DICOM-Based Conservative Volume (CV) & DVH Calculator – Python Script

Vendor-Independent Conservative Volume and DVH Calculation from DICOM

This Python script demonstrates how to calculate Conservative Volume (CV) and generate a cumulative DVH directly from DICOM RTSTRUCT and RTDOSE, without relying on any treatment planning system APIs.

The Conservative Volume is defined as the portion of a structure receiving less than a specified dose threshold. While this metric is commonly evaluated inside a TPS, this script shows how the same calculation can be reproduced using DICOM-only data, making it fully vendor-neutral and transparent.

What This Script Does

• Loads RTDOSE and converts the dose grid to physical dose (Gy)
• Reads RTSTRUCT and reconstructs the ROI as a voxelized mask on the dose grid
• Computes:
• Total ROI volume
• Volume above a user-defined dose threshold
• Conservative Volume (volume below the threshold)
• Generates a cumulative DVH for the same ROI
• Displays the dose threshold visually on the DVH plot
• Outputs a structured CV report suitable for QA review or documentation

Why This Is Useful

• Works across any TPS vendor that exports RTSTRUCT and RTDOSE
• Ideal for independent QA, automation pipelines, and research workflows
• Ensures internal consistency by computing CV and DVH from the same voxelized DICOM data
• Transparent and auditable — no black-box TPS calculations

Intended Audience

• Medical physicists
• Dosimetrists
• Researchers working with DICOM RT data
• Developers building TPS-independent QA or analytics tools

Requirements

• Python
• pydicom
• numpy
• matplotlib

📌 Note:

This product includes the Python script only. It is intended for educational, research, and workflow-development purposes.