Refer to: Sickles EA: Xeromammography versus screen-film mam- mography-Pros and cons of the two techniques (Infor- beams (40 to 50 kVp), produce satisfactory mam- mation). West J Med 134:273-274, Mar 1981 mograms without uniform-thickness breast com- pression and, therefore, can be used successfully Information with standard ceiling-mounted, general-purpose x-ray units (with few exceptions, screen-film tech- niques cannot). As a result, xeromammography is considerably more convenient and somewhat less expensive than screen-film techniques, especi- Xeromammography Versus ally for radiology departments or offices that do a low volume of mammography work. Screen-Film Mammography There are also inherent differences in image Pros and Cons of the Two Techniques quality between xeroradiographic and screen-film mammograms that merit discussion.1'3 The edge- EDWARD A. SICKLES, MD enhancement property unique to xeroradiog- San Francisco raphy facilitates the imaging of tiny breast cal- cifications, which may be the only indication, radiographic or otherwise, that breast cancer is XEROMAMMOGRAPHY and screen-film mammogra- present. Screen-film mammograms, on the other phy are the predominant techniques being used hand, have comparatively high inherent contrast, for the radiographic detection of breast cancer.' thereby facilitating the imaging of poorly defined Xeroradiography, a technique similar to the stan- breast masses, which also may be the only mani- dard photocopying process, works on the principle festation of carcinoma. Because approximately that x-rays partially dissipate a uniform electrical half of mammographically detectable cancer of charge applied to a selenium-alloy plate, thereby the breast presents with microcalcifications and producing a latent (electrostatic) radiographic the other half presents as poorly defined noncal- image, which is subsequently developed by dusting cified masses, there is no relative advantage to the plate with charged particles of (blue) plastic either technique, nor is it possible to know a powder. The colored powder is then transferred priori which technique is best for an individual and bonded to paper by a heat-sealing process, patient. More important, these differences in resulting in a blue and white image. Screen-film image quality between xeromammography and radiography is a more conventional technique, screen-film mammography are quite subtle and using regular x-ray film but coupled with a radi- of little clinical significance. Based on my own ographic screen, a device that converts x-rays to experience involving malignant lesions radio- visible light. The advantage of the screen is that graphed with both techniques, one technique will light darkens x-ray film much more efficiently permit carcinoma to be diagnosed with a greater than x-rays themselves, thereby producing a degree of confidence than the other approximately properly exposed image with only a small fraction 25 percent of the time, but the circumstance in of the x-rays otherwise needed. which cancer is detected by one technique but not Several differences between xeroradiography the other occurs very infrequently.3 and screen-film radiography cause important dis- Despite the lack of a substantial difference in parities in the manner in which these two tech- the quality of images between xeromammography niques can be adapted to breast imaging. Screen- and screen-film mammography, many radiologists film techniques require both uniform-thickness express a distinct preference for one or the other breast compression and very low-energy x-ray technique; interestingly, these personal preferences beams (25 to 28 kVp) foat diagnostically acceptable almost always are based-on extensive use of one images. 2 This necessitates the use of specialized technique and little or no familiarity with the x-ray equipment designed specifically for mam- other. There is, in fact, general agreement among mographic examinations.2 Xeroradiography tech- experienced mammographers that either technique niques, on the other hand, use higher-energy x-ray produces excellent results, if done by skilled per- sonnel using proper equipment. Most unfavorable The author is Chief, Mammography Section, Department of Radiology, University of California, San Francisco, School of experiences with the screen-film technique re- Medicine. re- Reprint requests to: Edward A. Sickles, MD, Chief, Mammog- ported by those favoring xeromammography raphy Section, Department of Radiology, M-396, University of from to to screen-film California, School of Medicine, San Francisco, CA 94143. sult trying