Iodine-131-Metaiodobenzylguanidine Dosimetry in Cancer Therapy: Risk Versus Benefit

• Published in: The Journal of nuclear medicine (1978) Vol. 37; no. 6; p. 1058
• Main Authors: Tristam, Maria, Alaamer, Abdulaziz S, Fleming, John S, Lewington, Valerie J, Zivanovic, Maureen A
• Format: Journal Article
• Language: English
• Published: United States Soc Nuclear Med 01.06.1996; Society of Nuclear Medicine
• Subjects: 3-Iodobenzylguanidine; Adolescent; Adult; Antineoplastic Agents - administration & dosage; Antineoplastic Agents - adverse effects; Antineoplastic Agents - therapeutic use; Child; Humans; Iodine Radioisotopes - administration & dosage; Iodine Radioisotopes - adverse effects; Iodine Radioisotopes - therapeutic use; Iodobenzenes - administration & dosage; Iodobenzenes - adverse effects; Iodobenzenes - therapeutic use; Neuroblastoma - diagnostic imaging; Neuroblastoma - radiotherapy; Pheochromocytoma - diagnostic imaging; Pheochromocytoma - radiotherapy; Radiotherapy Dosage; Risk; Tomography, Emission-Computed, Single-Photon
• ISSN: 0161-5505; 1535-5667

In the treatment of neural crest tumors, such as pheochromocytoma, with[131I]MIBG, bone marrow toxicity limits the amount of administered activity and, thus, a therapeutically useful tumor dose. We calculated tumor doses in a series of diagnostic studies with [123I]MIBG using accurate quantification of SPECT and planar scintigraphy. By extrapolating diagnostic results to therapeutic activities of [131I]MIBG, we could compare the results with whole-body doses from a series of therapies. The tumor dose was DT = 2.2 mGy MBq(-1) (median value of 27 measurements, range 0.04 < or = DT < or = 20 mGy MBq(-1) and the whole-body dose in a series of 16 patients undergoing 50 therapies was DWB = 0.12 +/- 0.04 mGy MBq(-1) (mean +/- s.d.). The therapeutic ratio varied between 130 to below 10 in some patients. The results were compared with published data. We found clearly skewed distribution of tumor doses, with a majority of tumors receiving only a few mGy per MBq administered activity. In some patients, however, doses did reach 20 mGy MBq(-1).