Program Information
Comparisons of Imaging Dose Between Two Types of LINAC KV CBCT Systems (Elekta Synergy Versus Varian Trilogy) and Two Types of CT Simulators (GE Light-Speed Versus Philips Brilliance)
R He1*, W Duggar2 , J Stanford3 , B Morris4 , A Markovich5 , J Lu6 , N Thorne7 , C Yang8 , (1) University of Mississippi Med. Center, Ridgeland, MS, (2) University of Mississippi Med. Center, Jackson, MS, (3) University of Mississippi Med. Center, Jackson, MS, (4) University of Mississippi Medical Center, Jackson, MS, (5) University of Mississippi Medical Center, Jackson, MS, (6) University of Mississippi Medical Center, Jackson, MS, (7) University of Mississippi Med. Center, Jackson, MS, (8) University of Mississippi Med. Center, Jackson, MS
Presentations
SU-I-GPD-J-10 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: Image-guided radiation therapy (IGRT) plays an important role in the accurate delivery of highly conformed dose to target in radiotherapy. However, x-ray imaging procedures in both computed tomography (CT) simulation and image guidance add radiation dose to patients, which may pose an increased risk to patients. In our institution, the Varian Trilogy cone beam CT (CBCT) and Elekta Synergy X-ray volumetric imaging system (XVI), along with GE light-speed and Philips Brilliance CT simulators are applied in the cancer treatment. This study is to evaluate the imaging doses from different imaging modalities and devices.
Methods: The imaging dose is measured using a CT dose index (CTDI) phantom and Unfors Xi pencil ionization chamber for both peripheral and central locations. The measurements are performed and compared between Varian Trilogy kV 3D CBCT and Elekta Synergy 3D kV XVI based on our clinical protocols for pelvis with a comparable image quality. Additionally, the 4D and 3D XVI imaging doses are measured and compared on Elekta Synergy. The CT imaging doses are measured and compared between GE light-speed RT16 and Philips Brilliance 16-slice CT simulators.
Results: The results show that the kV CBCT imaging dose is lower for Elekta Synergy compared to Varian Trilogy and the 4D XVI imaging dose is higher at the top peripheral location of the CTDI phantom compared to 3D XVI for Elekta Synergy. Furthermore, GE light-speed CT adds higher imaging doses for both 3D and 4D image modalities compared to Philips Brilliance counterparts.
Conclusion: Significant imaging dose differences were determined between different imaging modalities by using the CTDI method in this study. Although it is very difficult to evaluate the radiation risk from imaging dose to patients, it is worthwhile to monitor imaging dose in radiotherapy, which should be optimized and minimized as low as reasonably achievable.
Contact Email: