Paul Andrew Klenk BS, Presenter: Nothing to Disclose

W. Neal Simmons PhD, Abstract Co-Author: Nothing to Disclose

Franklin Hadley Cocks PhD, Abstract Co-Author: Nothing to Disclose

This work explores the use of a hollow needle together with a highly collimated primary x-ray beam for the delivery of ionizing radiation to interior body lumens for irradiation of cancerous tissues. The primary x-ray radiation intersects a fluorescent dispersion element, which absorbs the primary x-rays and fluoresces secondary x-rays. These secondary x-rays irradiate a tissue volume around the tip of the needle. By adjusting the fluorescent element geometry the treatment shape and volume can be modified. Such a new treatment procedure could potentially be used to treat a percentage of interior tumor masses and is especially applicable to the precision delivery of therapeutic dosages to small, localized tumors.

The therapeutic radiation field morphology producible as a function of dispersion element shape has been evaluated by computer modeling. The model results have then been compared to experimentally determined radiation therapy fields. Based on these results, the dose rates and therapy field geometries have been estimated for specific clinical applications.

Experimental and computer modeling results have demonstrated the ability of fluorescent dispersion tip elements to produce radiation fields of controlled geometry and intensity. The highest therapeutic radiation energies deliverable via this modality are limited to less than approximately 57 keV. For that reason, this treatment modality is primarily applicable to tumors less than 2 centimeters in diameter.

An x-ray transmitting fluorescent needle has a number of advantages over current radiation therapies. The use of an x-ray transmitting hollow needle with a dispersion element tip would enable the direct irradiation of small interior cancerous tissues without the side effects of high energy x-rays or gamma rays that pass through intervening normal tissue before reaching the target malignancy. Unlike brachytherapy, such a treatment procedure would not involve the difficulties associated with handling radioactive isotopes.

Klenk, P, Simmons, W, Cocks, F, Experimental Evaluation of a Novel X-ray Transmitting Fluorescent Needle for the Delivery of Low Energy (<60 keV), Therapeutic Radiation to Localized Tumors.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4415790.html