評估以TomoEDGE方法進行侖道假體鼻咽癌治療之劑量

Evaluating Doses of Rando Phantom in Nasopharyngeal Carcinoma Treatment Using TomoEDGE Technique

林弘智(Hung-Chih Lin)；廖鴻霖(Hong-Lin Liao)；曾顯群(Hsien-Chun Tseng)；張育誠(Yu-Cheng Chang)；陳健懿(Chien-Yi Chen)；黃小茹(Hsiao-Ju Huang)

鼻咽癌 ； 斷層治療機 ； 侖道假體 ； 熱發光劑量計 ； 動態準直儀 ； 固定準直儀 ； nasopharyngeal carcinoma (NPC) ； helical tomotherapy (TOMO) ； Rando phantom ； thermoluminescent dosimeters (TLD) ； dynamic jaw ； fixed jaw

中華放射線技術學雜誌

42卷2期（2018 / 06 / 01）

79 - 88

繁體中文

本研究為首次比較鼻咽癌（NPC）患者於斷層治療機（TOMO）的新TomoEDGE技術下，5 cm和2.5 cm固定式（fixed jaw）和動態式（dynamic jaw）準直儀調控。通過6 MV直線加速器，校正熱發光劑量計（TLD），然後佈點侖道擬人假體（Rando phantom）。實驗中，TLD經由Harshaw 3500計讀儀數據得知，各器官的劑量分布，隨著距離腫瘤中心點越遠，散射劑量越少。Rando phantom的腫瘤中心的劑量為2.0±0.1 Gy。其皮膚劑量距離腫瘤中心20 cm內較明顯，使用固定式5 cm劑量從1.10±0.20 Gy驟降至0.2±0.04 Gy，而動態式5 cm劑量從1.06±0.11 Gy驟降至0.07±0.01 Gy。另外，固定式2.5 cm劑量從0.96±0.17 Gy驟降至0.13±0.02 Gy，而動態式2.5 cm劑量從0.84±0.15 Gy驟降至0.08±0.01 Gy。此研究的目的除了得知兩者技術上，於各器官吸收劑量的差異之外，也可以發現動態式可以降低腫瘤邊緣正常組織的傷害，減少非必要的輻射劑量。本研究可以提供予患者、醫師、放射師與主管機關卓參。

This study is firstly to compare the conformity of nasopharyngeal carcinoma (NPC) patients with newly TomoEDGE technique in 5cm and 2.5cm fixed and dynamic jaws of helical tomotherapy (TOMO). Thermoluminescent dosimeters (TLDs) were calibrated by 6 MV TOMO and then inserted into Rando phantoms. TLDs were measured using the Harshaw 3500 TLD reader. From the measured dose distributions, the estimated scattering doses decreased with increasing distances from the tumor center. The results indicate that the tumor center dose of Rando phantom was 2.0 ± 0.1 Gy. The radiation dose rapidly decreased from 1.10±0.20 Gy to 0.2±0.04 Gy, 1.06±0.11 Gy to 0.07±0.01 Gy, 0.96±0.17 Gy to 0.13±0.02 Gy, and 0.84±0.15 Gy to 0.08±0.01 Gy using 5 cm fixed jaw, dynamic jaw, 2.5 cm fixed jaw, and dynamic jaw, respectively. This study stated not only understanding absorbed doses between two technologies, but also finding dynamic jaw could lower absorbed doses of normal organ which is close to tumor. It could reduce unnecessary radiation doses. These findings will be useful to patients, physicians, radiologists, and the public.