Radiopharmaceutical therapy (RPT) is an alternative cancer treatment to chemotherapy that has worked well in patients with lymphoma, late-stage, metastatic prostate cancer, and neuroendocrine tumors. A unique characteristic of RPT is that it is possible to calculate how much radiation energy is deposited in tumors and normal tissues within an individual patient (“dosimetry”) by imaging the radiation emitted by the RPT agent within the body. We know that patient-specific prescriptions based on absorbed dose lead to better patient outcomes. Our active Phase 2 SBIR grant aims to provide seamless integration and automation of RPT dosimetry in clinical practices that are currently ill-equipped in terms of expertise and resources to perform advanced dosimetry for RPT. To address this need we are integrating our dosimetry algorithm into an automated treatment planning solution, TorchTM, by adding additional features such as image registration, contour propagation, and pharmacokinetic modeling. However, we have identified that a lack of region of interest (ROI) segmentation is an important feature gap in the software. To address this need, Vox is requesting supplemental funding to achieve the following aims: (1) Develop free-hand and threshold-based segmentation tools to create and edit binary label volumes for normal organs and tumors in Torch. (2) Validate free-hand and threshold-based segmentation tools to create and edit binary label volumes for normal organs and tumors in Torch. Adding segmentation tools to Torch will help Vox achieve the overall goal of the Phase II SBIR award of making RPT treatment planning faster and more accurate.