| 摘要 |
The present solution falls into the branch of radiotherapy, where during the use of medical sources for ionising radiation for therapeutic scopes within the frame of relative dosimetry, it is necessary to map the distribution of the dose rate in radiation fields and within the frame of verification dosimetry, to monitor the absorbed rate directly in the patient's body during exposure. Previous types of commonly used detectors, represented by ionisation chambers, detectors with a semiconductor diode in certain applications, fail to meet the requirements for high degree miniaturization, shape, tissue equivalence of the probe coat, or effective electromagnetic shielding. The principle of the solution is the construction of two modifications of the miniature probe equipped with the semiconductor miniature photodiode (1) for measuring the dose rates during exposure in radiotherapy. For connecting contacts to the photodiode (1), conducting carbon putty (2) was used. For effective electromagnetic shielding (6), a carbon based conducting layer was used and for the photodiode (1), a coating mixture (7) of organic materials was used, and that with its contents of biogenic components approximates human soft tissue of a common composition. Geometrical characteristics of the coat are selected in accordance with an application type of each of the probes. The evaluation of response is similar to other detectors with a semiconductor photodiode, i.e. it is necessary to measure the current generated by the photodiode that is connected in the electromagnetic circuit in a short-circuit mode.<IMAGE>
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