Piermattei A, Azario L, Monaco G, Soriani A, Arcovito G
Università Cattolica S. Cuore, Istituto di Fisica, Roma, Italy.
Med Phys. 1995 Jun;22(6):835-9. doi: 10.1118/1.597486.
The sensitivity of a cylindrical p-type silicon detector was studied by means of air and water measurements using different photon beams. A lead filter cap around the diode was used to minimize the dependence of the detector response as a function of the brachytherapy photon energy. The radial dose distribution of a high-activity 192Ir source in a brachytherapy phantom was measured by means of the shielded diode and the agreement of these data with theoretical evaluations confirms the method used to compensate diode response in the intermediate energy range. The diode sensitivity was constant over a wide range of dose rates of clinical interest; this allowed one to have a small detector calibrated in terms of absorbed dose in a medium. Theoretical evaluations showed that a single shielding filter around the p-type diode is sufficient to obtain accurate dosimetry for 192Ir, 137Cs, and 60Co brachytherapy sources.
通过使用不同光子束进行空气和水测量，研究了圆柱形p型硅探测器的灵敏度。在二极管周围使用铅滤帽，以尽量减少探测器响应随近距离治疗光子能量的变化。通过屏蔽二极管测量了近距离治疗体模中高活度192Ir源的径向剂量分布，这些数据与理论评估结果的一致性证实了在中能范围内用于补偿二极管响应的方法。二极管灵敏度在临床感兴趣的宽剂量率范围内保持恒定；这使得可以拥有一个根据介质中吸收剂量校准的小型探测器。理论评估表明，p型二极管周围的单个屏蔽滤光片足以对192Ir、137Cs和60Co近距离治疗源进行精确剂量测定。
