Antiscatter grids currently employed on fluoroscopic systems are limited in their capability to control scatter. As a result, fluoroscopic radiation levels are higher for the average patient than they would be with a more efficient grid system, and higher still for large patients. Poor image quality often increases the beam-on time required to successfully perform interventional procedures, increasing the radiation dose still further. This problem is critical in interventional exams, where skin doses are occasionally high enough to induce radiation burns1-3, and effective doses often exceed those of CT exams4 and contribute about 14% of the nationwide effective dose from medical imaging procedures5. Our proposal is to develop a high efficiency antiscatter grid system that will result in a significant improvement in fluoroscopy system dose efficiency. The results of our benchmarked Monte Carlo modeling indicate that a factor of 1.5 to 2.0 or more improvement is achievable. Cardiologists and radiologists can use this improvement either to produce higher quality images at current fluoroscopic radiation levels, allowing them to shorten exams, or to produce images comparable to today's image quality standards at markedly lower dose rates. The proposed innovative antiscatter grid system will incorporate a coarse strip density, air interspaced grid and a reciprocating grid drive with innovative approaches to suppress vibrations and grid artifacts. In Phase I we will build a grid and drive system and demonstrate: 1) the use of the system in fluorographic (digital spot) imaging;2) the robust suppression of grid artifacts;and 3) a dose efficiency at least 1.5 times greater than that of commonly used grids. In Phase II we will build a vibration-free reciprocating drive system suitable for fluoroscopic imaging, a compact x-ray tube grid bias supply to perform fast x-ray switching for short x-ray pulses, and with our manufacturing partner we will modify a commercially available clinical fluoroscopy unit to demonstrate the use and performance of the grid system. Of practical importance is that the domestic manufacturer has already expressed interest in evaluating the grid system for inclusion in their product line and in commercializing the technology.
Millions of fluoroscopic examinations are performed each year, and these exams often result in high patient radiation doses and injury1-3, are among the highest dose exams in medical imaging4, and account for 14% of the effective dose from medical imaging in the United States5. We propose to improve the dose efficiency of fluoroscopy by a factor of 1.5 to 2.0 or more. This significant improvement will be accomplished by building an innovative high efficiency antiscatter grid system;clinical fluoroscopic systems using this grid system will be able to achieve markedly improved image quality at current radiation dose levels, or alternatively will be able to achieve image quality comparable to that obtained on today's fluoroscopic systems at a fraction of the radiation dose.
