Bone Density (DEXA) - Research Paper Example

 Bone Density (DEXA) Bone density, also known as Bone Mineral Density (BMD) refers to the amount of mineral matter in the bones per square centimeter. In medicine, BMD is used as an indirect indicator to find whether there is a fracture or osteoporosis. BMD is not the real density of the bone, but it is a measurement measured by a procedure called densitometry (Geusens, 1998). The measurement is normally carried out over the lumbar spine and upper part of the hips. If these parts are not accessible, the test can be carried out through forearm. There is a relationship between poor bone density and high probability of bone fracture. Bone fracture is always a problem to the old people, since it might lead to dead or inability to live independently (Geusens, 1998). The test is only necessary for those who risk factors of weak bones, unnecessary test should not be carried out because it might result in unnecessary treatment instead of discovering the real problem. There are several types of BMD test, and the most advanced type and mostly used test is Dual-energy X-ray absorptiometry (DEXA). During the 1960s, the radiologist was only in a position of diagnosing bone mineral loss by analyzing radiographic images. Between 30 to 50 percent analysis was only manageable and a more sensitive method was required to determine bone mineral loss. History Due to the need of better technology, Bone densitometry originated in nuclear science and it was developed by Cameron and Sorenson in 1963. That time it was called single photon absorptiometry (SPA), iodine125 was used and it was capable of emitting 35 keV gamma rays. As a result of further research, X-Ray tube was used instead of gamma ray source; this introduced single energy x-ray absorptiometry (SXA). The x-ray beam was filtered so that it can produce homogenous beam. In 1970s, dual photon absorptiometry (DPA) was developed, this technology applies radioactive source that can emit gamma radiation in 2 separate energies. DPA in 1980s was extended to form Dual-energy x-ray absorptiometry (DXA), the system uses fan beam. To achieve the dual energies, the variations of generator signal output are used. How the machine functions There are 2 types of DEXA scanning machines, central DEXA and peripheral DEXA machine. Central DEXA is large and powerful equipment that can measure the BMD at the centre of the skeleton (Sawyer, Bachrach, & Fung, 2007). Peripheral DEXA is a small machine that can be carried around and can measure the BMD at the peripheral part of the skeleton like a finger. DEXA machines work by emitting 2 x-rays beams that have different energy levels aimed at the patient bones. When the absorption by soft tissues is subtracted, the bone density is determined from absorption of every beam by the bone. The DEXA machine uses low energy X-rays. When the rays from the scanner are directed to the body, the bones block a certain amount of rays, when the bones are dense, little x-rays pass through unlike and vice versa (Sawyer, Bachrach, & Fung, 2007). When two different rays are used, it increases the accuracy. The amounts of rays that pass through the bones are measured by use of a detector. Radiation energy per pixel is detected and converted to area density. The number of pixels received is added and the total amount of bone in every pixel is calculated. The measured information is analyzed by specialized computer software to determine the average density of the bone. If the score is low, it means that the bone is less dense and may be some part has been lost. Pathology and amount of radiation Before the test is carried out, the patient should do some preparations. The patient can eat normally on the day of examination but he/she should avoid taking calcium 24 hours before the test is carried out. The patient should wear clothes which are loose, comfortable and should not have zippers or metal buttons. Metallic objects that are in the pockets should all be removed. A patient who have undergone examination such as barium or have been injected with contrast material should wait for at least 10 days before undergoing the test. To carry out the test, the patient lies on her back and keep still while the scanner is aimed at the area being tested. The bones that are normally checked are hips and wrist, this are the kind of bones that can easily break due to osteoporosis. For the spine to be accessed, the patients’ legs are raised up and supported by a box so as to flatten the pelvis and lower spine (Lineback, & Leadbetter, 2003). For the hip to be accessed, the legs of the patient are place in a brace that will rotate the hip inwards. The time for scanning is approximately 25 minutes depending on the machine being used and part of the body that is being examined. The scanning results have 2 measures, T-score and Z-score. Scores shows how much the BMD varies from the mean. Negative score shows lower bone density while the positive score shows higher bone density. T-score is normally used when screening for osteoporosis. This is the BMD at that site as compared to young normal reference mean. Young normal reference mean is the BDM of a healthy 30 years old person of the same sex and ethnicity. The world health organization has recommended the use of BMD from a white healthy lady aged 30 years. The normal T-score is -1.0 or above, osteoporosis is below -2.5. Z-score is a comparison BMD between two people of the same age; it is normally applied in situation of severe osteoporosis (Lineback, & Leadbetter, 2003). The test is normally quick and the patient does not experience any pain. Routine test is recommended to be carried out every two years to check the change in the BMD, whether it has increased or decreased. The amount of radiation from the scanner is very low, it is between 5 and 10 rem (Roentgen Equivalent Man). DEXA assessment of BMD of the femoral neck and the lumbar spine Statistics Globally, osteoporosis causes over 9 million fractures every year; this is approximately osteoporotic fracture within a period of 3 seconds. It is approximated that it affects 20 million women globally, of