3D-Printed Linear Compensator Array-Enabled Automated Treatment Planning System for High-Throughput Small Animal Intensity-Modulated Radiation Therapy
Abstract
Purpose
To achieve more favorable clinical VMAT/IMRT outcomes, preclinical studies that mimic clinical practices and provide highly statistically significant small animal (SA) studies are essential. However, such high-throughput studies are currently impractical because of the time it takes to treat one subject (>2 hours), due to manual organ contouring, computationally expensive dose calculation algorithms, and long treatments which are often overly complex for the radiobiologist to reliably complete without a physicist present. Presented is a user-friendly automated treatment planning system (TPS) with 3D-printed linear compensator array (LCA) for accelerated treatment delivery times, providing accurate and efficient preclinical SA-IMRT that matches the clinical IMRT workflow.
Methods
The presented workflow improves time-to-treatment efficiency by integrating deep learning-enabled automated organ contouring; GPU-accelerated, 1mm2 square beamlet kernel-based kV-photon dose calculation algorithm for heterogenous media; and beamlet intensity total variation regularization optimization for reduced complexity in Tungsten-doped 3D-printed LCA. To further improve treatment efficacy and efficiency, the LCA track mechanism provides automated or manual intra-treatment field changeability. Verification of the dose engine was done with both SA irradiator commissioning data and a well-verified Monte Carlo model used to create the kernels for all relevant materials.
Results
For a simulated 5-field mouse heart toxicity plan, workflow was timed and evaluated: CBCT scan (~2 min), auto-contouring (~2 sec), dose and fluence optimization (~2 min), 3D-printing (~15 min), and treatment (~6 min), for a total treatment time of ~25 minutes. Planning target volume coverage is reported: V50%,Rx = 99.5%, V95%,Rx = 93%, and V100%,Rx = 72.5%. Organ-at-risk minimum sparing (Left Lung) was V50%,Rx = 15.5%, V95%,Rx = 1.1%, and V100%,Rx = 0.9%. Phantom-imbedded Gafchromic film measurement and gamma analysis are pending.
Conclusion
This LCA-enabled automated TPS designed for high-throughput SA-IMRT enables relatively inexpensive, large-scale, precise preclinical results that can directly translate and improve clinical outcomes and experimental therapies.