Author: James Irrer, Charles K. Matrosic, Martha M. Matuszak, Charles S. Mayo, Kelly C. Paradis, Joann I. Prisciandaro, Benjamin S. Rosen, John Yao, Claire Zhang 👨🔬
Affiliation: University of Michigan, Department of Radiation Oncology, University of Michigan 🌍
Purpose: To introduce an in-house developed tool, BioDoseUI, designed to calculate and visualize 3D equieffective dose (EQD2Gy) for treatment planning systems (TPS) without such capabilities, to facilitate the special medical physics consult (SMPC) process for reirradiation (reRT) patients. BioDoseUI identifies and quantifies high-dose regions and gradients near organs-at-risk (OARs) to guide risk assessment.
Methods: SMPCs are frequently requested for patients with prior radiation treatments to address concerns for complications due to cumulative dose. During the process, a medical physicist reviews prior treatment data and image registration, calculates the equieffective dose (EQD2Gy in our workflow), and assesses previous OAR doses to guide treatment planning and evaluate post-planning cumulative dose. To facilitate this process, BioDoseUI was developed using Application Programming Interface (API) scripting. Upon launch, the tool 1) retrieves RTDose data from the TPS; 2) performs a grid-based calculation to generate EQD2Gy dose distributions using the LQ model (default α/β = 2.5); and 3) saves the equieffective dose distribution to the TPS for visualization and cumulative dose analysis. The equieffective dose distribution can then be used to evaluate spatial dose overlap between prior and current plans and to assess cumulative OAR doses with composite plans.
Results: The tool was commissioned using test plans across multiple body sites and is compatible with institutional records and external DICOM files. The ability to visualize equieffective cumulative doses offers several advantages: 1) enabling direct assessment of spatial dose overlap; 2) improving the quantification of plan evaluation metrics, including spatial dose features and gradients; and 3) guiding treatment plan optimization.
Conclusion: BioDoseUI enables the calculation and visualization of 3D equieffective dose distributions. This tool provides a practical solution for reRT evaluation in the absence of commercial software support and represents a step toward improving and streamlining reirradiation workflows.