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PubMed2004

International comparison of performance measures for screening mammography: can it be done?

OBJECTIVE: Published screening mammography performance measures vary across countries. An inter-national study was undertaken to assess the comparability of two performance measures: the recall rate and positive predictive value (PPV). These measures were selected because they do not require identification of all cancers in the screening population, which is not always possible. SETTING: The screening mammography programs or data registries in 25 member countries of the International Breast Cancer Screening Network (IBSN). METHODS: In 1999 an assessment form was distributed to IBSN country representatives in order to obtain information on how screening mammography was performed and what specific data related to recall rates and PPV were collected. Participating countries were then asked to provide data to allow calculation of recall rates, PPV and cancer detection rates for screening mammography by age group for women screened in the period 1997-1999. RESULTS: Twenty-two countries completed the assessment form and 14 countries provided performance data. Differences in screening mammography delivery and data collection were evident. For most countries, recall rates were higher for initial than for subsequent mammograms. There was no consistent relationship of initial to subsequent PPV, although PPV generally decreased as the recall rate increased. Recall rates decreased with increasing age, while PPV increased as age increased. CONCLUSION: Similar patterns for mammography performance measures were evident across countries.However, the development of a more standardized approach to defining and collecting data would allow more valid international comparisons, with the potential to optimize mammography performance. At present, international comparisons of performance should be made with caution due to differences in defining and collecting mammography data.

Breast Neoplasms↗
PubMed1992

One-view versus two-view mammography in baseline screening for breast cancer: a review.

Two-view mammography is generally preferred as an initial screening examination because the number of missed carcinomas and false positive results in one-view mammography is considered too large. The present review was performed to assess the difference in screening quality between one- and two-view mammography. Nineteen previous studies were reviewed and differences in sensitivity as well as specificity between two-view and one-view mammography were calculated. The results ranged from -5.7% to 19.4% (median 3.9%), and 2.7% to 36.1% (median 14.8%), respectively, and indicate a higher screening quality of two-view mammography. However, in the studies considered there is a large variation in study population, screening tests used and assessment of disease outcome, which makes the numerical results less conclusive. None of the studies provided adequate information for deciding whether two-view mammography in baseline screening for breast cancer is preferable to one-view mammography. If a screening programme using one-view mammography has already achieved high sensitivity and specificity, the value of an additional craniocaudal view is only marginal.

Breast Neoplasms↗
PubMed2005

Women's satisfaction with their mammography experience: results of a qualitative study.

OBJECTIVE: Many steps in getting a mammogram may produce a less than satisfactory experience. Dissatisfaction with mammography could lead to lower routine mammography adherence. The purpose of this study was to use qualitative research methods to assess patient satisfaction with all stages of the mammography experience. METHODS: Eleven focus groups were conducted with 103 women in rural (N=6) and urban (N=5) communities. Separate groups were held for African-American, non-Hispanic White, and Hispanic women. Participants spoke English, were 40 years of age or older, had a mammogram within the past three years, and had no history of cancer. Transcripts were analyzed for major themes related to mammography satisfaction. RESULTS: Participants described 39 variables that affected their mammography satisfaction that may be categorized into seven primary themes: (1) appointment scheduling, (2) facility, (3) general exam, (4) embarrassment, (5) exam discomfort/pain, (6) treatment by the technologist, and (7) reporting results. The most common issues voiced were convenience and ease of scheduling appointments and follow-up tests, waiting room time and comfort, treatment by technologists, pain, and results reporting procedure and timing. CONCLUSIONS: Satisfaction was not limited to the mammography procedure itself, but encompassed the entire experience from appointment scheduling to receipt of results and arranging follow-up. These findings indicated a variety of areas that mammography facilities might address to enhance mammography satisfaction.

Adult↗
PubMed2004

Microdosimetric analysis of various mammography spectra: lineal energy distributions and ionization cluster analysis.

In view of recent recommendations on the frequency and the starting age of mammography screening in healthy women, it is desirable to quantify the enhanced relative biological effectiveness (RBE) of mammography X rays compared to hard X rays. While there is little doubt that the former are more potent in inducing biological damage than the latter, the magnitude of the effect is still hotly debated in the literature. We used Monte Carlo simulations and track structure analysis in micrometer and nanometer volumes to investigate differences in distributions of lineal energy and ionization clusters for a range of mammography X-ray qualities. Dose-averaged lineal energies, (yD), in breast tissue for various mammography qualities were found to result in quality factors about 40% higher than unity. Among the various mammography qualities studied, the popular molybdenum/molybdenum target/filter combination was found to have the highest (yD) in 1-microm spheres (about 5.0 keV/microm near the entrance surface of breast tissue). In 10-nm radius spheres, the mean ionization cluster order was found to be about 35% higher in mammography X rays compared to 300 keV electrons (roughly representing 60Co or 192Ir photon radiation). In even smaller spheres (2 nm radius), no significant differences were observed for the mean ionization cluster order between mammography X rays and 300 keV electrons. We conclude that the potential of mammography X rays to induce biological damage is probably not much higher than a factor of two compared to hard X rays.

