Dosimetry of [۱۸F]Fluoro-pivalic acid ([۱۸F]FPIA) PET Tracer: Human dose estimates based on balb/c biodistribution data

Introduction: [۱۸F]Fluoro-pivalic acid ([۱۸F]FPIA) is a PET radiotracer under investigation for imaging short-chain fatty acid (SCFA) metabolism in gliomas. Accurate human radiation dosimetry is a prerequisite for its clinical translation. This study aimed to estimate human organ absorbed doses of [۱۸F]FPIA based on biodistribution data obtained from normal BALB/c mice.Methods: [۱۸F]FPIA was synthesized at the Karaj Cyclotron Center (Karaj, Iran) via nucleophilic fluorination of a tosyl precursor. For biodistribution studies, female BALB/c mice (n=۳ per time point, total n=۹) were intravenously injected with ۰.۵۲۶ mCi (۱۹.۴۶ MBq). Animals were sacrificed at ۱۵, ۳۰, and ۶۰ minutes post-injection. Radioactivity in major organs was measured using a well-type NaI(Tl) detector and expressed as percentage of injected dose per gram (%ID/g). Time-activity curves were generated via trapezoidal integration and exponential fitting. Cumulative organ activities were calculated and extrapolated to humans using the Sparks–Aydogan mass scaling method. Human organ absorbed doses and the effective dose were estimated using the Medical Internal Radiation Dose (MIRD) formalism implemented in OLINDA/EXM ۲.۰ software.Results: The highest estimated absorbed doses in human organs were observed in the bladder wall (۰.۲۰۱ mGy/MBq) and kidneys (۰.۱۴۳ mGy/MBq). In contrast, the brain (۰.۰۲۷۴ mGy/MBq) and intestines (۰.۰۱۹۶ mGy/MBq) received the lowest doses. The estimated effective dose was ۰.۰۱۶ mSv/MBq.Conclusion: The dosimetry profile of [۱۸F]FPIA, characterized by low background brain exposure and favorable dose estimates comparable to other clinical ۱۸F-tracers, supports its safe application for PET imaging. These results facilitate the clinical translation of [۱۸F]FPIA for tracing SCFA metabolism in glioma studies.

کلیدواژه ها:

[۱۸F]Fluoro-pivalic acid ، Dosimetry ، Glioma ، Fatty acid metabolism ، Positron emission tomography