一般的治療計畫,當鼻咽癌病人以亞瑟刀進行動態弧形調控放射治療時,不會考慮到其產生的大量二次輻射。若將二次輻射納入評估,更可增進準確評估健康風險之能力。本研究使用了Rando假體、SDM假體,並使用以直線加速器在6MV光子下,進行熱發光劑量計TLD-100H之校正。校正後TLD置入假體內的器官組織,量測後使用ICRP 103號告之標稱危險度評估罹患致死二次癌症之風險。Rando假體與SDM假體的有效劑量分別為7.11±0.61 mSv與5.66±0.63 mSv。並討論以回歸分析法,以腫瘤為中心於不同距離下,構成之指數函數。經計算TLD-100H之最小可測值為8.08nC。這些結果可望提供關於防輻射工作者,患者,家屬和公眾實際方向。
Routine treatment planning does not consider the secondary radiation resulting from radiotherapy exposure for nasopharyngeal carcinoma patients undergoing Volumetric modulated arc therapy of Axesse (Elekta 2538) linear accelerator, and the peripheral doses. However, such treatment is potentially important for improved accuracy of estimated health risks. Effective dose (E) and nominal risks were evaluated using Alderson Rando phantom and self-developed mathematic phantoms. Thermoluminescent dosimeters (TLD-100H) were calibrated using LINAC 6 MV photons. These TLDs were inserted into phantom positions that closely approximated organs or tissues. The risks of incurring fatal secondary malignancies were estimated by ICRP 103. E of Rando phantom was 7.11±0.61 mSv as well as SDM is 5.66±0.63 mSv, respectively. Fitting exponential functions to this trend created the relationships of the radiation dose with tumor center and regression analysis (R2) were also discussion. The minimum detectable limit (MDL) using this approach was estimated to be 8.08 nC. The quantitative results could provide practical guidance regarding radiation protection to workers, patients, the relatives and the public.