Encrypted login | home

Program Information

Investigation of Beta-Emitter 90Sr-90Y Dose Distribution Using Gafchromic EBT3 Film for Application On Conformal Skin Brachytherapy Device

C Ferreira

C Ferreira1*, D Johnson1, K Rasmussen2, S Ahmad1 , J Jung3 , (1) University of Oklahoma Health Sciences Center, Oklahoma City, OK, (2) University of Texas HSC SA, San Antonio, TX, (3) East Carolina University Greenville, NC


SU-G-201-12 (Sunday, July 31, 2016) 4:00 PM - 6:00 PM Room: 201

Purpose: To investigate ⁹⁰Sr-⁹⁰Y as a high dose rate (HDR) source for application in a conformal skin brachytherapy (CSBT) device. The CSBT device has been previously developed to provide patient specific treatment for small inoperable lesions and irregular surfaces.

Methods: A popular beta emitter, ⁹⁰Sr-⁹⁰Y was tested for feasibility in a CSBT device. A 1 cm diameter plaque was used to deliver dose to a solid water phantom containing EBT3 Gafchromic films arranged at the surface and perpendicular to it. Additionally, a 1 cm diameter 6 MeV electron beam was used to irradiate EBT3 film at 100 cm SSD with a 0.5 cm bolus. Films were digitized with an Epson Expression 10000 XL scanner and calibrated with a 6 MeV electron specific dose curve. Normalized percent depth doses (PDD) and dose profiles for both techniques were analyzed using ImageJ.

Results: Dose distributions achieved with the ⁹⁰Sr-⁹⁰Y sources were compared with those of external electron beam radiation therapy (EBRT). Penumbra (20%-80%) for EBRT and 90Sr-90Y were 4.3 mm and 1.6 mm, respectively. PDD values of 50% (normalized to 2 mm) were 10.1 mm and 2.8 mm for electron and ⁹⁰Sr-⁹⁰Y, respectively. Flatness (80% of the central beam profile) was 14.1% at a 5 mm depth for EBRT and 4.0% at surface for the ⁹⁰Sr-⁹⁰Y.

Conclusion: As expected, the PDDs of ⁹⁰Sr-⁹⁰Y in water are shallower than that of external electron beams for the same field size. ⁹⁰Sr-⁹⁰Y can be used in CSBT to provide patient specific treatment where shallower depth doses than that provided by electron external beams may be required: e.g. eyelids, nose, lips, ears, etc. The customizability of EBRT could be replicated by using multiple adjacent ⁹⁰Sr-⁹⁰Y plaque placements.

Contact Email: