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.
■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。