Breast↗
PubMed1995

Screening mammography in community practice: positive predictive value of abnormal findings and yield of follow-up diagnostic procedures.

OBJECTIVE: The purpose of this study was to gather from 50 community mammography practices that were included in the National Survey of Mammography Facilities data concerning abnormal findings on screening mammograms to determine the frequency of various recommendations made for patients who had abnormal findings and to compare these recommendations with the frequency with which the procedures were actually performed. We also determined the positive predictive value of screening mammograms (the number of cancers detected per 100 abnormal findings) and the yield (the number of cancers detected per 100 procedures done) of various diagnostic procedures done because of abnormal findings. MATERIALS AND METHODS: We identified 1717 screening mammograms done in the last half of 1991 that had abnormal findings. Radiologic recommendations and follow-up procedures, including repeat standard (screening) mammography, additional mammographic views, sonography, clinical breast examination, needle aspiration, needle biopsy, and open biopsy, were identified for all of the cases from the radiologic records, and follow-up data were obtained from referring physicians. The positive predictive value and yield in the National Survey of Mammography Facilities were compared with data from the mammography screening practice of the University of California at San Francisco (UCSF), a facility noted for its clinical efficiency. RESULTS: We estimate that 11% of all screening mammograms resulted in a recommendation for further diagnostic procedures. These 1717 mammograms with abnormal findings led to the following recommendations and procedures: repeat standard (screening) mammography, 610 (recommended)/635 (performed); additional mammographic views, 785/707; sonography, 400/345; biopsy, 189/229; and needle aspiration, 21/51. More procedures were done than were recommended in some cases because the results of certain procedures often led to the performance of other, additional procedures. The positive predictive value for screening examinations with abnormal findings was 3.5%, and the yield for open biopsy was 21%. In the UCSF data base, the positive predictive value for examinations with abnormal findings was 10%, and the yield for open biopsy was 34%. CONCLUSION: The positive predictive value for examinations with abnormal findings and the yield for diagnostic procedures performed as a result of abnormal findings in 50 community radiologic facilities were higher than those reported in some earlier studies, a fact that raised concern about the induced cost of screening mammography. However, these values were low compared with those in the UCSF data base. This fact was particularly true of repeat standard (screening) mammography.

Adult↗
PubMed2001

Association of recall rates with sensitivity and positive predictive values of screening mammography.

OBJECTIVE: The performance of screening mammography is measured mainly by its sensitivity, positive predictive value, and cancer detection rate. Recall rates are also suggested as a surrogate measure. The main objective of this study was to measure the effect on sensitivity and positive predictive value as recall rates increase in the community practice of mammography. MATERIALS AND METHODS: Mammography and pathology data are linked in the Carolina Mammography Registry, a population-based registry of screening mammography. Our mammography database is created from prospectively collected data from mammography facilities; the data include information on the woman and the imaging studies. Our pathology database is created from prospectively collected breast pathology data received from pathology sites and the Central Cancer Registry. Women in the registry who were 40 years old and older and who underwent screening mammography between January 1994 and June 1998 were included. "Recall rate" was defined as the percentage of screening studies for which further workup was recommended by the radiologist. RESULTS: The study included 215,665 screening mammograms. The mean age of the women was 56 years. The recall rates of the average practice ranged from 1.9% to 13.4%. Sensitivity rose from a mean of 65% in the lowest recall rates to 80.2% at the highest level of recall rates. The positive predictive value of screening decreased from 7.2% in the lowest level of recall to 3.3% in the highest. As recall rates increased, sensitivity increased very little beyond a recall rate of 4.8%, and positive predictive value began decreasing significantly at a recall rate of 5.9%. CONCLUSION: Practices with recall rates between 4.9% and 5.5% achieve the best trade-off of sensitivity and positive predictive value.

Adult↗
PubMed2005

Detection of breast cancer on screening mammography allows patients to be treated with less-toxic therapy.

