John A Micka

Learn More
(90)Y is utilized as a therapeutic radioisotope in radiolabeled monoclonal antibodies and in microspheres for targeted radiation therapy of the liver. Currently, the widely used dose calibrator assay of (90)Y can have uncertainties exceeding +/-10%. A non-destructive assay using spectroscopy is possible by reducing the currently published uncertainty(More)
PURPOSE AAPM TG-43 brachytherapy dosimetry parameters for a new, smaller diameter 1251 brachytherapy source (THINSeed, model 9011) were determined using LiF:Mg,Ti thermoluminescent dosimeter (TLD-100) microcubes and Monte Carlo simulations. METHODS Two polymethyl methacrylate phantoms were machined to hold TLD-100 microcubes at specific locations for the(More)
PURPOSE The purpose of this study is to perform an extensive investigation of an approximately 2.5 mm long 90Sr/90Y source designed for treating wet age-related macular degeneration. METHODS As part of this investigation, a NIST-traceable absorbed dose to water calibration technique was established, and a source deployment verification test was developed.(More)
The increased popularity of high dose rate (HDR) brachytherapy in the treatment of neoplastic disease has resulted in the introduction of new or redesigned 192Ir sources by various manufacturers. In order to provide accurate clinical dosimetry, accurate calibration of these sources is required. In this work, two new sources are calibrated with the standard,(More)
A trend is underway toward the use of prepackaged low dose rate brachytherapy sources, which come in the form of strands, coiled line sources, preloaded needles, and sterile cartridge packs. Since the medical physicist is responsible for verification of source strength prior to patient treatment, development of prepackaged source strength verification(More)
90Y-labeled SIR-Spheres are currently used to treat patients with hepatic metastases secondary to colorectal adenocarcinoma. In general, the prescribed activity is based on empirical data collected during clinical trials. The activity of the source vial is labeled by the manufacturer as 3.0 GBq +/- 10% and is not independently verified by the end user. This(More)
This paper describes the development and characterization of a fully automated in vitro cell irradiator using an electronic brachytherapy source to perform radiation sensitivity bioassays. This novel irradiator allows complex variable dose and dose rate schemes to be delivered to multiple wells of 96-well culture plates used in standard biological assays.(More)
PURPOSE This work presents the development of a phantom to verify the treatment planning system (TPS) algorithms used for high-dose-rate (HDR) brachytherapy. It is designed to measure the relative dose in a heterogeneous media. The experimental details used, simulation methods, and comparisons with a commercial TPS are also provided. METHODS To simulate(More)
The determination of the air kerma strength of a brachytherapy seed is necessary for effective treatment planning. Well-type ionization chambers are used on site at therapy clinics to determine the air kerma strength of seeds. In this work, an improved well-type ionization chamber for low energy, low dose rate brachytherapy sources is designed using Monte(More)
PURPOSE To propose a modification of the current dose calculation formalism introduced in the Task Group No. 43 Report (TG-43) to accommodate an air-kerma rate standard for electronic brachytherapy sources as an alternative to an air-kerma strength standard. METHODS Electronic brachytherapy sources are miniature x-ray tubes emitting low energies with(More)