Should We Update Hip DXA Protocols?

What is it about?

The study aimed to evaluate the interference of gamma radiation emitted by Lutetium (Lu) on simultaneous bone mineral density (BMD) measurements for patients undergoing Lu-PSMA and Lu-DOTATATE therapy. Nine patients undergoing Lu-PSMA therapy were randomly selected, and SPECT/CT scans were performed to assess activity in the abdominopelvic region. The study utilized DEXA scans with and without varying Lu-177 activities to measure BMD, finding no significant differences between the Hologic and Lunar devices. However, fluctuations in BMD readings were noted, suggesting gamma radiation from Lu can influence DEXA scan results. It is recommended to postpone DEXA scans by 8 to 11 days post-therapy to avoid erroneous measurements and ensure accurate bone assessments.

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Photo by CHUTTERSNAP on Unsplash

Photo by CHUTTERSNAP on Unsplash

Why is it important?

This research is important because it addresses the potential interference of gamma radiation emitted by Lutetium-177 (Lu-177) during bone mineral density (BMD) measurements in patients undergoing Lu-PSMA and Lu-DOTATATE therapy. Accurate BMD measurements are essential for assessing bone health, diagnosing osteoporosis, and evaluating fracture risk. The study's findings highlight the need to understand and mitigate the effects of gamma radiation on DEXA scans to ensure precise and reliable bone assessments in patients receiving these therapies. Key Takeaways: 1. Gamma Radiation Interference: The study emphasizes that gamma radiation emitted by Lu-177 can influence DEXA scans and the resulting BMD measurements, causing fluctuations in the readings. This interference could lead to inaccurate assessments of bone health if not properly accounted for. 2. Device Sensitivity: The research found that the Hologic and GE-Lunar DEXA devices showed different levels of fluctuation in BMD readings when exposed to varying Lu-177 activities. The Hologic device exhibited a fluctuation range of 0.3%-2%, whereas the Lunar device showed a higher range of 3.6%-10.3%. 3. Recommendation for Timing of DEXA Scans: To avoid erroneous BMD measurements caused by gamma radiation, the study recommends postponing DEXA scans until at least 8 days after Lu-PSMA therapy and 11 days after Lu-DOTATATE therapy. This delay helps to minimize the impact of residual gamma radiation and provides more accurate bone density assessments.