J Nucl Med 1996 Sep;37(9):1583-8
Radiation absorbed dose from indium-111-CYT-356.
Mardirossian G, Brill AB, Dwyer KM, Kahn D, Nelp W.
Indium-CYT-356 is an agent developed by CYTOGEN Inc. (CYT) (Princeton, NJ) for
the use in staging patients with prostate cancer. This investigation was
performed to provide the human dosimetry needed for Food and Drug Administration
approval for routine use in patients. METHODS: Biodistribution data collected
from three sites were obtained from prostate cancer patients who received
diagnostic doses of 111In-CYT-356. Data included blood and urine collections,
and the organ uptake value was measured from sequential conjugate whole-body and
planar images over a 7-10 day period. Dose contributions from radioactivity in
transit through the GI tract were estimated using a compartmental model. The
calculations used the MIRD methodology and MIRDOSE 3. RESULTS: The total-body
dose observed was 0.14 mGy/MBq, and the effective dose was found to be 0.25-0.29
mSv/MBq. The largest organ doses were found for the liver (1.0 mGy/MBq), kidneys
(0.67 mGy/MBq) and spleen (0.88 mGy/MBq). CONCLUSION: The radiation dose to the
patient from a typical 185 MBq administration of 111In-CYT-356 is comparable to
the dose from other 111In-labeled whole antibodies used in the diagnosis and
management of cancer patients. The inclusion of the GI tract as a source organ
increases the effective dose by 18%.
