Encrypted login | home

Program Information

A Feasibility Study of the Use of Hybrid Computational Phantoms for Improved Historical Dose Reconstruction in the Study of Late Radiation Effects for Hodgkin's Lymphoma

H Petroccia

H Petroccia1*, S O'Reilly1 , N Mendenhall2 , Z Li2 , R Slopsema2 , W Bolch1 , (1) J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida,USA (2) Radiation Oncology, University of Florida Proton Therapy Institute, Jacksonville, Florida, USA


SU-E-T-13 Sunday 3:00PM - 6:00PM Room: Exhibit Hall

Purpose: Radiation-induced cancer effects are well-documented following radiotherapy. Further investigation is needed to more accurately determine a dose-response relationship for late radiation effects. Recent dosimetry studies tend to use representative patients (Taylor 2009) or anthropomorphic phantoms (Wirth 2008) for estimating organ mean doses. In this study, we compare hybrid computational phantoms to patient-specific voxel phantoms to test the accuracy of University of Florida Hybrid Phantom Library (UFHP Library) for historical dose reconstructions.

Methods:A cohort of 10 patients with CT images was used to reproduce the data that was collected historically for Hodgkin’s lymphoma patients (i.e. caliper measurements and photographs). Four types of phantoms were generated to show a range of refinement from reference hybrid-computational phantom to patient-specific phantoms. Each patient is matched to a reference phantom from the UFHP Library based on height and weight. The reference phantom is refined in the anterior/posterior direction to create a ‘caliper-scaled phantom’. A photograph is simulated using a surface rendering from segmented CT images. Further refinement in the lateral direction is performed using ratios from a simulated-photograph to create a ‘photograph and caliper-scaled phantom’; breast size and position is visually adjusted. Patient-specific hybrid phantoms, with matched organ volumes, are generated and show the capabilities of the UF Hybrid Phantom Library. Reference, caliper-scaled, photograph and caliper-scaled, and patient-specific hybrid phantoms are compared with patient-specific voxel phantoms to determine the accuracy of the study.

Results:Progression from reference phantom to patient specific hybrid shows good agreement with the patient specific voxel phantoms. Each stage of refinement shows an overall trend of improvement in dose accuracy within the study, which suggests that computational phantoms can show improved accuracy in historical dose estimates.

Conclusion:Computational hybrid phantoms show promise for improved accuracy within retrospective studies when CTs and other x-ray images are not available.

Contact Email: