During radiotherapy treatment, critical organs are shielded using cerrobend blocks. The objective of this study was to define the minimal thickness of cerrobend blocks so that the relative absorbed dose in target less than 5%. All measurements were performed using linac Siemens/Primus Mclass 5633. Phantom relative absorbed dose were measured for square field 10 x 10 cm2. The thickness of cerrobend blocks were 2, 4, 6, 8 and 10 mm. The measurements in water were performed using compact chamber fitted with acrylic build up caps.The minimal thickness of cerrobend blocks for 5, 10 and 14 MeV electron beams are 2, 4 and 6 mm, respectively. The relative absorbed dose for phantom\u27s surface, maximum depth and x-ray tail using those blocks are 0.12%, 0.16%, 0.21%, 2.18%, 1.56%, 1.16%, 2.92%, 2.47% dan 1.70%.The relative absorbed dose decreases with the increasing of cerrobend block thickness and phantom depth. Therefore, if cerrobend blocks are used to protect critical organs, the thickness should be taken into account accurately.
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机译：在放射治疗过程中，关键器官被头尾神经阻滞屏蔽。这项研究的目的是确定神经阻滞块的最小厚度，以使靶标中的相对吸收剂量小于5％。所有测量均使用直线加速器Siemens / Primus Mclass 5633进行。幻像相对吸收剂量是针对10 x 10 cm2的方形场测量的。尾骨块的厚度为2、4、6、8和10mm。水中的测量是使用装有丙烯酸树脂堆积帽的紧凑型腔室进行的.5、10和14 MeV电子束的尾塞最小厚度分别为2、4和6mm。使用这些模块的体模表面，最大深度和X射线尾巴的相对吸收剂量为0.12％，0.16％，0.21％，2.18％，1.56％，1.16％，2.92％，2.47％和1.70％。吸收剂量随头尾神经阻滞厚度和体模深度的增加而降低。因此，如果使用头颅骨块保护关键器官，则应准确考虑厚度。
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