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The Image Reconstruction Problem of xray absorption tomography in words X-rays pass through the subject body and interact to a certain extent with those features they pass. The detected X-ray on the other side of the subject contains information relating to every obstacle in the path, and not just to one. The reconstruction problem is to decode these muddled mixes of information into spatial information throughout the subject, by combining information from many paths through the subject. The fi…
Slice Selection Slice selection is effected by two factors. The first is the bandwidth of the B1 RF pulse, and the second is the gradient throughout the field of view. The smaller the bandwidth shorter the pulse , the thinner the slice selected. The FOV gradient (z axis) intersects at its null point with the slice selection pulse to find the origin of the slice. Slice selection occurs simultaneously with the B1 pulse. Spatial Encoding The spatial encoding of the selected slice is effected by me…
Medical imaging came to be at the turn of the twentieth century with the discovery of X-Rays and their power to penetrate the skin. Their short wave lengths and high energy allowed physicians to see broken bone, and chest X-Rays were used to in the early diagnosis of tuberculosis. Computed Tomography, CT Scans, or CAT Scans Computed Axial Tomography were the second generation of X-Rays. Tomos is Greek for slice or section , graphia is describing. As named it describes an image of a particul…
Modern medical imaging has made invasive exploratory surgeries a thing of the past. The X-Ray portions of medical imaging are being phased out by technologies like MR angiography (MRA), CT angiography (CTA), and ultrasound angiography. These are way to detect blockages and plaque in blood vessels with. They also do away with the dyes that can cause anaphylactic shock in rare cases, and minor irritation in others. Conventional angiography will soon only be necessary as an aid for angioplasty sur…
Medical imaging was discovered just like many of histories greatest inventions, by accident in 1895. Physicist Wilhelm Roentgen was working with electron beams in a glass tube and noticed a fluorescent screen in the lab glowing when the beam was turned on. He found that even though his screen was covered with heavy black cardboard, waves of some type penetrated it. He put items between the screen and the tube, and found that he could see through or into items. The most famous being his wife s ha…