Elekta Synergy影像導引放射治療直線加速器之臨床化

Commissioning of Elekta Synergy Linear Accelerator for Image-Guided Radiation Therapy

陳思婷(Szu-ting Chen)

指導教授 ： 陳信雄

中臺科技大學/健康科學院/放射科學研究所/碩士(2011年)

https://doi.org/10.6822/CTUST.2011.00033

摘要

Elekta Synergy直線加速器的臨床化包含取得機器的射束參數以及確認出電腦輸出的劑量分佈與量測資料是否一致。當取得所有必要的射束參數並確認其適用於治療計畫系統之後，此治療機器才可用於病人的治療。台中署立豐原醫院於2010年購置安裝一部Elekta Synergy直線加速器，其輸出能量有4、6及10 MV的X光射束，以及6、9、12、15及18 MeV的電子射束。必須取得的光子射束參數有百分深度劑量、劑量剖面、總散射因子、準直儀散射因子、穿透因子和輸出校正因子等。百分深度劑量與劑量剖面在水假體中進行量測，其它資料則使用FC65-G 0.6 c.c.游離腔連接PTW Unidose電量計在固態假體中量測。劑量的計算是依據美國醫學物理師協會出版的21號報告。百分深度劑量隨著射束能量與照野大小增加而增加，平坦度小於109 %，對稱性小於103 %。總散射因子與準直儀散射因子隨著照野大小增加而增加。不同光子能量與不同照野大小的楔型濾片穿透因子介於20 %至33 %之間，x軸準直儀穿透率約為2.2 %，y 軸準直儀穿透率約為11 %。多葉式準直儀穿透率以及鉛擋塊穿透率皆小於2 %。所有能量的光子和電子其輸出校正因子在dmax處皆被調整為1 cGy/MU。此外，為確保其放射治療的高品質，建立出直線加速器的品質保證項目並持續執行品質保證作業。

關鍵字

臨床化 ； 影像導引放射治療 ； 錐狀射束電腦斷層

並列摘要

The commissioning of Elekta Synergy linac for clinical use includes obtaining the machine beam data and checking the computer-generated dose distribution against the measured data. It can be used for patient treatments after the necessary beam data have been acquired and adopted to the treatment planning systems. The Elekta Synergy linac was installed at Fong-Yuan Hospital Department of Health Executive Yuan in 2010. This linac has 4, 6 and 10 MV x-rays, and 6, 9, 12, 15 and 18 MeV electron beams. The required photon beam data included percent depth dose, dose profiles, total scatter factor (Sc.p), collimator scatter factor (Sc), transmission factor and output calibration data. PDD and profiles were measured in water phantom, and the other data were measured with FC65-G 0.6 c.c. ion chamber and PTW Unidose electrometer in solid phantom. Radiation dose was calculated following the protocol of the AAPM Task Group No.21 report. The PDD increased with beam energy and field size. The flatness were less than 109 %, and the symmetry were less than 103 %. Sc.p and Sc increased as the field size was increased. Wedge factors were between 20 % and 33 % for different photon energies and field sizes. The x jaw transmission factors were approximately 2.2 %, and y jaw transmission factors were about 11 %. Multileaf collimator transmission and block transmission were less than 2 %. The output calibration data were adjusted to 1cGy/MU at dmax for all energies of photon and electron beams. This linac could start treating patients after all the commissioning processes were completed. Additionally, a quality assurance program was established and performed continuously in order to keep this linac with high quality of radiation therapy.

並列關鍵字

Cone-beam computed tomography ； Commissioning ； Image-guided radiation therapy

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