SU-E-T-15: A Comparison of COMS and EP917 Eye Plaque Applicators Using Different Radionuclides

Journal Article · Mon Jun 15 04:00:00 EDT 2015 · Medical Physics

DOI:https://doi.org/10.1118/1.4924376· OSTI ID:22545150

Aryal, P; Molloy, JA ^[1]; Rivard, MJ ^[2]

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1. University of Kentucky, Lexington, KY (United States)
2. Tufts University School of Medicine, Boston, MA (United States)

Purpose: To investigate the effect of plaque design and radionuclides on eye plaque dosimetry. Methods: The Monte Carlo N-particle Code version 6 (MCNP6) was used for radiation transport simulations. The 14 mm and 16 mm diameter COMS plaques and the model EP917 plaque were simulated using brachytherapy seeds containing I-125, Pd-103, and Cs-131 radionuclides. The origin was placed at the scleral inner surface. The central axis (CAX) doses of both COMS plaques at −1 mm, 0 mm, 1 mm, 2 mm, 5 mm, 10 mm, 15 mm, 20 mm, and 22.6 mm were compared to the model EP917 plaque. Dose volume histograms (DVHs) were also created for both COMS plaques for the tumor and outer sclera then compared to results for the model EP917 plaque. Results: For all radionuclides, the EP917 plaque delivered higher dose (max 343%) compared to the COMS plaques, except for the 14 mm COMS plaque with Cs-131 at 1 mm and 2 mm depths from outer sclera surface. This could be due to source design. For all radionuclides, the 14 mm COMS plaque delivered higher doses compared to the 16 mm COMS plaque for the depths up to 5 mm. Dose differences were not significant beyond depths of 10 mm due to ocular lateral scatter for the different plaque designs. Tumor DVHs for the 16 mm COMS plaque with Cs-131 provided better dose homogeneity and conformity compared to other COMS plaques with I-125 and Pd-103. Using Pd-103, DVHs for the 16 mm COMS plaque delivered less dose to outer sclera compared to other plaques. Conclusion: This study identified improved tumor homogeneity upon considering radionuclides and plaque designs, and found that scleral dose with the model EP917 plaque was higher than for the 16 mm COMS plaque for all the radionuclides studied.

• OSTI ID: 22545150
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 6 Vol. 42; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
BRACHYTHERAPY
CESIUM 131
DOSIMETRY
EYES
IODINE 125
MONTE CARLO METHOD
NEOPLASMS
PALLADIUM 103
RADIATION DOSES
RADIATION TRANSPORT
SIMULATION