Reliability of histologic diagnosis of breast cancer with stereotactic vacuum-assisted biopsy

The purpose of this study was to determine the accuracy of 11-gauge stereotactic vacuum-assisted breast biopsy (SVAB) for the diagnosis of breast cancer. Percutaneous biopsies of 426 suspicious breast lesions in 365 patients using 11-gauge SVAB were performed between September 1996 and June 1998. Of these biopsies 59 (13.8%) resulted in a diagnosis of breast carcinoma and 56 (95%) were surgically excised. These 56 lesions constitute the basis of this study. Pathology of SVAB and surgically excised tissue of the 56 carcinomas as well as imaging findings were correlated. At percutaneous biopsy 34 (61%) lesions demonstrated ductal carcinoma in situ (DCIS) and 22 (39%) invasive carcinomas. Surgical excision demonstrated the presence of an invasive cancer in three lesions percutaneously diagnosed as DCIS (9%; confidence interval 2-24%). No residual carcinoma was surgically demonstrated in seven (12.5%) lesions. Sensitivity of 11-gauge SVAB for the diagnosis of invasion in breast cancer was 88 per cent. Using SVAB the diagnosis of invasive carcinoma is reliable. However, a percutaneous finding of DCIS does not exclude the presence of invasion in 9 per cent of cases as confirmed by subsequent surgery. Using SVAB 12.5% of carcinomas are completely excised.

Geographical distribution of breast cancers on the mammogram: an interval cancer database

Auditing interval cancers is an important part of a breast screening radiologist's continuing education. We set out to determine whether the position of interval cancers on the mammogram differs from those detected at screening. The 773 interval cancers so far identified, and the first 200 screen detected cancers, have been entered onto a Microsoft Access 97 database developed to record pathological and radiological features, including the position of the cancer on a stylized diagram using a "point and click" system. Reports were generated showing positions of all interval cancers by classification and reader. The distribution of true interval cancers is statistically different from screen detected cancers on both views. The distribution of the false negative and screen detected cancers only differs on the oblique view. False negative and true interval cancers are of the same distribution on both craniocaudal and oblique views. However, these differences do not appear to be practically useful when applied to individual readers. We have developed a database that allows systematic recording of pathological and radiological information regarding breast cancers. Additionally, it can record the geographic position of the cancer with minimal memory requirements. Statistical differences in the distribution of false negative and screen detected cancers have been demonstrated and the stylized diagrams reinforce the importance of the conventional review areas. Although this has not identified any "blind spots" in our own readers, it nevertheless provides film readers with a tool to audit their own work.

[From a mammographic station to the organization of the Federal Mammologic Center]

The history of radiation application for breast cancer diagnosis in Russia is illustrated by an experience gained at the Center. It was concerned with designing specialized X-ray equipment as well as development of Standards to be used at mammographic stations. Teaching programs were devised for training X-ray diagnosis specialists with all necessary qualification to operate high-tech equipment of a mammographic station and to use a wide range of radiation and invasive procedures.

Quality assurance for screening mammography: an international comparison

STUDY OBJECTIVE

In 1998, the International Breast Cancer Screening Network (IBSN) sponsored an assessment of quality assurance policies and practices to define their scope for population-based screening mammography programmes across IBSN countries.

DESIGN

Analysis of data from a survey designed to assess multiple elements of screening programme quality assurance, including organisation of quality assurance activities, mechanisms for site visits and accreditation, requirements for quality control and data systems, and inclusion of treatment, follow up, and programme evaluation in screening mammography quality assurance activities.

PARTICIPANTS AND SETTING

IBSN representatives in 23 countries completed a comprehensive questionnaire between May and December 1998.

MAIN RESULTS

Completed questionnaires were obtained from all 23 countries. Responses indicated that countries vary in their approaches to implementing quality assurance, although all monitor components of structure, process, and outcome. Nearly all have in place laws, surveillance mechanisms, or standards for quality assurance. In all countries, quality assurance activities extend beyond the screening mammography examination.

CONCLUSIONS

The assessment has enhanced understanding of the organisation of screening mammography programmes across countries, as well as the comparability of screening mammography data. All countries have established mechanisms for assuring the quality of screening mammography in population-based programmes, although these mechanisms vary across countries.

Measuring satisfaction with mammography results reporting

OBJECTIVE

To assess factors associated with patient satisfaction with communication of mammography results and their understanding and ability to recall these results.

DESIGN

Cross-sectional telephone survey.

SETTING

Academic breast imaging center.

