TR201820052A1 - A LASER DIFFUSE OPTICAL TOMOGRAPHY DEVICE WORKING IN REFLECTION GEOMETRY - Google Patents

Abstract

Meet; It is about a laser diffuse optical tomography (LDOT) device developed to diagnose and locate tissue tumors and operates in a back reflection geometry. In the optical device of the present invention, laser is sent from more than one source to the relevant tissue; The laser spreads inside the tissue by diffusion, the laser returning from the same surface is collected by more than one detector fiber and its intensity is measured with photodiodes. The measured light intensities are used in the reconstruction algorithm, and the tomographic image of the relevant area of the tissue is created depending on the blood distribution. The device subject to the invention; It is used especially for the diagnosis of breast tumors.

Description

DESCRIPTION A LASER DIFFUS OPTICS WORKING IN REFLECTION GEOMETRY TOMOGRAPHIC DEVICE TECHNICAL FIELD Meet; developed to diagnose and locate tissue masses/tumors and It relates to a laser diffuse optical tomography (LDOT) device operating in reflection geometry. Meet In the optical device in question, more than one fiber optic cable from a laser source is transferred to the relevant tissue. being sent; the laser spreads through the tissue by diffusion, the laser returning from the same surface multiple detectors are collected by the fiber and their intensity is measured with photodiodes. The measured light intensities are used in the reconstruction algorithm and the tomographic region of the tissue is related. image is created depending on the profit distribution. The device subject to the invention; especially the breast It is used for the diagnosis of tumors. PRIOR ART tomographic image; It is three-dimensional (3D) and is used to get information about the internal structure of objects. is used. Wave on the breast in laser breast diffuse optical tomography (LMDOT) device Infrared light with a length range of 700-900 nm is sent, measuring in two different ways. A tomographic image is created with the breast LM DOT Device. In the first of these; suddenly which are sent to the turbid environment by more than one source and after passing through the turbid environment, more than one light intensities collected and measured by the detector are used (US 6738658B2).

The light intensities passing through the turbid medium are photodiodes or a charge-matched device (charge-coupled device). device, CCD). “Back projection”, “algebraic reconstruction” with measurement results 3D images are created using algorithms such as “technique”, “least square method”.

In the second method, the laser sent from more than one source to the turbid environment undergoes diffusion. then it comes back from the same surface. Ejected laser by multiple detector optical fiber In diffuse optical tomography (DOT) devices; light is being sent from more than one source, again all at once Light intensities are measured with more detectors. The light transmitting efficiency of each source and the Since the light collection efficiency of a detector is not the same, source and detector calibrations needs to be done. Light intensities from all sources in source calibration is equated. In detector calibration, the light gathering efficiency of all detectors is is equated. Measurements taken in this way are independent of the device and depend only on the characteristics of the turbid environment. it becomes. Developed for DOT devices working in retroreflection geometry. source and detector calibration values in calibrations (recontruction) algorithms as parameters and calculated (WO 01/192241A1i.

In the present invention; a laser die-optic tomography device for diagnosing breast tumors is explained.

BRIEF DESCRIPTION AND OBJECTIVES OF THE INVENTION The invention in question; It is a laser diffuse optical tomography device working in retroreflection geometry; The aim of the invention is to determine the area of interest of the tissue to be diagnosed with tumor in a 5x5 cm27 area and 2.5- Effectively diagnosing the tumor by creating a 3D image with a depth of 3 cm. determination of its location.

Due to the high number of source-detector pairings (2500), the reconstruction algorithms were used. 3D images of the created tissue are high in spatial resolution.

The device subject to the invention; It is a compact and easy-to-use device, and it is a painless device to the patient during its use. does not cause discomfort.

BRIEF DESCRIPTION OF THE SETS Figure 1. View of the LM DOT device in use.

Figure 2. The schematic view of the LMDOT device.

Figure 3. Open design of the LM DOT device.

Figure 4. Detailed view of the Optical selector of the LMDOT device.

Figure 5. The view of the aluminum block on the main electronic board and detector.

Figure 6. Optical fibers used as detectors in cavities on the aluminum block. termination and appearance of the main electronic board.

Figure 7. Front surface of the optical probe and arrangement of fiber optic cables.

Figure 8. Source fibers used as a source on the front surface of the optical probe and as a detector Sequence view of the detector fibers used.

Figure 9. Tissue with laser sent from the source optical fibers to the tissue and the reflected laser image View of representative photon orbits inside.

