- 期刊
呼吸調控系統的影像驗證
Imaging Verification of Respiratory Gating Systems
摘要
對於體外放射線治療而言，電腦斷層影像是治療計畫演算的基礎，但呼吸常會造成某些器官的位置改變，使影像模糊或有殘影，影響劑量演算或治療前影像對位的準確度。在眾多呼吸調控系統中，RPM系統普遍為臨床所使用，且已有許多文獻證明RPM系統所取得的4DCT影像具臨床可信度。此外，近年來另一套呼吸調控系統ANZAI亦愈來愈廣泛應用，但其偵測方式與RPM系統迥異，故本文將針對這二套系統不同的偵測方式及其取得的4DCT影像，透過呼吸波形及不同呼吸相位的電腦斷層影像進行比對，以驗證ANZAI系統與RPM系統同樣準確可信。在呼吸波形的部分，二套系統的呼吸紀錄重疊後顯示二者波形幾乎一致，其振幅平均差異為2.12±6.13%。在4DCT影像的部分，十個相位的影像融合結果顯示，不論在波峰相位或是波谷相位，二組4DCT影像的鋼球位置幾乎一致，且鋼球直徑的測量結果亦相近，最大差異均不超過0.10 cm，鋼球體積的差異平均則為0.25 cm^3。由以上結果得知，二套系統的呼吸波形及4DCT影像誤差均在臨床可接受範圍內，顯示ANZAI系統與RPM系統具有相同的可信度，皆適合臨床放射治療中應用。
並列摘要
CT image plays an important role in treatment planning (TP) calculation especially for the treatment of external beam irradiation. However, moving organs by respiration motion may cause image blurring and decrease the accuracy of treatment alignment and TP calculation. The Varian® Real-time Position Management^(TM) (RPM) system is a non-invasive, video-based system that has been widely used for respiratory gating radiotherapy for years in our center. In addition, ANZAI system (AZ-733V version), another respiratory gating system, has been increasingly used in recent years. The aim of this study is to evaluate if the ANZAI system can be considered as an alternative tool for respiratory gating radiotherapy by comparing the respiratory wave and 4DCT of the two systems. The respiratory waves predicted by the two systems were subtracted and the mean differences (2.12±6.13 %) indicated that their wave patterns are highly consistent. For analyzing the images, both of the 4DCT data sets were assorted into 10 phases. The image fusion and target size measurement were performed for each phase. The image fusion results show that the target locations from the two systems are very close in all phases. Furthermore, all the differences of target diameter are less than 0.10 cm and the mean difference of target volume is 0.25 cm^3. In conclusion, the respiratory wave and 4DCT from ANZAI system are as reliable as RPM system and suitable for the application of gating treatment.