Brachytherapy has an excellent clinical outcome for different treatment sites. However, in vivo treatment verification is not performed in the majority of hospitals due to the lack of proper monitoring systems. This study investigates the use of an imaging panel (IP) and the photons emitted by a high dose rate (HDR) ¹⁹²Ir source to track source motion and obtain some information related to the patient anatomy. The feasibility of this approach was studied by monitoring the treatment delivery to a 3D printed phantom that mimicks a prostate patient. A 3D printed phantom was designed with a template for needle insertion, a cavity (‘rectum’) to insert an ultrasound probe, and lateral cavities used to place tissue-equivalent materials. CT images were acquired to create HDR ¹⁹²Ir treatment plans with a range of dwell times, interdwell distances and needle arrangements. Treatment delivery was verified with an IP placed at several positions around the phantom using radiopaque markers on the outer surface to register acquired IP images with the planning CT. All dwell positions were identified using acquisition times ≤0.11 s (frame rates≥9 fps). Interdwell distances and dwell positions (in relation to the IP) were verified with accuracy better than 0.1 cm. Radiopaque markers were visible in the acquired images and could be used for registration with CT images. Uncertainties for image registration (IP and planning CT) between 0.1 and 0.4 cm. The IP is sensitive to tissue-mimicking insert composition and showed phantom boundaries that could be used to improve treatment verification. The IP provided sufficient time and spatial resolution for real-time source tracking and allows for the registration of the planning CT and IP images. The results obtained in this study indicate that several treatment errors could be detected including swapped catheters, incorrect dwell times and dwell positions.

近距离放射治疗对不同的治疗部位都有很好的临床效果。然而，由于缺乏适当的监测系统，大多数医院没有进行体内治疗验证。本研究调查使用成像面板 (IP) 和高剂量率 (HDR) ¹⁹² Ir 源发射的光子来跟踪源运动并获取与患者解剖结构相关的一些信息。通过监测模拟前列腺患者的 3D 打印模型的治疗，研究了这种方法的可行性。一个 3D 打印的模型设计有一个用于针插入的模板、一个用于插入超声探头的腔（“直肠”）以及用于放置组织等效材料的侧腔。获取 CT 图像以创建 HDR ¹⁹²具有一系列停留时间、间隔距离和针头排列的 Ir 治疗计划。使用外表面上的不透射线标记将获取的 IP 图像与计划 CT 配准，通过放置在体模周围多个位置的 IP 验证治疗实施。使用采集时间≤0.11 s（帧速率≥9 fps）识别所有停留位置。以优于 0.1 cm 的精度验证了间隔距离和停留位置（相对于 IP）。不透射线标记在采集的图像中可见，可用于与 CT 图像配准。图像配准（IP 和计划 CT）的不确定性在 0.1 到 0.4 厘米之间。IP 对组织模拟插入物成分敏感，并显示出可用于改善治疗验证的幻象边界。IP 为实时源跟踪提供了足够的时间和空间分辨率，并允许对规划的 CT 和 IP 图像进行配准。在这项研究中获得的结果表明，可以检测到几个治疗错误，包括交换导管、不正确的停留时间和停留位置。