Program Information
Dose Escalation to Biological Tumor Volumes of Prostate Cancer Patients Using Gold Nanoparticles
M Jermoumi1,2*, E Sajo1, K Houari2 , W Ngwa1,2 (1)Department of Physics and Applied Physics,Medical Physics Program, University of Massachusetts Lowell (2)Department of Radiation Oncology, Dana Farber Cancer Insitute, Brigham and Women's Hospital, Harvard Medical, Boston, MA
Presentations
TU-G-CAMPUS-T-15 (Tuesday, July 14, 2015) 5:30 PM - 6:00 PM Room: Exhibit Hall
Purpose: Studies have shown that radiation boosting could help reduce prostate cancer (PCa) recurrence. Biological tumor volumes (BTV) are a high priority for such radiation boosting. The purpose of this study is to investigate the potential of radiation boosting of real patient BTVs using gold nanoparticles (GNP) released from gold-loaded brachytherapy spacers (GBS) during brachytherapy.
Methods: The BTVs of 12 patients having prostate adenocarcinoma identified with positron emission tomography (PET) and CT scanner using C-11 labeled tracer [11C]acetate were investigated. The initial GNP concentration and time to achieve a dose enhancement effect (DEF) of 2 was simulated using the freely downloadable software RAID APP. The investigations were carried out for low dose rate (LDR) brachytherapy sources (BTS) described in AAPM Task Group report 43: Cs-131, I-125, and Pd-103. In first case, we used 7 mg/g and 18 mg/g of GNP initial concentrations to estimate the time needed for released GNP to achieve a DEF of 2 for the different BTS, and compare with clinically relevant treatment times. In second case, we calculated the initial concentration of GNPs needed to achieve a DEF of 2 during the time the BTS would typically deliver 50%, 70% and 90% of the total dose.
Results: For an initial concentration of 18 mg/g, when using Cs-131, and Pd-103, a DEF of 2 could only be achieved for BTV of 3.3 cm3 and 1 cm3 respectively. Meanwhile a DEF of 2 could be achieved for all 12 BTVs when using I-125. To achieve a DEF of 2 for all patients using Cs-131 and Pd-103, much higher initial concentrations would have to be used than have been typically employed in pre-clinical studies.
Conclusion: The I-125 is the most viable BTS that can be employed with GBS to guide dose painting treatment planning for localized PCa.
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