表淺疾病卡波西氏肉瘤(Kaposi's sarcoma)為免疫抑制疾病及人類皰疹病毒感染共同引起的，其可能會逐漸惡化，造成四肢水腫，可透過放射線治療技術達到殺死癌細胞抑制生長之效果。放射治療可使用電子射束或光子射束，電子射束徑程較短，對腫瘤後方正常組織傷害較小，且表面劑量隨著電子能量提高而增加；光子射束徑程較長，表面劑量較低，可搭配組織補償器增加表面劑量。本研究使用6MV光子射束，並以水及米作為組織補償器注入壓克力水箱內，將水箱內模擬假體完整包覆，達到模擬假體表面劑量均勻的效果。研究結果顯示，使用米作為組織補償器所得到的兩側劑量差異略優於水，且量測劑量與計算劑量差異較小。若於壓克力水箱下方擺放厚5 cm固態水假體，則可以增加底部回散射劑量，提升底部劑量。研究裝置架設所需的時間，使用水的設置時間較使用米短，但以水當補償器時，須考量噴濺及病人傷口浸潤水中增加感染之風險。兩種組織補償器皆可達到臨床治療需求，建議在病人模擬定位時，依據治療部位及病人配合度，選擇合適之組織補償器，未來將進一步探討改變水箱之形狀對於病人舒適度及穩定性之關係。

Kaposi's sarcoma is caused by immunosuppressive disease and human herpes virus infection. Radiotherapy can kill cancer cells and inhibit growth by electron beams or photon beams. The electron beams have a shorter path and less damage to the normal tissue behind the tumor. The surface dose increases with the increase of the electron energy. The photon beams have a longer path and a lower surface dose. To improve the surface dose using tissue compensator is necessary. In this study, 6 MV photon beam was used. Water or rice was put into the acrylic box separately at the same height as the tissue compensator to cover the whole phantom. The results showed that using rice as a tissue compensator had a better bilateral dose difference than water, and less difference between measured and calculated dose. If a 5 cm thick solid water phantom is placed under the acrylic box, the bottom dose can be increased because of the backscattering. However, when using water as a compensator, the risk of wound infection and spattering must be considered. Both types of tissue compensators can meet the clinical treatment requirements. It's important to choose the appropriate tissue compensator according to the treatment site and the patient's condition during simulation. The relationship of changing the shape of the acrylic box to patient comfort and stability will be further investigated in the future.