ES2304073A1 - Method of measurement and control of dosage in radiation therapy. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Some radiation therapies give rise to an increase in temperature and changes in the emissivity of the skin as a result of the thermoregulatory function of the organism. The dosage control system is based on measuring the body's thermal response by means of a temperature sensor and the distance between the source and the treated area. This allows to know in real time the response of the patient to the treatment and calculate the dose. (Machine-translation by Google Translate, not legally binding)

Description

Dosage control system in therapy of radiation

Technical sector

Medical equipments.

Prior art

Currently the dosage in treatments With radiation it is done empirically (Rodríguez Martín J. M., Electrotherapy in physiotherapy, 2004).

The dose will depend on the power of the source, the distance to the source and the application time. Distance It is variable, sometimes it depends on the sensitivity of the patient to said radiation and time is set empirically. In case of sweating treatment is finished. Sweating is a indicative of the thermoregulation of the organism and will depend on the Therapist's appreciation.

In the proposed system the patient is part active system. The patient's thermal response during treatment (Figure 1), provides the control element of the dosage.

Fundamental contributions of the proposed procedure

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Supply the radiation, measure the thermal response of the organism to radiation and controls the dose (Figure 2).

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Measure of the energy received by the patient in real time, known the power of the source, the distance measured by the system and the time determined by the thermal response in the area treated.

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Employ the organism's thermoregulatory system as a mechanism for electronic control of treatment time.

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Protect the patient against damage caused by excess temperature or malfunction of the organism thermoregulation system. In case of any abnormal behavior turns off the radiation source so automatic and / or notify the physiotherapist.

Explanation

The proposed system consists of (figure 3):

- Source of radiation.

- Source activation circuit radiation.

- Distance and temperature sensors. The temperature measured by contact (thermocouple or thermistor, with dimensions much smaller than the irradiated area and with low inertia thermal) or remotely with sensitive infrared sensors in the band between 8 and 12 microns.

- Acquisition and control system.

- Measurement display element (Distance, temperature as a function of time) and dose Calculate by the system.

The radiation source works in a way independent or governed by the proposed system, through the source activation circuit. The system calculates the power per unit area that reaches the patient, known the power of the source and distance measured by the sensor, which depends on the patient sensitivity and specialist criteria.

The thermal response to radiation (Figure 1) It is different in each patient. Initially the temperature, as a consequence of thermoregulation the speed the temperature change becomes smaller as time goes by, The slope is finally reversed. If a fixed time is set of treatment runs the risk of damaging the patient.

The measurement and control system of the Dosage allows the specialist to program the time of post-start treatment of thermoregulation and calculate the total treatment time and power per unit area provided to the patient. It also allows programming the time of treatment according to the characteristic thermal response of the patient and record the evolution of the thermal response.

In case of abnormal system behavior Thermoregulator would deactivate the source.

Embodiment

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 Initially the system. System shutdown is configured in manual mode (turned off by the specialist in charge of the treatment) or in mode automatic (system shutdown automatically).

In the mode Automatic treatment time is programmed. This time is the that must pass once the thermoregulation

Always in case an abnormal behavior of the thermoregulator system shuts down automatically the source and / or warning of the danger of patient.

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 The patient is placed in front of the radiation source at a distance that the patient can tolerate radiation or the therapist wants.

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The system stores in memory the measured distance between the patient's treated area and the source of radiation during treatment and stored and / or visualized thermal response of the patient.

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The radiation source is turned off (manually or automatically) and the treatment time is stored. This time will be the one programmed plus the time elapsed in reach thermoregulation.

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With the data obtained, Calculate the dose delivered.

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The thermal response in function of the time is stored in file, as well as the time of treatment and the dose provided.

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Description of the figures

Figure 1. Describe the variation of the temperature in two patients undergoing infrared radiation. The temperature variation that takes place as result of the radiation applied (temperature rise) and the thermoregulation of the organism during treatment (decrease of the temperature growth rate and then a decrease in temperature). It was taken as the criterion of lamp off when the temperature in the patient it drops 1 ° C. Distance to the source: 40 cm.

Figure 2. Describe the difference between systems used in physiotherapy treatments based on radiation In the first, the system is the source of radiation and electronics that allows you to configure the source and in the proposed, the patient is part of the system. The distance is measured and temperature. The temperature provides the variable of control.

Figure 3. Block diagram showing the fundamental parts of a radiation system with control of the dosage.

101:

Variation of the temperature of a joint of one finger (Patient 1)

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Temperature

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Time in units of 30 seconds.

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Variation of the temperature of a joint of one finger (Patient 2)

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Temperature

106:

Time in units of 30 seconds.

201:

Activation and configuration circuit of the lamp power and exposure time.

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Radiation source

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Patient

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Dosage acquisition and control circuit provided with a temperature sensor and a distance sensor.

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Radiation source

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Patient

301:

Distance sensor

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Temperature sensor

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Radiation source

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Source activation circuit radiation

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Acquisition and control circuit

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Results Viewer

Claims (5)

1. Dosing control system in radiation therapy measured during the application of radiation, the patient's thermal response using a sensor  temperature and distance between source and patient through a distance sensor 2. The dosage control system in radiation therapy according to claim 1, allows the thermal characterization of the patient. Use the thermal response (thermoregulation process) of the patient for the measurement of time Effective duration of treatment. The effective time of duration of treatment is the sum of the time to reach the thermoregulation (depends on the patient) plus the scheduled time by the specialist 3. The dosage control system in radiation therapy, calculate the dose delivered to the patient at each instant of time, as well as the total dose at the end of treatment, known source power, distance between source and patient and effective duration of treatment according to claim 1 and 2. 4. The dosage control system in Radiation therapy controls the dose applied to the patient. The The patient's thermal response will determine the effective time of duration of treatment and thereby the dose according to claim 1, 2 and 3. The treatment ends once the Time programmed with automatic power off. 5. In the dosage control system in radiation therapy the automatic shutdown of the source in case of exceeding the maximum temperature programmed by the specialist and / or in case the thermoregulatory system of the organism does not regulate.