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Pretargeted immuno-PET of CEA-expressing intraperitoneal human colonic tumor xenografts: a new sensitive detection method.

Schoffelen R, van der Graaf WT, Sharkey RM, Franssen GM, McBride WJ, Chang CH, Laverman P, Goldenberg DM, Oyen WJ, Boerman OC - EJNMMI Res (2012)

Bottom Line: One hour after the radiolabeled peptide or FDG was given, micro-PET/computed tomography images were acquired.Thereafter, the uptake of the 68Ga or 18F in dissected tissue was determined.Pretargeted immuno-PET with bsmAb and a 68Ga-labeled peptide could be a very sensitive imaging method for imaging colonic cancer, disclosing occult lesions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dept, of Nuclear Medicine, Radboud University Nijmegen Medical Centre, 6500 HB, Nijmegen, 9101, The Netherlands. r.schoffelen@nucmed.umcn.nl.

ABSTRACT

Background: In this study, pretargeted immuno-positron-emission tomography [PET] with a bispecific monoclonal anti-carcinoembryonic antigen [CEA] (CEACAM5) × anti-hapten antibody (bispecific monoclonal antibody [bsmAb]) and a small (1.5 kD) peptide labeled with 68Ga was compared to fludeoxyglucose [18F-FDG]-PET for detecting intraperitoneal [i.p.] CEA-expressing human colonic tumor xenografts in nude mice.

Methods: Two groups of female BALB/c nude mice were inoculated with LS174T human colonic tumor cells i.p. One group received 5 MBq 18F-FDG, and the other received intravenous injections of the bsmAb, followed 16 h later with 5 MBq of 68Ga-labeled peptide. One hour after the radiolabeled peptide or FDG was given, micro-PET/computed tomography images were acquired. Thereafter, the uptake of the 68Ga or 18F in dissected tissue was determined.

Results: Within 1 h, high uptake of the 68Ga-labeled peptide in the tumor lesions (23.4 ± 7.2% ID/g) and low background activity levels were observed (e.g., tumor-to-intestine ratio, 58 ± 22). This resulted in a clear visualization of all intra-abdominal tumor lesions ≥ 10 μL and even some tumors as small as 5 μL (2 mm diameter). 18F-FDG efficiently localized in the tumors (8.7 ± 3.1% ID/g) but also showed physiological uptake in various normal tissues (e.g., tumor-to-intestine ratio, 3.9 ± 1.1).

Conclusions: Pretargeted immuno-PET with bsmAb and a 68Ga-labeled peptide could be a very sensitive imaging method for imaging colonic cancer, disclosing occult lesions.

No MeSH data available.


Related in: MedlinePlus

Biodistribution. (a) 6.0 nmol 125I-TF2 (0.37 MBq) and 0.25 nmol 68Ga-IMP288 (5 MBq) 1 h after i.v. injection of 68Ga-IMP288 in BALB/c nude mice with intraperitoneal CEA-expressing LS174T tumors. (b) 0.25 nmol 68Ga-IMP288 (5 MBq) and 18F-FDG (5 MBq) 1 h after i.v. injection in the BALB/c nude mice with intraperitoneal CEA-expressing LS174T tumors. Values are given as means ± standard deviation (n = 5).
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Figure 1: Biodistribution. (a) 6.0 nmol 125I-TF2 (0.37 MBq) and 0.25 nmol 68Ga-IMP288 (5 MBq) 1 h after i.v. injection of 68Ga-IMP288 in BALB/c nude mice with intraperitoneal CEA-expressing LS174T tumors. (b) 0.25 nmol 68Ga-IMP288 (5 MBq) and 18F-FDG (5 MBq) 1 h after i.v. injection in the BALB/c nude mice with intraperitoneal CEA-expressing LS174T tumors. Values are given as means ± standard deviation (n = 5).

Mentions: The biodistribution of 125I-TF2 and 68Ga-IMP288 in the mice is shown in Figure 1a. High uptake of the bsmAb (3.73 ± 1.2% ID/g) and peptide (23.4 ± 7.2% ID/g) in the tumor lesions was observed with very low accretion in the normal organs. This resulted in high tumor-to-normal-tissue ratios of 68Ga-IMP288 (e.g., tumor-to-intestine ratio, 58 ± 22; tumor-to-liver ratio, 15 ± 3).


