Human biodistribution and radiation dosimetry of 82Rb.
Prior estimates of radiation-absorbed doses from (82)Rb, a frequently used PET perfusion tracer, yielded discrepant results. We reevaluated (82)Rb dosimetry using human in vivo biokinetic measurements.


METHODS
Ten healthy volunteers underwent dynamic PET/CT (6 contiguous table positions, each with separate (82)Rb infusion). Source organ volumes of interest were delineated on the CT images and transferred to the PET images to obtain time-integrated activity coefficients. Radiation doses were estimated using OLINDA/EXM 1.0.


RESULTS
The highest mean absorbed organ doses (μGy/MBq) were observed for the kidneys (5.81), heart wall (3.86), and lungs (2.96). Mean effective doses were 1.11 ± 0.22 and 1.26 ± 0.20 μSv/MBq using the tissue-weighting factors of the International Commission on Radiological Protection (ICRP), publications 60 and 103, respectively.


CONCLUSIONS
Our current (82)Rb dosimetry suggests reasonably low radiation exposure. On the basis of this study, a clinical (82)Rb injection of 2 × 1,480 MBq (80 mCi) would result in a mean effective dose of 3.7 mSv using the weighting factors of the ICRP 103-only slightly above the average annual natural background exposure in the United States (3.1 mSv).
Senthamizhchelvan
Srinivasan
S
Division of Nuclear Medicine, Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21287, USA.
Bravo
Paco E
PE
Esaias
Caroline
C
Lodge
Martin A
MA
Merrill
Jennifer
J
Hobbs
Robert F
RF
Sgouros
George
G
Bengel
Frank M
FM
D001822:Body Burden; D006801:Humans; D009928:Organ Specificity; D011829:Radiation Dosage; D019275:Radiopharmaceuticals / Q000032:analysis / Q000493:pharmacokinetics; D012414:Rubidium Radioisotopes / Q000008:administration & dosage* / Q000032:analysis / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014915:Whole-Body Counting
D019275:Radiopharmaceuticals; D012414:Rubidium Radioisotopes