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Fetal dose estimates for (18)F-fluoro-L-thymidine using a pregnant monkey model
Rachel M Bartlett1, Robert J Nickles, Todd E Barnhart
1Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA.
Summary
Estimating fetal radiation dose from 18F-FLT PET scans is crucial. Fetal liver accumulates 18F-FLT, resulting in a dose of 53 microGy/MBq, requiring careful risk-benefit analysis for pregnant patients.
Area of Science:
- Nuclear medicine
- Radiology
- Medical imaging
Background:
- Fetal tissues are highly sensitive to ionizing radiation.
- 18F-fluoro-L-thymidine (FLT) PET imaging assesses cellular proliferation for tumor monitoring.
- Accurate fetal radiation dose estimation is vital for nuclear medicine procedures during pregnancy.
Purpose of the Study:
- To estimate the radiation absorbed dose to a human fetus following administration of 18F-FLT.
- To assess fetal radiation exposure using biodistribution data from pregnant rhesus monkeys.
Main Methods:
- Pregnant rhesus macaques underwent PET/CT imaging after 18F-FLT administration.
- Maternal and fetal organ time-activity curves were generated.
- Radiation doses were calculated using OLINDA/EXM software and a 6-month-pregnant human model.
Main Results:
- The extrapolated maternal whole-body dose was 11.4 microGy/MBq.
- The estimated total-body fetal dose was 24 microGy/MBq.
- Significant 18F-FLT accumulation in the fetal liver led to a fetal liver dose of 53 microGy/MBq.
Conclusions:
- The fetal dose from 18F-FLT is slightly higher than from 18F-FDG.
- 18F-FLT accumulation in the fetal liver necessitates consideration in risk-benefit assessments for pregnant patients undergoing PET scans.