PATIENTS

Two hundred ninety-eight patients who had either a screening or diagnostic mammogram.

MEASUREMENTS AND MAIN RESULTS

Survey items assessed waiting time for results, anxiety about results, satisfaction with several components of results reporting, and patients' understanding of results and recommendations. Women undergoing screening exams were more likely to be dissatisfied with the way the results were communicated than those who underwent diagnostic exams and received immediate results (20% vs 11%, P =.05). For these screening patients, waiting for more than two weeks for notification of results, difficulty getting in touch with someone to answer questions, low ratings of how clearly results were explained, and considerable or extreme anxiety about the results were all independently associated with dissatisfaction with the way the results were reported, while age and actual exam result were not.

CONCLUSIONS

Patients undergoing screening mammograms were more likely to be dissatisfied with the way the results were communicated than were those who underwent diagnostic mammograms. Interventions to reduce the wait time for results, reduce patients' anxiety, and improve the clarity with which the results and recommendations are given may help improve overall satisfaction with mammography result reporting.

The diagnostic accuracy of mammography in the evaluation of male breast disease

BACKGROUND

The role of mammography in the evaluation of male patients presenting with breast disease is controversial. This controversy is a function of the lack of specific data concerning the diagnostic accuracy of mammography when used in this clinical setting. The purpose of this study was to define the diagnostic accuracy of mammography in the evaluation of male breast disease.

METHODS

One hundred and four prebiopsy mammograms from 100 patients with tissue diagnoses were read blindly by two independent radiologists, and placed into one of five predetermined categories: definitely malignant, possibly malignant, gynecomastia, benign mass, and normal. Radiologic/pathologic correlation was performed and the sensitivity (Sn), specificity (Sp), positive (Ppv) and negative predictive value (Npv), and accuracy (Ac) for each of the mammographic diagnostic category determined.

RESULTS

The pathologic diagnoses were 12 cancers, including 1 patient with bilateral breast cancer, 70 cases of gynecomastia, 16 benign masses, and 6 normals. The accuracy data for the mammographic diagnostic categories are as follows: malignant (combined definitely and possibly malignant), Sn 92%, Sp 90%, Ppv 55%, Npv 99%, Ac 90%; and overall benignity (combined gynecomastia, benign mass, and normal), Sn 90%, Sp 92%, Ppv 99%, Npv 55%, Ac 90%. Six cancers (50%) coexisted with gynecomastia.

CONCLUSIONS

Mammography can accurately distinguish between malignant and benign male breast disease. Although not a replacement for clinical examination, its routine use could substantially reduce the need for biopsy in patients whose mammograms and clinical examination suggest benign disease.

Is variation in quality of mammographic services race linked?

The purpose of this investigation was to (1) determine whether there was variability in the quality of services offered in mammography facilities across Connecticut and (2) determine whether African American women were more likely than white women to receive mammograms in facilities that offered substandard services. Since most facilities do not routinely record information on race, this investigation represents a unique opportunity to address the question of race-linked variation in the quality of screening mammography. Information on equipment, personnel, and record keeping in mammography facilities was used to construct indices that represented separate domains of quality: technical attributes, educational practices, and tracking of clients. While some variation in the quality of mammography services was found, there were no significant differences between the two race categories in the mean scores for each of three quality indices. Thus, variation in quality of screening mammographic services does not appear to be race linked.

[Localization of non-palpable breast lesions with black carbon powder (experience of the Catholic University of Louvain)]

PURPOSE

The authors report their experience in presurgical localization of non palpable lesions with black carbon powder.

MATERIALS AND METHODS

153 cases of primary tumorectomies and mastectomies have been reviewed. The suspension is prepared in the hospital's pharmacy, the procedure is performed days or weeks before scheduled surgery without diffusion in the surrounding tissues.

RESULTS

In 92% of cases, the carbon marker was observed less than 5 mm from the target and no significant interference with the pathologic diagnosis has been observed.

CONCLUSION

Patient tolerance is good and providing close collaboration between the different members of the treating team, the authors believe that this technique may be a good alternative to wire localization.

Clinically challenging mammographic artifacts: a pictorial guide

Artifacts on mammographic images detract from the overall quality of the images and often present clinical and technical troubleshooting difficulties for the interpreting radiologist, technologist, and medical physicist and for the equipment and processor service personnel. This presentation demonstrates several types of mammographic artifacts that may pose a clinical challenge. They are arranged in the following categories: (1) particularly dangerous artifacts, (2) masses, (3) calcifications, (4) density variations, and (5) miscellaneous artifacts. Examples of such findings as summation shadows, normal anatomic variations, and incorrect positioning are also demonstrated as artifacts in this guide, because they may affect image quality or patient radiation dose. Under the Mammography Quality Standards Act, the lead interpreting physician has the responsibility for ensuring that the facility meets quality assurance requirements and is required to follow up with the technologist on poor-quality images. It is vital to recognize and correct for artifacts, whether they simulate non-existent lesions or obscure real pathology, because misinterpretation can lead to undesirable consequences.

Interval cancer peer review in East Anglia: implications for monitoring doctors as well as the NHS breast screening programme

AIM

To devise a method for reviewing interval cancers that will both educate radiologists and facilitate improvement of breast screening practice. To evaluate different methods for case classification to find one that best serves this purpose.

METHOD

The method of peer review and the means by which interval cancers are classified is described. The way in which cases are designated false-negative is an issue of acceptability for radiologists, and so three different methods are evaluated. Each is applied to the data set collected in this region over a 3-year period.

RESULTS

For cases read by five readers, when a consensus method was used for classifying cases, the proportion of cases classified as false-negative was 14%. Using a method in which only one of the five readers had to classify a case as false-negative for it to be categorized as such, the proportion of false-negative cases rose to a maximum of 38%. The minimum proportion of cases that could be considered to be false-negative was 6% and was obtained when all five readers had to classify a case as false-negative for it to be so categorized. Consistent with its majority viewpoint, the consensus method gave results for proportions of total cases classified as false-negative which were similar to those given by methods in which cases are classified as false-negative if either three of five readers, or at least 60% of readers, classified it as such.

CONCLUSION

For the peer review method to achieve its dual aims of educating radiologists and auditing performance, the participating radiologists must share ownership of the results and view the analysis as fair. The method used to classify interval cancers as false-negative will influence the number so classified. A consensus method has been found to give a result that is both fair and acceptable to our radiologist. Using this method 16% of all reviewed cases were classified as false-negative and 60% as true interval cancers. Britton, P. D. (2001). Clinical Radiology56, 44-49.

Impact of mammographic interval on stage and survival after the diagnosis of contralateral breast cancer

BACKGROUND

Following treatment for primary breast cancer, annual mammography and regular clinical breast examination is advised. The aim of this study was to investigate whether annual mammography resulted in an improvement in stage of contralateral breast cancers compared with mammography performed at a longer interval.

METHODS

This was a retrospective analysis of patients treated for breast cancer, who developed a contralateral breast cancer between 1977 and 1998. Patients were stratified into two groups according to mammographic interval.

RESULTS

Data were available for 275 patients who developed contralateral breast cancer during follow-up. Annual mammography was performed in 51 per cent; these patients were a mean of 5 years younger at diagnosis. Patients who had annual or biennial mammography had comparable rates of impalpable contralateral breast cancer, 30 and 27 per cent respectively. The tumours were of favourable stages in 60 and 58 per cent respectively. Five-year disease-free survival following diagnosis of contralateral breast cancer was 75 per cent in both groups. When the contralateral lesion was detected by mammography, disease-free survival was better, irrespective of the stage of the ipsilateral breast cancer.

CONCLUSION

No difference was found between the two groups in stage distribution and disease-free survival after the diagnosis of contralateral breast cancer. Survival was better in patients in whom the contralateral breast cancer was first detected by mammography.

Mammography screening in Norway: results from the first screening round in four counties and cost-effectiveness of a modeled nationwide screening

OBJECTIVE

To evaluate whether the results of the first screening round in the Norwegian Breast Cancer Screening Program predict future mortality reduction and to explore the cost-effectiveness of the program.

METHODS

The results of surrogate measures were calculated and compared with the targets. A cost-effectiveness analysis was performed assuming a nationwide program starting in 1996 with an attendance rate of 80% and a mortality reduction of 30%.

RESULTS

The attendance rate was 79.5% and the detection rate was 0.67%. The proportion of invasive tumors smaller than 15 mm was 53.1%, and 21.7% of the patients who underwent axillary surgery had lymphatic metastasis. The C/E ratios were found to be 3750 US dollars (USD) per year of life saved and 86,045 USD per life saved.

CONCLUSION

The results of the first screening round will lead to a mortality reduction of at least 30%. The cost-effectiveness analysis shows that it is possible to run a highly cost-efficient screening program in Norway.

