Abstract
Whether the g-emission by radioisotopes influences the outcome of dual-energy X-ray absorptiometry (DXA)
measurements is not fully elucidated. The aim of this study was to evaluate the effect of antecedent administration
of
99m
Tc on DXA measurements regarding body composition and bone mineral density (BMD) using a K-edge filter
scanner. The phantom measurements were performed by placing a urinary bladder phantom containing 40 mL of
radioisotope solution on the pelvic region of a whole-body phantom. Twenty-seven patients attending our department for a routine examination involving the administration of a tracer marked with
99m
Tc were included. The patients underwent a whole-body DXA scan before and within 2 h after tracer injection using a GE/Lunar Prodigy
scanner. Control scans were performed on 40 volunteers, who had not received any radioactive tracer. In both phantom and patient measurements, we found a significant dose-related decrease in fat mass and BMD and a corresponding increase in fat-free mass ( p! 0.001). Based on the linear regression analysis, we suggest upper dose limits for
the measurement of BMD at 0.77 mSv/h and body composition at 0.21 mSv/h (dose rate measured at a distance of
1 m from the patient). Caution should be taken when interpreting the results of DXA scans performed in close
temporal proximity to procedures involving the administration of
99m
Tc.
Key Words: Body composition; bone mineral density; dual-energy X-ray absorptiometry; gamma radiation;
radiopharmaceuticals.
measurements is not fully elucidated. The aim of this study was to evaluate the effect of antecedent administration
of
99m
Tc on DXA measurements regarding body composition and bone mineral density (BMD) using a K-edge filter
scanner. The phantom measurements were performed by placing a urinary bladder phantom containing 40 mL of
radioisotope solution on the pelvic region of a whole-body phantom. Twenty-seven patients attending our department for a routine examination involving the administration of a tracer marked with
99m
Tc were included. The patients underwent a whole-body DXA scan before and within 2 h after tracer injection using a GE/Lunar Prodigy
scanner. Control scans were performed on 40 volunteers, who had not received any radioactive tracer. In both phantom and patient measurements, we found a significant dose-related decrease in fat mass and BMD and a corresponding increase in fat-free mass ( p! 0.001). Based on the linear regression analysis, we suggest upper dose limits for
the measurement of BMD at 0.77 mSv/h and body composition at 0.21 mSv/h (dose rate measured at a distance of
1 m from the patient). Caution should be taken when interpreting the results of DXA scans performed in close
temporal proximity to procedures involving the administration of
99m
Tc.
Key Words: Body composition; bone mineral density; dual-energy X-ray absorptiometry; gamma radiation;
radiopharmaceuticals.
Originalsprog | Engelsk |
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Tidsskrift | Journal of Clinical Densitometry |
ISSN | 1094-6950 |
DOI | |
Status | Udgivet - 2012 |