Basic Types of Mammography - Research Paper Example

Basic Types of Mammography Before going into the details of digital and film screen mammography, let us get a better understanding of what mammography actually is. Mammography is a form of imaging that is used to examine the breast tissues. “Mammography is an x-ray of the breast that creates an image of the breast tissue” (Kahane, 1995, p.293). Mammography makes use of low-dose x-rays to create detailed images of breasts. X-ray is the most widely used technology of medical imaging, which help the physicians in the diagnosis of various breast-related diseases. Mammography exams, also known as mammograms, are very helpful in detecting breast-related diseases including breast cancer. Successful treatment of breast cancer is only possible if it is diagnosed in early stages. The changes, which occur in the breasts of the women with the passage of time, can also be observed through mammography. In the United States of America, a large number of mammography tests are performed each year. In the breast examination tests, a high exposure is required to produce clear images of breasts as compared to the level of exposure required for other radiographic tests. The reason for high exposure is that the breasts are composed of very soft tissues which require high exposure in order to be visible. The high exposure not only helps the physicians get accurate images of breast’s anatomy but also helps them observe the signs of various breast related diseases. A high radiation dose, along with benefits, also gives rise to some fears and misconception regarding its effects on the skin of the breast. High radiation dose is still a common concern for many people these days although it does not produce any harmful effect on the breast’s skin. Two of the major functions of mammography are to produce the images of the breast’s anatomy and to observe the symptoms of diseases. Mammography does not prevent breast cancer rather it only detects the cancer. Kahn (2010) talks about use of mammography for detecting breast cancer and states that “mammography does not prevent it but only detects it”. Basic Types of Mammography There are two basic types of mammography which include film screen mammography and digital mammography. Let us discuss both of them in comparison with each other in order get a better understanding of their uses, benefits, and costs. Film Screen Mammography Film screen mammography (FSM), also known as conventional or traditional mammography, is a predominant breast radiographic method which makes use of special films and intensifying screens in order to examine the anatomy of breasts and to detect the breast-related diseases. A good and clear image can be taken at exposure levels of even less than 1 rad. “It provides reasonably high quality images in the vast majority of patients at low radiation doses” (DeFelice, 2002, p. 12). For the diagnostically acceptable images, a very low energy x-ray beam and a uniform thickness breast compression is required in case of film screen mammography. Low energy x-rays pass through the compressed breast during the breast examination. “The exiting x-rays are absorbed by film (x-ray film) which is then developed into a mammography image that can be held and looked at by the radiologist” (Helvie, n.d.). Film screen mammography has better spatial resolution as compared to digital mammography. “Film screen mammography uses low-dose radiation, radiographic film, and equipment dedicated to breast imaging” (Chang et al., 2006, p. 320). In film screen mammography, darker images are produced by higher radiation doses and those images are clinically less than the optimal as compared to the digital mammography. Film screen mammography is a traditional method of breast examination that produces a picture of breast’s anatomy on a paper that can neither enlarged not can it be easily focused whereas in case of digital mammography, the images can not only be stored in a computer system but also they can be enlarged or focused for getting a more visible picture of the breast’s anatomy. If we talk about the cost of a mammogram, we come to know that film screen method of mammography is 3 to 4 times less expensive as compared to digital mammography system because film screen mammography does not make use of the image storage and maintenance mechanism, which adds up to the overall cost of a mammogram in case of digital mammography. Equipment cost for digital mammography method is 3-5 times the cost of film screen mammography (Helvie, n.d.). In case of detecting small and high contrast images such as calcium specks, film screen mammography is considered a good option. A drawback regarding film screen mammography is that in case of patients with dense breast tissues, it does not always provide adequate diagnostic information for some patients. Another negative point is that the radiologists do not find it easy to determine the breast cancer disease through film screen mammography method and miss approximately 15% of all breast cancer cases. “From 60-85% of all lesions detected by FSM alone are benign (non-cancerous) and may lead to many unnecessary biopsies” (DeFelice, 2002, p. 12). “The major limitation of traditional mammography is that the film serves simultaneously as the image receptor, display medium, and long term storage medium for the