目的：本研究建立188Re液體貝化射源於血管內近接治療之劑量評估與量測技術，並應用於血管再狹症幅射治療。材料與方法：完成二組6 mm 管徑血管假體、一組4mm管徑血管假體與一組3 mm 管徑血管假體的理論評估與實驗量測結果比較，理論評估使用蒙地卡羅法MCNP4C 程式，實驗量測則使用GafChromic MD-55 膠片。結果：實驗量測與理論評估的平均差異介於3.7% - 6.1%之間，落於不確定度範圍內，證明兩種研究方法與結果的一致性，計算結果顯示，要得到準確的劑量分佈，需模擬擴張氣球中心導管實際尺寸。血管假體模擬計算則顯示，擴張氣球外隨其和氣球表面距離的增加而迅速降低，且較大管徑血管之劑量降低速度稍小於較小管徑血管之劑量降低速度，對 6 mm 、 4 mm與3 mm 直徑之擴張氣球而言，離開氣球表面0.5mm距離處之劑量分別為擴張氣球表面劑量的56.1%、52.4%與50.9%，當離開氣球表面距離至3 mm 時，劑量則僅分別為氣球表面劑量的6.1%、5.5%與5.2%。結論：本研究確認了蒙地卡羅法MCNP4C程式應用於血管內近接治療劑量評估結果的正確性，同時也初步建立簡易劑量評估介面程式、可提供符合188 Re射源處方劑量所需之照射時間。

Purpose: This study performed the simulation of the dose distribution around the embedded high-den-sity metal material. Materials and Mathods: The simulation is focused on the Varian 21EX LINAC machine and imple-mented by the OMEGA/BEAM code system. For modeling the linear accelerator, the simulation para-meters are adjusted by comparing the results of the depth doses and the setup of 6 MV, 40 × 40 cm2, SAD= 100 cm in a homogeneous water phantom. Then, the dose disturbance has been investigated for the setup of 6 MV, 10 × 10 cm2 SAD= 100 cm with a denture sample. Results and Discussion : The adjusted LINAC parameters have been proved by the verifications of the depth doses and dose profiles calculated by DOSXYZ with the measurement setup of 6 MV, 40 × 40 cm2, SSD = 100 cm. It shows that the capability of simulating the Varian 21EX LINAC has been established. For the Degubond 4 denture sample at a depth of 5 cm with a setup of 6 MV, 10 × 10 cm2, SAD = 100 cm, the dose disturbance range in depth dose is around 2 cm. The back scattering electrons cause a 40% dose increment in front of the sample and the shielding effect decreases the dose of about 20% behind the sample. Maximum range disturbs the dose profile is about 1.2 cm. The energy range of the back scattering photons is between 0.2 and 0.6 MeV. Conclusion : The size of the denture sample used in the study is small, but the density is quite high, hence the perturbation effect is still significant. Besides, the spatial range of the perturbation is relative-ly small; it is difficult to be measured. In this study, it shows that the detailed information includes depth dose, dose profile at several depth, and the photon/electron spectrums could be obtained by Monte Carlo simulation, and could provide for the further study.