REFERENCE NUMBERS IN THE FIGURES ) Laser diffuse optical tomography (LDOT) device ) optical probe 21) Optical probe front surface 22) Weld optical fiber front surface 23) Detector Optical fiber front surface ) texture 40) Optical selective stepper motor 50) Fiber optic cable 51) Fiber optic cable transmitting the laser to the device 52) Source optical fiber 53) Detector optical fiber 60) Aluminum block 61) Optical selector 70) Main electronic board 71) IC 72) Microprocessor 80) Aluminum block on detector 81) Owl 90) Photodiode 91) Main board power supply 92) Output of main board controlling stepper motor and optical selector 93) Connection cable 94) Computer 95) Computer monitor 100) Representative photon orbits in tissue 101) Laser sent to the tissue 102) Laser reflected back from tissue 110) Laser welding DETAILED DESCRIPTION OF THE INVENTION This finding is important in patients with a mass in their body, whether the mass is a tumor, a cyst, or a hamartoma. It is an Optical instrument that detects the presence of the tumor and determines the location of the mass/tumor. It was related to the device. The subject of the invention is the optical device; especially if the mass in the breast is a tumor or a cyst or A device developed to detect whether it is a hamartoma and to locate the tumor. laser diffuse optical tomography (LDOT) device (10).

The laser diffuse optical tomography (LDOT) device (10) gently touches the tissue (30) that may be a mass. used by contact. Tissue (30) of laser diffuse optical tomography (LDOT) device Its use on the . is shown in Figure 1 . The LDOT device (10) makes contact with the tissue (30) optically. by means of the probe (20). As shown in Figure 2, the LDOT device of the invention (10); a diode laser source (10) for transmitting light to the tissue, the tissue (30) and the LDOT device (10) The optical probe (20) that provides the contact with the probe (20) is positioned on the probe front surface (21) and transfers the laser to the optical probe (20). Fiber Optic cables (50) that carry and collect the laser reflected back from the tissue (30) board (70), optical selector (61), optical selector stepper motor (40), optical selector (61) positioning cable includes computer monitor. The main board controls the stepper motor and optical selector. Its output (92) sends the information from the motherboard (70) to the source optical fibers (52) for a specified period of time. During the measurement made for diagnosis, the laser diffuse optical tomography (LDOT) device (10) has Full contact of the front surface (21) of the optical probe with the tissue (30) is ensured. optical probe Fiber optic cables (50) connected on the front surface (21) are positioned. Fiber optic While the cables (50) are connected to the optical probe (20) at one end, the other ends are connected to the detector on the detector. it is connected to the aluminum block (80) and the optical selector (61). The fiber optic cables (50) in question some of the detectors are Optical fibers (53) in cavities (81) in the aluminum block (80). is located. Photodiodes (90) are inserted into the cavities (81) in the aluminum block (80). are placed. In this way, the light carried by each detector Optical fiber (53) is transmitted to a single photodiode. (90) is transmitted. At least one fiber optic cable (50) entry from one end of said cavities (81) while the other end of the cavities (81) is located on the main electronic board (70), in figure 5 It is connected in key-lock relationship with the photodiodes (90) shown. Photodiodes with cavities (81) By connecting the (90) with each other, the optical probe (20) and the main electronic board (70) They are associated with each other in such a way as to provide the communication between them with detector fiber optics (53).

The main electronic board (70) has electronic components on it, as shown in Figure 47. It is located at the bottom of the aluminum block (80) where it is positioned.

The optical probe front surface (21) of the optical probe (20) is shown in Figure 7*. Optical Fiber optic cables (50) are positioned on the front surface (21) of the probe. On the front surface of the optical probe Some of the fiber optic cables (50) positioned (21) carry the laser to the tissue (30), while the other part used as a sensor by collecting the returning laser after diffusion from the tissue (30) and It transmits it to the photodiodes (90) located on the main electronic board (70). In question, fiber the source optical fibers (52) of the optical cables (50) that carry the laser to the optical probe (20) are (30) detector optic fibers (53) are the ones that collect the back-reflected laser and transmit it to the photodiodes (90).

As seen in the ship view of the LDOT device (10) in Fig. laser from laser source Source on optical probe (20) with optical selector via fiber optic cable (51) transmitting to LDOT device transmitted to the optical fiber 52 . Laser (101) delivered to tissue (30) by source optical fibers (52) It is scattered in the tissue (3).

