| Abstract | PURPOSE: The aim of this study was to analyze the effect therapeutic injections of (177)Lu-DOTA(0)-Tyr(3)]-octreotate (DOTATATE) had on the tumor uptake of a subsequent injection with (111)In-DOTATATE in GOT1-bearing nude mice. METHODS AND MATERIALS: Nude mice, xenografted with the human midgut carcinoid, GOT1, were first intravenously injected with a curative (30 MBq) or a suboptimal (7.5 MBq) amount of (177)Lu-DOTATATE. At various intervals thereafter (4-13 days), a second injection with (111)In-DOTATATE (0.5 MBq) was given. One (1) day after the second injection, the animals were sacrificed, tumor tissues collected, the tumor (111)In and (177)Lu activity concentration determined, and tumor regression/cell density was recorded. RESULTS: In animals given curative amounts, the uptake of (111)In was lower than in untreated animals. On the other hand, a second late injection (3-13 days) after suboptimal amounts resulted in a twofold higher tumor activity concentration versus untreated animals. When the uptake of the curative injection was corrected for tumor cell density, which decreased from 66% to 4% over 2 weeks, an enhanced uptake per tumor cell was observed. The curative and suboptimal amounts resulted in a different uptake and retention of (177)Lu in tumors. The suboptimal amount resulted in a constant activity concentration, while the curative amount resulted in an increased activity concentration over time. CONCLUSIONS: Our results, as presented in this paper, describe how the second injection in a fractionation protocol will be affected by the first therapeutic amount. This new information might be useful in the optimization of radionuclide therapy. |
| Authors | Peter Bernhardt, Jenny Oddstig, Lars Kölby, Ola Nilsson, Håkan Ahlman, Eva Forssell-Aronsson
(Affiliation: Department of Radiation Physics, Sahlgrenska University Hospital, Göteborg, Sweden. peter.bernhardt at radfys.gu.se)
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| Journal | Cancer biotherapy & radiopharmaceuticals
(Cancer Biother Radiopharm)
Vol. 22
Issue 5
Pg. 644-53
(Oct 2007)
ISSN: 1084-9785 United States |
| PMID | 17979567
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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| Chemical References |
- (177lutetium-DOTA(O)Tyr3)octreotate
- 111In-octreotate, DOTA(0)-Tyr(3)-Thr(8)-
- Indium Radioisotopes
- Organometallic Compounds
- Radioisotopes
- Lutetium
- Octreotide
|
| Topics |
- Animals
- Carcinoid Tumor
(metabolism, pathology, radiotherapy)
- Cell Line, Tumor
- Dose-Response Relationship, Radiation
- Humans
- Indium Radioisotopes
(pharmacokinetics)
- Injections, Intravenous
- Lutetium
(analysis, pharmacokinetics)
- Mice
- Mice, Nude
- Octreotide
(administration & dosage, analogs & derivatives, pharmacokinetics)
- Organometallic Compounds
(administration & dosage, pharmacokinetics)
- Radioisotopes
(pharmacokinetics)
- Time Factors
- Tumor Burden
- Xenograft Model Antitumor Assays
|
