title: High-resolution positron emission tomography of human ovarian cancer in nude rats using 124I-labeled monoclonal antibodies.
abstract: PET has inherently high resolution and excellent contrast imaging and accurately measures radioactivity concentrations in vivo. When combined with specific immunological targeting it might provide a highly specific and sensitive radioimmunoscintigraphic tool. To investigate this we injected 124I-labeled MAb MX35 or MAb MH99 monoclonal antibodies (doses 200-400 mu Ci) intravenously into nude rats bearing subcutaneous human ovarian cancer xenografts (SK-OV-7 and SK-OV-3 cell lines). A melanoma cell line (SK-MEL-30) was used as a control tumor. These murine monoclonal antibodies react with cell-surface antigens expressed by most ovarian cancer cells, including the ovarian cell line used. Imaging was performed at 1-6 days using a high-resolution positron emission tomograph (PCR-I) with a spatial resolution of 4.5 mm. The slice thicknesses were 0.5 and 1.0 cm. Forty to seventy thousand coincident pulses were obtained per frame. The PET results were compared with those of autopsy and histology. Samples of blood, tumor, and normal tissues were obtained at various time points. PET calculation of isotope uptake ratios demonstrated specific localization of the antibodies in tumor, with ratios of tumor to normal tissue uptake as high as 6:1. Subcutaneous ovarian cancer nodules as small as 7 mm were identified with PET imaging. The results corresponded well with tissue sampling. Our findings suggest that PET imaging of tumors with 124I-labeled monoclonal antibodies may be useful in human diagnostic and therapeutic applications in ovarian cancer as well as other diseases.
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY.
authors.forename: S C
authors.initials: SC
authors.lastname: Rubin
authors.forename: K J
authors.initials: KJ
authors.lastname: Kairemo
authors.forename: A L
authors.initials: AL
authors.lastname: Brownell
authors.forename: F
authors.initials: F
authors.lastname: Daghighian
authors.forename: M G
authors.initials: MG
authors.lastname: Federici
authors.forename: K S
authors.initials: KS
authors.lastname: Pentlow
authors.forename: R D
authors.initials: RD
authors.lastname: Finn
authors.forename: R M
authors.initials: RM
authors.lastname: Lambrecht
authors.forename: W J
authors.initials: WJ
authors.lastname: Hoskins
authors.forename: J L
authors.initials: JL
authors.lastname: Lewis
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D009368:Neoplasm Transplantation; D010051:Ovarian Neoplasms / Q000000981:diagnostic imaging*; D016719:Radioimmunodetection; D051381:Rats; D011923:Rats, Nude; D014055:Tomography, Emission-Computed / Q000379:methods*
chemical_list: D007457:Iodine Radioisotopes