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PubMed1999

Role of technetium tetrofosmin scintimammography in the diagnosis of malignant breast masses and axillary lymph node involvement: a comparative study with mammography and histopathology.

OBJECTIVE: To assess the role of Technetium-99m (99mTc) tetrofosmin scintimammography in the detection of breast cancer and involvement of axillary nodes. DESIGN: Open study. SETTING: General hospital, Turkey. SUBJECTS: 128 women who presented with masses in the breast. INTERVENTIONS: Scintimammography, standard mammography, and either excision or fine-needle aspiration biopsy to confirm the diagnosis. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive value of scintimammography compared with mammography. RESULTS: Sensitivity, specificity, and positive and negative predictive value (%) of 99mTc scintimammography were 95, 96, 97 and 92, respectively. The corresponding figures for standard mammography were 87, 26, 68 and 52. Scintimammography changed the 34 false positive mammograms into true negatives, at the expense of four false negatives. The sensitivity of scintimammography in detecting axillary lymph node metastases was 72% and specificity 100%. CONCLUSION: Scintimammography with 99mTc tetrofosmin seems to be of value in the detection of breast malignancy and axillary metastases. It may help to avoid unnecessary operations in patients whose mammograms do not give a definite diagnosis.

Adult↗
PubMed1994

Dual-energy digital mammography utilizing stimulated phosphor computed radiography.

Dual-energy subtraction is a radiographic technique for the acquisition of a material selective image by the weighted subtraction of low- and high-energy digital X-ray images. This is achieved by exploiting the energy dependence of the X-ray attenuation components in the image. This can allow the removal of background morphology to enhance the presentation of otherwise obscured details. The detection of microcalcifications in a mammogram by dual-energy techniques has previously been investigated. These investigations indicated that, using dual-energy techniques, small microcalcifications could be extracted from the background breast morphology with sufficient signal to noise ratio (SNR) to be full visualized. The authors present the extension of a theoretical dual-energy model to incorporate practical considerations and then compare the results with experimentally derived data using a commercially available computed radiography system. In particular the extended model now takes into account the energy dependent detective quantum efficiency of a system. This is thought to be a major factor in reducing the efficiency of dual-energy mammography. The theoretical model predicts that dual-exposure dual-energy mammography, utilizing HRIII image plates, could not provide a detail SNR of five for calcifications smaller than 470 mu m. The experimental results verify this and indicate that dual-energy subtraction mammography, utilizing computed radiography, is currently not a viable technique for the detection of clinically significant microcalcifications. Further advances in X-ray image detector efficiency will be required if the full potential of this technique is to be achieved.

Breast Diseases↗
PubMed1997

Determination of average glandular dose with modern mammography units for two large groups of patients.

Until recently, for mammography Mo anode-Mo filter x-ray tube assemblies were almost exclusively used. Modern mammography units provide the possibility to employ a variety of anode-filter combinations with the aim of adapting the x-ray spectrum to compressed breast thickness and composition. The present contribution provides information on the radiation exposure of two large groups of patients (one of 1678 and one of 945 women) who were mammographed with modern x-ray equipment, and on the dosimetry necessary for the evaluation. For dosimetric purposes spectral information is essential. X-ray spectra have been determined for various anode-filter combinations from measurements with a Ge detector. Based on these spectra, conversion factors from air kerma free in air to average glandular dose (g factors) have been calculated for different anode-filter combinations, compressed breast thickness ranging from 2 to 9 cm and breast compositions varying from 0 to 100% glandular tissue. Determinations of various quantities, including entrance surface air kerma (ESAK), tube output, tube loading (TL), fraction of glandular tissue (FGL) and compressed breast thickness, were made during actual mammography. Average glandular dose (AGD) was determined using g factors corrected for tissue composition as well as g values for standard breast composition, i.e. 50% adipose tissue and 50% glandular tissue by mass. It is shown that, on average, the influence of the actual breast composition causes variations of the order of about 15%. For group 1 and group 2, the mean values of average glandular dose (using g factors corrected for tissue composition) were 1.59 and 2.07 mGy respectively. The number of exposures per woman was on average 3.4 and 3.6 respectively. The mean value of compressed breast thickness was 55.9 and 50.8 mm respectively. The mean age of group 1 was 53.6 years (for group 2 the age was not recorded). The fraction by mass of glandular tissue FGL decrease with increasing compressed breast thickness and age of patient (from 75% at 25 mm to 20% at 80 mm, and from 65% at 20 years to 30% at 75 years). For a medium-sized breast, i.e. a compressed breast thickness of 55 mm, FGL is about 35%, indicating that the standard mix (FGL = 50%) might need some modification, particularly because of additional evidence from another investigation with similar results on FGL.