adapt imaging THE WESTERN JOURNAL OF MEDICINE 273 INFORMATION the same general-purpose x-ray equipment that raphy produce images of very similar quality, with works so well for xeromammography; such an un- only subtle, probably insignificant differences in fortunate combination of equipment and technique informational content. The major differences be- at best produces substandard images. Very few tween the two techniques are as follows: ( 1 ) xero- negative experiences with xeromammography have radiographic processing can be done using con- been reported by screen-film mammographers- ventional x-ray units, whereas screen-film imaging they rarely consider switching to the xeroradiogra- requires specialized x-ray equipment and (2) phic technique because (1 ) they already have in- screen-film mammography imparts a considerably vested in the necessary specialized mammography lower dose of radiation than does xeromammog- equipment; (2) xeromammography is a technique raphy. The overall trend among radiologists is that uses much higher doses of radiation, and (3) clearly toward screen-film imaging, but xeromam- very few breakdowns interrupt the day-to-day mography still retains a substantial following, operation of screen-film mammography, whereas primarily because of economic considerations. is noted for xeromammography considerable REFERENCES "downtime" because of repeated malfunctions in 1. Gold RH: Breast, In Steckel RJ, Kagan AR (Eds): Diagno- sis and Staging of Cancer: A Radiologic Approach. Philadelphia, the image-processing apparatus. W.B. Saunders Co, 1976, pp 263-287 2. Logan WW, Norlund AW: Screen-film mammography tech- Among the various differences between xero- nique: Compression and other factors, In Logan WW, Muntz EP mammography and screen-film (Eds ): Reduced Dose Mammography. New York, Masson, 1979, mammography, pp 415428 perhaps the most important concerns radiation 3. Sickles EA: Mammographic interpretation: False negatives and heroic positives, In Logan WW, Muntz EP (Eds): Reduced dose; here, screen-film technique has the clear- Dose Mammography. New York, Masson, 1979, pp 479485 cut lower in 4. Hammerstein GR, Miller DW, White DR, et al: Absorbed advantage, being considerably dose.4 radiation dose in The most pertinent of the several dose determina- mammography. Radiology 130:485491, Feb 1979 tions is the "average dose to mammary glandular tissue," and the dose for screen-film mammog- raphy is a fourth to a tenth that for xeromam- Refer to: Heimbach DM, Engrav LH, Marvin JA: Advances in mography. Although it remains unclear whether burn care (Information). West J Med 134:274-279, Mar the radiation risk of mammography, is great 1981 enough to be clinically meaningful, there is gen- eral agreement that because the risk of radiation- Information induced cancer appears to be directly proportional to radiation dose, any reduction in dose is ac- companied by a parallel decrease in risk. Over the past several years there has been considerable reduction in radiation doses for all mammography Advances in Burn Care techniques, so that even the xeromammography DAVID M. HEIM.BACH, MD breast tissue dose is now less than 1 rad per LOREN H. ENGRAV, MD examination at most installations. Screen-film JANET A. MARVIN, RN, MN mammography doses are so low now that the Seattle lowest of these approaches the dose of a standard x-ray examination of the chest. The dose differ- ential between the screen-film and xeromammog- EACH YEAR in the United States approximately raphy techniques is most meaningful when con- 2,000,000 people sustain burns serious enough to sidering the screening of asymptomatic women. require seeing a physician. Of these, 50,000 people In this situation we face a relatively low yield of are admitted to hospital and approximately 12,000 cancer detection and the cumulative dose of of them die. multiple mammographies; the benefits derived As late as 1960 a 30 percent total body surface do not exceed the presumed risk by as great a area (TBSA) burn carried a mortality of 50 per- cent. At in margin as they do for diagnostic mammography present, many specialized burn centers (the one-time examination of women with signs From the Department of Surgery, University of Washington Burn and Trauma Centers, University of Washington, Harborview or symptoms that suggest the possibility of breast Medical Center, Seattle. Submitted July 9, 1980. cancer). Reprint requests to: David M. Heimbach, MD, Department of Surgery, ZA-16, Harborview Medical Center, 325 Ninth Ave., Xeromammography and screen-film mammog- Seattle, WA 98104. 274 MARCH 1981 * 134 * 3.