Reproducibility--an important factor determining the quality of computer-aided detection (CAD) systems

PURPOSE

To test the reproducibility of markings on mammography films set by a commercial computer aided detection (CAD) system.

PATIENTS AND METHODS

One hundred unilateral mammography examinations (each in CC and MLO) of 100 patients with mammographically detected suspicious foci, which were histopathologically proven to be malignant, were scanned three times with the CAD system, retrospectively. Every fifth patient of the institutional tumor case sampler was enrolled in the study. Only cases with one visible lesion were included in the study. Reproducibility and sensitivity (in both the strict and the broader sense) were determined. Strict sensitivity means the correct set of markers in both images, whereas broader sensitivity means the correct set in at least one of the images. Sixteen of 100 malignancies were indicated by focal suspicious microcalcification clusters, 53 tumors by masses and 31 cases by both signs of breast cancer. The CAD evaluation was divided into only two different markers: one for microcalcifications and one for masses. Thus, 47 (16+31) tumor-induced microcalcifications and 84 (53+31) malignancy-related masses were checked using the CAD system.

RESULTS

Eighteen of 100 unilateral mammography examinations revealed identical patterns in all three scans (18% reproducibility). Eleven of 47 suspicious focal microcalcification clusters and 43/84 masses were correctly marked on both mammographic views in all three CAD scans (strict and broader sensitivity, 23.4 and 51.1%, respectively). Six of 47 microcalcification clusters and 8/84 masses were totally missed in all images by the system (false negative rate, 12.8 and 9.6%, respectively).

CONCLUSION

Reproducibility is essential for CAD systems. Currently, reproducibility of the used CAD system appears to be insufficient for clinical routine. Improvement of the system characteristics would make such systems valuable as a 'second reader' in clinical examination.

Effect of variations in operational definitions on performance estimates for screening mammography

RATIONALE AND OBJECTIVES

The Mammography Quality Standards Act requires practices to measure limited aspects of their performance. The authors conducted this study to calculate the differences in measurements of sensitivity and specificity due only to differences in the definitions used in the analysis. This included definitions for case inclusion.

MATERIALS AND METHODS

Data from the New Mexico Mammography Project for January 1991 to December 1995 on 136,540 women who underwent screening mammography were analyzed. A starting definition was created for each performance measure. The components of the definition were varied, and estimates of sensitivity and specificity for the different definitions were calculated.

RESULTS

Sensitivity was lower and specificity was higher when assessed on the basis of the results of all imaging performed in the screening work-up rather than on the initial screening examination alone. Sensitivity was higher and specificity was lower in women who did not undergo rather than in women who did recently undergo a previous examination. When the definition of a positive examination included cases that were recommended for short-term follow-up, the work-up sensitivity was slightly higher and the work-up specificity was considerably lower. Longer follow-up times for determining the diagnosis of cancer were associated with decreasing sensitivity, particularly when the follow-up period extended beyond 12 months.

CONCLUSION

Variations in the operational definitions for measures of mammographic performance affect these estimates. To facilitate valid comparisons, reports need to be explicit regarding the definitions and methods used.

Regulating radiology: ethical issues in mammography and federal legislation

One in nine women can expect to develop breast cancer over the course of a lifetime, which suggests that a posture of vigilance is appropriate. The form of breast imaging known as mammography will detect masses that self-examination and yearly clinical examinations may miss. Given that most types of breast cancer are not clinically preventable, early detection of such masses offers the best opportunity for survival for the affected women. Recognizing the need to ensure quality testing and interpreting procedures for so many women, the federal government has enacted legislation that requires breast imagers to read 240 mammograms in 6 months to qualify for certification and another 960 mammograms in the following 2 years. The burdensome nature of these requirements has had the effect of reducing the number of radiologists certified to read mammograms, and this has decreased the overall availability of this service to women. I explore two possible rationales for instituting such strict federal regulation of breast imagers: that breast cancer is more prevalent than other diseases that affect women and that legislating such high standards ensures the accuracy of interpretation. On neither ground is such legislation justified. Instead, I contend that this regulation was instituted as a way for politicians to make up for disregarding women and women's health concerns in the past by focusing on a current issue that predominantly affects women. As a consequence, I argue that more women may be harmed than benefited by such legislation.

