LOOKING INSIDE THE BODY WITHOUT SURGERY
THANKS to advances in computers, mathematics and science, the scalpel are giving way to nonsurgical tool in the diagnosis of certain diseases. Besides X-ray imaging, now over 100 years old, the technologies include computed tomography (CT scan), positron-emission tomography (PET scans), magnetic resonance imaging (MRI), and ultrasound imaging, or sonography. * How do these techniques work? What are their health risks? And what are their advantages?
Thursday, December 11, 2008
X-ray Radiography
X-ray Radiography
How does it work?
Have a shorter wavelength than visible light and can penetrate body tissues. When a certain part of the body is x-rayed, dense tissues, such as bones, absorb the rays and appear as bright areas on the developed film, called radiography. Soft tissues appear in shade of gray. X-rays are commonly used to diagnose problems or disease involving teeth, bones, breasts, and between adjacent soft tissues of the same density, a doctor may inject radiopaque dye into the patient's blood stream to enhance the contrast. Nowadays, X-rays are often digitized and viewed on a computer screen.
Risks: there is a slight chance of damage to cells and tissues, but the risk is usually very low compared with the benefits. * Women who may pregnant should inform their doctor before they submit to an X-ray. Contrast agents, such as iodine, may cause allergic reactions. So inform your doctor or technician if you have any allergies to iodine and to seafood which contains this element.
Benefits: X- ray imaging is fast, generally painless, relatively inexpensive, and quite easy to perform. Hence it is particularly useful in such areas as mammography and emergence diagnosis. No radiation remains in the body after the X- ray is administered, and usually there are no side effects.
Have a shorter wavelength than visible light and can penetrate body tissues. When a certain part of the body is x-rayed, dense tissues, such as bones, absorb the rays and appear as bright areas on the developed film, called radiography. Soft tissues appear in shade of gray. X-rays are commonly used to diagnose problems or disease involving teeth, bones, breasts, and between adjacent soft tissues of the same density, a doctor may inject radiopaque dye into the patient's blood stream to enhance the contrast. Nowadays, X-rays are often digitized and viewed on a computer screen.
Risks: there is a slight chance of damage to cells and tissues, but the risk is usually very low compared with the benefits. * Women who may pregnant should inform their doctor before they submit to an X-ray. Contrast agents, such as iodine, may cause allergic reactions. So inform your doctor or technician if you have any allergies to iodine and to seafood which contains this element.
Benefits: X- ray imaging is fast, generally painless, relatively inexpensive, and quite easy to perform. Hence it is particularly useful in such areas as mammography and emergence diagnosis. No radiation remains in the body after the X- ray is administered, and usually there are no side effects.
Computed Tomography
Computed Tomography
How does it work?
CT scans involve in more sophisticated and intense use of X-rays, along with special. The patient lies on a table that slides into a tunnel in the machine. Images are produced by numerous narrow beams of radiation and detectors that rotates 360 degrees around the patient. The process has been compared to examining a loaf of bread by photographically cutting it into very thin slice. A computer resembles the "slice," providing a detailed cross- sectional view of the body's interior. The latest machines stand the body in a helical, or spiral, fashion, thereby speeding up the process. Because CT scans provides much details, they are often used for examining the chest, the abdomen and the skeleton, and for diagnosing various cancers and other disorders.
Risks:
Risks:
CT scans usually involve higher doses of radiation than regular X- ray. The additional exposure carries a small but significant increased risk of cancer, and this should be carefully weighed against the benefits. Some patients have an allergic reaction to contrast agents, which commonly include iodine; and in certain patients, there may also be an element of risk to the kidney. If a contrast fluid is used, nursing mothers’ may have to wait 24 hours or more before resuming breast feeding.
Benefits:
Benefits:
Painless and noninvasive, CT scans provide finely detailed data that can be digitally converted into three-dimensional images. Scans are relatively fast and simple, and they can save lives by revealing internal injuries. CT scanners do not affect implanted medical devices.
Positron-Emission Tomography
Positron-Emission Tomography
How does it work?
For PET scan, a radioactive substance is attached, or tagged, to a natural body compound, most commonly glucose, and injected into the body. The image results from emission of positrons-positively charge particles-from the tissues. PET scans operate on the principle that cancerous cells use small glucose that normal ones do, those attracting a larger amount of the radioactive substance. As a result, diseased tissues emit a greater number of positrons which register as a variation in color or degree of lightness on the final image.