OBJECTIVE: Therapy for breast cancer is accompanied by acute and chronic toxicity. Little research has been conducted to determine the impact of the mode of breast cancer detection on the likelihood of receiving different types of treatment. The objective of this study was to determine whether detection of breast cancer on screening mammography is associated with less-toxic therapy. MATERIALS AND METHODS: The study group for this retrospective cohort study consisted of 992 women with invasive breast cancer detected on screening mammography (n = 460) or at physical examination (n = 532) at a single institution between 1990 and 2001. To address the generalizability of study findings, we compared the characteristics of study participants with those diagnosed with breast cancer in a population-based mammography registry. RESULTS: The patients whose breast cancer was detected on screening mammography more frequently had lymph nodes free of metastases (84% vs 58%, p < 0.0001), had smaller tumors (1.5 vs 2.9 cm, p < 0.0001), were more likely to be treated with breast conservation (56% vs 32%, p < 0.0001), and were less likely to be treated with chemotherapy (28% vs 56%, p < 0.0001). In a multivariate analysis with adjustments for age and functional status, patients whose cancer was detected at physical examination were more than twice as likely to undergo mastectomy (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.9-3.3) and nearly three times as likely to be treated with chemotherapy (OR, 2.9; 95% CI, 2.1-3.9). For younger women (40-49 years old), the likelihood of receiving chemotherapy was more than doubled if the cancer was detected at physical examination rather than on screening mammograms (OR, 2.3; 95% CI, 1.3-4.0). For older women (>/= 70 years old), patients whose cancer was detected at physical examination were five times more likely to undergo mastectomy (OR, 5.8; 95% CI, 3.2-10.5) and four times more likely to receive chemotherapy (OR, 4.6; 95% CI, 1.6-13) than the group whose tumors were detected on screening mammography. CONCLUSION: Breast cancers detected on screening mammography are smaller, are less likely to metastasize to lymph nodes, and are more likely to be treated with breast conservation and without chemotherapy. These findings provide an additional rationale for performing screening mammography, especially for women at age extremes for whom the survival benefit of screening mammography is debated.

Adult↗
PubMed2003

Digital mammography: a review of technical development and clinical applications.

For detecting and diagnosing breast cancer at its earliest stage, mammography is the most sensitive technique currently available and is therefore the method of choice. Screen-film mammography has been used successfully as a screening test for breast cancer for > 2 decades. However, conventional mammography has substantial limitations and, therefore, digital mammography systems have been developed to improve image quality and overcome the limitations of screen-film technique limitations. Herein we discuss the differences between screen-film and digital mammography systems and the processes related to digital mammography that differ from conventional mammography, including detector technology, digital image formation, image processing, image display, and image archival. Finally, we review the results from currently available clinical trials regarding the performance of digital mammography and discuss clinical implications such as cost-effectiveness.

Breast Neoplasms↗
PubMedDate not supplied

Factors influencing acceptance of mammography: implications for enhancing worksite cancer control.

PURPOSE: The purposes of this article are to review what is known about participation in mammography programs and to propose several elements that warrant consideration in planning mammography screening programs in occupational settings. Breast cancer is the most common female cancer. Regular screening programs including mammography, clinical breast examination, and monthly breast self-examination can reduce breast cancer deaths by as much as 35%. However, mammography is underutilized. This review examines factors affecting acceptance of mammography and possible worksite-based strategies to increase its appropriate use. SEARCH METHODS: We identified the sources cited in this review through a combination of literature searches of computerized data bases, backward searches of reference lists, and contacts with active investigators. The article includes a selected subset of the most recent and relevant references. SUMMARY OF IMPORTANT FINDINGS: A variety of individual factors, environmental influences, health care system factors, and employer factors influence the acceptance of mammography. Workplace mammography programs can be especially important in reducing access barriers. MAJOR CONCLUSIONS: Six program elements which are central to planning successful worksite mammography programs are discussed: location and facilities; health professional involvement; the range of services; education and referral; employer policies, and plans for follow-up and repeat screening.

Adult↗
PubMed2000

Performance of screening mammography among women with and without a first-degree relative with breast cancer.

