H Jung*, S Kim, Virginia Commonwealth University, Richmond, VA

• 
  H Jung

• 
  
• 
  
• 
  
• 
  
• 
  
• 
  
• 
  

PO-GePV-T-278 (Sunday, 7/25/2021)   [Eastern Time (GMT-4)]

Purpose: To implement TBI-VMAT, we developed a technology that can obtain 3D whole-body information using both CT and 3D optical surface imaging and bring it to a treatment planning system (TPS).

Methods: This process consists of 5 steps. Step1: Take a CT scan, only the upper body (i.e., head to pelvis). Step2: Take a surface image for the lower body using a handheld 3D scanner while keeping the same position as CT scanning. At this time, reference markers are placed on the body surface and that part of the body is overlapped in both image sets for proper alignment later. Step3: Convert the surface image to the “.stl” format to get the lower body outline. Step4: Expand the field-of-view of the CT image and assign a density equivalent to air. Merge both the expanded CT and the lower body outline utilizing the overlapped area and markers. Then it is saved as a new CT DICOM set. Step5: Import the new DICOM set to the TPS (Eclipse) and assign water density inside the lower body. Finally, organ-at-risk structures in the upper body including the pelvis are delineated. The feasibility of the proposed method was tested using a Rando phantom and a cost-effective Structure Sensor 3D scanner (Occipital, Inc., USA).

Results: Image registration accuracy between CT and the 3D surface image was within 3 mm on average. The time required for surface imaging was about 5 minutes. The process of image alignment and registration took about 30 minutes. A treatment plan with homogeneous dose distribution in the whole body while effectively reducing the dose to normal organs was successfully obtained without compensators/shields.

Conclusion: It was demonstrated that a whole-body image set for modern TBI treatment planning could be obtained in a single setup by using both CT and 3D surface imaging.

ePosters

Keywords

Not Applicable / None Entered.

Taxonomy

Not Applicable / None Entered.

Contact Email