Introduction
Mammography is simply an X-ray performed on a woman’s breast in order to detect if the woman is having breast cancer symptoms or the disease itself. Burnett notes that mammography is able to detect very small variations in the breasts which are so minute to be detected by the woman herself or her doctor.[1] There is evidence that, mammography decreases mortality rates resulting from breast cancer. Currently, there is no any other imaging method which has proved to reduce the risk of breast cancer, though, breast self examination as well as doctor’s examination are necessary measures of standard breast care. But, it is important to note that mammography has got a missed cancer proportion (a false-negative) of a bout 10%. This error occurs owing to thick tissues blocking the cancer tissues and the truth how cancer appears on mammography is normally overlapped with a large look of normal healthy tissues.[2] However, as for now, mammography together with physical breast check is the main method of preference for testing for symptoms for breast cancer.
The history of mammography
Mammography history can be traced back to 1913, when Albert Salomon a surgeon from Berlin concluded a study on roentgeno-histological on 3,000 mastectomies. His work was the foundation of mammography. Before 1938, very little literature was available on mammography; indeed the available literature offered very limited information on mammography.
The second phase of history of mammography began in 1947 going to 1970, this phase brought out the results from roentgenologic study as well as clinical correlation. The person responsible for the broad development of this approach was Raul Leborgne, However beginning 1951, a lot of American radiologists their European counterparts made their contribution. Charles-Marie Gros radiologist is highly acknowledged for his contributions, he is the one who gave the mammography technique being used until today for detecting breast diseases.[3]
The third phase of history of mammography began in 1970; this period has emphasized the importance of mammography technique in detecting breast cancer. Today many screening working teams are being built to screen women for breast cancer. The only problem now, is the economical difficulties of breast cancer screening.
Table 1: Important dates in history of mammography
1895
A German physicist, William Roentgen, discovers X-rays.
1913
A surgeon Berlin, Albert Solomon uses a normal X-ray machine to picture breast cancers in 3000 mastectomy samples.
1940s
Stafford Warren, in America, invents a stereoscopic technology for tumor recognition.
1949
A Uruguayan Raul Leborgne underlines the requirement for breast compression to recognize calcifications.
1956
A radiologist Robert Egan, in Houston, initiates special film for mammography to generate simple as well as reproducible images having improved features, Egan as well identified the requirement to instruct technologists to generate excellence images and radiologists to offer precise and reliable readings of the images produced.
1966
X-ray mammography becomes extensively applied in imaging the breasts since numerous manufacturers commence selling special mammography systems.
1970s
The very first dedicated mammography equipment is developed.
1980s-1990s
Key advancements in mammography machine including decreased radiation amount, improved film, digital imaging as well as computer-aided detection
New developments and technological improvements,
In the recent past, much important technological advancement in mammographic equipments such as x-ray, and image recording machines has taken place. Various key technical improvements as well as quality control high points in mammographic techniques are highlighted in Table 2.
As recent as in mid 1980s, a lot of X -ray units which were used in mammography was not specialized for mammography. The X-ray tungsten tubes which were being used were originally meant for medical imaging practices, for example chest radiography. A number of these equipment used compression mechanism which was home made; Thus, breast compression images were less optimal than it is presently. A lot of these apparatus had extremely big focal spots or a short focal distance to the breast which resulted in a high rate of blurriness or un-sharpness of the images taken.
Presently, it is possible to perform mammography with specialized mammographic x-ray machines. These machines have special devised tube targets, with smaller focal spots, highly advanced breast compression equipments and other special features. The cassettes as well as screen-film blending are formulated only for mammography. How films are processed and viewed has as well been improved a lot over time.
X-ray equipments
Before the end of 1960s, special mammography unit were not available commercially. Instead x-ray units meant for medical imaging process were used in mammography. A number of these units had poor compression units and a big focal spot that they resulted in produce unclear or burred images.[4]
Screen film combinations
Today, many of the combinations of single-screen and single- emulsion film used presently have got high film contrast hence require comparatively reduced amounts of radiation exposure compared to those used in the previous years. Films used presently in mammography normally have got a single emulsion, there are used together with a singly back screen. This has resulted in higher absorption of X -rays and better and clear images.