Adipose Tissue↗
PubMed1998

Phase mammography--a new technique for breast investigation.

A new phase radiography technique for investigation and diagnosis of neoplasms in breast tissue is proposed. Forty-four mammography samples with adenocarcinoma that had been prepared after mastectomy were tested in a new phase radiography device. It was shown that the phase images manifest the changes in parenchyma structure due to malignancy and microcalcifications up to 50 microm in size. Results obtained were verified by histological examination. A contrast of the phase images of small microcalcifications and distortions of the stroma architecture ranges up to 40-60%; spatial resolution is about 20 microm. The proposed technique offers outstanding possibilities for digital mammography. The small and large details of structure manifest themselves with practically the same contrast. Phase images differ from those obtained in mammography and many details still require further decoding.

Adenocarcinoma↗
PubMed2003

Dual-energy imaging in full-field digital mammography: a phantom study.

A dual-energy technique which employs the basis decomposition method is being investigated for application to digital mammography. A three-component phantom, made up of plexiglas, polyethylene, and water, was doubly exposed with the full-field digital mammography system manufactured by General Electric. The 'low' and 'high' energy images were recorded with a Mo/Mo anode-filter combination and a Rh/Rh combination, respectively. The total dose was kept within the acceptable levels of conventional mammography. The first hybrid images obtained with the dual-energy algorithm are presented in comparison with a conventional radiograph of the phantom. Image-quality characteristics at contrast cancellation angles between plexiglas and water are discussed. Preliminary results show that a combination of a standard Mo-anode 28 kV radiograph with a Rh-anode 49 kV radiograph provides the best compromise between image-quality and dose in the hybrid image.

Algorithms↗
PubMed2006

Theoretical analysis of high-resolution digital mammography.

The performance of a high-resolution charge coupled device-based full-field digital mammography imager was analysed using a mathematical framework based on an adaptation of cascaded linear systems theory described by other investigators. This work has been conducted in order to understand the impact of various design parameters on the physical performance characteristics of the imager. Specifically, the effect of pixel size, scintillator thickness and packing density, x-ray spectra, air kerma, dark current, charge integration time, and pixel fill-factor on the frequency dependent detective quantum efficiency was studied using a charge-coupled device as a reference platform. The imaging system was modelled as a series of physical processes with gain and spatial spreading. For each stage, the signal and noise power spectra were computed and propagated through the imaging chain as inputs to subsequent stages. Good agreement between experimental and theoretical predictions was obtained for various x-ray spectral conditions that were investigated. The modulation transfer function, MTF(f) and detective quantum efficiency DQE(f) characteristics obtained in this study are encouraging and comparable to other digital mammography systems. The results of this study strongly suggest the feasibility of large area scintillator-based digital mammography imagers with pixel sizes below 100 microm.

Algorithms↗
PubMed2000

Variability in mammography screening legislation across the states.