Whereas CT scans and MRI scans review the shape and structure of organs and tissue PET scans shows how they are functioning thus revealing chances at an earlier stage. PET scans can be performed in combination with CT scan, the superimposed image enhancing the details. PET scans may give false result, however, if patient have eaten within a certain time prior to the scan of if there blood sugar levels, perhaps because of diabetes are out side the acceptable range. Also, because of the radioactivity is very short-lived, timing is important.
Risks:
For PET scan, a radioactive substance is attached, or tagged, to a natural body compound, most commonly glucose, and injected into the body. The image results from emission of positrons-positively charge particles-from the tissues. PET scans operate on the principle that cancerous cells use small glucose that normal ones do, those attracting a larger amount of the radioactive substance. As a result, diseased tissues emit a greater number of positrons which register as a variation in color or degree of lightness on the final image.
Whereas CT scans and MRI scans review the shape and structure of organs and tissue PET scans shows how they are functioning thus revealing chances at an earlier stage. PET scans can be performed in combination with CT scan, the superimposed image enhancing the details. PET scans may give false result, however, if patient have eaten within a certain time prior to the scan of if there blood sugar levels, perhaps because of diabetes are out side the acceptable range. Also, because of the radioactivity is very short-lived, timing is important.
Risks:
Because the amount of radioactive substance which is very low and it radioactivity short-lived, radio exposure is low. Still, it can pose the risk to a developing fetus. Hence, women who may be pregnant to inform their doctor and imaging staff. And women of child bearing age may be asked to give a blood or urine sample to test for pregnancy. If a PET scan is used in conjunction with a CT scan, then the risk associated with CT scans should also be taken into account.
Benefits:
Benefits:
because PET scans show not just the shape of organ and tissue but also how well they are working, this scans can uncover problems before changing in tissue structure can be seen with CT or MRI.
Magnetic Resonance Imaging
Magnetic Resonance Imaging
How does it work?
MRI uses a powerful magnetic field along with radio waves (Not X- ray) and a computer to produce highly detailed slice- by -slice" picture of virtually all the internal structures of the body. The result enables physician to examine part of the body in minute detail and identify disease in the ways that are not possible with other techniques. For examples, MRI is one of the few imaging tools that can see through bones, making it an excellent tool for examining the brain and other soft tissues.
Patient must remain still during the imaging process. And because the scan takes place as the patient slides through a rather small tunnel in the machine some people experience claustrophobia. In recent times, though, open MRI scanners have been developed for patience who are anxious or obese. Naturally no metal object such as pens, watches, jewelry hairpins, and metal zippers as well as credit cards and other magnetically sensitive items are allowed into examination room.
Risk:
Patient must remain still during the imaging process. And because the scan takes place as the patient slides through a rather small tunnel in the machine some people experience claustrophobia. In recent times, though, open MRI scanners have been developed for patience who are anxious or obese. Naturally no metal object such as pens, watches, jewelry hairpins, and metal zippers as well as credit cards and other magnetically sensitive items are allowed into examination room.
Risk:
If a contrast fluid is used, there is a slight risk of allergic reaction, but the risk is less than associated with the iodine based substances commonly used with X-ray and CT scans. Otherwise MRI poses no known risk to patient however because of the effect of strong magnetic field, patient with certain surgical implants or metal fragment from injury may be unable to have MRI. So if MRI is recommended for, be sure to tell your doctor and your MRI technologist if you have any of those things.
Benefits:
Benefits:
MRI does not use partially harmful radiation, and it is particularly good at dictating tissue abnormalities, especially those that may be obscured by bone.
Ultrasound Imaging
Ultrasound Imaging
How does it work? Also called ultrasound scanning or sonography, this technology is essentially informed of solar that uses sound wave above the range of human hearing. When the waves reaches a boundary where there is a change in tissue density that the surface of an organ, for example- an Echo results. A computer analysis the echo, revealing two or three dimensional features of the organs, such as it depth, size, shape and consistency. No frequency waves enable the imaging of deeper part of the body; Ultrahigh frequencies permit the study of surface organs such as the eye and the layers of skin, perhaps assisting in the diagnosis of skin cancer.