BACKGROUND: Although it is recommended that women with a family history of breast cancer begin screening mammography at a younger age than average-risk women, few studies have evaluated the performance of mammography in this group. OBJECTIVE: To compare the performance of screening mammography in women with a first-degree family history of breast cancer and women of similar age without such history. DESIGN: Cross-sectional. SETTING: Mammography registries in California (n = 1), New Hampshire (n = 1), New Mexico (n = 1), Vermont (n = 1), Washington State n = 2), and Colorado (n = 1). PARTICIPANTS: 389 533 women 30 to 69 years of age who were referred for screening mammography from April 1985 to November 1997. MEASUREMENTS: Risk factors for breast cancer; results of first screening examination captured for a woman by a registry; and any invasive cancer or ductal carcinoma in situ identified by linkage to a pathology database, the Surveillance, Epidemiology, and End Results program, or a state tumor registry. RESULTS: The number of cancer cases per 1000 examinations increased with age and was higher in women with a family history of breast cancer than in those without (3.2 vs. 1.6 for ages 30 to 39 years, 4.7 vs. 2.7 for ages 40 to 49 years, 6.6 vs. 4.6 for ages 50 to 59 years, and 9.3 vs. 6.9 for ages 60 to 69 years). The sensitivity of mammography increased significantly with age (P = 0.001 [chi-square test for trend]) in women with a family history and in those without (63.2% [95% CI, 41. 5% to 84.8%] vs. 69.5% [CI, 57.7% to 81.2%] for ages 30 to 39 years, 70.2% [CI, 61.0% to 79.5%] vs. 77.5% [CI, 73.3% to 81.8%] for ages 40 to 49 years, 81.3% [CI, 73.3% to 89.3%] vs. 80.2% [CI, 76.5% to 83.9%] for ages 50 to 59 years, and 83.8% [CI, 76.8% to 90.9%] vs. 87.7% [CI, 84.8% to 90.7%] for ages 60 to 69 years). Sensitivity was similar for each decade of age regardless of family history. The positive predictive value of mammography was higher in women with a family history than in those without (3.7% vs. 2.9%; P = 0.001). CONCLUSIONS: Cancer detection rates in women who had a first-degree relative with a history of breast cancer were similar to those in women a decade older without such a history. The sensitivity of screening mammography was influenced primarily by age.

Adult↗
PubMed1998

[Value of mammography and ultrasound in diagnosis of breast carcinoma].

The assessment of the value of mammography and ultrasound studies of the breast was the aim of this work. Mammography has consistently demonstrated its value as a good screening method, but also in the differentiation between several diagnoses. The sensitivity of the mammography is high with 85% to 90%. The specificity should be considered critically and can't be used in every case. But the use of additional methods of the mammography sometimes arrives more information. Therefore the mammography is the basic method for detection of early clinically occult cancer. Advantages of ultrasound are the better differentiation of cysts from solid lesions and the dissolution of dense breast masses in the mammography. However the mammary ultrasonography has more limitations than mammography. Some different kinds and materials for improving ultrasound are high resolution or colour Doppler ultrasound and the using of ultrasound contrast agent. At present mammasonography seems to be the most important additional method behind mammography.

Breast Neoplasms↗
PubMedDate not supplied

The effects of standard care counseling or telephone/in-person counseling on beliefs, knowledge, and behavior related to mammography screening.

PURPOSE/OBJECTIVES: To determine the most effective methods of increasing mammography adherence while also considering ease of intervention delivery in evolving healthcare systems. DESIGN: Experimental. SETTING: Women from a health maintenance organization and a large general medicine practice. SAMPLE: Women 50-85 years of age who had not had breast cancer and did not have a mammogram within the last 15 months. METHODS: Once consent and baseline information were obtained, women were randomized to receive in-person, telephone, or no mammography counseling. MAIN RESEARCH VARIABLES: Mammography adherence, perception of susceptibility to breast cancer, and benefits, barriers to, and knowledge of mammography. FINDINGS: Compared to standard care, telephone counseling was more than twice as effective at increasing mammography adherence, whereas in-person counseling resulted in almost three times the mammography adherence postintervention. Both telephone and in-person counseling are successful in changing perceived susceptibility, knowledge, barriers, and benefits. CONCLUSION: Both telephone and in-person counseling interventions were successful in changing beliefs, which, in turn, increased mammography adherence. IMPLICATIONS FOR NURSING PRACTICE: Interventions based on altering beliefs are effective for increasing mammography adherence.

Aged↗
PubMed2001

Is (99m)Tc-sestamibi scintimammography complementary to conventional mammography for detecting breast cancer in patients with palpable masses?

