Deterministic Radiotherapy Dose Calculation Method

描述（由申请人提供）：目前需要开发准确有效的剂量计算方法，用于体外放射治疗的临床治疗计划。由于最近图像引导定位技术的进步和更精确的光束传递方法的发展，如调强放射治疗（IMRT）和立体定向放射外科（SRS），存在着大幅减少边缘和提高剂量一致性的潜力。然而，目前临床使用的大多数剂量计算方法都采用近似值，这限制了它们的准确性和使用范围，特别是在存在异质性的窄光束时。因此，采用更精确的方法，如蒙特卡罗，被认为是非常可取的。然而，蒙特卡罗计算可能是耗时的，限制了它们在临床治疗计划中的有效性。提出了求解中性粒子和带电粒子控制输运方程微分形式的一种新的确定性剂量计算方法的应用。正如初步研究表明的那样，这种方法有可能提供与详细的蒙特卡罗模拟相当的准确性，并且计算速度要快得多。该方法结合各向异性单元自适应，有效地解决了复杂的解剖特征和尖锐的解梯度，并借助于对变尺寸四面体单元使用高阶不连续有限元方法。在第一阶段，将开发一个概念验证过程，以量化患者特定剂量计算的性能。这将通过详细的蒙特卡罗结果来验证选择的治疗方案，包括骨，空气和肺的异质性，使用宽和窄光束。成功将根据与蒙特卡罗相关的性能来衡量，根据速度和准确性的组合来定义。将确定进一步提高2期效率的潜在增强措施，并提供可实现的临床表现的估计。

DESCRIPTION (provided by applicant): A present need exists for the development of accurate and efficient dose calculation methods for clinical treatment planning in external beam radiotherapy. Due to recent advances in image guided localization techniques and the development of more precise beam delivery methods such as Intensity Modulated Radiation Therapy (IMRT) and Stereotactic Radiosurgery (SRS), the potential exists to substantially reduce margins and improve dose conformity. However, most dose calculation methods in clinical use today employ approximations that limit their accuracy and scope of use, especially with narrow beams in the presence of heterogeneities. As a result, the adoption of more accurate methods such as Monte Carlo is seen as highly desirable. However, Monte Carlo calculations can be time consuming, limiting their effectiveness for clinical treatment planning. The application of a novel deterministic dose calculation method, which solves the differential form of the governing transport equations for neutral and charged particles is proposed. As indicated in preliminary studies, this approach has the potential to provide accuracy comparable to detailed Monte Carlo simulations with a substantially faster computational speed. The proposed approach incorporates anisotropic element adaptation to efficiently resolve complex anatomical features and sharp solution gradients, which is aided by the use of higher-order discontinuous finite element methods on variably sized tetrahedral elements. In Phase 1, a proof-of-concept process will be developed to quantify performance for patient specific dose calculations. This will be validated with detailed Monte Carlo results for selected treatment plans incorporating bone, air and lung heterogeneities, using both wide and narrow beams. Success will be measured on performance relative to Monte Carlo, defined in terms of combined speed and accuracy. Potential enhancements to further improve efficiency in Phase 2 will be identified, and an estimate of achievable clinical performance will be provided.