Clinical considerations for using PET/CT in Radiation Therapy

2647 Objectives PET/CT imaging is being increasingly used in radiation therapy planning. There are several considerations when expanding PET/CT to offer these services. The objective of this work is to discuss fundamental concepts on developing departmental PET/CT service lines and collaborations between radiology and radiation oncology (RO). Methods A review of PET/CT imaging services used to support RO was performed. Each service was assessed to determine all critical hardware and staffing for RO support. Additionally, collaborations between departments were assessed and key items isolated as critical information before beginning such collaborations. Results Following PET/CT RO service analysis, three major categories of requirements were identified to properly support RO workflows. Equipment A number of key pieces of PET/CT equipment are needed to be able to accommodate radiation therapy planning workflows and include the following. • Contrast Injector: Most radiation therapy CT studies require the use of contrast for optimal planning images. An autoinjector improves accuracy and efficiency when delivering contrast for these studies. • External lasers: External alignment lasers are critical for proper support of RO PET/CT services. These lasers provide critical position information that enables accurate repositioning of patients during imaging and therapy. • Flat radiation pallet: A flat pallet that fits the PET/CT bed structure is critical. Typical PET/CT beds are rounded for comfort but result in patient positions that are difficult to repeat and deform organ structures in the body. Flat pallets can be uncomfortable so an RO department approved thin cushion for the table is recommended to maintain patient comfort. Scheduling • Radiation therapy should have dedicated time slots on the daily PET/CT schedule that are only used for scheduling therapy patients. When adjusting the PET schedule for these slots take into consideration the time that may be required for patient prep and mask molding. Communication • Interdepartmental communication with all staff is critical for the success of supporting RO with radiology services PET/CT. • RO, radiology, and referring physician communication during tumor boards can be critical in best setting up advanced PET/CT workflows for radiation therapy patients. With appropriate equipment and communication channels in place, it is possible to support RO with a number of workflows. • PET/CT Whole-body(WB) imaging: Used for routine follow-up and assessment of disease progression • CT radiation therapy planning studies: Used primarily for initial therapy planning • CT and or PET radiation planning using 4D gating: Used to provide an accurate assessment of motion that could impact the therapy plan. In addition, use of phase-matched PET/CT can provide key information on anatomical and functional images during respiratory motion. • Combined PET/CT WB and CT RO Therapy planning: Used for initial planning. The addition of PET with a standard CT radiation therapy planning can aid in drawing more accurate isocontours. At our facility, we have worked with oncologists and radiation Oncologists to promote ordering the PET/CT and rad therapy CT on the same day. This allowed for two scans that are normally done on separate days to be acquired in one day and on one scanner (Figure 1). Conclusions There are three major categories to consider when starting collaboration with the RO department including equipment, scheduling, and communication. With these areas in place there are many new services that can be offered. All of these services can help build strong clinical collaborations and strengthen the PET/CT business while also improving the quality of patient care.