these one tenth are aged 60 years, one fifth are aged 70, two fifths are aged 80 years, and lastly, two thirds of women who are aged 90 years. For the women above the age of 50, one out of three experience osteoporotic fractures, while in men is 1 out of five. In U.S, 44 million people above the age of 50 are at a risk of suffering from osteoporosis. In 2013, it was approximated that 15 million was affected by osteoporosis, both men and women. Causes of pathology Not everybody should undergo this test; it is advised to be done on people who have increased risk of developing osteoporosis. Osteoporosis shows no sign but if you have it, there is an increased chance of fracturing a bone. The scan is normally recommended when you have a fracture resulting from a fall, loss of weight as a result of vertebrate breakage, early menopause, having history of stopping periods, have a parathyroid condition, having thyroid condition and having a body mass index below 20 (Margulis, & Eisenberg, 2011). The test has certain limitations, the size of the patient and tissue covering the bones can affect the measurement. Reference standards for certain races and population like children are not available, and if the vertebrate crushed, it sometimes results in high bone density. Benefits There are several benefits resulting from this test, on is that it requires no anesthesia, the amount of X-ray used is minimal, it is less than a dose of standard chest X-ray, the method is the most accurate to test osteoporosis, the DXA equipments are cheap and widely available making it easy for patients to access, and finally, after the test, no radiation remains in the body which means it has no side effects. Risk factors Apart from benefits, there are also risks associated with scanning. There is a small chance of getting cancer from excessive exposure to X-ray, and it is dangerous if performed on pregnant women. The exposure to X-rays can result in carcinogenic effects, Carcinogenic effects manifest in a patient after a long period of time. The risk factors associated with osteoporosis is getting old; this will raise the chances of getting the problem since the bones become weaker as a person gets old. Osteoporosis is known to run in families, if one of your parents had a hip fracture the chances of you getting the same problem is high. The third risk is bone structure and the weight of the body. These women have high probability of developing the problem, losing the weight at the age of 50 for the women make them vulnerable for hip fractures. Weight gain brings down the risk. Men with small bones will likely suffer the problem unlike those who have well build bodies. The last risk is the use of drugs. The use of certain drugs like steroids, and antacids make the bones fragile. Treatment There are several treatments given to patients suffering from osteoporosis. One is weight bearing exercise, this will strengthen the muscle and it will prevent osteoporosis. Taking medications like Boniva, Binosto, Fortical, and Actonel. Injecting Prolia to women at high risk of developing the problem, stop smoking and use of drugs, increase calcium in food stuff, and lastly, injecting Forteo to women so as to rebuild their bones. Conclusion Following the problems resulting from weak bones especially for the elderly, there was need for early detection if the problem could occur. Following the advancement in nuclear science, Dual-energy X-ray absorptiometry (DEXA) was developed by Cameron and Sorenson in 1963. There are 2 types of DEXA scanning machines used in this text, central DEXA and peripheral DEXA machine. The machines functions by emitting two X-rays beams from the scanner, the beams are directed towards the part of the body that is being tested, the bones block a certain amount of rays, when the bones are dense, little x-rays pass through, the amounts of rays that pass through the bones are measured by use of a detector. To carry out the test, the patient lies on her back and keep still while the scanner is aimed at the area being tested. The scanning results have 2 measures, T-score and Z-score. Scores shows how much the BMD varies from the mean. Worldwide, osteoporosis causes over 9 million fractures every year. Over 44 million people in U.S over the age of 50 are at a risk of suffering from osteoporosis. The test is advised on people who have fractures resulting from a fall, loss of weight as a result of vertebrate breakage, early menopause, having history of stopping periods, have a parathyroid condition, having thyroid condition and having a body mass index below 20. The problem can be treated by weigh bearing exercise, taking medication such as Boniva and Binosto, and Injecting Prolia to women at high risk of developing the problem. I believe this process is important since it will assist in early detection of osteoporosis, early detection is important because the problem can be treated at an early stage, hence preventing death and bone fractures. References Bolotin, H. (n.d.). The significant effects of bone structure on inherent patient-specific DXA in vivo bone mineral density measurement inaccuracies. American Association of Physicists in Medicine Bonnick, S. L. (2010). Bone densitometry in clinical practice: Application and interpretation. New York, NY: Humana Press Geusens, P. (1998). Osteoporosis in clinical practice: A practical guide for diagnosis and treatment. London: Springer. Krahe, C., Friedman, R., & Gross, J. L. (1997). Risk factors for decreased bone density in premenopausal women. (Brazilian journal of medical and biological research, 30, 9, 1061-6.) Lineback, K. T., & Leadbetter, C. W. (2003). Osteopilates: Increase bone density, reduce fracture risk, look and feel great! Franklin Lakes, N.J: New Page Books Margulis, M. D. A., & Eisenberg, JD, MD, FACR, Ronald. (2011). A Patient's Guide to Medical Imaging. Oxford University Press USA Measuring bone density. (January 01, 1997). Journal of Internal Medicine. Supplement, 739, 1 Sawyer, A. J., Bachrach, L. K., & Fung, E. B. (2007). Bone densitometry in growing patients: Guidelines for clinical practice. Totowa, N.J: Humana Press Read More