Digital mammography
There has been an ongoing development of digital image receptors over the years in mammography recently. The use of small spot digital detectors was introduced a few years ago. Most recently, efforts to use digital detectors referred to as Full Field Digital Mammography (FFDM); however, this method is slow in mammography field compared to the advancement made in general radiology. The reasons are that:
Mammography demands higher resolutions
The equipment is highly expensive
The reality that FFDM have not proved to produce superior images than those produced by film-screen mammography when detecting breast cancer.[5]
Another latest improvement in mammography is the use of computed radiography which is used to assist to speed up the transition. Computed radiography permits facilities to keep on using their present screen-film units, however it does the cassettes using an imaging plate which is used as a digital adapter.[6]
Table 2 below shows important technological advancements in mammography
Year
technological development
Before 1969
Normal tungsten end x-ray tubes which had express exposure industrial variety films were in use
1969
Specific mammographic unit having compressed cone and molybdenum target tube were pioneered
1971
Introduction of Xero-radiography (Xerox)system for mammography
1972
Introduction of screen-film system for mammography
1976
Introduction of rare earth screen-film technology and introduction of special cassette
1977
Introduction of mammography x-ray for enlargement with micro-focal spot
1978
Philips introduced mammography unit with grid
1994
Mammography quality standards Act (MQSA) is implemented by The Food and Drug Administration
2000
FDA approves digital mammography system
Discussion of the benefits and supporting statistics of increased mammogram use to increase women’s quality of life
For the past two decades, Mammograms have been attributed for saving thousands of live of women. Though, its not 100% perfect, the ability for mammogram detecting small tumors in the breast presents patients and their doctors the chance to treat the cancer whilst still in its initial stages. In this 21st century, breast cancer is still the main common feminine cancer apart from skin cancers. It’s among the leading causes of early deaths in many women. About 1 in every 8 women in America will suffer from breast cancer in her life, and among these, 1 in every 30 will succumb to death due to breast cancer. [7]
Current day screening machines produces very low amounts of radiation, thus the odds that a mammogram will result in development of cancer are thus exceptionally reduced. The benefits in regards to the number of cancer cases detected outnumber the small dangers of performing a mammography.[8]
Radiation exposure related to mammography is an impending danger of cancer screening. Studies have indicated that the risk is higher in women aged below 40 years. But, in related studies carried out by National Cancer Institute of USA, it was established that radiation dangers associated with mammography screening in women aged 40 and over was low compared to the possible benefits of having the screening. The studies concluded that the benefit-to-danger proportion was 48.5 lives saved against 1 lost because of radiation exposure. It’s against this background that the National Cancer institute has encouraged women aged between 40 and 49 to go for screening after once in every two years, and the response has been good.[9]
Even though there are lots of negative public sentiments regarding screening, continues studies carried out by various bodies have indicated that the cases of deaths due to breast cancer in women aged between 50 and 65 are decreased by about 40% in those women who undergo breast screening.[10]
However, about 7% of women who undergo mammography screening are given false-positive results.[11] It has been shown that women who get false-positive results about their screening become worried, distressed and anxious concerning the likelihood of suffering from breast cancer, these negative feeling can go on for several years and have negative effects on a woman’s life.
Conclusion
Mammography is simple an X-ray taken of breasts, the objective of this x-ray is to detect symptoms or signs of breast cancer. Mammography is able to detect any minute changes in a woman’s breast which are too minute to be sensed by the woman or her doctor. The benefit of carrying out a mammography is that it highly increases the chances to detect tumors in their initial stages when they are still small. This allows effective treatment of breast cancer and its cure becomes possible. Over the years, there have been a lot of improvements in mammogram technology that now days it’s possible to have clear images produced by computer aided detection.
Reference:
Kopans D, Meyer E and Sadowsky, N: Breast Imaging: New England Journal of Medicine 310 (15); 962–7; (1984)
Lehman, D: Role of MRI in screening women at high risk for breast cancer: Journal of Magnetic Resonance Imaging 24 (5); 964; (2006)
National Cancer Institute Statement on Mammography Screening (2008): www.cancer.gov/newscenter/mammstatement31jan02
Burnett, S: Mammography: women’s health: available online from www.netdoctor.co.uk/whoisnd.htm Accessed on 11/10/2008
Shapiro S, Strax, P and Venet L (1996): Evaluation of Periodic Breast Cancer Screening With Mammography: Journal of the American Medical Association (JAMA) 197(9); 111.
[1] Burnett, S: Mammography: women’s health: available online from www.netdoctor.co.uk/whoisnd.htm Accessed on 11/10/2008
[2] Shapiro S, Strax, P and Venet L (1996): Evaluation of Periodic Breast Cancer Screening With Mammography: Journal of the American Medical Association (JAMA) 197(9); 111.
[3] Kopans D, Meyer E and Sadowsky, N: Breast Imaging: New England Journal of Medicine 310 (15); 962–7; (1984)
[4] Kopans D, Meyer E and Sadowsky, N: Breast Imaging: New England Journal of Medicine 310 (15); 962–7; (1984)
[5] Burnett, S: Mammography: women’s health: available online from www.netdoctor.co.uk/whoisnd.htm Accessed on 11/10/2008
[6] Ibid 5
[7] National Cancer Institute Statement on Mammography Screening (2008): www.cancer.gov/newscenter/mammstatement31jan02
[8] Shapiro S, Strax, P and Venet L (1996): Evaluation of Periodic Breast Cancer Screening With Mammography: Journal of the American Medical Association (JAMA) 197(9); 111.
[9] National Cancer Institute Statement on Mammography Screening (2008): www.cancer.gov/newscenter/mammstatement31jan02
[10] Lehman, D: Role of MRI in screening women at high risk for breast cancer: Journal of Magnetic Resonance Imaging 24 (5); 964; (2006)
[11] Ibid 10