Risks and benefits[ edit ] Normal left versus cancerous right mammography image. The use of mammography as a screening tool for the detection of early breast cancer in otherwise healthy women without symptoms is controversial.
Risks and benefits[ edit ] Normal left versus cancerous right mammography image. The use of mammography as a screening tool for the detection of early breast cancer in otherwise healthy women without symptoms is controversial. The Cochrane analysis of screening indicates that it is "not clear whether screening does more good than harm".
According to their analysis, 1 in 2, women will have her life prolonged by 10 years of screening, while 10 healthy women will undergo unnecessary breast cancer treatment.
Additionally, women will suffer from significant psychological stress due to false positive results.
Most of these recalls will be false positive results. Of every 1, U. Of the 10 referred for biopsy, about 3. Mammography may also produce false negatives. Furthermore, one form of breast cancer, lobular cancer, has a growth pattern that produces shadows on the mammogram that are indistinguishable from normal breast tissue.
Mortality[ edit ] The Cochrane Collaboration states that the best quality evidence does not demonstrate a reduction in mortality or a reduction in mortality from all types of cancer from screening mammography. For women ages 40 to 49, 2, women would need to be screened at the same frequency and period to prevent a single death from breast cancer.
There are four categories of cancers found by mammography: Cancers that are so easily treated that a later detection would have produced the same rate of cure women would have lived even without mammography.
Cancers so aggressive that even early detection is too late to benefit the patient women who die despite detection by mammography.
Cancers that would have receded on their own or are so slow-growing that the woman would die of other causes before the cancer produced symptoms mammography results in over-diagnosis and over-treatment of this class.
A small number of breast cancers that are detected by screening mammography and whose treatment outcome improves as a result of earlier detection. Clinical trial data suggests that 1 woman per 1, healthy women screened over 10 years falls into this category.
These patients are then referred for further, usually more invasive, testing. Thus a screening exam is not intended to be definitive; rather it is intended to have sufficient sensitivity to detect a useful proportion of cancers.
The cost of higher sensitivity is a larger number of results that would be regarded as suspicious in patients without disease. This is true of mammography.
There is a trade-off between the number of patients with disease found and the much larger number of patients without disease that must be re-screened.
Research shows  that false-positive mammograms may affect women's well-being and behavior.
One significant problem that tomosynthesis of the breast must overcome, however, is the reduction of x-ray scatter inclusion in the projection images. In tomosynthesis, due to the projection geometry and radiation dose considerations, the use of an antiscatter grid presents several challenges. Tomosynthesis. Tomosynthesis is an imaging technique in which multiple X-rays of the breast are taken from a discrete number of angles. These cross-sectional images are used to reconstruct 3-D images of the breast being imaged. Mar 27, · This document supersedes “Class II Special Controls Guidance Document: Full-Field Digital Mammography System,” issued November 5, On .
Some women who receive false-positive results may be more likely to return for routine screening or perform breast self-examinations more frequently. However, some women who receive false-positive results become anxious, worried, and distressed about the possibility of having breast cancer, feelings that can last for many years.
False positives also mean greater expense, both for the individual and for the screening program. Since follow-up screening is typically much more expensive than initial screening, more false positives that must receive follow-up means that fewer women may be screened for a given amount of money.
Thus as sensitivity increases, a screening program will cost more or be confined to screening a smaller number of women. Overdiagnosis[ edit ] The central harm of mammographic breast cancer screening is overdiagnosis: Gilbert Welcha researcher at Dartmouth College, states that "screen-detected breast and prostate cancer survivors are more likely to have been over-diagnosed than actually helped by the test.
This means an over-diagnosis rate of women per 10, invited to screening. Estimates of the false negative rate depend on close follow-up of a large number of patients for many years.
This is difficult in practice because many women do not return for regular mammography making it impossible to know if they ever developed a cancer. In his book The Politics of Cancer, Dr.年09月16日up 第43回日本放射線技術学会秋季学術大会 一般研究発表プログラム.
Mammography (also called mastography) is the process of using low-energy X-rays (usually around 30 kVp) to examine the human breast for diagnosis and screening.
The goal of mammography is the early detection of breast cancer, typically through detection of characteristic masses or microcalcifications.. As with all X-rays, mammograms use doses of ionizing radiation .
Scatter radiation intensities around a clinical digital breast tomosynthesis unit and the impact on radiation shielding considerations. Authors. Kai Yang, Division of Diagnostic Imaging Physics, Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts Study of the scatter radiation in Digital Breast Tomosynthesis (DBT).
Generally in DBT no scatter grid is used due to the low exposure per projection. Energy that maximizes the image quality parameter is not affected by scatter. Tomosynthesis. Tomosynthesis is an imaging technique in which multiple X-rays of the breast are taken from a discrete number of angles.
These cross-sectional images are used to reconstruct 3-D images of the breast being imaged. Digital tomosynthesis of the breast is being investigated as one possible solution to the problem of tissue superposition present in planar mammography.