Educating physicians about ventilation-perfusion scanning (VQ) as an alternative to CT for the diagnosis of pulmonary embolisms led to a 23% decrease in patient exposure, according to a study performed at Albert Einstein College of Medicine, Montefiore Medical Center in Bronx, NY. “VQ scanning is a nuclear test which shows blood flow to the lung and airflow. When there is a pulmonary embolism, the air can enter normally, but the blood flow will be disrupted, resulting in an abnormal scan,” said Linda Haramati, MD, lead author of the study.
“We are very conscious of radiation exposure in our population,” said Dr. Haramati. Collaborative and educational seminars were held between radiology, nuclear medicine and emergency medicine departments regarding the radiation dose and comparable sensitivities of VQ and CT pulmonary angiography for pulmonary emboli. “The proportion of CT to VQ changed dramatically after our seminars. In 2006 about 60% of the studies were CT, while in 2007, about 60% were VQ. When we looked at radiation exposure, the mean effective dose was reduced by 23%, from 11.5 mSv in 2006 to 8.9 mSv in 2007,” she said.
“CT confers a much higher radiation exposure than VQ scans. However VQ scans are harder to interpret in patients with abnormal chest x-rays, so we, along with our emergency department physicians have decided to perform VQ scans as the preferred imaging modality in patients with normal chest x-rays who were suspected of having pulmonary embolism–in order to decrease radiation exposure,” said Dr. Haramati.