Bon Ryu

Date of Award


Degree Type


Degree Name

Master of Science




Dr. Eugene Wong

Second Advisor

Dr. Aaron Fenster


The goal of this thesis was to evaluate the use of oblique needle trajectories in low dose rate prostate brachytherapy for large glands with pubic arch interference (PAI).

A planning study was conducted with five Subject prostate contours, from 3D Transrectal Ultrasound (TRUS) images, artificially enlarged to 60 cc to increase PAI. Oblique needles no template plans (OBL) and parallel needle no template plans (PNT), were compared to parallel needle template plans for each prostate. Iodine-125 (145 Gy prescription dose), 0.43 U air kerma strength, and needle angles < 15° were used. Beneficial improvements (p < 0.05) in dose parameters were shown for OBL plans (all organs), and PNT plans (only PTV VI00), when compared to template plans in paired one-sided t-tests.

An oblique plan was delivered to a 60 cc prostate phantom with PAI using a 3D TRUS guided mechatronic system. Seed placement accuracy was sub-millimeter in all directions.



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