評估以TomoEDGE進行鼻咽癌治療計劃之劑量分佈

這項研究，為首次比較鼻咽癌（NPC）患者於斷層治療機（TOMO）TomoEDGE技術下，5 cm和2.5 cm固定（Fixed jaw）和動態式準直儀（Dynamic jaw）調控。通過6MV直線加速器，校正熱發光劑量計（TLD），然後佈點至固態水假體（Solid water phantom）和侖道擬人假體（Rando phantom）中。由於TLD體積很小，為了確認Rando假體中的TLD位置，必須先進行CT掃描，由資深放射師進行NPC治療計劃上的TomoEDGE技術。通過治療計畫來確定危急器官（OAR）和組織的位置。於每個實驗中還評估等效劑量（D）和皮膚劑量（Dskin），隨著距離中心點越遠，散射劑量越少。於結果Rando假體的腫瘤中心的劑量為2.0±0.1 Gy。距離腫瘤中心3.2 cm處，使用Fixed jaw 5劑量為1.27±0.23 Gy，Dynamic jaw 5劑量為0.14±0.03 Gy，高達9倍的差異，距離腫瘤中心3.3 cm處，Fixed jaw 2.5劑量為0.57±0.10 Gy，而Dynamic jaw 2.5劑量為0.14±0.03 Gy，高達4倍的差異。

This study compares the conformity of Nasopharyngeal Carcinoma （NPC） patients with newly TomoEDGE technique, in 5-cm and 2.5-cm Fixed and Dynamic jaws of Helical Tomotherapy （TOMO）.Thermoluminescent dosimetry （TLD） were calibrated by 6MV TOMO, then inserted into solid water and Rando phantoms. For precise TLD locations among 3 and 4 slices of Rando phantom, TLDs were first scanned by CT. NPC Treatments were performed by senior radiotherapist.The locations of organ at risk （OAR） and tissues were determined by visually comparing sections to an atlas of cross-sectional anatomy. Equivalent dose （D） and skin dose （Dskin） were also evaluated in each experiment.Radiation doses ware 2.0±0.1 Gy at the tumor center of Rando phantom. Those were effectively reduced to near 10 times using 5-cm Dynamic jaw than 5-cm Fixed jaw at 3 cm away from tumor center of Rando phantom. Extra radiations were found to decreases with tumor center.Results away from TLD-100H approach was suitable for radiation measurements.Extra radiations doses ware 1.27±0.23 Gy using 5-cm Fixed jaw, 9times more than those of 0.14±0.03 Gy using 5-cm Dynamic jaw, 3.6-cm away from center.Radiations doses ware 0.57±0.10 Gy using 2.5-cm Fixed jaw, 4 times more than those of 0.14±0.03 Gy using 2.5-cm Dynamic jaw, 3 cm away from center.Keywords：Dosimetric conformity, Nasopharyngeal Carcinoma （NPC）, Helical Tomotherapy （TOMO）, Rando phantom, Thermoluminescent dosimetry, Fixed jaw, Dynamic jaw