It collects the light reflected back from the tissue (30) and transmits it to the photodiodes (90) as shown in Figure 5 . One end of the detector optic tiber (53) is on the aluminum block (80) on the detector. it is attached to the recesses (81). In the device subject to the invention; sensor on main electronic board (70) The photodiodes (90) used as the cavities are placed in the cavities (81) (Figure 6). Photodiode (90) outputs it is transmitted to at least one DDC232 integrated circuit (71) on the main electronic board (70). Here The data is converted to digital and the photodiode (90) currents are converted to voltage at different integration times. converted to a computer (94) as output.

The light reflected back from the source optical fibers (52) and tissue (30) carrying the laser to the optical probe (20) detector optical fibers (53) that collect and transmit to the photodiodes (90) are on the matrix. Diameters of fiber optic cables (50) used in the optical probe (20) 1- 3 mm, the center-to-center distance between the nearest source-detector pair is 1-10 mm are in between. Source fiber (22) and detector fiber (23) locations on the optical probe front surface (21) is seen. The source optics attached to the optical probe front surface (21) of the optical probe (20) The fiber 52 ends at the weld Optical fiber front surface 22 . Similarly, the detector optical fibers (53) also terminate on the detector optical fiber front surface (23). In this way, the optical probe On its front surface (21) the source optical fibers (52) carry the light to the optical probe (20), while they return from the tissue (30). touch (30) with detector optical fibers (53) that collect the reflected light and transmit it to the photodiodes (90) contact is established.

In Figure 9, the laser (101) sent from the source optical fiber (52) to the tissue (30) and the diffusion in the tissue. Representative photon trajectories in tissue (100) of Iazer (102) reflected back from tissue after exposure and their aggregation by 5 separate detector optical fibers (53) illustrated schematically. is shown. This illustration is representative only, and the source optical fibers (52) and The number of detector optic fibers (53) can vary, the representative photon in the tissue. their orbits can also increase or decrease in proportion to this number.

Selecting the laser (101) delivered to the tissue as the source in the representative structure shown in Figure 9 in case of; Iazerin (102) reflected back from tissue collected by detectors close to the source While the depth of penetration in the tissue is small, as the source-detector distance increases, the trajectory of the laser increases. the depth of penetration within the tissue (30) increases. By detectors close to the source The depth at which the laser (102), which is reflected back from the collected tissue, enters the tissue, is the distance from the source. Iazer (102) reflected back from the tissue collected by the detectors is from the depth it enters into the tissue. is always smaller.

In the LDOT device (10), which is the subject of the invention; laser is sent to the tissue (30) from multiple sources and the laser, which diffuses in the tissue (30) by diffusion and returns on the same surface, has multiple detectors. are collected by the optical fiber (53) and their intensity is measured by photodiodes (90). measured By using the light intensities in the reconstruction algorithm, a 3D tomographic image is created and the location of the tumor and mass is determined.

The working principle of the LDOT device (10), which is the subject of the invention, is developed; - Optical fiber optic cable (51) that transmits the laser to the device of a diode laser source (110) - Fiber optic cable (51) connected to the output of the laser source (110) and transmitting the laser to the device with the optical selector (61) and the source optical fibers (52) by guiding the optical probe in sequence. On its front surface (21) the source optical fiber front surface (22) and the laser on the object are different. forwarding to locations - Source optical fibers (52) terminating in the source fiber (22) on the optical probe front surface (21) sending the laser to the subject to be diagnosed with a mass/tumor, - The laser reflected back after diffusion on the subject to be diagnosed with a mass/tumor, The detector located on the detector tiber (23) located on the front surface of the optical probe (21) Gathering with optical fibers (53), - Main electronics on which detector optical fibers (53) are located on photodiodes (90) routing to the card (70), - Photodiode (90) current outputs at different integration times with at least one IC converting it to voltage, converting it to digital data and transferring it to a computer (94), - The source-detector calibration of the measurements taken on the subject is a homogeneous turbid It is made by dividing the measurement result taken in the environment, - “Simultaneous iterative reconstruction technique (SIRT)”, “truncated conjugate gradient (CG)” or “truncated singular value decomposition (TSVD)” methods It is used to create a three-dimensional image of the part of the subject under the optical probe (20). (3D) creation and determination of the presence and location of the mass/tumor, if any, The subject of the method of the invention is a tissue, especially the breast.

