Autoradiography-based, three-dimensional calculation of dose rate for murine, human-tumor xenografts.
A Fast Fourier Transform method for calculating the three-dimensional dose rate distribution for murine, human-tumor xenografts is outlined. The required input includes evenly-spaced activity slices which span the tumor. Numerical values in these slices are determined by quantitative 125I autoradiography. For the absorbed dose-rate calculation, we assume the activity from both 131I- and 90Y-labeled radiopharmaceuticals would be distributed as is measured with the 125I label. Two example cases are presented: an ovarian-carcinoma xenograft with an IgG 2ak monoclonal antibody and a neuroblastoma xenograft with meta-iodobenzylguanidine (MIBG). Considering all the volume elements in a tumor, we show, by comparison of histograms and also relative standard deviations, that the measured 125I activity and the calculated 131I dose-rate distributions, are similarly non-uniform and that they are more non-uniform than the calculated 90Y dose-rate distribution. However, the maximum-to-minimum ratio, another measure of non-uniformity, decreases by roughly an order of magnitude from one distribution to the next in the order given above.
Koral
K F
KF
Division of Nuclear Medicine, University of Michigan Medical Center, Ann Arbor 48109.
Kwok
C S
CS
Yang
F E
FE
Brown
R S
RS
Sisson
J C
JC
Wahl
R L
RL
D000818:Animals; D001345:Autoradiography; D004305:Dose-Response Relationship, Drug; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009447:Neuroblastoma / Q000532:radiotherapy*; D010051:Ovarian Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D014183:Transplantation, Heterologous
D007457:Iodine Radioisotopes