Category: C

Poisoning that is caused by the inhalation or ingestion of cadmium. Cadmium may be accidentally inhaled in fumes from melting, welding, or other industrial processes that involve soldering. Ingestion or breathing in of the cadmium used in photography or engraving causes serious symptoms, such as vomiting, difficulty breathing, and headache. Kidney disease and liver damage…

A device used to accelerate charged particles or ions. The particles bombard special targets where they create radioactive species to be used as radiopharmaceuticals or to make neutrons which can be used for radiotherapy. A machine in which positively charged atomic particles are so accelerated that they acquire energies equivalent to those produced by millions…

Rate at which temperature decreases with time (°C/min) immediately following the completion of hyperthermia treatment.  

A measure of the differences between two adjacent areas in an image. Contrast may be based upon differences in optical density, on differences in radiation transmission or other parameters. Contrast plays an important role in the ability of a radiologist to perceive image detail. In radiology, the difference between adjacent densities in an image. This…

The principal interaction process of photons with tissue in the diagnostic and therapeutic radiology energy range. In this process, the incoming photon transfers energy to an electron in the material and is deflected with reduced energy into a path that generally leads to additional interactions.    

A device used in radiotherapy to correct for irregularities in body surfaces by providing a differential attenuation of the beam before it reaches the patient. The result is a more uniform distribution of radiation dose in the tumor. Compensators are generally mounted on the collimator system of a teletherapy unit.  

A device that channels radiation by blocking it except for a specific aperture. This device might limit the radiation field during a diagnostic examination so that it does not extend beyond the film. A collimator is also used to restrict the radiation received by a gamma camera to that emitted from a specific area in…

The detection of two photons that arrive at separate counters simultaneously as the result of annihilation of a positron (created during a radioactive decay) and an electron. As an imaging technique, the coincidence counting of two photons greatly reduces the significance of any background radiation.  

Methods for determining temperature in heated tissue.  

A method developed in 1932 that moves the x-ray source and the x-ray plate during an exposure to produce an image in which all but a particular plane is blurred out. This enables an approximate isolation of the image of a detail which might otherwise be obscured by overlying or underlying structures.