In the working method of the LDOT device (10), which is the subject of the invention, with the applied calibration method. The light transmitting and light gathering efficiencies of sources and detectors are normalized to each other. and the measurement values between the source-detector distances with the kalibraSVOn method. is made independent of changes. The calibrated data or logarithms, 3D images as perturbation data used in reconstruction algorithms is created. Taken on tissue with reference to an optically homogeneous medium Calculation of perturbation values in measurements and 3D results depending on tissue blood distribution. image is created.

When the LDOT device (10) is operating, laser from each source optical fiber (52) to the tissue (30) in turn while all detector optic fibers (53) have diffused through the tissue (30). collects the laser (102) reflected back from the tissue and transmits it to the photodiodes (90). of the LDOT device (10) The photodiode (90) Output on the main electronic board (70) has at least two The ana0g digital converter DDC232 is directed to the ICs (71). Switches, integrator circuits, analog to digital converters (preferably 20 bits) and deduplicators DDC232 ICs (71) are on it. 2 integrals for each photodiode in the DDC232 integrated circuit (71) There is a receiving circuit. These integrator circuits can operate in continuous time current voltage are translators. Integration time varies between 1-900 ms. different for each detector. integration times are used. Data logging and control of DDC232 integrated circuits (71) It is done on a microprocessor 72. Measurement for close source-detector neighborhoods small integration time when the values do not go to saturation, remote source-detector pairs, high integration times are required to receive a sufficiently high-value signal. is used. In this way, the data collection dynamic range of the system is increased. Table 27 circuit board current/power measurement values are given.

Table 2. Circuit board current/power measurements Instantaneous Measured Current (mA) Calculated Power (mW) There is communication connected to the computer 90 mA 1081 .8mW Connected to computer and measuring 90.5mA 1087.81mW Calibration of the Device Measurement is taken in a homogeneous turbid environment for calibration purposes, Mkai. Taken on the breast each source-detector by dividing the measurement, Mme, by the measurement taken on a homogeneous turbid medium. calibration is performed for the pair (R: Nozzle/ Mkai).

Linear reconstruction to generate tomographic images from calibrated breast measurements (recunstruction) techniques are used. In these techniques, for each source detector pair, perturbation data need to be calculated. Perturbation data, no tumor from breast It is the difference between the measurement taken when the tumor is present and the measurement taken when the tumor is present. From the breast in this way consecutively approximate calculation of perturbation in a different way since two measurements cannot be taken required. In the present invention, the calibration data is directly referred to as perturbation values. is used. These values are; optically homogeneous measurements of the breast with tumor gives its variation according to an environment. The obtained perturbation data are derived from the diû'ision equation by Rytov. obtained by the approach used in equality. where y is the perturbation data in the format Mx], M is the total measurement is the number. A is the weight matrix and its size is MXN. where N is in the rendered volume. is the number of voxels. The x in the equation is the attenuation coefficient of each voxel. coefficient is the difference with the background and its size is le”.

Equation 1 is expressed in its explicit form as follows: ây(rsl,rd1)l WLM Wi,i;2 - - - -Wi.i,n l &ua (il il öv(r51, id; l Wi`2;1 Wi,2;2 - - - 'Wl.1,n 51%(er Die/(rsi › rdjlJ Wi,l;l Wi,l;2 - - - -Wi,i.nJ 5Ha(rn ll Here y(r51, rdz) is the texture of the laser sent from the first source and collected by the second detector. (30] perturbation measurement due to absorption in. The second matrix in the middle during W1,2;1 is the weight of the light sent from the first source and collected by the second detector. matrix at the first voxel, and the voxel at position öua(r2l, I'2 relative to the background is the difference in the absorption coefficient. Here, the background is optically used for calibration purposes. It is a homogeneous opaque medium and is defined by the values of Mal and MS'. Equation 2° weight matrix It is obtained by linearizing the diffusion equation with the Rynov approximation. The laser used The emission wavelength of the source (110) is 810 nm, and the light at this wavelength is deflected by oil and water. Its absorption is low, but its absorption by blood is high. in the tumor area Due to the increased blood supply, the absorption of light is increased and it is absorbed by the photodiodes (90]. measured intensity decreases. Solving the equation 2, the absorption in each voxel by calculating the values of eu(r) which is the change in the coefficient of absorption by calculating their values. For this, “simultaneous iterative reconstruction” technique (SIRT)”, “truncated conjugate gradient (CG)” and “truncated singular value” 3 of the breast under the probe using decomposition (TSVD)” methods. A dimensional image (3D) is created and the location of the tumor is determined.

