세기조절방사선치료의 선량정확도에 대한 품질보증 과정에서 측정된 데이터를 기반으로 실제 치료 환자 신체 내의 치료 선량분포를 재계산하여 치료계획 시 계산된 선량분포와 비교, 분석을 수행할 수 있는 프로그램들이 개발되어 임상에 사용 중에 있다. 본 연구에서는 아크첵(ArcCHECK)을 사용하여 품질보증 과정에서 측정한 토모테라피 선량 데이터를 기반으로 환자 내 치료선량 분포를 재구성할 수 있는 3DVH 프로그램의 새로운 기능 및 선량정확도를 평가하고자 하였다. 이를 위한 가상의 환자로 이차원 다이오드 검출기 배열 장치인 MapCHECK 영상을 사용하여 토모테라피 치료계획을 수립하고, 아크첵으로 선량을 측정 후 다시 3DVH를 사용하여 MapCHECK 검출기 영역의 선량분포를 재계산한 후, 실제 MapCHECK에서 측정된 선량분포와 비교하여, 그 오차를 분석하였다. 분석 결과, 측정값과 3DVH 계산값 비교를 위한 감마평가에서 평균 합격률은 $92.6{\pm}3.5%$로 측정값과 토모치료계획에서 계산된 선량과의 감마평가 평균 합격률 $99.0{\pm}1.2%$보다 오차가 큼을 보였다. 래피드아크에서 비교한 3DVH 계산값과 측정값의 감마평가 평균 합격률 $99.3{\pm}0.9%$와 비교하였을 경우에도 더 큰 오차를 보여, 토모테라피에서 3DVH 선량 계산 기능을 임상에서 신뢰하고 사용하기에는 더 많은 측정 결과들의 분석과 오차 원인에 대한 분석이 수행되어야 할 것으로 생각된다.
세기조절방사선치료의 선량정확도에 대한 품질보증 과정에서 측정된 데이터를 기반으로 실제 치료 환자 신체 내의 치료 선량분포를 재계산하여 치료계획 시 계산된 선량분포와 비교, 분석을 수행할 수 있는 프로그램들이 개발되어 임상에 사용 중에 있다. 본 연구에서는 아크첵(ArcCHECK)을 사용하여 품질보증 과정에서 측정한 토모테라피 선량 데이터를 기반으로 환자 내 치료선량 분포를 재구성할 수 있는 3DVH 프로그램의 새로운 기능 및 선량정확도를 평가하고자 하였다. 이를 위한 가상의 환자로 이차원 다이오드 검출기 배열 장치인 MapCHECK 영상을 사용하여 토모테라피 치료계획을 수립하고, 아크첵으로 선량을 측정 후 다시 3DVH를 사용하여 MapCHECK 검출기 영역의 선량분포를 재계산한 후, 실제 MapCHECK에서 측정된 선량분포와 비교하여, 그 오차를 분석하였다. 분석 결과, 측정값과 3DVH 계산값 비교를 위한 감마평가에서 평균 합격률은 $92.6{\pm}3.5%$로 측정값과 토모치료계획에서 계산된 선량과의 감마평가 평균 합격률 $99.0{\pm}1.2%$보다 오차가 큼을 보였다. 래피드아크에서 비교한 3DVH 계산값과 측정값의 감마평가 평균 합격률 $99.3{\pm}0.9%$와 비교하였을 경우에도 더 큰 오차를 보여, 토모테라피에서 3DVH 선량 계산 기능을 임상에서 신뢰하고 사용하기에는 더 많은 측정 결과들의 분석과 오차 원인에 대한 분석이 수행되어야 할 것으로 생각된다.
The new function of 3DVH software for dose calculation inside the patient undergoing TomoTherapy treatment by applying the measured data obtained by ArcCHECK was recently released. In this study, the dosimetric accuracy of 3DVH for the TomoTherapy DQA process was evaluated by the comparison of measu...
The new function of 3DVH software for dose calculation inside the patient undergoing TomoTherapy treatment by applying the measured data obtained by ArcCHECK was recently released. In this study, the dosimetric accuracy of 3DVH for the TomoTherapy DQA process was evaluated by the comparison of measured dose distribution with the dose calculated using 3DVH. The 2D diode detector array MapCHECK phantom was used for the TomoTherapy planning of virtual patient and for the measurement of the compared dose. The average pass rate of gamma evaluation between the measured dose in the MapCHECK phantom and the recalculated dose in 3DVH was $92.6{\pm}3.5%$, and the error was greater than the average pass rate, $99.0{\pm}1.2%$, in the gamma evaluation results with the dose calculated in TomoTherapy planning system. The error was also greater than that in the gamma evaluation results in the RapidArc analysis, which showed the average pass rate of $99.3{\pm}0.9%$. The evaluated accuracy of 3DVH software for TomoTherapy DQA process in this study seemed to have some uncertainty for the clinical use. It is recommended to perform a proper analysis before using the 3DVH software for dose recalculation of the patient in the TomoTherapy DQA process considering the initial application stage in clinical use.
