Rakumar Venkatramani MD,MS, Abstract Co-Author: Nothing to Disclose

Andrew Phillips BS, Presenter: Nothing to Disclose

Arthur Olch PhD, Abstract Co-Author: Nothing to Disclose

Kenneth Wong MD, Abstract Co-Author: Nothing to Disclose

There has been a greater emphasis on respiratory motion in the treatment of adult malignancies. With the presence of a new PET/CT scanner with respiratory-correlated multislice CT (4D CT) capability, further means to reduce radiation delivered to surrounding normal tissue in pediatric patients became available. We will review the issues and challenges associated with the utilization of 4D CT in pediatric age group.

Since 2009, we have utilized Philips Gemini PET/CT scanner for radiation therapy simulation. We performed 4D CT scans with the respiratory air bellows belt and Mayo respiratory feedback system. The simulations were performed by 2 radiation therapists, 1 medical physicist, and 1 radiation oncologist. Intravenous contrast was often utilized. Around one-third of the scans were performed under sedation. Simulation scans were transferred to the Varian Eclipse treatment planning workstation. Our indications for 4D CT scans include lower thoracic and upper abdominal tumors such as Hodgkins lymphoma with pericardial involvement, selected right adrenal neuroblastomas and bilateral Wilms tumors, which require IMRT for normal tissue sparing and/or dose escalation

We found that utilizing 4D CT scanning reduces motion artifact and reveals the range of motion of the tumor and normal organs. In some cases, margins were significantly refined based on the 4D CT scan. Although the technology seems to have many of the same advantages that are seen with adults, we noticed a few important differences. The impact of 4D CT scan is reduced in children who require sedation, as their diaphragmatic motion is decreased. In addition, in many of the younger patients, the respiratory bellows was too large, preventing us from performing a 4D CT. Breath coaching young children with the Mayo system was not possible. We are exploring the possibility of using the respiratory trace from a Philips Intellivue patient monitor or a real-time 3D surface imaging system rather than the bellows system. In addition, CT dose with 4D CT must be monitored for patient safety.

4D CT may be useful in certain pediatric patients in reducing radiation delivered to normal tissues.  Adaptations have to be made for pediatric patients before wider application of 4D CT in this age group.

Adaptations have to be made for pediatric patients before wider application of 4D CT in this age group.

Venkatramani, R, Phillips, A, Olch, A, Wong, K, Initial Experience with Integration of Respiratory-correlated Multislice CT in a Pediatric Radiation Oncology Department.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034650.html