Defense Date

2026

Document Type

Thesis

Degree Name

Master of Science

Department

Medical Physics

First Advisor

Jianqiao Luo, Ph.D.

Second Advisor

William Y,Song , Ph.D

Third Advisor

Monica Ghita, Ph.D.

Abstract

Abstract

Lutetium-177 (Lu-177) is widely used in radionuclide therapy, where accurate activity measurement prior to administration is essential for safe and effective treatment delivery. However, variability in dose calibrator response due to measurement conditions and source geometry remains a practical challenge in routine clinical settings. This study presents a practical clinical calibration strategy under real-world constraints for Lu-177 activity measurement using standard nuclear medicine instrumentation. A vial-based approach was implemented using a well-type ionization chamber (Capintec CRC-15R) to evaluate measurement repeatability, temporal stability, and geometry dependence. All measurements were performed under consistent conditions with appropriate decay correction applied using the physical half-life of Lu-177. Patient radiation survey measurements were also included as a qualitative consistency check. The results demonstrated excellent short-term repeatability and stable measurement performance over time when consistent conditions were maintained. Decay-corrected activity values were in agreement with the prescribed activity at the time of administration. Small variations in dial setting produced controlled differences in measured activity, highlighting the sensitivity of the system to calibration parameters. Patient survey measurements were consistent with expected dose rates, supporting the clinical validity of the approach. These findings confirm that a simple, standardized vial-based calibration strategy can provide reliable and reproducible activity measurements in routine clinical practice. The proposed approach addresses a practical gap between controlled calibration methods and real-world clinical implementation, and may serve as a foundation for developing simplified calibration tools and protocols.

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Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

5-6-2026

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