Before passage of the Federal legislation, National Breast and Cervical Cancer Screening Act (NBCCSA) in 1991, over half the states (65%) had preexisting laws requiring health insurers, for example, Blue Cross/Blue Shield and HMOs, to provide services beyond the federal coverage for mammography screening and care following breast cancer. This study examined mammography screening legislation across the states. Data were derived from telephone interviews with six NBCCSA program directors or coordinators from July 1999 to October 1999. A review of existing documents from the Institute for Women's Policy Research, online data from the Centers for Disease Control and Prevention, and state laws provided by the Governmental Affairs Division of the American Cancer Society was undertaken. There was considerable variability in relation to factors potentially related to the extent of state laws. The states with the lowest age-adjusted breast cancer mortality rates among black women had the least comprehensive state legislation. Several states with the least percent of women above the federal poverty threshold also had the least comprehensive legislation. Some states had a wide gap between the provision of health insurance coverage and scope of legislation to ensure care following breast cancer. Some states were more aggressive in their efforts to ensure care following breast malignancy at diagnosis. Lessons could be learned by states that enacted the least comprehensive legislation. With the passage of the federal legislation nearly a decade ago, more women are receiving timely and available mammography screening, resulting in earlier diagnosis of breast cancer. Greater efforts must be undertaken by all states to provide the full array of breast cancer treatment for women in the millennium.

Adult↗
PubMed2005

Applying recursive partitioning to a prospective study of factors associated with adherence to mammography screening guidelines.

Although a number of predictors of adherence to mammography screening guidelines have been identified using traditional statistical methods, many women are not screening according to these guidelines. Recursive partitioning may aid in developing novel intervention strategies to promote this screening behavior by identifying subgroups of women that differ on adherence across predictor variables. In a prospective study of 1,229 African-American and White women in Connecticut whose adherence to mammography screening guidelines was ascertained over a 26-month follow-up period from initial screening in 1996-1998, recursive partitioning selected six of 22 candidate predictors and identified subgroups that differed on adherence across predictors by age (40-49 and 50-79 years). Among the five subgroups identified for women aged 50-79 years, the subgroup most adherent to screening guidelines during follow-up included four predictors: a history of adherence, annual family income of 15,000 dollars or more, a belief that mammograms were very useful, and low or moderate perceived breast cancer susceptibility. Among the three subgroups identified for women aged 40-49 years, the most adherent subgroup included only one predictor: receipt of a health-care provider's recommendation to obtain a mammogram. These findings suggest that recursive partitioning may be a useful statistical tool and may aid in developing interventions to promote adherence to mammography screening guidelines.

Adult↗
PubMed2004

Lower costs of hospital treatment of breast cancer through a population-based mammography screening programme.

BACKGROUND: The objective of this study was to evaluate the hospital treatment costs of invasive breast cancer in relation to the mode of detection, i.e. by mammography screening, between screenings or without screening during a population-based mammography screening programme, which started in 1987 among 36,000 women aged 40 to 74 years in the city of Turku, Southwest Finland. METHODS: The treatment costs and survival days of 556 women diagnosed with invasive breast cancer at the age of 40 to 74 years in 1987 to 1993 were followed up for five years from diagnosis or until death, whichever occurred first. RESULTS: Screen-detected cancers had the lowest average costs. The mean treatment costs per patient were 1.4-fold for clinical cancers and 1.3-fold for interval cancers compared to screen-detected cancers (p<0.001). The corresponding ratios in the mean treatment costs per survival day were 3.5 for clinical cancers and 1.9 for interval cancers (p<0.001). The mean treatment costs per patient were 1.3-fold for the non-screened group (clinical cancers) compared to the screened group (screen-detected and interval cancers) (p<0.001). The corresponding ratio was 3, when the mean treatment costs per survival day were compared (p<0.001). The estimated savings resulting from early treatment were 26-30% measured as a proportion of the screening costs for 1987 to 1993. CONCLUSION: The treatment costs of screen-detected cancers are lower than those of cancers detected by other methods. The study shows the potential for reducing treatment costs through early detection of breast cancer by mammography screening.

Adult↗
PubMed1991

Development of a strategy to encourage attendance for screening mammography.

