Red Marrow Absorbed Dose Calculation in Thyroid Cancer Patient Using a Simplified Excel Spreadsheet

Area of Science:

• Medical Physics
• Nuclear Medicine
• Radiological Dosimetry

Background:

• Traditional blood dosimetry for red marrow absorbed dose (Drm) is laborious and invasive.
• Image-based dosimetry is preferred, but commercial software is costly.
• Developing cost-effective dosimetry tools is crucial for clinical applications.

Purpose of the Study:

• To develop a simplified Excel spreadsheet for image-based radioiodine red marrow dosimetry.
• To assess the feasibility and accuracy of this simplified method compared to commercial software.
• To provide a low-cost alternative for dosimetry in nuclear medicine.

Main Methods:

• Retrospective analysis of serial whole-body images from 29 patients.
• Calculation of whole-body time-integrated activity coefficient (TIACWB) and Drm using commercial OLINDA/EXM software.
• Development of an Excel spreadsheet to compute TIACWB by fitting time-activity curves and scaling S factors.
• Statistical comparison of results from both methods using non-inferiority tests.

Main Results:

• No significant difference in TIACWB between the simplified Excel spreadsheet and OLINDA/EXM (p=0.243).
• The Drm calculated by the Excel spreadsheet was statistically non-inferior to the commercial software (non-inferiority margin of 0.02, p<0.05).

Conclusions:

• A simplified Excel spreadsheet is a feasible and cost-effective tool for image-based radioiodine red marrow dosimetry.
• This method offers a viable alternative to expensive commercial software for dose assessment.
• The developed spreadsheet simplifies dosimetry, potentially improving accessibility in clinical settings.