What are positive effects of using radiation in the field of medicine? What are positive use nuclear...?

Question

reactions. How is it used? please give exmples

Answer 1

Technically, there is no such thing as "good" exposure to radiation. In my training in x-ray and nuclear medicine we are taught to limit any unnecessary exposure both to ourselves as technologists and to the patient. In the case of the patient, the risk/reward factor must be considered. If a patient is a has high risk coronary artery disease, then the 40 mCi dose (10 & 30 mCi dose) we give them is such a low risk of damage due to exposure when compared to the value the test has in grading the severity of the patient's disease. A little fact I learned in nukes school I like to tell the apprehensive of my field is this: The chance of dying from a cancer caused by exposure from a nuclear medicine exam has the same probability of driving 100 miles and being in a fatal car crash.
I don't think I've directly answered the question, so here is the other part of the answer. Here's a breakdown of some of the nuclear reactions going on in radiology and how they are used for good.

X-ray: reaction-a high voltage beam hits a rotating anode made of tungsten, which through Bremstrahlung ("braking") reactions and "K" shell cascading characteristic radiation creates the x-rays. It doesn't actually make a cingular beam like you would think, it bascially goes in every direction, but the only opening in the lead casing is where the exposure comes out of. The x-rays penetrate tissues and are attenuated according to tissue density, the remaining rays that make it through affect the screen within the film casing. The xrays themselves don't affect the film, a screen actually turns x-rays into light, which affects the film. Of course, with digital imaging prevalent today, there is no film within the cassette anymore, it is actually a screen that stores the image and is reusable. Barium and other contrast agents can be ingested, injected, or placed in body cavities by other means to highlight anatomy that otherwise is homogenous in tissue density, therefore indecipherable by a regular exposure. How x-ray contrast works is that it has a high Z number, like lead, it has very dense electrons, therefore, not many, if any rays can make it through, thus leaving that part of the image light/white.
How x-ray is used- x-ray is used basically to acess internal anatomy, such as bones. With the used of barium the gastrointestinal tract can be imaged. It is used in CT (or CAT) to produce cross-sectional images, based on anatomical detection.
Nuclear Medicine reactions- The predominant radionuclides in nuclear medicine are short-lived isotopes that emit only gamma rays and decay by isomeric transition, such as Technetium99m, Strontium 87m, and Gallium68. Others, like Iodine131 and Iodine123 decay by electron capture. These isotopes give off gamma rays that can be imaged, and in the case of some like I131 emit a beta and can be used to treat. There are also PET agents, which decay by positron emission and create an annhiliation reaction.
How nuclear medicine is used- Each of these different isotopes have an affinity to bind to different things, depending on their pharmacodynamics. Tc99m if injected will concentrate in the thyroid, salivary glands, choroid plexus, and gastric mucosa. But Tc99m can be "tagged" with various pharmaceuticals to alter its distribution in the body. For instance, Tc99m can be tagged with MDP (methylene disphosphonate), which mimics the phosphate building blocks that the bone uses to continuously repair bone. When injected the Tc99m MDP goes to the bone, but if there is a fracture or bone metastasis for instance there will be more repair going on there, thus more of the radiopharmaceutical will go there and be detected by the gamma camera. I131 therapy works by having a patient ingest I131 capsules, the thyroid tissue is the only organ in the body that takes up iodine, it also takes up radioactive iodine. Thus it takes up a large percentage of this goes to the thyroid tissue, wherever it is in the body (since metastasis go to the lungs and elsewhere). I131 emits a Beta radiation that destroys tissue, thus killing all thyroid tissue. If you're going to get cancer, thyroid cancer is the least bad to get, it is very treatable, you just gotta take hormone replacers the rest of your life. Blood cells may also be "tagged", red-blood cells can be tagged to find gastrointestinal bleeds, or to image the chambers of the heart and find how much blood the heart pumps each time. White blood cells can be tagged to find where infection is. Lastly, the PET agents, the most common is Fluorine18 FDG. This is basically a radioactive sugar, because most tumors are assoctiated with a higher glycolytic rate (they eat more sugar) 18FDG is useful in differentiation of benign lesions versus malignant or metastatic disease. There are too many other radiopharmaceuticals to mention, there are some cool ones out there too.

In short, xray is based on detecting anatomical signs, while nuclear medicine is based on physiological signs.

Answer 2

X-radiation is used to image body parts for diagnosis.

High-intensity x-rays are used to treat cancer.

Radioisotopes like thallium-201 and technetium-99m are used markers in such tests as the stress test to detect heart damage.

Answer 3

No two positives equal a positive. To negatives equal a positive in multiplication