In most instances, the examiner uses the handheld device called a transducer. After applying a clear gel to the skin, he robs the transducer over the area of interest, and the resulting image immediately shows up on a computer screen. When necessary a small transducer can be attached to a probe and inserted into a natural opening inn the body to make certain internal examination possible.
A Technologist called Doppler Ultrasound is sensitive to movement and is used to reveal blood flow. This, in turn can be helpful when making diagnosis involving other and tumors, which tends to have an abnormally large amount of blood vessel.
Ultrasound imaging helps physicians to diagnose and array of conditions and to the discern the underlying course of symptoms from heart-value disorder to lumps in the breast of the status of an unborn infant. On the other hand, because ultrasound waves are reflected by gas, the technology has limitations when applied to certain part of the abdomen. Also, the resolution may not be as high as that of the other technologies such as radiography.
Risks: Even though ultrasound is generally safe when used properly, it is inform of energy and can produce physical effect on tissue including those of the unborn. Prenatal ultrasound therefore should not be considered risk free.
How does it work? Also called ultrasound scanning or sonography, this technology is essentially informed of solar that uses sound wave above the range of human hearing. When the waves reaches a boundary where there is a change in tissue density that the surface of an organ, for example- an Echo results. A computer analysis the echo, revealing two or three dimensional features of the organs, such as it depth, size, shape and consistency. No frequency waves enable the imaging of deeper part of the body; Ultrahigh frequencies permit the study of surface organs such as the eye and the layers of skin, perhaps assisting in the diagnosis of skin cancer.
In most instances, the examiner uses the handheld device called a transducer. After applying a clear gel to the skin, he robs the transducer over the area of interest, and the resulting image immediately shows up on a computer screen. When necessary a small transducer can be attached to a probe and inserted into a natural opening inn the body to make certain internal examination possible.
A Technologist called Doppler Ultrasound is sensitive to movement and is used to reveal blood flow. This, in turn can be helpful when making diagnosis involving other and tumors, which tends to have an abnormally large amount of blood vessel.
Ultrasound imaging helps physicians to diagnose and array of conditions and to the discern the underlying course of symptoms from heart-value disorder to lumps in the breast of the status of an unborn infant. On the other hand, because ultrasound waves are reflected by gas, the technology has limitations when applied to certain part of the abdomen. Also, the resolution may not be as high as that of the other technologies such as radiography.
Risks: Even though ultrasound is generally safe when used properly, it is inform of energy and can produce physical effect on tissue including those of the unborn. Prenatal ultrasound therefore should not be considered risk free.
Benefits: the technology is widely available, noninvasive, and relatively inexpensive. It also provides real-time imaging.
Future Technologies
Future Technologies
At present the main thrust of research seems to be to improve technology that is already available. For Example, researchers are developing MRI scanners that operate with a much weaker magnetic field than that of the present devices, thus considerably reducing costs. A new technology under development is called molecular imaging (MI). Designed to detect changes within the body at the molecular level, MI promises very early detection and treatment of disease.
Imaging technology has reduced the need for many painful, risky, and even unneeded exploratory operations. And when imaging leads to early diagnosis and treatment of disease, the out come may be much better. The equipment, however, is expensive some machines costing well over a million dollars.
Of course, the prevention of disease is better than its detection and cure. So try to stay healthy through proper diet, regular exercise, sufficient rest, and a positive mental outlook. “A heart that is joyful does good as a curer”, says proverbs 17: 22
At present the main thrust of research seems to be to improve technology that is already available. For Example, researchers are developing MRI scanners that operate with a much weaker magnetic field than that of the present devices, thus considerably reducing costs. A new technology under development is called molecular imaging (MI). Designed to detect changes within the body at the molecular level, MI promises very early detection and treatment of disease.
Imaging technology has reduced the need for many painful, risky, and even unneeded exploratory operations. And when imaging leads to early diagnosis and treatment of disease, the out come may be much better. The equipment, however, is expensive some machines costing well over a million dollars.
Of course, the prevention of disease is better than its detection and cure. So try to stay healthy through proper diet, regular exercise, sufficient rest, and a positive mental outlook. “A heart that is joyful does good as a curer”, says proverbs 17: 22
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