University of Washington, Department of Radiation Oncology, Seattle, WA, USA; University of Miami, Department of Radiation Oncology, Miami, FL, USA.
Loma Linda University Medical Center, Loma Linda, CA, USA.
Phys Med. 2021 Feb;82:211-218. doi: 10.1016/j.ejmp.2021.01.078. Epub 2021 Feb 27.
We propose a novel cost-effective compensator that can be used to facilitate access to IMRT in low-and-middle income countries. The compensator has the advantages of simplicity, less downtime, increased reliability and less impact on treatment quality from patient motion during treatment. Moreover, the system can be used with either a cobalt-60 unit or linear accelerator. In this Monte Carlo study, the dosimetric properties of the new compensator design have been evaluated. Results were obtained for different field sizes of cobalt teletherapy machine, and the dose was scored at 0.5 cm depth in a water phantom. The effects of compensator thickness, filling material type and shape, and field size were identified. Furthermore, the percentage depth dose and beam profiles for various field sizes and at different depths were obtained. Beam profiles show no significant signature of the beads relative to a solid compensator; in addition, they exhibit a better flatness while preserving symmetry for all field sizes. A reusable bead-based compensator appears to be feasible, and provides dose distribution similar to a solid compensator with low cost and no hazards. Our results avail the ongoing efforts to expand the reach to IMRT in low- and middle-income countries.
我们提出了一种新颖的、具有成本效益的补偿器，可以用于促进中低收入国家进行调强适形放射治疗。该补偿器具有结构简单、停机时间短、可靠性提高以及在治疗过程中患者运动对治疗质量影响较小等优点。此外，该系统可与钴-60 装置或线性加速器一起使用。在这项蒙特卡罗研究中，我们评估了新补偿器设计的剂量学特性。我们针对不同的钴远距离治疗机射野大小获得了结果，并在水模体中 0.5cm 深度处对剂量进行了评分。确定了补偿器厚度、填充材料类型和形状以及射野大小的影响。此外，还获得了不同射野大小和不同深度的百分深度剂量和射束轮廓。射束轮廓相对于实心补偿器没有明显的珠子特征；此外，它们在保持对称性的同时，所有射野的平坦度都更好。可重复使用的基于珠子的补偿器似乎是可行的，并且可以提供与实心补偿器相似的剂量分布，成本低且没有危险。我们的结果支持了在中低收入国家扩大调强适形放射治疗应用的努力。