Pretargeted immuno-PET of CEA-expressing intraperitoneal human colonic tumor xenografts: a new sensitive detection method.

Schoffelen R, van der Graaf WT, Sharkey RM, Franssen GM, McBride WJ, Chang CH, Laverman P, Goldenberg DM, Oyen WJ, Boerman OC - EJNMMI Res (2012)

Biodistribution. (a) 6.0 nmol 125I-TF2 (0.37 MBq) and 0.25 nmol 68Ga-IMP288 (5 MBq) 1 h after i.v. injection of 68Ga-IMP288 in BALB/c nude mice with intraperitoneal CEA-expressing LS174T tumors. (b) 0.25 nmol 68Ga-IMP288 (5 MBq) and 18F-FDG (5 MBq) 1 h after i.v. injection in the BALB/c nude mice with intraperitoneal CEA-expressing LS174T tumors. Values are given as means ± standard deviation (n = 5).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3298693&req=5

Figure 1: Biodistribution. (a) 6.0 nmol 125I-TF2 (0.37 MBq) and 0.25 nmol 68Ga-IMP288 (5 MBq) 1 h after i.v. injection of 68Ga-IMP288 in BALB/c nude mice with intraperitoneal CEA-expressing LS174T tumors. (b) 0.25 nmol 68Ga-IMP288 (5 MBq) and 18F-FDG (5 MBq) 1 h after i.v. injection in the BALB/c nude mice with intraperitoneal CEA-expressing LS174T tumors. Values are given as means ± standard deviation (n = 5).
Mentions: The biodistribution of 125I-TF2 and 68Ga-IMP288 in the mice is shown in Figure 1a. High uptake of the bsmAb (3.73 ± 1.2% ID/g) and peptide (23.4 ± 7.2% ID/g) in the tumor lesions was observed with very low accretion in the normal organs. This resulted in high tumor-to-normal-tissue ratios of 68Ga-IMP288 (e.g., tumor-to-intestine ratio, 58 ± 22; tumor-to-liver ratio, 15 ± 3).

Bottom Line: One hour after the radiolabeled peptide or FDG was given, micro-PET/computed tomography images were acquired.Thereafter, the uptake of the 68Ga or 18F in dissected tissue was determined.Pretargeted immuno-PET with bsmAb and a 68Ga-labeled peptide could be a very sensitive imaging method for imaging colonic cancer, disclosing occult lesions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dept, of Nuclear Medicine, Radboud University Nijmegen Medical Centre, 6500 HB, Nijmegen, 9101, The Netherlands. r.schoffelen@nucmed.umcn.nl.

ABSTRACT

Background: In this study, pretargeted immuno-positron-emission tomography [PET] with a bispecific monoclonal anti-carcinoembryonic antigen [CEA] (CEACAM5) × anti-hapten antibody (bispecific monoclonal antibody [bsmAb]) and a small (1.5 kD) peptide labeled with 68Ga was compared to fludeoxyglucose [18F-FDG]-PET for detecting intraperitoneal [i.p.] CEA-expressing human colonic tumor xenografts in nude mice.

Methods: Two groups of female BALB/c nude mice were inoculated with LS174T human colonic tumor cells i.p. One group received 5 MBq 18F-FDG, and the other received intravenous injections of the bsmAb, followed 16 h later with 5 MBq of 68Ga-labeled peptide. One hour after the radiolabeled peptide or FDG was given, micro-PET/computed tomography images were acquired. Thereafter, the uptake of the 68Ga or 18F in dissected tissue was determined.

Results: Within 1 h, high uptake of the 68Ga-labeled peptide in the tumor lesions (23.4 ± 7.2% ID/g) and low background activity levels were observed (e.g., tumor-to-intestine ratio, 58 ± 22). This resulted in a clear visualization of all intra-abdominal tumor lesions ≥ 10 μL and even some tumors as small as 5 μL (2 mm diameter). 18F-FDG efficiently localized in the tumors (8.7 ± 3.1% ID/g) but also showed physiological uptake in various normal tissues (e.g., tumor-to-intestine ratio, 3.9 ± 1.1).

Conclusions: Pretargeted immuno-PET with bsmAb and a 68Ga-labeled peptide could be a very sensitive imaging method for imaging colonic cancer, disclosing occult lesions.

No MeSH data available.


Related in: MedlinePlus