32.1 Medical Imaging and Diagnostics

• Two people were caught entering the United States from Canada.

• Nuclear radiation is used in a number of medical techniques.
• It is a useful probe to monitor conditions inside the body because radiation can easily penetrate tissue.
• Nuclear radiation depends on the nuclide and not on the chemical compound it is in, so that a radioactive nuclide can be put into a compound designed for specific purposes.
• The location and concentration of a radiopharmaceutical can be determined by radiation detectors outside of the body.
• Another application uses a radiopharmaceutical that the body sends to bone cells to detect tumors or healing points.
• Images can be produced from bone scans.
• Radioisotopes can be used to determine the functioning of body organs, such as blood flow and heart muscle activity.

• A radiopharmaceutical is used to produce a brain image.
• The features are computer enhanced.
• Table 32.1 lists certain uses of radiopharmaceuticals.
• Many organs can be imaged with a variety of nuclear isotopes.

• Isidore is used to image the thyroid, since it is concentrated in that organ.
• The most active cancer cells concentrate the most iodine and emit the most radiation.
• Hypothyroidism is indicated by lack of iodine.
• There are more than one isotope that can be used for multiple types of scans.
• The thallium scans are used to evaluate the cardiovascular system and look at heart activity.
• The salt is similar to NaCl and can be used.
• There is rapid cell growth where Gallium-67 accumulates.
• It's useful in cancer scans.
• It can take several days for the gallium to build up after the injection, so it's best to have a body Scan 3 or 4 days after the injection.

• There are many diagnostic uses for radiopharmaceuticals, where "m" stands for a metastable state of the technetium nucleus.

• 80% of radiopharmaceutical procedures use it because of its many advantages.
• The decay of its metastable state produces a single, easily identified 0.142-MeV ray.
• The radiation dose to the patient is limited by the short half-life.
• Its half-life is short, but it is easy to produce on site.

• The basic process for production is.

• A piece of lead with holes bored through itcollimates rays emerging from the patient, allowing detectors to receive rays from specific directions only.
• An image is produced by the computer analysis of detector signals.

• One of the disadvantages of this method is that it doesn't give a depth view of the tumor, because radiation from any location under that detector produces a signal.

• An Anger camera has a lead collimator and an array of detectors.
• There are light flashes in the scintillators.
• The photomultipliers convert the light output to an electrical signal.
• A computer creates an image.

• Nuclear activity in patients is used to form threedimensional images in x-ray computed tomography (CT) scans.
• The spatial resolution is poor, about 1 cm.
• The difference in visual properties that make an object different from other objects is good.

• An image of the concentration of a radiopharmaceutical compound is created by SPECT using a geometry similar to aCT.

• In recent years, images produced by emitters have become important.
• Two rays are produced when the emitted positron encounters an electron.
• It requires detectors on opposite sides to detect the same photon at the same time.

• The advantage of this list is that they can be used as tags for natural body compounds.
• The accuracy and sensitivity of the scans make them useful for examining the brain's function.
• The brain's use of oxygen and water can be monitored.
• It is used to diagnose brain disorders.
• A confirmation of Alzheimer's disease can cause decreased metabolism in certain regions.
• When a person carries out specific activities, such as speaking, closing their eyes, and so on, the brain can become active.

• The two identical -ray photons produced by positron-electron annihilation are used in a PET system.
• The line along which each pair is emitted is determined by the rays that are emitted in opposite directions.
• The events detected by several pairs of detectors are analyzed by a computer to create an accurate image.

• MRI can tell.
• Nuclear spins of the hydrogen nuclei of your water molecule are what radio transmitters are made of.
• These little radios can be made to broadcast their positions, giving a detailed picture of the inside of your head.