Female Breast Radiation Exposure During CT Pulmonary Angiography
Female Breast Radiation Exposure During CT Pulmonary Angiography
Objective: The objective of our study was to estimate the effective radiation dose to the female breast during CT pulmonary angiography compared with other routine diagnostic imaging techniques.
Materials And Methods: We retrospectively reviewed the demographic data of patients who underwent CT pulmonary angiography between May 2000 and December 2002, the diagnostic yield of those studies, and the estimated effective radiation dose to the breast incurred during CT. The estimated effective radiation dose was calculated using the ImPACT CT (Impact Performance Assessment of CT) dosimetry calculator and the CT dose index (CTDI) and was compared with the average glandular dose for two-view screening mammography.
Results: During the study period, 1,325 CT pulmonary angiograms were obtained. Sixty percent (797) of the scans were obtained on female patients. The mean age of scanned females was 52.5 years (range, 15–93 years). Of the studies performed in females, 401 (50.31%) were negative, 151 (18.95%) were nondiagnostic, and 245 (30.74%) were positive for pulmonary thromboembolism. The calculated effective minimum dose to the breast of an average 60-kg woman during CT was 2.0 rad (20 mGy) per breast compared with an average glandular dose of 0.300 rad (3 mGy) for standard two-view screening mammography.
Conclusion: CT pulmonary angiography delivers a minimum radiation dose of 2.0 rad (20 mGy) to the breasts of an average-sized woman. This greatly exceeds the American College of Radiology recommendation of 0.300 rad (3 mGy) or less for standard two-view mammography. The potential latent carcinogenic effects of such radiation exposure at this time remain unknown. We encourage the judicious use of CT pulmonary angiography and lower doses and nonionizing radiation alternatives when appropriate.
Radiologic imaging studies have become an integral diagnostic tool in the practice of clinical medicine. The role of body CT in particular has grown exponentially since its introduction in the mid 1970s. Today, more than 35 million CT scans are obtained annually in the United States alone. It is estimated that CT is now responsible for approximately 13% of all radiologic procedures performed in the United States and contributes 30% of the medical diagnostic radiation dosage to patients. As the use of CT has markedly increased over the past two decades, so have its technical capabilities. CT now plays a critical role in the diagnosis and management of most patients with complex thoracic and cardiopulmonary disease, including pulmonary thromboembolism.
With the advent of multidetector scanners, CT has become the de facto gold standard for imaging pulmonary emboli. Although the morbidity and mortality of unrecognized and untreated acute pulmonary embolism are well known, the potential carcinogenic effects of ionizing radiation on radiosensitive tissues such as the eye, thyroid gland, and female breast in particular are often not considered or deemed relevant to acute patient care. Because a large percentage of patients evaluated with CT pulmonary angiography are women of reproductive age, our objective was to estimate the effective radiation dose to the female breast incurred during these studies and compare that value with the average glandular breast dose for routine mammography. This information will allow referring physicians and radiologists to describe the effective radiation dose and relative risk of CT in terms patients understand. We also encourage the judicious use of CT pulmonary angiography and lower doses and nonionizing radiation alternatives when appropriate.
Objective: The objective of our study was to estimate the effective radiation dose to the female breast during CT pulmonary angiography compared with other routine diagnostic imaging techniques.
Materials And Methods: We retrospectively reviewed the demographic data of patients who underwent CT pulmonary angiography between May 2000 and December 2002, the diagnostic yield of those studies, and the estimated effective radiation dose to the breast incurred during CT. The estimated effective radiation dose was calculated using the ImPACT CT (Impact Performance Assessment of CT) dosimetry calculator and the CT dose index (CTDI) and was compared with the average glandular dose for two-view screening mammography.
Results: During the study period, 1,325 CT pulmonary angiograms were obtained. Sixty percent (797) of the scans were obtained on female patients. The mean age of scanned females was 52.5 years (range, 15–93 years). Of the studies performed in females, 401 (50.31%) were negative, 151 (18.95%) were nondiagnostic, and 245 (30.74%) were positive for pulmonary thromboembolism. The calculated effective minimum dose to the breast of an average 60-kg woman during CT was 2.0 rad (20 mGy) per breast compared with an average glandular dose of 0.300 rad (3 mGy) for standard two-view screening mammography.
Conclusion: CT pulmonary angiography delivers a minimum radiation dose of 2.0 rad (20 mGy) to the breasts of an average-sized woman. This greatly exceeds the American College of Radiology recommendation of 0.300 rad (3 mGy) or less for standard two-view mammography. The potential latent carcinogenic effects of such radiation exposure at this time remain unknown. We encourage the judicious use of CT pulmonary angiography and lower doses and nonionizing radiation alternatives when appropriate.
Radiologic imaging studies have become an integral diagnostic tool in the practice of clinical medicine. The role of body CT in particular has grown exponentially since its introduction in the mid 1970s. Today, more than 35 million CT scans are obtained annually in the United States alone. It is estimated that CT is now responsible for approximately 13% of all radiologic procedures performed in the United States and contributes 30% of the medical diagnostic radiation dosage to patients. As the use of CT has markedly increased over the past two decades, so have its technical capabilities. CT now plays a critical role in the diagnosis and management of most patients with complex thoracic and cardiopulmonary disease, including pulmonary thromboembolism.
With the advent of multidetector scanners, CT has become the de facto gold standard for imaging pulmonary emboli. Although the morbidity and mortality of unrecognized and untreated acute pulmonary embolism are well known, the potential carcinogenic effects of ionizing radiation on radiosensitive tissues such as the eye, thyroid gland, and female breast in particular are often not considered or deemed relevant to acute patient care. Because a large percentage of patients evaluated with CT pulmonary angiography are women of reproductive age, our objective was to estimate the effective radiation dose to the female breast incurred during these studies and compare that value with the average glandular breast dose for routine mammography. This information will allow referring physicians and radiologists to describe the effective radiation dose and relative risk of CT in terms patients understand. We also encourage the judicious use of CT pulmonary angiography and lower doses and nonionizing radiation alternatives when appropriate.