CT patient dose reduced by monitoring

Significant reduction in patient doses for both adult and pediatric patients

The effort was part of an International Atomic Energy Agency (IAEA) technical project called: Strengthening Radiation Protection in Medicine.

Researchers described their experiences in monitoring, optimizing, and comparing diagnostic reference levels of radiation dose indexes at the hospital over approximately four years. In explaining their research, they noted that there are few publications that give information about dose-monitoring experience on a long-term basis.

“This is the first study done in a period of years,” said study author Jamila AlSuwaidi, PhD, from the department of medical education, Dubai Health Authority, United Arab Emirates. “The previous ones were to compare different systems at different places.”

During the past five years, the number of CT studies has doubled at Dubai Health Authority hospitals, and this situation prompted the Dubai Health Authority to adopt a systematic approach in recording, observing, and controlling CT dose.

The researchers monitored patient dose delivered by a four-slice MDCT scanner located at Dubai Hospital. CT machine output was monitored using head and body phantoms accredited by the American College of Radiology.

Steps to reduce radiation dose were taken and image quality was monitored. The effects were monitored on a monthly basis and with respect to third-quartile values, which are used to indicate abnormally high doses on a local, national, or regional scale. Sites in the third quartile represent the 75% of hospitals/X-ray rooms that are giving patients doses below the reference value.

The study successfully demonstrated significant CT dose reduction with acceptable image quality, wrote the study authors.

“Establishment of strategies for CT radiation dose optimization represents an essential step to be incorporated within hospital quality development programs,” they added. “This article shows that continuous CT dose index monitoring is an important component of such CT radiation dose optimization strategies.”

The results also indicate the need to introduce local diagnostic reference levels to substitute for the adapted ones, the authors noted.

“The diagnostic reference levels that we used at our hospital were based on [those of the] U.K. and [European Community], i.e., we adopted a level closer to their levels,” explained AlSuwaidi. “To implement the diagnostic reference levels on a local level, we need to carry out a survey on CT patient dosimetry at all our CT facilities at our area in Dubai.”

The most enlightening finding remains the significant reduction in patient doses for both adult and pediatric patients, AlSuwaidi added. “We expected a reduction but not to this extent,” she said. She noted that it is important to monitor CT patient doses because repeated CT scans have the risk of inducing cancer, particularly in younger patients.

“Working as a team of radiologists, radiographers, and medical physicists, a reduction in CT doses can be achieved without sacrificing clinical information obtained from CT examinations,” she concluded. “Reduction of radiation doses can only be manifested once it is carried out over a period of time such as three to five years.”