The new function of 3DVH software for dose calculation inside the patient undergoing TomoTherapy treatment by applying the measured data obtained by ArcCHECK was recently released. In this study, the dosimetric accuracy of 3DVH for the TomoTherapy DQA process was evaluated by the comparison of measured dose distribution with the dose calculated using 3DVH. The 2D diode detector array MapCHECK phantom was used for the TomoTherapy planning of virtual patient and for the measurement of the compared dose. The average pass rate of gamma evaluation between the measured dose in the MapCHECK phantom and the recalculated dose in 3DVH was $92.6{\pm}3.5%$, and the error was greater than the average pass rate, $99.0{\pm}1.2%$, in the gamma evaluation results with the dose calculated in TomoTherapy planning system. The error was also greater than that in the gamma evaluation results in the RapidArc analysis, which showed the average pass rate of $99.3{\pm}0.9%$. The evaluated accuracy of 3DVH software for TomoTherapy DQA process in this study seemed to have some uncertainty for the clinical use. It is recommended to perform a proper analysis before using the 3DVH software for dose recalculation of the patient in the TomoTherapy DQA process considering the initial application stage in clinical use.
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제안 방법
The 3DVH software for the dose recalculation inside the body of the patient in the TomoTherapy DQA process is esti-mated to have some uncertainty like the results in this study considering the initial application in clinical cases. A proper verification study on the dosimetric accuracy should be performed by comparing the recalculated dose in the 3DVH software with the measured dose before application to a real clinical case.
1. After acquisition of a computed tomography (CT) image of the MapCHECK combined with the MapPHAN, a total of ten TomoTherapy plans (five prostate and five head plans) were prepared based on the CT images. The virtual target and organ at risk (OAR) were contoured differently in each plan (Fig.
The DQA plans of the prepared TomoTherapy plans were made for the acquisition of measured dose data by using the ArcCHECK device. After the DQA measurement by using the ArcCHECK, as shown in Fig. 3, the error compared with the calculated dose in the TomoTherapy planning system was evaluated using the gamma evaluation method with a 3% dose difference and 3-mm distance-to-agreement criteria. The measured dose data by using the ArcCHECK was imported to 3DVH, and the 3D dose distribution in the MapCHECK phantom was recalculated.
In this study, the dosimetric accuracy of 3DVH for the TomoTherapy DQA process was evaluated in order to verify the accuracy in the application of clinical cases. For this study, the real dose distribution was measured during the TomoTherapy treatment and compared with the dose calculated using 3DVH. In addition, the accuracy was evaluated with the comparison results of the 3DVH application in the RapidArc DQA process.
In this study, the dosimetric accuracy of 3DVH for the TomoTherapy DQA process was evaluated in order to verify the accuracy in the application of clinical cases. For this study, the real dose distribution was measured during the TomoTherapy treatment and compared with the dose calculated using 3DVH.
In this study, we mainly evaluated the dosimetric accuracy of a recently released 3DVH software for dose verification of the patient in the TomoTherapy treatment, which should be confirmed before application in real clinical cases. The evaluated results in this study showed that the accuracy of 3DVH in the TomoTherapy DQA process was not good compared with the accuracy in the RapidArc DQA process.
The Novalis Tx linear accelerator (Varian Medical Systems, Palo Alto, CA) was used, as shown in Fig. 4 and the RapidArc plans were prepared using the Eclipse (Varian Medical Systems, Palo Alto, CA) planning system. The photon energy was 6MV, which is similar to the photon energy in the TomoTherapy plans, and a single arc was used in all the RapidArc plans.
The measured dose data by using the ArcCHECK was imported to 3DVH, and the 3D dose distribution in the MapCHECK phantom was recalculated. The calculated 2D coronal dose distribution at the level of diode detector array was exported in order to compare it with the dose distribution measured in the MapCHECK detector array during the TomoTherapy treatment beam delivery.
1-3) A conventional basic procedure for DQA is the measurement of dose distribution in a phantom structure. The dosimetric errors are then analyzed by comparing the measured data with the calculated dose in a treatment planning system (TPS).
이론/모형
The DQA plans of the prepared TomoTherapy plans were made for the acquisition of measured dose data by using the ArcCHECK device. After the DQA measurement by using the ArcCHECK, as shown in Fig.
The additional ten RapidArc plans were prepared with the same MapCHECK phantom, target, OARs and dose prescription as used in the TomoTherapy plans. The DQA plans were prepared for dose measurement by using the ArcCEHCK. After the DQA accuracy was confirmed, the measured dose data by using the ArcCHECK was imported to 3DVH for 3D dose calculation in the MapCHECK phantom.
The calculated 2D coronal dose distribution at the level of MapCHECK diode detector array was exported, as in the case of the TomoTherapy analysis. The dose difference between the dose measured during RapidArc beam delivery and dose calculated in 3DVH was evaluated using the gamma evaluation method with the same criteria of the TomoTherapy case.
The dose difference between the measured and calculated dose in 3DVH was evaluated using the gamma evaluation method with a 3% dose difference and 3-mm distance-toagreement criteria.
성능/효과
The evaluated 3DVH accuracy in the RapidArc DQA process was compared with the results in the TomoTherapy case and the suitability of the 3DVH application in the TomoTherapy DQA was examined.
In this study, we mainly evaluated the dosimetric accuracy of a recently released 3DVH software for dose verification of the patient in the TomoTherapy treatment, which should be confirmed before application in real clinical cases. The evaluated results in this study showed that the accuracy of 3DVH in the TomoTherapy DQA process was not good compared with the accuracy in the RapidArc DQA process. Although the average pass rate in gamma evaluation was greater than 99.
후속연구
Therefore, it is better to perform a proper analysis before using the 3DVH software for dose recalculation of the patient in the TomoTherapy DQA process. The further study on the error analysis will be done with the additional phantom measurements data in order to find the proper method to apply the 3DVH in TomoTherapy DQA.
참고문헌 (13)
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