The present study describes a method for the data-driven structuring of interventions to increase participation in screening mammography. We interviewed 668 randomly selected women from the target population of an Australian pilot screening mammography program before this Program commenced. The aims of the study were to use cross-sectional data to determine factors which predicted women's intentions regarding attendance at the Program, and on the basis of these results to develop optimal strategies to encourage attendances. Of the sample, 64% said they intended to go to the Program, while 11% were unsure. A number of variables were significantly associated with intention and regression analysis was used to determine the best model for predicting intention. Ten variables entered the final regression model: the intensity of thought about getting breast cancer; a belief that early detection is extremely desirable and that screening mammograms are accurate; having had a Pap test within the last 2 years; a belief that health is controlled by chance; perceived ease of getting to the hospital; subjective familiarity with the hospital location of the Program; age; having heard about screening mammography; and a feeling of personal susceptibility to breast cancer. This model explained 20% of the variance in intention to have a mammogram (R 2 = 0.20, F(10,492) = 12.08; P less than 0.0001). The practical applications of these findings are discussed in this report. It is recommended that if a campaign were to concentrate on changing women's perceptions on the dimensions found to be significantly associated with intention, then it would have maximum chance of encouraging attendance amongst women in the target population. The strategies we have developed based on these findings are discussed in this paper.

Aged↗
PubMed2001

Breast biopsy for mammographically detected non-palpable lesions using a vacuum-assisted biopsy device (Mammotome) and an upright-type stereotactic mammography unit.

BACKGROUND: It is planned to start screening mammography throughout Japan in the near future. However, a minimally invasive biopsy procedure for mammographically detected non-palpable breast lesions is not available in almost all Japanese hospitals. It is crucial to develop a useful minimally invasive biopsy method which can be applied without difficulty. METHODS: Eighty-nine biopsies for 88 mammographically detected non-palpable breast lesions, consisting of 70 lesions with microcalcifications alone, eight masses without calcifications and 10 with both masses and microcalcifications, were performed using the combination of a vacuum-assisted biopsy device (Mammotome) and an upright-type stereotactic mammography unit. RESULTS: Microcalcifications were confirmed radiographically in the tissue obtained from 78 biopsies among 81 biopsies for the lesions with microcalcifications (96.3%). All the lesions without calcifications were considered to be biopsied successfully. Five patients complained of nausea or fainted during the localization or biopsy procedure and an additional patient suffered from hyperventilation syndrome. Five cases experienced mild subcutaneous bleeding in the breasts. CONCLUSIONS: The biopsy technique using the combination of a vacuum-assisted biopsy device and an upright-type stereotactic mammography unit is a cost-effective, safe and very useful method for mammographically detected non-palpable breast lesions. It is expected to be a standard method of biopsy for such lesions in many developed countries other than the USA. However, it is important to make the patients relaxed during the biopsy to prevent mental strain.

Adult↗
PubMed1998

Diagnostic testing following screening mammography in the elderly.

BACKGROUND: To provide some sense of the general frequency and timing of diagnostic testing following screening mammography in the United States, we investigated the experience of women screened in the Medicare population. METHODS: By use of Medicare's National Claims History System, we identified a cohort (n=23172) of women 65 years old or older screened during the period from January 1, 1995, through April 30, 1995, and tracked each woman over the subsequent 8 months for the performance of additional breast imaging and biopsy procedures. Using two claims-based definitions for newly detected breast cancer, we also estimated the positive predictive value of screening mammography. RESULTS: For every 1000 women aged 65-69 years who underwent screening, 85 (95% confidence interval [CI]=79-91) had follow-up testing in the subsequent 8 months; 76 (95% CI=71-82) had additional breast imaging, and 23 (95% CI=20-26) had biopsy procedures. Corresponding numbers for women aged 70 years or more were similar. Some women underwent repeated examinations; 13% of those receiving diagnostic mammograms had more than one; 11% of those undergoing biopsy procedures had more than one. About half of the women who underwent a biopsy had the procedure more than 3 weeks after the imaging test upon which the decision to perform a biopsy was presumably made. The estimated positive predictive value of an abnormal screening mammogram (defined as a mammogram that engendered additional testing) was 0.08 (95% CI=0.06-0.10) for women aged 65-69 years and 0.14 (95% CI=0.12-0.16) for women aged 70 years or more. CONCLUSION: Additional testing is a frequent consequence of screening mammography and may require a considerable period of time to come to closure. The need for additional testing, however, is weakly predictive of cancer.

