Program Information
A Preliminary Method of Risk-Informed Optimization of Tube Current Modulation for Dose Reduction in CT
Y Gao1*, T Liu2 , X Li3 , B Liu4 , M Kalra5 , P Caracappa6 , X Xu7 , (1) Rensselaer Polytechnic Institute, Troy, NY, (2) ,,,(3) Massachusetts General Hospital, Boston, MA,(4) ,,, (5) ,,, (6) Rensselaer Polytechnic Institute, Troy, NY, (7) Rensselaer Polytechnic Inst., Troy, NY
Presentations
TU-EF-204-9 (Tuesday, July 14, 2015) 1:45 PM - 3:45 PM Room: 204
Purpose: X-rays from CT scans can increase cancer risk to patients. Lifetime Attributable Risk of Cancer Incidence for adult patients has been investigated and shown to decrease as patient age. However, a new risk model shows an increasing risk trend for several radiosensitive organs for middle age patients. This study investigates the feasibility of a general method for optimizing tube current modulation (TCM) functions to minimize risk by reducing radiation dose to radiosensitive organs of patients.
Methods: Organ-based TCM has been investigated in literature for eye lens dose and breast dose. Adopting the concept in organ-based TCM, this study seeks to find an optimized tube current for minimal total risk to breasts and lungs by reducing dose to these organs. The contributions of each CT view to organ dose are determined through simulations of CT scan view-by-view using a GPU-based fast Monte Carlo code, ARCHER. A Linear Programming problem is established for tube current optimization, with Monte Carlo results as weighting factors at each view. A pre-determined dose is used as upper dose boundary, and tube current of each view is optimized to minimize the total risk.
Results: An optimized tube current is found to minimize the total risk of lungs and breasts: compared to fixed current, the risk is reduced by 13%, with breast dose reduced by 38% and lung dose reduced by 7%. The average tube current is maintained during optimization to maintain image quality. In addition, dose to other organs in chest region is slightly affected, with relative change in dose smaller than 10%.
Conclusion: Optimized tube current plans can be generated to minimize cancer risk to lungs and breasts while maintaining image quality. In the future, various risk models and greater number of projections per rotation will be simulated on phantoms of different gender and age.
Funding Support, Disclosures, and Conflict of Interest: National Institutes of Health R01EB015478
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