UNLABELLED: The aim of this trial was to evaluate in developing countries from different regions the diagnostic performance of (99m)Tc-sestamibi scintimammography (SM) in palpable breast lesions and to verify the clinical usefulness of a joint evaluation with mammography and SM. METHODS: From 10 countries, a total of 238 patients with palpable breast masses (n = 245) were included in this prospective multicenter trial. Prone SM was performed 10 min and 60-90 min (157 patients) after injection using an isotime acquisition of 10 min. Mammography was assessed by the same dedicated imaging radiologist according to breast imaging reporting and data system (BI-RADS) categories for malignancy and breast density. Masked SM findings and mammography findings were checked for a correlation with histopathology findings for excisional biopsy samples. Diagnostic values for breast cancer detection were calculated per lesion. RESULTS: Histopathology revealed 189 cancerous lesions and 56 benign lesions. The sensitivity and specificity of SM were 0.83 and 0.77, respectively. SM diagnostic values did not depend on the incidence of breast cancer in the country of origin or on the timing of imaging (early vs. delayed scans). On mammography, the technique yielded a sensitivity and specificity of 0.85 and 0.66, with 27 mammograms classified as BI-RADS category 1, 33 as category 2, 5 as category 3, 56 as category 4, and 124 as category 5. Thirty-seven lesions were considered to show increased radiologic density. No significant difference was found in SM diagnostic values among different BI-RADS categories or between the groups with low and high breast density. A sensitivity of 96% was calculated when SM and mammography results were combined, with 75% of all false-negative mammography findings classified as true-positive results by SM. CONCLUSION: SM complements mammography in patients with palpable masses and negative mammography findings.

Adult↗
PubMed2001

Inreach and outreach interventions to improve mammography use.

OBJECTIVE: to assess the effectiveness of patient-targeted interventions in increasing mammography use when performed outside (outreach) or inside the primary care medical setting (inreach). METHODS: We performed a meta-analysis of controlled interventions to increase mammography use in patients in the United States published between 1980 and February 2001. Interventions were classified by setting (inreach or outreach), mechanism of action (behavioral, cognitive, sociologic, or a combination), type of control group (active or usual care), number of strategies, and mode of delivery (static or interactive). Summary estimates were calculated with DerSimonian and Laird random effects models for each group of interventions. RESULTS: We included 66 studies with 98 separate interventions. Inreach and outreach interventions were equally effective in increasing mammography use. Compared to active controls, behavioral interventions with multiple strategies increased mammography use by 14.0% (95% CI, 8.7-19.2) in inreach and 18.7% (95% CI, 4.9-32.4) in outreach settings. Theory-based educational strategies delivered interactively increased mammography use by 10.7% (95% CI, 6.8-14.7) and 19.9% (95% CI, 10.6-29.1) in inreach and outreach settings, respectively. Interventions that combined behavioral and theory-based educational strategies with usual care controls increased mammography use by 14.0% (95% CI, 7.9-20.2) in inreach and 27.3% (95% CI, 14.7-40.0) in outreach settings. Finally, sociologic interventions increased mammography use by 10.7% (95% CI, 3.4-18.0) and 9.1% (95% CI, 1.7-13.3) in inreach and outreach settings, respectively. CONCLUSIONS: Inreach and outreach interventions to increase mammography use were similarly effective within intervention categories based on mechanism of action, mode of delivery, and type of control group. Ultimate decisions about intervention strategies will depend on the characteristics of the target population, practical considerations, and relative cost-effectiveness.

Breast Neoplasms↗
PubMedDate not supplied

Digital mammography: state of the art.

After completing this update on digital mammography, readers will: Understand some limitations of film-screen mammography. Know the potential advantages and disadvantages of digital mammography. Compare and contrast some different digital mammography systems. Describe how digital images are captured, processed, displayed and stored. Know how digital mammography affects radiation dose, exposure time and contrast resolution. Understand how digital images are transmitted. Be familiar with new techniques that build on digital mammography, such as 3-D mammography, digital subtraction mammography and computer-aided detection.

Breast Neoplasms↗
PubMed2003

Comparison of 99mTc-sestamibi scintimammography and dynamic MR imaging as adjuncts to mammography in the diagnosis of breast cancer.

