Dosimetry of the dopamine transporter radioligand 18F-FPCIT in human subjects.
This study was designed to evaluate the radiation dosimetry in human subjects for a new radiopharmaceutical, N-(3-(18)F-fluoropropyl)-2beta-carbomethoxy-3beta-(4-iodophenyl)nortropane ((18)F-FPCIT). The goal was to determine a limiting dose consistent with accepted guidelines for use in clinical studies and to compare the radiation burden with other agents such as (123)I-FPCIT, (18)F-fluorodopa, and (18)F-FDG.


METHODS
Dynamic PET scans of the urinary bladder were obtained in 6 subjects; 2 subjects had brain scans and 5 subjects had scans of the thorax or abdomen. Regions of interest were placed over composite images of each organ for which activity was visualized to generate time-activity curves. Doses were calculated from residence times using the MIRDOSE3 program.


RESULTS
The critical organ for dosimetry is the urinary bladder wall with a dose of 0.0586 +/- 0.0164 mGy/MBq. The dose comes primarily (97.2%) from activity in the urinary bladder contents. The dose is lower than any of the other agents used commonly in PET to assess dopaminergic function. The effective dose equivalent (0.0120 mGy/MBq) is also lower than comparable compounds.


CONCLUSIONS
(18)F-FPCIT has favorable dosimetry when compared with other agents used to study dopaminergic function. Doses as high as 853 MBq (23 mCi) may be given to adult patients and remain within accepted guidelines.
Robeson
William
W
Center for Neurosciences, North Shore University Hospital, Manhasset, New York, USA. robeson@nshs.edu
Dhawan
Vijay
V
Belakhlef
Abdel
A
Ma
Yilong
Y
Pillai
Von
V
Chaly
Thomas
T
Margouleff
Claude
C
Bjelke
David
D
Eidelberg
David
D
D000328:Adult; D000368:Aged; D001822:Body Burden; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008168:Lung / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins / Q000378:metabolism; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D009662:Nortropanes / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D009928:Organ Specificity; D011874:Radiometry / Q000379:methods*; D019275:Radiopharmaceuticals / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D014055:Tomography, Emission-Computed / Q000379:methods; D014326:Tropanes; D001743:Urinary Bladder / Q000378:metabolism*; D014915:Whole-Body Counting / Q000379:methods
D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D009662:Nortropanes; D019275:Radiopharmaceuticals; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane