PDF(Pubmed)
Abstract：
UNASSIGNED: Several cases of inaccurate irradiation in brachytherapy have been reported, occurring similarly to external radiation. Due to a large dose per fraction in brachytherapy, inaccurate irradiation can seriously harm a patient. Although various studies have been conducted, systems that detect inaccurate irradiation in brachytherapy are not as developed as those for external irradiation. This study aimed to construct a system that analyzes the source dwell position during irradiation using computed tomography (CT) scout images. The novelty of the study was that by using CT scout images, high versatility and analysis of absolute coordinates can be achieved.
UNASSIGNED: A treatment plan was designed with an iridium-192 (192Ir) source delivering radiation at two dwell positions in a tandem applicator. CT scout images were taken during irradiation, and acquired under different imaging conditions and applicator geometries. First, we confirmed whether a source was visible in CT scout images. Then, employing in-house MATLAB program, source dwell coordinates were analyzed using the images. An analysis was considered adequate when the resulting source dwell coordinates agreed with the treatment plan within ±1 mm, in accordance with AAPM TG56 guidelines for source dwell position accuracy.
UNASSIGNED: The source dwelling was visible in CT scout image, which was enlarged or reduced depending on applicator geometries. The applicator was enlarged by 127% when 130 mm away from the center of CT gantry. The analysis results using our in-house program were considered adequate; although, analysis parameters required adjustments depending on imaging conditions.
UNASSIGNED: The proposed system can be easily implemented for image-guided brachytherapy and can analyze the absolute coordinates of source dwell position. Therefore, the system could be used for preventing inaccurate irradiation by verifying whether brachytherapy was performed properly.
UNASSIGNED: A treatment plan was designed with an iridium-192 (192Ir) source delivering radiation at two dwell positions in a tandem applicator. CT scout images were taken during irradiation, and acquired under different imaging conditions and applicator geometries. First, we confirmed whether a source was visible in CT scout images. Then, employing in-house MATLAB program, source dwell coordinates were analyzed using the images. An analysis was considered adequate when the resulting source dwell coordinates agreed with the treatment plan within ±1 mm, in accordance with AAPM TG56 guidelines for source dwell position accuracy.
UNASSIGNED: The source dwelling was visible in CT scout image, which was enlarged or reduced depending on applicator geometries. The applicator was enlarged by 127% when 130 mm away from the center of CT gantry. The analysis results using our in-house program were considered adequate; although, analysis parameters required adjustments depending on imaging conditions.
UNASSIGNED: The proposed system can be easily implemented for image-guided brachytherapy and can analyze the absolute coordinates of source dwell position. Therefore, the system could be used for preventing inaccurate irradiation by verifying whether brachytherapy was performed properly.
摘要：
■已经报道了几例近距离放射治疗不准确的情况，类似于外部辐射。由于近距离放射治疗中每个部分的剂量很大，不准确的照射会严重伤害患者。尽管已经进行了各种研究，在近距离放射治疗中检测不准确照射的系统不如用于外部照射的系统发达。本研究旨在构建一个系统，该系统使用计算机断层扫描（CT）侦察图像分析辐照过程中的源驻留位置。这项研究的新颖之处在于通过使用CT侦察图像，可以实现高度的通用性和绝对坐标分析。
■设计了一种治疗计划，其中铱-192（192Ir）源在串联施加器中的两个停留位置处递送辐射。CT侦察图像是在照射过程中拍摄的，并在不同的成像条件和施加器几何形状下获取。首先,我们确认了在CT侦察图像中是否可见源。然后，采用内部MATLAB程序，使用图像分析了源驻留坐标。当得到的源驻留坐标与治疗计划在±1mm内一致时，分析被认为是充分的。根据AAPMTG56关于源驻留位置准确性的指南。
■在CT侦察图像中可以看到源居住，根据涂药器的几何形状放大或缩小。当远离CT台架中心130mm时,涂药器扩大127%。使用我们的内部计划的分析结果被认为是足够的；尽管，分析参数需要根据成像条件进行调整。
■所提出的系统可以很容易地实现用于图像引导的近距离放射治疗，并且可以分析源驻留位置的绝对坐标。因此,该系统可用于通过验证近距离放射治疗是否正确进行来防止不准确的照射。
■设计了一种治疗计划，其中铱-192（192Ir）源在串联施加器中的两个停留位置处递送辐射。CT侦察图像是在照射过程中拍摄的，并在不同的成像条件和施加器几何形状下获取。首先,我们确认了在CT侦察图像中是否可见源。然后，采用内部MATLAB程序，使用图像分析了源驻留坐标。当得到的源驻留坐标与治疗计划在±1mm内一致时，分析被认为是充分的。根据AAPMTG56关于源驻留位置准确性的指南。
■在CT侦察图像中可以看到源居住，根据涂药器的几何形状放大或缩小。当远离CT台架中心130mm时,涂药器扩大127%。使用我们的内部计划的分析结果被认为是足够的；尽管，分析参数需要根据成像条件进行调整。
■所提出的系统可以很容易地实现用于图像引导的近距离放射治疗，并且可以分析源驻留位置的绝对坐标。因此,该系统可用于通过验证近距离放射治疗是否正确进行来防止不准确的照射。