PURPOSE: To compare the diagnostic accuracy of planar 99mTc-sestamibi scintimammography with dynamic contrast-enhanced MRI (CE-MRI) on the basis of histopathologic results, and to determine the clinical value of these methods as adjuncts to mammography. MATERIAL AND METHODS: A total of 90 consecutive women with 111 histopathologically verified breast lesions were enrolled in the study. Patients underwent scintimammography and CE-MRI in addition to mammography. Each finding was classified on a BI-RADS-like five-point rating scale describing the degree of suspicion for malignancy, and all findings were correlated with the histopathological results. RESULTS: The overall sensitivity/specificity/accuracy was 85%/59%/78% for mammography, 94%/47%/80% for CE-MRI, and 82%/75%/80% for scintimammography, respectively. CE-MRI showed higher sensitivity (p = 0.008), but its specificity was lower than scintimammography (p = 0.049). Using ROC analysis, significant improvement ( p = 0.034) was found between mammography and the combination of mammography + CE-MRI, while mammography + scintigraphy showed no higher diagnostic accuracy than mammography alone. CONCLUSION: If high sensitivity and spatial resolution are needed, CE-MRI is to be preferred in clinical practice as an adjunct to mammography, rather than scintigraphy.

Adult↗
PubMed2005

[The attendance of the first screening round (2002-2003) of the Hungarian organized breast cancer screening program and its effect on the number of diagnostic and screening mammography].

AIM: Organised, nationwide screening for breast cancer with mammography in the age group 45-65 years with 2 years screening interval started in Hungary in January 2002. The aim of this study is to analyze the attendance rate of breast screening programme, including the analysis of the ratio of screening and diagnostic mammography examinations. DATA AND METHODS: The data derive from the financial database of the National Health Insurance Fund Administration (NHIFA) covering the period 2000-2003. The ratio of women was calculated in the age group 45-65 years having either a screening mammography or a diagnostic mammography. The analysis was carried out for the years 2000-2001 (mainly opportunistic screening) before and 2002-2003 after the implementation of nationwide organized programme. RESULTS: In the years 2000-2001 7,26% of the women aged 45-65 had an opportunistic screening mammography while in 2002-2003 33,95% of the target population had screening mammography within the organized programme. During the same periods 19,67% (2000-2001) and 22,05% (2002-2003) of women aged 45-65 had a diagnostic mammography. Thus the total (screening and diagnostic) coverage of mammography increased from 25,85% (2000-2001) to 53,46% (2002-2003). CONCLUSIONS: The attendance of the Hungarian organized breast cancer screening programme - compared to the previous period before the implementation of the organized screening programme - is promising, although to achieve the expected results in mortality decrease a further improvement of the uptake is necessary.

Breast Neoplasms↗
PubMed1987

Mammography equipment: principles, features, selection.

1. Three-phase and constant potential generators may offer advantages over single-phase generators. These include shorter exposure times with less chance for motion unsharpenss, more adequate exposure and possible lower dose, and longer tube life. 2. Control of tube voltage in increments of 1 kVp are desirable for screen-film mammography and 2 kVp for xeromammography. 3. Tube loading limitations should be capable of allowing an adequate mA and mAs output. A mammography unit with a lower mA output may require longer exposure times with consequent motion unsharpness and/or higher dose. The maximum mA output is limited by the power rating of the tube and not by the power rating of the generator, which is usually much higher. Thus, tube rating charts rather than generator power rating should be used to compare the mA output of different mammography units. 4. Phototimer capability can reduce exam time, facilitate proper exposure, and reduce radiation dose. Units with a greater number of density steps and three or more photocell locations, one of which is near the edge of the film holder, provide better phototimer results. 5. A molybdenum target, beryllium window tube with 0.03 mm molybdenum added filtration is presently preferred for screen-film mammography. A tungsten target tube with 1 to 2 mm added aluminum filtration is advised for xeromammography. 6. Effective local spot size for contact mammography should be in the range of 0.2 to 0.5 mm. However, high resolution also requires sufficiently long source-to-image-receptor distances. Using measured focal spot size and source-to-image-receptor distance, it has been shown that some mammography units do not fully utilize the resolution capabilities of some available screen-film systems. On the other hand, a focal spot that is too small may limit the field size and lead to uneven energy distribution in the x-ray field. 7. In order to perform standard and supplementary mammographic projections, the C arm assembly must be capable of being located at multiple positions within a 180 degrees rotation. Greater degrees of rotation are not required. 8. The heat dissipation capability should be adequate to accommodate the anticipated work-load in terms of number of patients and patient scheduling. A mammographic unit with an anode heat capacity of 90,000 heat units or more should be adequate for most practices. A mammography unit with a heat capacity of 20,000 heat units or less may require waiting time between exposures or studies in a high-volume mammography practice. 9. The compression plate should be made of plastic, usually 1 to 4 mm thick.(ABSTRACT TRUNCATED AT 400 WORDS)

Female↗