image” (Denise & Farleigh, 2005). This limitation sometimes results in the loss of image contrasts, which is not good for the identification of subtle abnormalities. Film screen mammography takes a very long time screening as compared to digital mammography method. Generally, it takes up to 12 minutes to complete a mammography test using film screen mammography method while it takes up to 3 minutes to complete the same test using digital mammography method. It is estimated that approximately 60% of test duration can be reduced using digital mammography method for breast examination. The time taken by film screen mammography method is longer due to involvement of various steps in the test. These steps include positioning the patient for films, marking the film cassettes, studying the bar code, walking to the processors, inserting the cassettes into the processors, waiting for the films to be processed, placing the film in the jacket, and providing the processed film to the medical professionals for further study. In case of digital mammography method, the total number of processes is very less which makes it quicker as compared to film screen mammography method. However, if we talk about the time needed to interpret a mammogram, we come to know that interpretation of film screen mammogram takes less time as compared to digital mammogram. For a digital mammogram, it takes about 2 minutes to interpret a mammogram whereas it takes about 1.2 minutes to interpret a film screen mammogram. From the patient’s point of view, there is a slight difference between the digital method of mammography and the film screen method. Patients have to spend less time in uncomfortable position in case of digital mammography. Sensitivity of film screen mammography is also an important issue. “Sensitivity of screen-film mammography is highest in women with complete fatty breasts (sensitivity 88%, specificity 97%) compared with women with extremely dense breasts (sensitivity 62%, specificity 90%)” (Hashimoto, 2008, p.2). The sensitivity of film screen mammography is influenced by some important factors. These factors include dense breast parenchyma, age of the person being examined, and time between last and current mammography exams. The uptake into screening practice of film screen mammography is high as compared to digital mammography. In we compare film screen mammography and digital mammography in terms of accuracy, researches from the past 10 years show that accuracy is almost same in both types of mammography methods but the number of women who are recalled for another film screen mammography test is higher as compared to the number of women recalled for digital mammography tests, which gives a clear indication that digital mammograms possess more accuracy as compared to film screen mammograms. If we talk about the radiation doses used by both digital mammography method and film screen mammography method, we come to know that radiation doses used by digital mammography system are less as compared to film screen mammography system. Film screen mammography is less sensitive for those women who have very dense breast tissues. There are three important factors that need to be considered while deciding to go for a film screen mammography test or a digital mammography test. These factors include age of the patient, type of breast tissues, and menstruating time of the patient. Digital mammography is considered a better option in case the age of the patient is below 50 years, she is still having periods, or she has very dense breast tissues. Black and white images of breast’s anatomy appear on the paper if the radiologists make use of film screen mammography for breast examination whereas if they make use of digital mammography, the high contrast images are produced and they are recorded into the database of a computer system. The recorded images can not be enlarged or highlighted in case of film screen mammography method whereas they can be enlarged or clearly focused using digital mammography method. Digital mammography method makes use of computer technology which facilitates the physicians to enlarge the image or magnify any specific portion of the image whereas there is no such technology in case of film screen mammography. The radiologists can not focus or take a closer look of an image using film screen mammography. Another difference is that the images can be transferred to any other computer system in case of digital mammography, whereas if the images produced by film screen mammography are required to be photocopied due to any reason, they get more invisible and create difficulties for the radiologists during the phase of image interpretation. The film mammogram obtained using film screen mammography cannot be altered and the contrast is lost once the film is underexposed. Another thing that needs to be mentioned here is that in case of a person having extremely dense breast tissues, film screen mammography is not a good option. It is because the images of dense breast tissues are difficult to be produced clearly on the film whereas digital mammography method can easily produce and display the exact images of the tissues on screen of a computer system. Digital Mammography As we have discussed film screen mammography in detail, let us now discuss different issues related to digital mammography. Digital mammography, also known