MRI CT scan. CT scan vs. MRI and ultrasound scan. What radiation dose exposure for you?
Yes, there is a difference between the two imaging technologies. CT scans are often used to show changes in a bone, jaw and mouth. It is an X-ray study in which many sections processed in the computer and show bone structure very accurately. CT scanning is used by eg slipped disc, but are replaced increasingly by MRI, most often used to show changes in soft tissue discs and muscles. It is a magnetic survey, focusing on the liquid content in the tissue. If there is an area of tissue damage attracts fluid and it is clearly seen on MRI scan, which is thus typically used in suspected herniated disk and to display tissue damage in the muscles and bones and in detecting tumors and bleeding in the brain.
MRI (Magnetic Resonance Imaging)
By MRI (magnetic resonance imaging) uses a strong magnetic field - and not X-ray radiation by CT scan. The magnetic field is so strong that one can not have metal parts in the body, at least not near the part of the body being scanned. This excludes those metal parts which are not magnetic, such as fillings in your teeth. With MRI, you can undergo an examination of the bile ducts and pancreatic ducts, called MRCP (magnetic resonance cholangio pancreaticografi). The MRI scan is mentioned based on the use of magnetic fields and radio waves. Therefore, the investigated person is not exposed to X-rays or other damaging forms of radiation. MRI provides over other imaging techniques good images of body parts, which is surrounded by bone tissue, and the technique is particularly suitable to show the brain, spinal cord and tissue damage in the muscles and bones. MRI can provide highly detailed images, and is the best technique to show tumors in the brain. The technique can detect the tumors in the brain has grown into the surrounding brain tissue. Indeed, the technique allows to focus on details in the brain so specific that it can reveal the scar tissue that forms in nerve sheaths by multiple sclerosis. MRI can show changes in the composition of body tissues. For example, you can see the changes that arise in the brain tissue in a brain hemorrhage or stroke, where brain tissue has suffered lack of oxygen. MRI can also show the heart and major blood vessel separate from the surrounding tissue. It is possible to detect congenital heart defects, and changes of the heart musculature's thickness after heart attacks. Finally, the method can also be used for examination of the joints and soft tissue, liver, spleen, intestines, etc..
MRI scans are often done outpatient, meaning that you go home after the examination. During the scan, you lie perfectly still so as not to disturb the recordings. In some cases the need to anesthetize children. The examination is painless and can not be marked on the body. When MRI is frequently used contrast that is given by injection into a vein. Contrast is harmless to the body and leaves no discomfort or risk of allergy. During the scan, one lies inside a large cylindrical magnet 5000-60000 times stronger than Earth's magnetic field (0.23 T - 3.0 T). Here you are exposed to pulsed radio waves with a frequency of 42.6 MHz / Tesla. There is placed an electrical coil around the portion of the body to be scanned. By means of this coil transmitted pulses shortly alter the high magnetic field. When the pulse is then terminated, the hydrogen atoms to swing back to the starting point in the strong magnetic field. This emitted a weak radio signal which is intercepted by the coil. The signals are translated by a computer into images of the limb. As is known, most of the body of water. Water contains hydrogen atoms, and therefore plays brintatomers nuclei an important role in MRI, and can thus form images of almost all body tissues. When not using ionizing radiation, the investigation may be repeated several times without problems.
CT scan (Computed Tomography)
CT scan is an x-ray. The scanner sends pulses on to a computer that converts them into images. This forms a series of images of all layers in the part of the body being studied. Using CT scans, doctors can see where and how deep, any node sits. The technology behind MRI and CT scanning is different. Pictures taken with a CT scan are more detailed than ordinary X-rays. In addition, information from the recording is processed in a computer so they appear 3-dimensional and from several different angles. A CT scan works differently than a conventional x-ray apparatus. Instead of sending a single bundle of rays through the body, as happens in ordinary X-rays, transmitted rays from an X-ray tube that rotates around the patient bed. Beam bunches are captured by sensors that detect the jets strengthen and pass them on to a computer. X-rays will be attenuated depending on the type of the tissue goes through. The recorded data are processed in the computer and converted to a 2-dimensional image displayed on a screen. CT scan, is particularly useful to test bleeds, aneurysms (herniated an artery), brain tumors, and brain damage, in addition, the scan is used to check tumors and abscesses in the whole body can finally CT scans used for evaluating damage to organs by trauma as as tearing of the kidneys, spleen or liver.