Aged↗
PubMed2004

Changes in breast cancer detection and mammography recall rates after the introduction of a computer-aided detection system.

BACKGROUND: Computer-aided mammography is rapidly gaining clinical acceptance, but few data demonstrate its actual benefit in the clinical environment. We assessed changes in mammography recall and cancer detection rates after the introduction of a computer-aided detection system into a clinical radiology practice in an academic setting. METHODS: We used verified practice- and outcome-related databases to compute recall rates and cancer detection rates for 24 Mammography Quality Standards Act-certified academic radiologists in our practice who interpreted 115,571 screening mammograms with (n = 59,139) or without (n = 56,432) the use of a computer-aided detection system. All statistical tests were two-sided. RESULTS: For the entire group of 24 radiologists, recall rates were similar for mammograms interpreted without and with computer-aided detection (11.39% versus 11.40%; percent difference = 0.09, 95% confidence interval [CI] = -11 to 11; P =.96) as were the breast cancer detection rates for mammograms interpreted without and with computer-aided detection (3.49% versus 3.55% per 1000 screening examinations; percent difference = 1.7, 95% CI = -11 to 19; P =.68). For the seven high-volume radiologists (i.e., those who interpreted more than 8000 screening mammograms each over a 3-year period), the recall rates were similar for mammograms interpreted without and with computer-aided detection (11.62% versus 11.05%; percent difference = -4.9, 95% CI = -21 to 4; P =.16), as were the breast cancer detection rates for mammograms interpreted without and with computer-aided detection (3.61% versus 3.49% per 1000 screening examinations; percent difference = -3.2, 95% CI = -15 to 9; P =.54). CONCLUSION: The introduction of computer-aided detection into this practice was not associated with statistically significant changes in recall and breast cancer detection rates, both for the entire group of radiologists and for the subset of radiologists who interpreted high volumes of mammograms.

Breast Neoplasms↗
PubMed1997

Mammography outcomes in a practice setting by age: prognostic factors, sensitivity, and positive biopsy rate.

The separate unplanned analysis of women ages 40-49 in population-based randomized controlled trials has resulted in demonstration of statistically significant breast cancer mortality reduction due to screening mammography in only two of the individual trials, and in all such trials only through meta-analysis. Therefore, many researchers have utilized the surrogate endpoints of tumor size and axillary lymph node status to evaluate screening efficacy. For the present study, these endpoints were evaluated in an audit of 854 screen-detected cancers found in 147,125 mammographic examinations performed in women over 40 between 1988 and 1994 in a community practice setting. The concerns that mammography in the 40-49 group has a lower sensitivity and higher biopsy rate were also addressed. Median invasive tumor size and lymph node positivity were found to be equally small (1.0-1.1 cm and 13.5-12.2%, respectively), and the sensitivity and overall biopsy rate were found to be constant over all ages 40 and above. Positive biopsy rate (PBR) varied directly with increasing age, paralleling the measured cancer detection rate in each decade, with no abrupt change at age 50. We conclude that modern mammography in a community practice setting can successfully detect breast cancers with favorable prognostic factors and achieve constant sensitivity and acceptable PBRs in all women over 40. Our data also suggest that many of the large differences seen by inappropriately dividing data at age 50 decrease or disappear when analysis is performed by decade.

Adult↗
PubMed1997

Radiation risk from screening mammography of women aged 40-49 years.

