JACR: Community hospitals can reduce CT dose

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Although community hospitals contend with challenges in the implementation of comprehensive CT dose reduction programs, these organizations can effectively deploy long-term, ongoing programs to successfully curb radiation dose, according to an article published in the August issue of the Journal of American College of Radiology.

Gundersen Lutheran Health System, a physician-led healthcare system in La Crosse, Wis., began its dose reduction program in 2006 and has achieved reductions up to nearly 70 percent for some exams.

CT dose reduction resources such as Image Gently and Image Wisely are widely available. However, their adoption by small facilities is uncertain. “Staffing and time limitations at such facilities make the implementation of CT dose reduction programs challenging,” wrote Mary Ellen Jafari, MS, of Gundersen Lutheran, which is comprised of a tertiary hospital, multispecialty physician group practice and related services.

The health system started its dose reduction program in 2006 and began recording volumetric CT dose index and dose-length product (DLP) for coronary CT angiography (CTA) studies.

Results for the first 59 patients revealed a higher-than-expected dose at 21 mSv and led to protocol changes, which cut dose to 15 mSv in subsequent patients, and sparked development of a comprehensive CT dose reduction program.

"The focus of our program is on easily implemented, practical actions. Prioritized for dose reduction actions are high-dose examinations, patients scanned repeatedly for chronic conditions, pediatric patients and pregnant patients," said Jafari.

Strategies tackled multiple components of CT imaging: scanner functionality, staff training, dose monitoring and evaluation, CT acquisition protocols and referring physician and patient education.

Gundersen Lutheran utilizes regular quality control testing, following the American College of Radiology’s (ACR) Technical Standard for Diagnostic Medical Physics Performance Monitoring of CT equipment and quality control tests as required by the Wisconsin Department of Health Services, and its service engineers and clinical engineers perform regular preventive maintenance and services to ensure proper CT scanner functionality.

Staff must meet state and accreditation body requirements for initial and continuing education. In addition, the health system requires CT techs to obtain American Registry of Radiologic Technologists (ARRT) advanced certification in CT. Gundersen Lutheran leverages webinars and staff radiologists and physicists to complement and bolster educational offerings.

The community hospital has recorded DLP for all CT studies and calculated effective dose since 2006. These calculations allow the health system to evaluate changes in dose resulting from CT protocol modification and enable comparison with other modalities, explained Jafari and colleagues.

The health system’s CT protocol modification process emphasizes a balance between reduced dose and adequate image quality. Since its inaugural CTA protocol modification, Gundersen Lutheran has further revised that protocol to reduce dose an additional 67 percent, implemented a low-dose renal stone CT protocol and deployed a reduced dose CT topographic bone growth protocol as well as developed other reduced dose protocols.

In addition to internally recording and evaluating CT dose, the health system considers current research as it revises its protocols. For example, Gundersen Lutheran uses bismuth breast shielding for women younger than 40 years old, but the organization plans to revisit this strategy based on studies suggesting that the shields may compromise image quality.

To raise awareness of CT dose across the organization, radiologists and physicists provide educational presentations for physicians in emergency medicine, urology and pediatrics and share dose monitoring results with them. The presentations emphasize alternate modalities and lower dose CT techniques for children, pregnant patients and patients with multiple previous CT scans.

To educate patients, Gundersen Lutheran created a brochure to answer questions about CT radiation in lay language and included typical adult doses for common studies compared with background radiation or other imaging studies.

The system has been able to calculate reduced DLP and effective dose through monitoring efforts. However, other results such as marginal exams avoided are not easily quantified, the organization noted. Nevertheless,