CT scans, also used in modern dentistry
Furthermore, forming the CT scanning light for a new cutting edge dental technique which makes it possible to have fixed teeth of one hour (teeth-in-an-hour). That is, the toothless one hour can be inserted implants and fixed teeth, where before it could take up to six months to get a new over the mouth. In preliminary studies CT-jaws are scanned with a model of the required future teeth and to produce a 3-dimensional view of a mouth and jaw bone. Recordings are edited on the computer where the dentist exactly determine where the implants should sit in order to be placed in good bone. From the computer model, using CAD / CAM technique produced both the completed bridge and also a guide rail that is placed on the patient, so the implants will sit exactly where desired. - Learn more about teeth here >>
A CT scan does not hurt. The jet impacts the body is exposed to during a CT scan is a lot bigger than an ordinary x-ray absorption, so scanning is not recommended, unless there are really good medical and professional reasons. There may occasionally result in adverse effects in the investigation. This is particularly the case when using contrast medium. There may be allergic to constituents of the contrast agent. A CT scan has hundreds of contrast levels compared to conventional radiographs, which has only a few contrasts between bone and soft tissues. Tissues of different densities, such as bones, jaw, muscle and adipose tissue imaged clearly by CT scan. When a recording of the brain can clearly see the brain's fluid-filled spaces (ventricles).
Through the help of totally harmless sound waves (ultrasound) it is possible to produce images of internal organs. Ultrasonic studies works by sound waves are sent out and thrown back into a scanner. Depending on what affects the sound waves, they send back different signals. For example, the formed image of a womb of a fetus. Ultrasound scanning is used in many different contexts, for example during pregnancy, women's diseases and associated with various stomach, intestinal and liver diseases. The way the ultrasound scan performed depends on the purpose of the study. The best connection between the scanner head and the patient is ensured by the fact that distributed a portion of jelly on the skin where the scan will be conducted. Many other parts of the body can be examined with an ultrasound scanner. This may be through the body's natural body orifices such as mouth or vagina. An ultrasound scan does not hurt.
Ultrasound and early fetal scan
Ultrasound is mentioned sound waves are sent out of the scanner head and then sent back as echoes, which are translated into images. Studies have shown that ultrasound with the frequencies and the strength used in pregnancy scans are harmless. The technique is specially designed for example to perform pregnancy scans in traditional 2D and 3D / 4D. The scanner is connected to a flat panel so that you effortlessly live can follow the investigation closely. Several factors affect the quality of scanning images such as the distance between the scanner head and the child, why uterine location, intestine and adipose tissue may be a contributing factor to image quality. The child's posture in the womb is also crucial. Furthermore, it can be an advantage if the pregnant woman's bladder has not emptied one hour before the scan, since water in the bladder may also increase the quality of the images. - Click to read about pregnancy scan in 3D and 4D >>
An X-ray study provides detailed images of the skeleton and soft tissues in the body and remains a very important tool to examine some of the body's internal structures. X-rays are closely related to both radio and light waves. In an X-ray study halted a portion of the rays of the body, while the rest passes and hits a photographic film, a TV camera or special detectors. Dense tissue such as bones, absorb more radiation than soft tissue. When the image is prepared, it is easy to separate the bones from the pulp, but more difficult to separate the pulp from one another. Therefore one often uses a contrast agent so that the investigated member may appear clearer. Contrast agents can for example be injected into a vein of certain renal studies. Upon examination of the intestines can contrast medium drink.
X-ray examinations may be performed on all parts of the body and is often used in combination with other studies to refute or confirm a diagnosis. The simplest form of X-ray investigation is a single recording, which is the most common form and special velegent to examine the spine, chest, skull and other parts of the skeleton. Is there a need to examine the cavity or fluid filled structures, it is possible to use the contrast agents - e.g. barium contrast for the examination of the esophagus, stomach and intestines, and iodinated contrast media for the detection of e.g. the kidneys. In many cases, the previously used X-ray examinations, you choose today CT scan that produces series of sectional images.
The amount of radiation dose depends on the type of X-ray examination to be carried out. The more complicated an investigation, the greater the radiation dose. Radiation dose is a measure of the amount of energy absorbed by the body in a study. The dosage is measured in Sievert (A), which is a large device. Therefore, given radiation dose by X-ray studies usually in millisievert (mSv). 1 Sv = 1,000 mSv. - Radiation Doses from typical studies: Arm: 0.1 mSv - Lungs: 0.3 mSv - Stomach: 1.5 mSv - low back: 5.0 mSv - Colon: 6.0 mSv - Renal Study: 7 , 0 mSv - CT scan head: 2.0 mSv.
What other radiation exposure we humans?
A person is typically a radiation dose of about 5 mSv per year. The majority comes from natural sources such as: From your own body, radioactive substances in the body: 0.2 mSv - From outer space and the sun: 0.3 mSv - From the ground: 0.5 mSv - Radon, radioactivity in soil and building materials: 3, 0 mSv - Studies: 0.6 mSv.