Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins School of Medicine, Baltimore, MD.
Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Champaign, IL.
Brachytherapy. 2022 Nov-Dec;21(6):799-805. doi: 10.1016/j.brachy.2022.07.005. Epub 2022 Aug 30.
PURPOSE/OBJECTIVES: There is a clinical need to develop anatomic phantoms for simulation-based learning in gynecological brachytherapy. Here, we provide a step-by-step approach to build a life-sized gynecological training phantom based on magnetic resonance imaging (MRI) of an individual patient. Our hypothesis is that this phantom can generate convincing ultrasound (US) images that are similar to patient scans.
Organs-at-risk were manually segmented using patient scans (MRI). The gynecological phantom was constructed using positive molds from 3D printing and polyvinyl chloride (PVC) plastisol. Tissue texture/acoustic properties were simulated using different plastic softener/hardener ratios and microbead densities. Nine readers (residents) were asked to evaluate 10 cases (1 ultrasound image per case) and categorize each as a "patient" or "phantom" image. To evaluate whether the phantom and patient images were equivalent, we used a multireader, multicase equivalence study design with two composite null hypotheses with proportion (p) at H: p ≤ 0.35 and H: p ≥ 0.65. Readers were also asked to review US videos and identify the insertion of an interstitial needle into the pelvic phantom. Computed Tomography (CT) and magnetic resonance (MR) images of the phantom were acquired for a feasibility study.
Readers correctly classified "patient" and "phantom" scans at p = 53.3% ± 6.2% (p values 0.013 for H and 0.054 for H, df = 5.96). Readers reviewed US videos and identified the interstitial needle 100% of the time in transabdominal view, and 78% in transrectal view. The phantom was CT and MR safe.
We have outlined a manufacturing process to create a life-sized, gynecological phantom that is compatible with multi-modality imaging and can be used to simulate clinical scenarios in image-guided brachytherapy procedures.
目的/目标：在妇科近距离放射治疗中，基于模拟的学习需要开发解剖体模。在此，我们提供了一种基于个体患者磁共振成像（MRI）构建真人大小妇科培训体模的分步方法。我们的假设是，这种体模可以生成与患者扫描相似的逼真超声（US）图像。
使用患者扫描（MRI）手动分割危及器官。使用 3D 打印和聚氯乙烯（PVC）糊状塑料的正模构建妇科体模。使用不同的塑料软化剂/硬化剂比例和微珠密度模拟组织纹理/声特性。9 位读者（住院医师）被要求评估 10 个病例（每个病例 1 个超声图像），并将每个病例归类为“患者”或“体模”图像。为了评估体模和患者图像是否等效，我们使用了具有两个复合零假设的多读者、多病例等效性研究设计，复合零假设 1 的比例（p）为 H：p≤0.35，复合零假设 2 的比例（p）为 H：p≥0.65。读者还被要求查看 US 视频并识别将间质针插入盆腔体模。获取体模的计算机断层扫描（CT）和磁共振（MR）图像以进行可行性研究。
读者在 p=53.3%±6.2%（H 的 p 值为 0.013，H 的 p 值为 0.054，df=5.96）时正确分类“患者”和“体模”扫描。读者在经腹视图中 100%的时间、在经直肠视图中 78%的时间查看 US 视频并识别间质针。体模在 CT 和 MR 上是安全的。
我们已经概述了一种制造工艺，用于创建与多模态成像兼容的真人大小妇科体模，并可用于模拟图像引导近距离放射治疗程序中的临床场景。
