SPECT quantitation of iodine-131 concentration in phantoms and human tumors.
The validity of SPECT measurement of iodine-131 (131I) concentration was tested in vitro in phantoms and in vivo by measuring bladder urine concentrations. Phantom studies comparing known and SPECT measured concentrations showed a good correlation for 131I (r = 0.98, s.e.e. = 20.94 counts/voxel) for phantoms of 25 to 127 cc and concentrations of 0.13 to 9.5 microCi/cc. The in vivo, in vitro correlation of 131I concentrations in the urine was also good (r = 0.98, s.e.e. = 0.677 microCi/cc). Quantitative SPECT was used to calculate the effective half-life and dosimetry of radioiodine in 12 sites of thyroid carcinoma in seven patients. SPECT was also used to determine the dosimetry of [131I]MIBG (metaiodobenzylguanidine) in two patients with carcinoid, two with neuroblastoma, and one with pheochromocytoma. The radiation dose for thyroid carcinoma metastases varied between 6.3 and 276.9 rad/mCi. The dose from MIBG varied between 13.4 and 57.8 rad/mCi. These results indicate the validity of quantitative SPECT for in vivo measurement of 131I and the need to measure the concentration of 131I in individual human tumor sites.
Israel
O
O
Department of Nuclear Medicine, Rambam Medical Center, Haifa, Israel.
Iosilevsky
G
G
Front
D
D
Bettman
L
L
Frenkel
A
A
Ish-Shalom
S
S
Steiner
M
M
Ben-Harush
M
M
Kolodny
G M
GM
D019797:3-Iodobenzylguanidine; D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000378:metabolism; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000378:metabolism / Q000556:secondary; D002276:Carcinoid Tumor / Q000378:metabolism / Q000532:radiotherapy; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007462:Iodobenzenes / Q000493:pharmacokinetics; D008113:Liver Neoplasms / Q000378:metabolism / Q000556:secondary; D008175:Lung Neoplasms / Q000378:metabolism / Q000556:secondary; D008297:Male; D008875:Middle Aged; D008961:Models, Structural; D009369:Neoplasms / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism; D010673:Pheochromocytoma / Q000378:metabolism; D011879:Radiotherapy Dosage; D015899:Tomography, Emission-Computed, Single-Photon
D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D019797:3-Iodobenzylguanidine