Although direct evidence of carcinogenic risk from mammography is lacking, there is a hypothetical risk from screening because excess breast cancers have been demonstrated in women receiving doses of 0.25-20 Gy. These high-level exposures to the breast occurred from the 1930s to the 1950s due to atomic bomb radiation, multiple chest fluoroscopies, and radiation therapy treatments for benign disease. Using a risk estimate provided by the Biological Effects of Ionizing Radiation (BEIR) V Report of the National Academy of Sciences and a mean breast glandular dose of 4 mGy from a two-view per breast bilateral mammogram, one can estimate that annual mammography of 100,000 women for 10 consecutive years beginning at age 40 will result in at most eight breast cancer deaths during their lifetime. On the other hand, researchers have shown a 24% mortality reduction from biennial screening of women in this age group; this will result in a benefit-to-risk ratio of 48.5 lives saved per life lost and 121.3 years of life saved per year of life lost. An assumed mortality reduction of 36% from annual screening would result in 36.5 lives saved per life lost and 91.3 years of life saved per year of life lost. Thus, the theoretical radiation risk from screening mammography is extremely small compared with the established benefit from this life-saving procedure and should not unduly distract women under age 50 who are considering screening.

Adult↗
PubMed1997

Efficacy of screening mammography among women aged 40 to 49 years and 50 to 69 years: comparison of relative and absolute benefit.

In randomized controlled trials, screening mammography has been shown to reduce mortality from breast cancer about 25% to 30% among women aged 50 to 69 years after only five to six years from the initiation of screening. Among women aged 40 to 49 years, trials have reported no reduction in breast cancer mortality after seven to nine years from the initiation of screening; after 10 to 14 years there is a 16% reduction in breast cancer mortality. Given that the incidence of breast cancer for women aged 40 to 49 years is lower and the potential benefit from mammography screening smaller and delayed, the absolute number of deaths prevented by screening women aged 40 to 49 years is much less than in screening women aged 50 to 69 years. Because the absolute benefit of screening women aged 40 to 49 years is small and there is concern that the harms are substantial, the focus should be to help these women make informed decisions about screening mammography by educating them of their true risk of breast cancer and the potential benefits and risks of screening.

Adult↗
PubMed2002

Mammography dose in relation to body mass index, race, and menopausal status.

Mammography dose increases with compressed breast thickness (CBT), but few studies have examined other correlates of dose. The purpose of this study was to evaluate the relation between factors such as race, age, body mass index (BMI), CBT, and menopausal status and mammography screening dose, measured for 509 women in a US population. A multiple linear regression model was developed for dose, based on consideration of these factors as well as examination characteristics. BMI and number of films during examination were positively related to dose. After adjusting for these factors, high CBT also leads to higher dose. Whites receive lower doses than black women but differences are slight after controlling for the effects of CBT and BMI, which were significantly higher among black women. Pre-menopausal women receive higher doses, after adjusting for all other factors, than post-menopausal women. Jointly, these factors account for approximately 75% to 80% of the variability in dose among this study population. Because rates of overweight are increasing in the US, average doses from mammography may be increasing as well.

Adult↗
PubMed2005

Dose to population as a metric in the design of optimised exposure control in digital mammography.

This paper describes a method for automatic optimisation of parameters (AOP) in digital mammography systems. Using a model of the image chain, contrast to noise ratio (CNR) and average glandular dose (AGD) are computed for possible X-ray parameters and breast types. The optimisation process consists of the determination of the operating points providing the lowest possible AGD for each CNR level and breast type. The proposed metric for the dose used in the design of an AOP mode is the resulting dose to the population, computed by averaging the AGD values over the distribution of breast types in the population. This method has been applied to the automatic exposure control of new digital mammography equipment. Breast thickness and composition are estimated from a low dose pre-exposure and used to index tables containing sets of optimised operating points. The resulting average dose to the population ranges from a level comparable to state-of-the-art screen/film mammography to a reduction by a factor of two. Using this method, both CNR and dose are kept under control for all breast types, taking into consideration both individual and collective risk.

Breast↗