Faculty of Electrical Engineering, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands.
Oncology Solutions Department, Philips Research, 5656 AE, Eindhoven, The Netherlands.
Med Phys. 2018 Jul;45(7):3185-3195. doi: 10.1002/mp.12972. Epub 2018 Jun 14.
The use of ultrasound imaging is not widespread in prostate cancer radiotherapy workflows, despite several advantages (eg, allowing real-time volumetric organ tracking). This can be partially attributed to the need for a trained operator during acquisition and interpretation of the images. We introduce and evaluate an algorithm that can propose a patient-specific transperineal ultrasound probe setup, based on a CT scan and anatomical structure delineations. The use of this setup during the simulation and treatment stage could improve usability of ultrasound imaging for relatively untrained operators (radiotherapists with less than 1 yr experience with ultrasound).
The internal perineum boundaries of three prostate cancer patients were identified based on bone masks extracted from their CT scans. After projection of these boundaries to the skin and exclusion of specific areas, this resulted in a skin area accessible for transperineal ultrasound probe placement in clinical practice. Several possible probe setups on this area were proposed by the algorithm and the optimal setup was automatically selected. In the end, this optimal setup was evaluated based on a comparison with a corresponding transperineal ultrasound volume acquired by a radiation oncologist.
The algorithm-proposed setups allowed visualization of 100% of the clinically required anatomical structures, including the whole prostate and seminal vesicles, as well as the adjacent edges of the bladder and rectum. In addition, these setups allowed visualization of 94% of the anatomical structures, which were also visualized by the physician during the acquisition of an actual ultrasound volume.
Provided that the ultrasound probe setup proposed by the algorithm, is properly reproduced on the patient, it allows visualization of all clinically required structures for image guided radiotherapy purposes. Future work should validate these results on a patient population and optimize the workflow to enable a relatively untrained operator to perform the procedure.
尽管超声成像是实时容积器官追踪等方面具有优势，但在前列腺癌放射治疗工作流程中并未广泛应用。这在一定程度上是由于在获取和解释图像时需要经过训练的操作人员。我们引入并评估了一种算法，该算法可以根据 CT 扫描和解剖结构描绘为每个患者提出特定的经会阴超声探头设置。在模拟和治疗阶段使用这种设置可以提高相对未经训练的操作人员（具有少于 1 年超声经验的放射治疗师）使用超声成像的可用性。
根据从 CT 扫描中提取的骨骼掩模，确定了三名前列腺癌患者的内部会阴边界。将这些边界投影到皮肤上并排除特定区域后，就得到了在临床实践中可用于经会阴超声探头放置的皮肤区域。该算法提出了在该区域上的几种可能的探头设置，并自动选择了最佳设置。最后，通过与放射肿瘤学家获得的相应经会阴超声体积进行比较来评估此最佳设置。
该算法提出的设置允许可视化 100%的临床所需解剖结构，包括整个前列腺和精囊，以及膀胱和直肠的相邻边缘。此外，这些设置还可以可视化 94%的解剖结构，这些结构在医生获取实际超声体积时也可以看到。
只要算法提出的超声探头设置在患者身上得到正确再现，就可以为图像引导放射治疗目的可视化所有临床所需的结构。未来的工作应在患者人群中验证这些结果，并优化工作流程，使相对未经训练的操作人员能够执行该程序。
