Abstract
The use of non-invasive imaging modalities, including micro X-ray computed tomography (micro-CT), is starting to be used extensively to investigate normal and pathological states in a variety of animal models. This increased use of in vivo imaging requires a better understanding of the radiation dose delivered during routine imaging. Our laboratory is equipped with a micro X-ray computer tomography unit (MicroCAT II®, ImTek Inc., Knoxville, TN) with a 60 kVp X-ray source and a reconstruction volume resolution as low as 15 microns that is used for proton radiation therapy treatment planning. In order to determine the X-ray radiation dose delivered to skin and internal organs by our micro-CT we implanted new, calibrated Harshaw TLD-100 Lithium Fluoride thermo-luminescent detectors (TLDs), into five C57BL/6 male mice and ten Sprague-Dawley male rats. Implants were made into the brain, heart, right lung, liver, stomach, cecum, bladder, dorsal thoracal skin and ventral abdominal skin in each animal. Animals were each scanned once using 50 kVp at 800 μA with 360 projections per scan with each projection lasting 400 msec. Using the TLD readings, the radiation dose from each body location was measured with the dorsal thoracal skin receiving the highest average dose (4.5 cGy, mouse; 2.8 cGy, rat) and other internal organs receiving significantly lower average doses. Therefore, knowing the radiation doses delivered during routine imaging, care can be taken to avoid significant and potentially lethal doses of radiation.
Get full access to this article
View all access options for this article.