on the track that connects the detector apparatus to the processing device. For example, the signal conditioning provided by the processing module comprises one or more steps of filtering, amplifying, limiting and linearizing the signal supplied by the sensor. For this purpose, the processing module may comprise circuits, and a number thereof, which are different from those described with reference to the exemplary embodiment. For example, the processing module may comprise one or more filtering circuits in addition and/or as an alternative to the preamplifier circuit and the amplifier circuit. Of course, all details may be replaced with other technically equivalent elements.
For example, the packaging of the detector apparatuses may have ball grid array (BGA) or flat no-leads (FN) terminals, or other equivalent types of terminals.
Lastly, the materials employed, as well as the shapes and dimensions of the above-mentioned devices, apparatuses and terminals, may vary according to specific implementation requirements, without however departing from the protection scope of the following claims.

Claims

1. Probe (1; la; lb) for detecting ionizing radiation, comprising: an elongated flexible support (10), a detector apparatus (20; 20a; 20b), coupled to the flexible support (10) near one end (11) thereof, wherein the flexible support (10) comprises a plurality of electrically conductive tracks (19a-f) coupled to corresponding electrical terminals (24a-f) of the detector apparatus (20; 20a; 20b) to allow the exchange of electrical signals between the apparatus and a processing device (40) electrically connected to said plurality of tracks (19a-f), characterized in that the detector apparatus (20; 20a; 20b) comprises: a sensor (21) adapted to generate a signal indicative of an intensity of ionizing radiations hitting the detector apparatus (20; 20a; 20b), and a processing module (22) adapted to condition the signal provided by the sensor (1) and transmit the conditioned signal through at least one track of the plurality of tracks (19a-f).
2. Probe (1; la; lb) according to claim 1, wherein the processing module comprises: a preamplifier circuit (221) for processing the signal supplied by the sensor (21), and an amplifier circuit (222) adapted to amplify the signal processed by the preamplifier circuit (221), thereby generating an output signal indicative of the intensity of radiations hitting the detector apparatus (20; 20a; 20b), which is transmitted by the detector apparatus (20; 20a; 20b) to the computing device (40) through at least one of the conductive tracks (19a- f).
3. Probe (1; la; lb) according to claim 1 or 2, wherein the detector apparatus (20; 20a; 20b) is a monolithic device, in which the sensor (21) and the processing module (22) are integrated in the same semiconductor material substrate.
4. Probe (1; la; lb) according to claim 3, wherein the detector apparatus (20; 20a; 20b) is a flip-chip technology device.
5. Probe (1; la; lb) according to any one of the preceding claims 2 to 4, wherein the preamplifier circuit (221) is programmable, and wherein the detector apparatus (20; 20a; 20b) comprises a programming terminal (24e) connected to a respective programming track (19e) for receiving a conditioning programming signal from the processing device (40), wherein the preamplifier circuit (221) being adapted to adjust the transfer function based on the programming signal.
6. Probe (1; la; lb) according to claim 5, wherein the preamplifier circuit (221) comprises a programmable resistor and a programmable capacitor, wherein the preamplifier circuit (221) is adapted to adjust the resistance value of the programmable resistor and the capacitance value of the programmable capacitor as a function of the programming signal to obtain a desired gain and/ or cut-off frequency of the transfer function.
7. Probe (1; la; lb) according to any one of the preceding claims 2 to 6, wherein the amplifier circuit (222) comprises a programmable gain block, and wherein the detector apparatus (20; 20a; 20b) comprises a gain programming terminal (24f) connected to a respective gain programming track (19f) for receiving a gain programming signal from the processing device (40), the amplifier circuit (222) being adapted to adjust the gain with which the signal is amplified as a function of the programming signal.
8. Probe (la; lb) according to any one of the preceding claims, comprising a plurality of detector apparatuses (20; 20a; 20b), the detector apparatuses (20; 20a; 20b) being arranged in series along a main extension direction of the flexible support (10), wherein the detector apparatuses (20; 20a; 20b) are spaced apart from each other by a distance ranging between 1 cm and 1.5 cm.
9. Probe (la; lb) according to claim 8, wherein the plurality of tracks (19a-f) comprise a power supply track (19a), a reference track (19b), a bias track (19c) and a plurality of signal tracks (19d), wherein the power supply track (19a) is connected to a power supply terminal (24a) of each detector apparatus (20; 20a; 20b), the reference track (19b) is connected to a reference terminal (24b) of each detector apparatus (20; 20a; 20b), and the bias track (19c) is connected to a bias terminal (24c) of each detector apparatus (20; 20a; 20b), so that each one of the detector apparatuses (20; 20a; 20b) will receive the same supply voltage, the same reference voltage and the same bias voltage, and wherein each signal track (19d) is connected to a respective output terminal (24d) of the detector apparatuses (20; 20a; 20b), so that the detector apparatuses (20; 20a; 20b) will transmit the respective output signal in parallel.
10. Probe (1; la; lb) according to any one of the preceding claims, wherein the flexible support (10) is a multilayer tape comprising at least one pair of external insulating layers (13a, 13b), one pair of conductive layers (14a, 14b), and an internal insulating layer (16) placed between said pair of conductive layers (14a, 14b), wherein the tracks (19a-f) are formed on said conductive layers (14a, 14b) and have a maximum width of approximately 100 pm, the tracks (19a-f) formed in one same layer being spaced apart by a maximum distance of approximately 100 pm.
11. Probe (1; la; lb) according to any one of the preceding claims, further comprising a protective container (30), which envelops the detector apparatus (20; 20a; 20b) to protect it from the external environment, said container being transparent to ionizing radiation.
EP24704900.0A 2023-01-19 2024-01-18 Probe for radiation detection Pending EP4695631A1 (en)

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IT102023000000762A IT202300000762A1 (en) 2023-01-19 2023-01-19 RADIATION DETECTION PROBE
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IT201700122669A1 (en) 2017-10-27 2019-04-27 Lfoundry Srl Integrated ionizing radiation sensor and ionizing particles
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