The distance between the source and the detector on the optical probe (20) of the LM DOT device (10], which is the subject of the invention, is 0.5- Since it is between 7 cm and 2.5-3 cm deep from the breast surface, spatial distribution of blood can be observed.

Claims (15)

REQUESTS A laser diffuse optical tomography (LDOT) device (10) working in retroreflection geometry to be used in the diagnosis and location determination of tissue (30) tumors, and its feature is; a diode laser source (10) for delivering light to the tissue; Optical probe (20) that provides the contact of the tissue (30) with the LD OT device (10), optical fiber cables (50) positioned on the probe front surface (21) and carrying the laser to the optical probe (20) and collecting the laser reflected back from the tissue (30), The main electronic board (70) that controls the optical selector (61) and has the integrated circuit (71) and microprocessor (73) on it, the optical fiber cable (51) connected to the diode laser source (110) and the optical fiber cables (52) used as the source. with the optical selector (61), optical selector stepper motor (40), aluminum block (60) positioning the optical selector (61) and at least one integrated circuit (with analog to digital converter) 71), microprocessor (73) that controls the integrated circuit (71) and provides communication between electronic motherboard (70) and computer (94), photodiodes (90) used as sensors by measuring the intensity of light, computer (94), connection cable, computer monitor it contains. . It is a laser diffuse optical tomography device (10) according to the claim, and its feature is; detector fiber optic cables (53) are positioned in the cavities (81) of the aluminum block (80). It is a laser diffuse optical tomography device (10) according to the request, and its feature is; Some of the fiber optic cables (50) are source optical fibers (52) that carry the laser to the optical probe (20). . It is a laser dental optical tomography device (10) according to claim 1, and its feature is; Some of the fiber optic cables (50) are detector optical fiber (53) that collects the laser that returns after diffusion in the tissue (30) and transmits it to the photodiodes (90) located on the main electronic board (70) and used as a sensor. . It is a laser diffuse optical tomography device (10) according to claim 4, and its feature is; the detector optic fibers contain ends that are attached to the cavities (81) in the aluminum block (80) on the photodiodes. . It is a laser diffuse optical tomography device (10) according to claim 1, and its feature is; It contains photodiodes (90) used as sensors on the main electronic board (70). . It is a laser diffuse optical tomography device (10) according to claim 6, and its feature is; the photodiodes (90) are positioned in the cavities (81). It is a laser diffuse optical tomography device (10) according to claim 1 and its feature is; it contains at least one DDC232 integrated circuit (71) on the main electronic board (70). It is the working method of a laser dental optical tomography device (10) according to claim 1, and its feature is; A fiber optic cable (51) that transmits the laser of a diode laser source (110) to the device and a fiber optic cable (51) that is connected to the output of the optical laser source (l 10) and transmits the laser to the device, and the optical selector (61) and the source to the optical fibers (52) Sending the laser to the subject to be diagnosed mass/tumor with the source optical fibers (52) ending in the source fiber (22) on the optical probe front surface (21) on the object with the source optical fiber front surface (21) on the optical probe front surface (21) respectively , Collecting the detector optical fibers (5 3) after the mass/tumor is dilution in the subject to be diagnosed, Directing the detector optical fibers (53) to the main electronic board (70) on which the photodiodes (90) are located, Photodiode (90) is the most important of the current outputs. Converting to voltage at different integration times with a small integrated circuit, converting to digital data and transferring to a computer (94), Source-detector calibration of the measurements taken on the subject is carried out in a homogeneous turbid environment. It is made by dividing the measurement result, using gradient (CG)” or “truncated singular value decomposition (TSVD)” methods, creating a three-dimensional image (3D) of the part of the subject under the optical probe (20), and determining the presence of mass/tumor and its location, if any, It contains the process steps. It is a method according to claim 9 and its feature is; the subject is a texture. It is a method according to claim 10 and its feature is; tissue is breast. It is a method according to claim 9 and its feature is; It is the normalization of the light agenda and light collection efficiencies of sources and detectors to each other with the applied calibration method. 13. It is a method according to claim 95, and its feature is; is to make the measurement values independent of the changes between the source-detector distances with the applied calibration method. 14. It is a method according to claim 9 and its feature is; It is the creation of a 3D image by using the calibrated data or logarithms as 5 perturbation data in reconstruction algorithms. 15. It is a method according to claim 9 and its feature is; It is the creation of a 3D image based on the blood distribution in 10 breasts by calculating the perturbation values in the measurements taken on the breast with reference to an optically homogeneous environment.