Abstract
505
Objectives Arising immunomodulatory treatment options in lung cancer patients lead to the increased need of small animal studies for the evaluation of therapeutic potential of newly introduces subtances. In order to detect therapy response over time, we evaluated non-invasive dynamic micro-PET and multiphase contrast-enhanced micro-CT for the detection of lymph node metastases in an orthotopic lung cancer model in rats.
Methods 1 x 106 NCI-H460 cells were injected transthoracically into the 5thintercostal space of four Rowett Nude rats (NIH-RNU). Another four animals served as controls. After two weeks of tumour growth, animals underwent multiphase contrast-enhanced micro-CT and dynamic micro-PET. Thereafter, animals were sacrificed for histological analysis.
Results Late phase micro-CT 24 hours after the injection of contrast agent revealed the best possible delineation of lymph node metastases, as compared to earlier scans before, during and 20 minutes after the injection of contrast agent (p < 0.05). By terms of an increased FDG-uptake over time, dynamic micro-PET reliably demarked lymph node metastases in the first 57 minutes after FDG-injection and so enabled for metabolic examinations of the induced lung cancer metastases.
Conclusions The combination of contrast-enhanced micro-CT and dynamic micro-PET seems to allow longitudinal follow-up examinations of small animals, especially helpful for the examination of therapy response during the evaluation of new treatment substances.