OAR Dose Distribution Prediction and gEUD Based Automatic Treatment Planning Optimization for Intensity Modulated Radiotherapy

Abstract

In current knowledge-based treatment planning for intensity-modulated radiation therapy (IMRT), 3-dimensional dosimetric goals are predicted to provide abundant and appropriate starting points for planning optimization, but considering there're uncertainties with those dose distribution predictions, how to tailor the objective function and constraints accordingly is quite a concern. Here, we represent a novel automatic treatment optimization method that is capable of making the most of dose distribution prediction meanwhile achieving its optimum as much as possible. On the foundation of an in-house organsat-risk (OARs) dose distribution prediction model, we reformulate a traditional fluence map optimization (FMO) model by a predicted dose distribution-based objective, an equivalent uniform dose sparing for OARs and hard dose constraints for planning target volume (PTV). Feasibility and performance of the method is evaluated with 10 gynecology (GYN) cancer IMRT cases by comparing the plan quality of the generated to the original clinical ones, in the term of dose-volume-histogram (DVH) curves, dose distribution and detailed dosimetric endpoints. Results show plan quality improvement by our proposed method, with comparable PTV dose coverage but further dose sparing for OARs. Among 6 investigated OAR dosimetric endpoints, 4 of them are observed with significant improvement (P<0.05), V 30 , V 45 of rectum is decreased by (8.42±7.88) %, (15.49±7.48) %, respectively and V 30 , V 45 of bladder is decreased by (14.47±5.08) %, (14.24±4.71) %, respectively. We have successfully developed a novel automatic optimization method which is able to make good use of 3D dose prediction and ensure the output plan quality for IMRT. INDEX TERMS 3D dose distribution prediction, equivalent uniform dose, intensity modulated radiation therapy, prediction guided treatment planning optimization.

Effective optimization strategy for large optimization volume object, remaining volume at risk (RVR): α-value selection and usage from generalized equivalent uniform dose (gEUD) curve deviation perspective

“…Even though the gEUD is derived from a tissue-specific biological dose, a gEUD optimization object enables the exploration of large solution spaces and improves the sparing of normal tissue doses (Wu et al 2002) by reducing the trial and error required for optimization (Jia et al 2019). To simplify the OAR dose constraints for optimization, effective gEUD use for optimization is essential (Li et al 2012).…”

“…2.3. Optimization process from gEUD deviation perspective Single a-value gEUD optimization with a changed a-value in the phantom and patient cases has been widely reported (Wu et al 2002, Thieke et al 2003, Hartmann and Bogner 2008, Li et al 2012, Liang et al 2016, Feng et al 2017, Fogliata et al 2018, Jia et al 2019. Specifically, Fogliata et al reported their results using a phantom considering the Eclipse PO gradient solver for optimization.…”

“…Originally, the a-value represented a tissue-specific parameter, whereas it behaves as the DV cost function for particular domains of the DVH in the optimization process. The appropriate use of the gEUD enables simple and effective optimization, whereas elusive characteristics that depend on an arbitrary DVH shape remain in empirical usage (Jia et al 2019).…”

Research on Intraoperative Organ Motion Tracking Method Based on Fusion of Inertial and Electromagnetic Navigation

“…Especially for cancer radiotherapy surgery, it requires that the radiation can precisely cover the tumor cells while avoiding excessive damage to normal tissues. However, in clinical practice, factors such as respiration, digestion, postural changes, and instrument disturbances may cause unintended movements of target organs and even cause tumors to leave the planned target volume (PTV) range [2][3][4], resulting in tumor remnants. And also expose a large amount of healthy tissues to the radiation range, causing inevitable unnecessary damage or even serious side effects.…”