Mammographic image quality and exposure in South East Asia

Generally there is a significant delay before optimized performance of mammography is fully realized in the developing countries. To evaluate the status of mammographic performance, a survey of mammographic image quality and exposure was performed in nine hospitals from four selected South East Asian countries. The entrance exposure on the surface of the American College of Radiology (ACR) mammographic phantom (ACR-RMI model 156) was made using both thermoluminescent dosimeters (TLDs) and an ionization chamber. The TLDs were mailed from the University of Wisconsin Radiation Calibration Laboratory (UWRCL) to the cooperating hospitals. The surveyed hospitals processed the images and returned them to the UWRCL for subsequent evaluation of the image quality of the mammographic phantom. Machine-specific data, technique factors and sensitometric data were also obtained. At 28 kVp, the mean entrance exposure is 0.91 R (0.46 to 2.6 R), mean glandular dose is 1.61 mGy (0.90 to 4.15 mGy), mean optical density is 1.37 (0.66 to 2.30), mean total phantom image score is 9.1(4-12). Only three of the nine hospitals tested achieved an acceptable score above the minimum 10. Results for 25 and 30 kVp showed similar trend. The variation between the ion chamber measurements and TLD measurements ranged from 4 to 24%. There is a wide variation in the image quality and entrance exposure among hospitals in South East Asia. There is a need for a quality assurance program. The factors that cause low score in the phantom images must be corrected. Calibration and the use of appropriate ionization chambers for mammography is important.

Additional factors for the estimation of mean glandular breast dose using the UK mammography dosimetry protocol

The UK and European protocols for mammographic dosimetry use conversion factors that relate incident air kerma to the mean glandular dose (MGD) within the breast. The conversion factors currently used were obtained by computer simulation of a model breast with a composition of 50% adipose and 50% glandular tissues by weight (50% glandularity). Relative conversion factors have been calculated which allow the extension of the protocols to breasts of varying glandularity and for a wider range of mammographic x-ray spectra. The data have also been extended to breasts of a compressed thickness of 11 cm. To facilitate the calculation of MGD in patient surveys, typical breast glandularities are tabulated for women in the age ranges 40-49 and 50-64 years, and for breasts in the thickness range 2-11 cm. In addition, tables of equivalent thickness of polymethyl methacrylate have been provided to allow the simulation for dosimetric purposes of typical breasts of various thicknesses.

[Radiologic analysis of interval cancers in the screening program called Florence Woman Project]

PURPOSE

The aim of the present study was to provide data on interval cancer incidence after the first round of the screening program in the city of Florence, and to provide and discuss the results of the review of previous screening mammograms.

MATERIAL AND METHODS

The screening program "Progetto Firenze Donna" involves all women age 50 to 69 years resident in the city of Florence. In the interval from the end of the first and the start of the second screening round 51 interval cancers were identified, of which 41 were available for radiological review. Films were reviewed by expert screening radiologists, not involved in the program and blinded to the final diagnosis, according to the review criteria recommended by the UK Guidelines for radiologists (blind and informed review).

RESULTS

Sensitivity (screening errors/total) was different among blind reviewers (reader A = 7.3%, reader B = 14.6%), as well as specificity which shows an inverse pattern (reader A = 98.4%, reader B = 97.6%). Informed review classified 5 cases as "screening error" (12.2%), 11 as "minimal sign" (26.8%) and 25 as "occult" (61%). Informed review classified a higher proportion of cases as "minimal sign" (minimal abnormalities are better perceived with the knowledge of the site and the pattern of subsequent cancer).

DISCUSSION AND CONCLUSIONS

Analysis of interval cancers is fundamental for the quality control of a screening program. According to this experience, informed review tends to overestimate "minimal signs" in the cancer site and should not be used (or "minimal signs" should be anyhow assumed as negative). Identification of interval cases as "minimal signs" may be influenced by individual variability. Standard criteria should be adopted to identify and review/classify interval cancers to allow comparisons between different programs.

MASTOS: Mammography Simulation Tool for design Optimization Studies

Mammography is a high quality imaging technique for the detection of breast lesions, which requires dedicated equipment and optimum operation. The design parameters of a mammography unit have to be decided and evaluated before the construction of such a high cost of apparatus. The optimum operational parameters also must be defined well before the real breast examination. MASTOS is a software package, based on Monte Carlo methods, that is designed to be used as a simulation tool in mammography. The input consists of the parameters that have to be specified when using a mammography unit, and also the parameters specifying the shape and composition of the breast phantom. In addition, the input may specify parameters needed in the design of a new mammographic apparatus. The main output of the simulation is a mammographic image and calculations of various factors that describe the image quality. The Monte Carlo simulation code is PC-based and is driven by an outer shell of a graphical user interface. The entire software package is a simulation tool for mammography and can be applied in basic research and/or in training in the fields of medical physics and biomedical engineering as well as in the performance evaluation of new designs of mammography units and in the determination of optimum standards for the operational parameters of a mammography unit.

