Integrated Small Animal PET/CT/RT with Onboard PET/CT Image Guidance for Preclinical Radiation Oncology Research

We have integrated a compact and lightweight PET with an existing CT image-guided small animal irradiator to enable practical onboard PET/CT image-guided preclinical radiation therapy (RT) research. The PET with a stationary and full-ring detectors has similar to 1.1 mm uniform spatial resolution over its imaging field-of-view of 8.0 cm diameter and 3.5 cm axial length and was mechanically installed inside the irradiator in a tandem configuration with CT and radiation unit. A common animal bed was used for acquiring sequential dual functional and anatomical images with independent PET and CT control and acquisition systems. The reconstructed dual images were co-registered based on standard multi-modality image calibration and registration processes. Phantom studies were conducted to evaluate the integrated system and dual imaging performance. The measured mean PET/CT image registration error was similar to 0.3 mm. With one-bed and three-bed acquisitions, initial tumor focused and whole-body [F-18]FDG animal images were acquired to test the capability of onboard PET/CT image guidance for preclinical RT research. Overall, the results have shown that integrated PET/CT/RT can provide advantageous and practical onboard PET/CT image to significantly enhance the accuracy of tumor delineation and radiation targeting that should enhance the existing and enable new and potentially breakthrough preclinical RT research and applications.

Automated summary

We integrated a compact and lightweight PET with an existing CT image-guided small animal irradiator for practical onboard PET/CT image-guided preclinical radiation therapy research. The integrated system showed a mean PET/CT image registration error of approximately 0.3 mm. The results demonstrated that integrated PET/CT/RT can significantly enhance the accuracy of tumor delineation and radiation targeting, enabling breakthrough preclinical RT research and applications.