as full-field digital mammography, makes use of solid-state detectors in place of x-ray films in order to produce images of breasts on the computer screen. Digital technology takes an x-ray image and stores it in a computer through the use of RIS PACS (Hemrick, 2009). These detectors, which are similar to the image detectors found in digital cameras, convert the x-rays into electric signals. There is not much difference between the examination styles of digital mammography method and film screen mammography method from the patient’s perspective. The presence of a digital receptor and a computer system makes digital mammography system different to film screen mammography system. Some of the key advantages of using digital mammography system for breast examination include improved contrast, lower radiation dose as compared to traditional mammography systems, facility to magnify the images, facility to transfer the images to other computer systems, real time interpretation of mammograms, better cancer detection ability, reduced image processing time, and facility to electronically transfer and store the images using computer technology. The difference between the two methods of mammography is the same as the difference between a film-based camera and a digital camera. In case of film screen mammogram, the image is displayed on the film whereas the image is displayed on the computer screen in case of digital mammography. Digital mammography method eliminates the need for a film library as it allows digital storage of images in the computer systems. The images can easily be transmitted, magnified, or altered whenever required. The images can easily be sent to other physicians through emails and the same quality images can also be given to the patients if they want to save them for personal use. Digital mammography has gained immense popularity over the last 5 years or so due to its considerable advantages over film screen mammography. One of the key advantages of digital mammography is that of its efficacy in contemporary screening practices. “Digital mammography may be more effective than screen-film mammography in contemporary screening practice in mobile units” (Turco et al., 2007). A faster and more accurate breast examination is possible through digital method of mammography, which not only results in reducing the duration of the test but also provides comfort to the patients due to reduced examination time. Digital mammography method also provides the radiologists with the facility to alter, magnify, or brighten the images stored in the computer system. “One of the principal advantages of any digital imaging system is the separation of image acquisition, process and display, allowing optimization of each of these steps” (Denise & Farleigh, 2005). Digital mammography also makes use of some new technologies such as CAD (Computer Aided Detection) that assists the radiologists during the process of image interpretation. The CAD software also helps the physicians in early detection of breast cancer. Speed is one of the major advantages of digital mammography system. The radiologists can produce the images very quickly using digital mammography system as compared to film screen mammography. Patients’ comfort is also a big issue in mammography. In digital mammography system, patients have to spend less time in uncomfortable positions as the images are taken very quickly. Physicians and radiologists are able to produce the images in a couple of seconds using digital method of mammography while they have to wait for 7 to 8 minutes in case of film screen mammography. If we talk about cost of a mammogram, we can say that digital mammogram is more expensive as compared to a film screen mammogram due to implementation of additional technology and equipment such as digital receptors and computer systems that are needed to produce a high quality image in a very short time. Digital method of mammography has many significant advantages over traditional methods, particularly in terms of breast cancer detection rate. Various current researches show that digital method of mammography detects more breast cancer cases as compared to the breast cancer cases detected by the film screen system. Digital method of mammography offers various potential advantages over film screen mammography. “Near instantaneous image acquisition and the ability to transmit images electronically around the world are also significant advantages” (Helvie, n.d.). Digital mammography makes use of low radiation doses for taking breast images. Medical professionals can adjust the brightness, darkness, and contrast using digital mammography method and these utilities do not come with film screen mammography. Any specific section of any image can be magnified in order to properly analyze the subtle differences between the breast’s tissues. High contrast of breast tissues is very important for having a proper analysis of the breast’s anatomy (Layni, 2003). Malignant cells and breast tissues appear white on a film screen mammogram whereas their contrast can easily be adjusted using digital technology. Digital method of mammography makes use of various new technologies, which assist the radiologists and physicians properly diagnose the breast tumors and detect breast cancers. Some of these technologies include 3-D imaging, computer aided technology, and