Image quality and dose in film-screen magnification mammography

Extended exposure times in magnification mammography are a result of the reduced X-ray tube currents required for a small focal spot. The consequences of this are the potential for reduced image quality through motion blur during exposure as well as the onset of film reciprocity law failure. Previous investigators have suggested increasing the X-ray tube potential as a practical mechanism for reducing exposure times in magnification mammography and have demonstrated negligible image quality degradation at least up to 32 kVp. This paper describes a film-screen magnification mammography study that expands upon this previous work to investigate the magnitude of the reduction of breast mean glandular dose and exposure time and the changes in subjective image quality (visibility of low contrast details in an RMI 152 phantom) with increases in tube potential between 28 kVp and 35 kVp. Measures of changes in the radiographic contrast and in the scatter-to-primary ratio (SPR) in magnification geometry as a function of tube potential were also obtained. Evidence for reciprocity law failure was also assessed. For a constant film optical density, increasing the X-ray tube potential from 28 kVp to 35 kVp reduced the mean glandular dose from 3.9 mGy to 2.7 mGy and reduced the exposure time from 3.2 s to 1.0 s. Over this range, the detection rate of fibrils and microcalcification-mimicking specks did not vary with tube potential at the 0.05 level of significance. It was found that only the low contrast mass detail detection rate at 35 kVp was significantly less than that at 28 kVp. The measured radiographic contrast decreased with tube potential and the SPR increased with tube potential. However, both changes were weak, and linear regressions determined that the 95% confidence intervals of the slopes relating both contrast and SPR with tube potential encompassed zero. It is concluded that magnification mammography performed at 34 kVp yields significant reductions in exposure time and mean glandular dose, with a detail detection capability similar to that at 28 kVp.

Objectivity and accuracy of mammogram interpretation using the BI-RADS final assessment categories in 40- to 49-year-old women

To determine if use of the five final assessment categories of the American College of Radiology's Breast Imaging Reporting and Data System (BI-RADS) improved objectivity or accuracy of mammographic evaluation in 40- to 49-year-old women, fifty mammograms of 40- to 49-year-old women that were obtained at a tertiary referral teaching hospital were classified according to those five final assessment categories. The mammograms were blinded to six American Osteopathic Board of Radiology-certified radiologists who were asked to classify each mammogram within the five final BI-RADS categories based on the mediolateral oblique and craniocaudal views presented. No history was allowed. Use of the BI-RADS five final assessment categories provided moderate interobserver objectivity, moderately high agreement among the radiologists' interpretation (reliability), and moderate accuracy of interpretation (validity) when compared to criterion. Moderate interobserver reliability and accuracy has been previously identified; however, no scientific review of the BI-RADS five final assessment categories in 40- to 49-year-old females was discovered in the current literature. No overall improvement of objectivity or accuracy was demonstrated using the five final assessment categories of the BI-RADS lexicon in 40- to 49-year-old women.

Influence of anode/filter material and tube potential on contrast, signal-to-noise ratio and average absorbed dose in mammography: a Monte Carlo study

The comparative performance of mammographic X-ray systems that use different anode/filter combinations has been assessed for screen-film and digital imaging. Monte Carlo techniques have been used to calculate average glandular dose as well as contrast and signal-to-noise ratio for imaging two test details. Five anode/filter combinations have been studied to establish the potential for dose saving or image quality improvement. For screen-film mammography, it was found that little benefit is gained by changing from a standard 28 kV molybdenum/molybdenum spectrum for breasts up to 6 cm thick. For thicker breasts, where the tube potential for the standard technique might be increased, 20% improvement in contrast can be achieved without dose penalty using molybdenum/rhodium or rhodium/rhodium spectra, whereas dose savings of more than 50% can be attained whilst maintaining contrast using tungsten/rhodium or rhodium/aluminium spectra. In digital mammography, a molybdenum/molybdenum spectrum delivers the lowest dose for a 2 cm breast, but gives the highest dose for thicker breasts. Tungsten/rhodium or rhodium/aluminium spectra provide the lowest doses at greater thicknesses. It is concluded that for screen-film mammography, molybdenum/molybdenum is the spectrum of choice for all but the thickest or most glandular breasts. In digital mammography, an alternative spectrum is preferable for breasts thicker than 2 cm.