Bezak Eva, Takam Rundgham, Marcu Loredana G
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, Australia School of Chemistry and Physics, Adelaide University, Adelaide, Australia.
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, Australia School of Chemistry and Physics, Adelaide University, Adelaide, Australia Faculty of Science, University of Oradea, Oradea 410087, Romania.
Radiat Prot Dosimetry. 2015 Dec;167(4):591-601. doi: 10.1093/rpd/ncu362. Epub 2015 Jan 5.
Peripheral photon and neutron doses from external beam radiotherapy (EBRT) are associated with increased risk of carcinogenesis in the out-of-field organs; thus, dose estimations of secondary radiation are imperative. Peripheral photon and neutron doses from EBRT of prostate carcinoma were measured in Rando phantom. (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P glass-rod thermoluminescence dosemeters (TLDs) were inserted in slices of a Rando phantom followed by exposure to 80 Gy with 18-MV photon four-field 3D-CRT technique. The TLDs were calibrated using 6- and 18-MV X-ray beam. Neutron dose equivalents measured with CR-39 etch-track detectors were used to derive readout-to-neutron dose conversion factor for (6)LiF:Mg,Cu,P TLDs. Average neutron dose equivalents per 1 Gy of isocentre dose were 3.8±0.9 mSv Gy(-1) for thyroid and 7.0±5.4 mSv Gy(-1) for colon. For photons, the average dose equivalents per 1 Gy of isocentre dose were 0.2±0.1 mSv Gy(-1) for thyroid and 8.1±9.7 mSv Gy(-1) for colon. Paired (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P TLDs can be used to measure photon and neutron doses simultaneously. Organs in close proximity to target received larger doses from photons than those from neutrons whereas distally located organs received higher neutron versus photon dose.
外照射放疗（EBRT）产生的外周光子和中子剂量与野外器官致癌风险增加相关；因此，二次辐射的剂量估计至关重要。在朗多人体模型中测量了前列腺癌EBRT产生的外周光子和中子剂量。将（6）LiF:Mg,Cu,P和（7）LiF:Mg,Cu,P玻璃棒热释光剂量计（TLD）插入朗多人体模型切片中，然后采用18兆伏光子四野三维适形放疗技术照射80戈瑞。TLD使用6兆伏和18兆伏X射线束进行校准。用CR-39蚀刻径迹探测器测量的中子剂量当量用于推导（6）LiF:Mg,Cu,P TLD的读出值与中子剂量转换因子。甲状腺每1戈瑞等中心剂量的平均中子剂量当量为3.8±0.9毫希沃特每戈瑞（-1），结肠为7.0±5.4毫希沃特每戈瑞（-1）。对于光子，甲状腺每1戈瑞等中心剂量的平均剂量当量为0.2±0.1毫希沃特每戈瑞（-1），结肠为8.1±9.7毫希沃特每戈瑞（-1）。配对的（6）LiF:Mg,Cu,P和（7）LiF:Mg,Cu,P TLD可用于同时测量光子和中子剂量。靠近靶区的器官接受的光子剂量大于中子剂量，而远处的器官接受的中子剂量高于光子剂量。
