Dosimetry of 188Re-hydroxyethylidene diphosphonate in human prostate cancer skeletal metastases.
188Re-Hydroxyethylidene diphosphonate ((188)Re-HEDP) was used in previous studies for the palliative treatment of metastatic bone pain. However, the kinetic and radiation-absorbed doses have not been well documented. Therefore, the aim of this study was to gather dosimetric data for (188)Re-HEDP.


METHODS
Thirteen prostate cancer patients with skeletal involvement were treated with 2,700-3,459 MBq (mean dose, 3,120 MBq) (188)Re-HEDP. Patients underwent whole-body scans 3, 20, and 28 h after therapy. The effective half-life, residence time, and radiation-absorbed dose values were calculated for the whole body, bone marrow, kidneys, and bladder as well as for 29 bone metastases. The urinary excretion rate was determined in 6 urine samples of each patient collected over 48 h at 8-h intervals beginning immediately after the administration of (188)Re-HEDP. After injection of (188)Re-HEDP, blood samples were taken weekly for 6 wk, and platelet and leukocyte counts were performed.


RESULTS
The mean effective half-life was 15.9 +/- 3.5 h in bone metastases, 10.9 +/- 2.1 h in the bone marrow, 11.6 +/- 2.1 h in the whole body, 12.7 +/- 2.2 h in the kidneys, and 7.7 +/- 3.4 h in the bladder. The following radiation-absorbed doses were calculated: 3.83 +/- 2.01 mGy/MBq for bone metastases, 0.61 +/- 0.21 mGy/MBq for the bone marrow, 0.07 +/- 0.02 mGy/MBq for the whole body, 0.71 +/- 0.22 mGy/MBq for the kidneys, and 0.99 +/- 0.18 mGy/MBq for the bladder. (188)Re-HEDP showed a rapid urinary excretion within the first 8 h after therapy, with 41% of the (188)Re-HEDP administered being excreted. Forty-eight hours after therapy, the excretion rate was 60% +/- 12%. Only 1 patient showed a decrease of platelet count below 100 x 10(9) counts/L. None of the patients presented with a decrease of leukocyte count below 3.0 x 10(9) counts/L.


CONCLUSIONS
(188)Re-HEDP is an effective radiopharmaceutical used in the palliative treatment of metastatic bone pain. The radiation-absorbed dose is acceptable for bone pain palliation with low doses for the normal bone marrow and the whole body.
Liepe
Knut
K
Department of Nuclear Medicine, University Hospital Dresden, Dresden, Germany. liepe@rcs.urz.tu-dresden.de
Hliscs
Reiner
R
Kropp
Joachim
J
Runge
Roswitha
R
Knapp
Furn F
FF
Franke
Wolf-Gunter
WG
D000368:Aged; D000369:Aged, 80 and over; D001822:Body Burden; D001853:Bone Marrow / Q000378:metabolism; D001859:Bone Neoplasms / Q000378:metabolism* / Q000556:secondary*; D012968:Etidronic Acid / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D006207:Half-Life; D006801:Humans; D007275:Injections, Intravenous; D007668:Kidney / Q000378:metabolism; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D009942:Organometallic Compounds; D011471:Prostatic Neoplasms / Q000473:pathology*; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods; D012211:Rhenium / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D014018:Tissue Distribution; D001743:Urinary Bladder / Q000378:metabolism; D014915:Whole-Body Counting / Q000379:methods*
D009942:Organometallic Compounds; C101598:rhenium-186 HEDP; D012211:Rhenium; D012968:Etidronic Acid