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Comparison Between COMS Plaques and Personalized 3D Printed 103Pd-Loaded Plaques with Dose Modulations for Ocular Melanomas

Y Ma1*, T Lescot2, M Fortin3, L Beaulieu4, (1) CHU de Quebec, Quebec, QC, CA, (2) CHUQ-Hospital St Francis d'Assise, Quebec, QC, CA, (3) CHUQ-Hospital St Francis d'Assise, Quebec, QC, CA, (4) Centre Hospitalier Univ de Quebec, Quebec, QC, CA

Presentations

(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Purpose:
To investigate the dosimetric advantages of 3D printed ¹°³Pd-emissive eye plaques over the currently used Cooperative Ocular Melanoma Study (COMS) plaques in the brachytherapy treatments for intraocular tumors.

Methods:
The 3D printed eye plaques proposed in this study consist of a back, printed with gold alloy, and an insert, printed with polyether ether ketone (PEEK) mixed with the radioactive ¹°³Pd loaded nanoparticle. Three intraocular melanoma test cases were proposed based on clinical data showing different tumor geometries: 1) a medium sized dome-shaped tumor, 2) a thick mushroom-shaped tumor and 3) an asymmetric bean-shaped tumor. For each test case, the COMS 18mm eye plaque full loaded with 21 Amersham Oncoseed model 6711 ¹²5I seeds is simulated to serve as benchmark data. The 3D printed plaques are properly positioned. The distribution of ¹°³Pd in the printed insert is planned such that the 100% isodose lines cover the tumor. The Monte Carlo code used this study is ALGEBRA (a Geant4 application in brachytherapy).

Results:
Before comparison, the resultant dose distributions of 3D printed and COMS eye plaques were such normalized such that the 100% isodose line covers completely the gross tumor volume. For the three tumor geometries, the 100% isodose lines wrap the gross target volume (GTV) more tightly. For most voxels in GTV, for the three cases, the 3D printing technique results in >1.2 times of dose than the COMS technique. For the voxels outside GTV, the 3D printing technique results in lower doses ranging from 0.9 down to about 0.3.

Conclusion:
The 3D printed eye plaques demonstrate favorable dose distributions for three different tumor geometries. This technique is able to better escalate dose to GTV and better spare the sclera, optical nerves, etc. than currently used COMS plaques. Based on this technique, personalized brachytherapy becomes possible.

Download ePoster [PDF]

Keywords

Eye Plaques, Pd-103, Monte Carlo

Taxonomy

TH- Brachytherapy: Development (new technology and techniques)

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