Dosimetry of 223Ra-chloride: dose to normal organs and tissues.
OBJECTIVE
(223)Ra-Chloride (also called Alpharadin®) targets bone metastases with short range alpha particles. In recent years several clinical trials have been carried out showing, in particular, the safety and efficacy of palliation of painful bone metastases in patients with castration-resistant prostate cancer using (223)Ra-chloride. The purpose of this work was to provide a comprehensive dosimetric calculation of organ doses after intravenous administration of (223)Ra-chloride according to the present International Commission on Radiological Protection (ICRP) model for radium.


METHODS
Absorbed doses were calculated for 25 organs or tissues.


RESULTS
Bone endosteum and red bone marrow show the highest dose coefficients followed by liver, colon and intestines. After a treatment schedule of six intravenous injections with 0.05 MBq/kg of (223)Ra-chloride each, corresponding to 21 MBq for a 70 kg patient, the absorbed alpha dose to the bone endosteal cells is about 16 Gy and the corresponding absorbed dose to the red bone marrow is approximately 1.5 Gy.


CONCLUSIONS
The comprehensive list of dose coefficients presented in this work will assist in comparing and evaluating organ doses from various therapy modalities used in nuclear medicine and will provide a base for further development of patient-specific dosimetry.
Department of Nuclear Medicine, University of Würzburg, 97080 Würzburg, Germany. lassmann@nuklearmedizin.uni-wuerzburg.de
Michael
M
Lassmann
Dietmar
D
Nosske
D000512:Alpha Particles / Q000627:therapeutic use; D001853:Bone Marrow / Q000378:metabolism; D001842:Bone and Bones / Q000473:pathology; D006801:Humans; D007700:Kinetics; D008297:Male; D009362:Neoplasm Metastasis; D011471:Prostatic Neoplasms / Q000628:therapy; D011874:Radiometry / Q000379:methods*; D019275:Radiopharmaceuticals / Q000494:pharmacology*; D011879:Radiotherapy Dosage; D011883:Radium / Q000737:chemistry; D011886:Radon / Q000494:pharmacology*; D012306:Risk; D013997:Time Factors; D014018:Tissue Distribution
D019275:Radiopharmaceuticals; D011886:Radon; D011883:Radium