Implications of the uptake of 131I-radiolabelled meta-iodobenzylguanidine (mIBG) for the targeted radiotherapy of neuroblastoma.
Selective uptake of radiolabelled meta-iodobenzylguanidine (mIBG) in neuroblastoma provides a possible approach to biologically targeted radiotherapy of this disease. A mathematical model was used to predict absorbed doses to tumours of varying size from therapeutic 131I-mIBG, based on measurements of 125I-mIBG uptake in surgically excised tumours from six patients. Two size categories of tumour target were considered: bulk tumour and microscopic disease. The predicted absorbed doses were compared with doses calculated to achieve a 50% probability of tumour cure. The analysis shows that the probability of tumour cure depends strongly on mIBG uptake, effective half-life of mIBG in tumour and tumour diameter. Small microtumours may be relatively resistant to mIBG treatment owing to the limited absorption of 131I beta-energy. The product of patient mass and percentage uptake per unit mass of tumour may be a useful indicator of therapeutic outcome when targeted radiotherapy is used for the treatment of paediatric tumours.
O'Donoghue
J A
JA
Beatson Oncology Centre, Belvidere Hospital, Glasgow, UK.
Wheldon
T E
TE
Babich
J W
JW
Moyes
J S
JS
Barrett
A
A
Meller
S T
ST
D019797:3-Iodobenzylguanidine; D002648:Child; D003287:Contrast Media / Q000493:pharmacokinetics*; D006207:Half-Life; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics* / Q000627:therapeutic use; D007462:Iodobenzenes / Q000493:pharmacokinetics* / Q000627:therapeutic use; D008433:Mathematics; D008954:Models, Biological; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage
D003287:Contrast Media; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D019797:3-Iodobenzylguanidine