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Medical imaging GapFill
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An important aspect of medical diagnoses is being able to image the interior of a patient's body, without surgery, which can pose risks to the patient.
One of the most important tools in medical imaging is X-ray imaging. X-rays are high-energy photons, created when . X-rays can cause mutations and burns if absorbed by a patient, so X-ray doses are kept to a minimum. One way of doing this is by using a which is opaque to X-rays, increasing the contrast and detail on an X-ray image while exposing the patient to the same dose of X-rays.
Standard X-ray imaging produces a very rough, 2D image, so sometimes are taken, which use a wide beam of X-rays and a ring of detectors to take images of many thin sections of a patient's body, which are then built up into a 3D image. This provides a much more detailed look at the human body, but is much more expensive than standard X-ray imaging.
Medical tracers can be used to follow the specific functions of a body. A patient is injected with a radioactive source such as , which can bind to biological molecules and be carried to sites of biological activity. Typically, sources which emit are used, as this type of radiation won't pose too much risk to the patient, while still producing a clear image when detected. Other medical tracers, which emit positrons, are used in ; the positrons emitted quickly annihilate with electrons in the body, producing two gamma rays at 180° from each other, which are detected by a gamma camera outside the body.
Ultrasound scans are used when exposing the patient to any amount of radiation is risky, such as for pregnant women. These are sound waves with , which are emitted into the body in pulses, with the reflected wave detected. An ultrasound transducer uses the effect, where crystals are exposed to an alternating current, causing them to expand and contract. Different materials absorb, transmit or reflect the resulting ultrasound waves differently, depending on the of the material.
One of the most important tools in medical imaging is X-ray imaging. X-rays are high-energy photons, created when . X-rays can cause mutations and burns if absorbed by a patient, so X-ray doses are kept to a minimum. One way of doing this is by using a which is opaque to X-rays, increasing the contrast and detail on an X-ray image while exposing the patient to the same dose of X-rays.
Standard X-ray imaging produces a very rough, 2D image, so sometimes are taken, which use a wide beam of X-rays and a ring of detectors to take images of many thin sections of a patient's body, which are then built up into a 3D image. This provides a much more detailed look at the human body, but is much more expensive than standard X-ray imaging.
Medical tracers can be used to follow the specific functions of a body. A patient is injected with a radioactive source such as , which can bind to biological molecules and be carried to sites of biological activity. Typically, sources which emit are used, as this type of radiation won't pose too much risk to the patient, while still producing a clear image when detected. Other medical tracers, which emit positrons, are used in ; the positrons emitted quickly annihilate with electrons in the body, producing two gamma rays at 180° from each other, which are detected by a gamma camera outside the body.
Ultrasound scans are used when exposing the patient to any amount of radiation is risky, such as for pregnant women. These are sound waves with , which are emitted into the body in pulses, with the reflected wave detected. An ultrasound transducer uses the effect, where crystals are exposed to an alternating current, causing them to expand and contract. Different materials absorb, transmit or reflect the resulting ultrasound waves differently, depending on the of the material.