PET-based radiation dosimetry in man of 18F- fluorodihydrotestosterone, a new radiotracer for imaging prostate cancer Journal Article


Authors: Zanzonico, P. B.; Finn, R.; Pentlow, K. S.; Erdi, Y.; Beattie, B.; Akhurst, T.; Squire, O.; Morris, M.; Scher, H.; McCarthy, T.; Welch, M.; Larson, S. M.; Humm, J. L.
Article Title: PET-based radiation dosimetry in man of 18F- fluorodihydrotestosterone, a new radiotracer for imaging prostate cancer
Abstract: 16β-fluoro-5α-dihydrotestosterone (FDHT) is a promising new PET radiopharmaceutical for the imaging of prostate cancer. A recent clinical trial provided the opportunity for refinement of normal-tissue radiation-absorbed dose estimates based on quantitative PET. The objective of the current study was to derive estimates of normal-tissue absorbed doses for 18F-FDHT administered to patients with advanced prostate cancer. Methods: Absorbed dose estimates were derived from 10 18F-FDHT PET studies (administered activity, 111-407 MBq) of 7 prostate cancer patients. Activity concentrations in plasma and red marrow (assuming a plasmacrit of 0.58, an extracellular fluid fraction of 0.40, and equilibration of activity between plasma and marrow extracellular fluid) were measured ex vivo from a peripheral blood sample. Liver, spleen, urinary bladder contents, and total-body activities were measured by region-of-interest analysis of quantitative whole-body studies acquired with a dedicated PET scanner. Total organ activities and residence times were calculated from the respective PET scan-derived activity concentrations assuming standard (70 kg) man organ masses. Urinary excretion was corrected for hepatobiliary excretion (liver activity), and a first-order adjustment was made for the bladder-wall mass based on the patient's total-body mass. Mean organ absorbed doses were calculated with the MIRD formalism and the standard man model using the MIRDOSE3 software program. Results: The absorbed doses (mean ± SD) ranged from 0.00057 ± 0.000281 cGy/MBq (to skin) to 0.00868 ± 0.00481 cGy/MBq (to bladder wall) (voiding intervals, 1-2 h), and the effective dose equivalent was 0.00177 ± 0.000152 cSv/MBq. Conclusion: The maximum absorbed dose among all tissues in all 10 studies, 0.0151 cGy/MBq, occurred for the urinary bladder wall (with hydration and 1- to 2-h voiding intervals). To ensure that the maximum normal-tissue absorbed dose is kept below the recommended maximum permissible dose of 5 cGy per single administration, a maximum administered activity of 331 MBq (5 cGy/[0.0151 cGy/MBq]) is recommended for 18F-FDHT.
Keywords: clinical article; controlled study; human tissue; aged; unclassified drug; clinical trial; dose response; radiation dose; positron emission tomography; methodology; metabolism; image interpretation, computer-assisted; risk factors; risk factor; histology; risk assessment; radiation dosage; prostate cancer; prostatic neoplasms; diagnostic agent; drug distribution; tissue distribution; computer assisted diagnosis; dosimetry; quantitative analysis; prostate tumor; positron-emission tomography; organ specificity; radiopharmaceutical agent; drug derivative; scintiscanning; antibody specificity; metabolic clearance rate; radiometry; relative biological effectiveness; drug blood level; body burden; relative biologic effectiveness; whole body counting; whole-body counting; ex vivo study; computer program; peripheral circulation; androgens; androstanolone; radiation protection; fdht; dihydrotestosterone; 18f; urinary excretion; fluorodihydrotestosterone f 18; humans; human; male; priority journal; article; 16 fluorodihydrotestosterone; 16-fluorodihydrotestosterone
Journal Title: Journal of Nuclear Medicine
Volume: 45
Issue: 11
ISSN: 0161-5505
Publisher: Society of Nuclear Medicine  
Date Published: 2004-11-01
Start Page: 1966
End Page: 1971
Language: English
PROVIDER: scopus
PUBMED: 15534070
DOI/URL:
Notes: J. Nucl. Med. -- Cited By (since 1996):41 -- Export Date: 16 June 2014 -- CODEN: JNMEA C2 - 15534070 -- Source: Scopus
Citation Impact
MSK Authors
  1. Michael Morris
    578 Morris
  2. Ronald D Finn
    279 Finn
  3. Timothy J Akhurst
    139 Akhurst
  4. John Laurence Humm
    433 Humm
  5. Pat B Zanzonico
    355 Zanzonico
  6. Yusuf E Erdi
    118 Erdi
  7. Steven M Larson
    959 Larson
  8. Keith S Pentlow
    70 Pentlow
  9. Howard Scher
    1130 Scher
  10. Bradley Beattie
    131 Beattie
  11. Olivia D Squire
    32 Squire