HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Milne, E. N. C. Search for Related Content PubMed PubMed Citation Articles by Milne, E. N. C. Social Bookmarking                      What's this?

Female Breast Radiation Exposure

University of California, Irvine
College of Health Sciences Irvine, CA

I was delighted to read the excellent article by Parker et al. [1] in the November 2005 issue of the AJR titled "Female Breast Radiation Exposure During CT Pulmonary Angiography." Consideration of the possible mutagenic effects of irradiation from thoracic CT is long overdue, partly because the topic is an unpopular one. None of us would be happy to know that a valuable diagnostic procedure, CT of the thorax, might be a cause of breast cancer, but unfortunately the numbers tell us that this is almost certainly true.

Parker et al. [1] calculated, but did not actually measure, the amount of radiation being received by the chest and breast. The number they derived for the breast dose in an "average" woman is 2.0 rad (0.02 Gy), but somewhat surprisingly, they did not include in their calculations (to quote the authors) "the radiation dose delivered to the breasts during the unenhanced image acquisition"; later, they state that if this had been included it would have increased the quoted 2.0 rad "two- to three-fold," making the breast dose 4-6 rad (0.04-0.06 Gy) in an average woman. This value is close to the average level that my colleagues and I found in 58 women (7.1 rads [0.07 Gy]) when we measured the radiation dose to the breast (using thermoluminescent dosimeters) during standard CT examinations of the thorax [2, 3].

However, quoting the dose to an "average" woman (based on her weight rather than actual breast size) does not, because of the great variation in breast size and texture, tell us much about the danger to an individual patient. As would be anticipated on simple physical principles, we found that the absorbed dose to the breast increased progressively with increasing breast size and that there is a linear relationship between bra cup size (as a measure of breast volume, irrespective of a patient's size) and absorbed dose. Taking this into account, the measured dose varied from 1.8 rad (0.018 Gy) in a patient with small breasts (32A) to as much as 19.6 rad (0.19 Gy) in a patient with large breasts (42D), for whom multiple slices and repeat examinations were needed. This means that the radiation dose to the breast during CT angiography is equivalent not, as the authors suggest, to 10-25 mammograms or 100-400 chest radiographs but to 30-100 mammograms or 300-1,000 chest radiographs.

If Parker et al. [1] had included the radiation from the unenhanced portion of the examination, I believe that their calculations would have been similar to our measurements. In the Discussion section, the authors quote articles (based on clinical findings, not theoretic statistical extrapolations) showing that the risk of inducing cancer in this highly mutagenic tissue is real. As a one-time chest physician who practiced at the end of the era of pneumothoraces for the treatment of tuberculosis, I am familiar with the large radiation doses given by biweekly fluoroscopic (non-image-intensified) screenings to determine whether a pneumothorax was still present. Fifteen plus years later, the incidence of breast cancer on the side subjected to fluoroscopy was doubled [4]. The dose level given to those patients is now being approached by the doses given by thoracic CT, particularly, as the authors point out, if multiple examinations are performed, a frequent occurrence in patients with suspected pulmonary embolism. I strongly support the authors' recommendations for reducing radiation doses from thoracic CT and congratulate the authors on this important article.

References

1. Parker MS, Hui FK, Camacho MA, Chung JK, Broga DW, Sethi NN. Female breast radiation exposure during CT pulmonary angiography. AJR 2005; 185:1228 -1233[Abstract/Free Full Text]
2. Milne ENC. Breast: the forgotten organ. Radiology 2004;233 : 937-938[Free Full Text]
3. Milne ENC. Dosage to the breast during CT of the thorax. In: Names of editor(s) of entire syllabus, eds. Title of the course syllabus for the Fleischner Society 34th Annual Conference on Chest Disease. City, State/Country of publisher: name of publisher, year of publication:131-134
4. Miller AB, Howe GR, Sherman GJ, et al. Mortality from breast cancer after irradiation during fluoroscopic examinations in patients being treated for tuberculosis. N Engl J Med 1989;321 : 1285-1289[Abstract]

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				J. R. Mayo Radiation Dose Issues in Longitudinal Studies Involving Computed Tomography Proceedings of the ATS, December 15, 2008; 5(9): 934 - 939. [Abstract] [Full Text] [PDF]

				H. D. Sostman, M. Miniati, A. Gottschalk, F. Matta, P. D. Stein, and M. Pistolesi Sensitivity and Specificity of Perfusion Scintigraphy Combined with Chest Radiography for Acute Pulmonary Embolism in PIOPED II J. Nucl. Med., November 1, 2008; 49(11): 1741 - 1748. [Abstract] [Full Text] [PDF]

				M. Remy-Jardin, M. Pistolesi, L. R. Goodman, W. B. Gefter, A. Gottschalk, J. R. Mayo, and H. D. Sostman Management of Suspected Acute Pulmonary Embolism in the Era of CT Angiography: A Statement from the Fleischner Society Radiology, November 1, 2007; 245(2): 315 - 329. [Full Text] [PDF]

				A. Gottschalk, P. D. Stein, H. D. Sostman, F. Matta, and A. Beemath Very Low Probability Interpretation of V/Q Lung Scans in Combination with Low Probability Objective Clinical Assessment Reliably Excludes Pulmonary Embolism: Data from PIOPED II J. Nucl. Med., September 1, 2007; 48(9): 1411 - 1415. [Abstract] [Full Text] [PDF]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Milne, E. N. C. Search for Related Content PubMed PubMed Citation Articles by Milne, E. N. C. Social Bookmarking                      What's this?