contrast-enhanced mammography. If we make a comparison between the two types of mammography in terms of accuracy, we come to know that digital mammography systems are clinically more accurate as compared to film screen mammography particularly in case of those women who have very dense breast tissues. But for those women, who are over the age of 50 years, accuracy of both types of mammography exams is almost same. The radiation delivered by digital mammography system is very less as compared to film screen mammography. Digital mammography delivers 3/4th of the total radiation delivered by the film screen mammography system. The cost of a digital mammogram is one of the disadvantages of digital mammography system. “Digital systems currently cost approximately 1.5 to 4 times as much as film systems” (Pisano et al., 2005). But the digital mammograms are still getting popular due to its advantages over traditional systems. The additional costs do not overcome the variety of advantages provided by the digital mammography systems. Most of the doctors recommend digital mammography to the patients because it not only facilitates the radiologists in terms of reduction in examination time but also the patients feel more comfortable with digital mammography system. Higher accuracy, proper maintenance, and reduced examination time are those advantages of digital mammography which are making most of the radiologists switch over from film screen mammography to digital mode of mammography. A research study published in the American Journal of Roentgenology found that the patients’ recall rate for the examination has significantly decreased as a result of using the combination of digital mammography system and digital breast tomosynthesis. Digital mammography system provides the medical professionals with the facility to zoom in and out of the breast images. This facility plays a very important role in the successful analysis the breast tissues. Images taken by digital mammography are very bright, which are easier to be studied by the physicians. Along with many advantages, some disadvantages are also associated with digital mammography systems. Some of those disadvantages include low spatial resolution as compared to traditional mammography systems, difficulty in making comparison between older film studies and the recently taken digital images, and high cost of the digital mammograms. Conclusion Summing it up, mammography is a form of imaging that is used to examine breasts for various breast related diseases including breast cancer. There are two basic types of mammography which include film screen mammography and digital mammography. Digital mammography system is more effective in detecting the breast cancer as compared to film screen mammography system. Film screen mammography makes use of special films and intensifying screens to examine the breasts. In film screen mammography, darker images are produced by higher radiation doses and those images are clinically less than the optimal as compared to the images that are taken using digital mammography. Digital method of mammography makes use of solid-state detectors in place of x-ray films to display high quality images on the computer screen. Film screen mammography is a less expensive and lengthy breast examination process as compared to digital mammography system. It is due to the increased levels of popularity and acceptability of digital mammography that most of the imaging centers are switching over their technology from traditional to digital form of mammography. References Chang, A., Ganz, P., Hayes, D., Kinsella, T., Pass, H., Schiller, J., … Strecher, V. (2006). Oncology: An Evidence-Based Approach. New York, NY: Springer Science+Business Media, Inc. DeFelice, E. (2002). Breast Cancer: Web Resource Guide for Consumers, Healthcare Providers, Patients, and Physicians. Lincoln: Writers Club Press. Denise, D., & Farleigh, M. (2005). Advantages of Digital Mammography. Retrieved from http://www.providence.org/Alaska/MedStaff/digitalmammography.htm Hashimoto, B. (2008). Practical Digital Mammography. New York, NY: Thieme Medical Publishers, Inc. Helvie, M. (n.d.). Full Field Digital Mammography: A New Breast Cancer Screening Tool. Retrieved from http://www.cancernews.com/data/Article/210.asp Hemrick, W. (2009). Digital Mammography For Breast Cancer of High Risk Women. Retrieved from http://ezinearticles.com/?Digital-Mammography-For-Breast-Cancer-of-High-Risk-Women&id=1856567 Kahane, D. (1995). No Less a Woman: Femininity, Sexuality & breast Cancer (2nd ed.). Alameda: Hunter House Inc., Publishers. Kahn, A. (2010). New Mammography Guidelines - Mammography Can Be Risky. Retrieved from http://ezinearticles.com/?New-Mammography-Guidelines---Mammography-Can-Be-Risky&id=4558075 Layni, M. (2003). Mammography: Diagnosis and Pathological Analysis. Heidelberg: Springer-Verlag. Pisano, E., Gatsonis, C., Hendrick, E., Yaffe, M., Baum, J., Acharyya, S., … Rebner, M. (2005). Diagnostic Performance of Digital versus Film Mammography for Breast-Cancer Screening. The New England Journal of Medicine, 353(17), 73-83. Turco, M., Mantellini, P., Ciatto, S., Bonardi, R., Martellini, F., Lazzari, b., & Houssami, N. (2007). Full-Field Digital Versus Screen-Film Mammography: Comparative Accuracy in Concurrent Screening Cohorts. American Journal of Roentgenology, 189, 860-866. Read More