To obtain better images through more tissue, a higher kV level is required (shorter wavelength), especially in obese patients. Increasing mA increases radiation exposure and scatter to patient and cath lab personnel. Level of mA limited by tube heat capacity. Increasing mA reduces “mottling” or the spotty appearance. The greater the electrical current, the greater number of photons, resulting in improved image resolution. The number of photons generated per unit of time. Given one of the following factors involved in the generation of x-rays mA, kVp, select the correct definition and factors involved with each Smaller input screen diameter = smaller image field size = sharper resolution. Are equipped with different-sized image fields that alter the image resolution. Converts the invisible x-ray image into a visual image. Only 0.2% - 0.6% of the electric energy provided to the tube eventually is converted to x-ray.() It converts electrical energy, provided from the generator, to an x-ray beam. Provides the power source necessary to accelerate the electrons through the x-ray tube. Given a component of the x-ray system, select its proper function All participants in the cardiac cath lab have accepted some degree of radiation exposure, but they are obliged to minimize risks to other personnel and themselves. No known level of ionizing radiation is a permissible dose or absolutely safe. The less exposure, the less chance of absorbed-energy biologic interaction. Select the four principles in radiation safety Use extra shielding(thyroid guards, lead glasses, table shields). Keep the image magnification as low as possible. Angled views almost double the radiation. Use slower panning, and provide good initial angiographic setup. Limit the milliamperes per kilovolts as much as possible for an adequate image. Maximize the distance between the X-Ray source and staff. Reduce the distance between the X-Ray source and patient. Wear leaded aprons, preferably wraparound > 0.5 mm, provide 80% protection. List five of the methods used to limit radiation exposure The radiographer receives the least amount of scatter radiation, by standing at right angles to the scattering object, the patient. Select the correct position for the operator to stand in order to receive the least amount of scatter radiation List or select the components involved in the generation of the x-ray image For soft tissue 1 R = 1 Rad, for bone 1 R = 4 Rad (greater absorption). rad – (Radiation absorbed dose) is the amount of radiation energy deposited per unit mass of tissue the amount of absorbed dose depends on the tissue type. Rem – (Radiation equivalent dose in man) is used to express the biologic impact of a given exposure. Roentgen (R) – is the measure of ionization delivered to a specific point(exposure). Given a definition of a radiation unit(Roentgen, Rad, & REM), select its name Like lead aprons, thyroid shields should also be properly stored, and they should be checked periodically. Should be examined under fluoroscopy at least once a year Repeatedly throwing an apron over a chair or stretcher may damage the lead lining. Aprons should be placed in an appropriate hanger or storage rack after each use. Wrap around lead aprons should be considered, and they should be long enough to cover the long bones and should extend to the knee or just below the knee. Aprons should be fluoroscopied at least once a year to asses the integrity Should contain 0.5 mm thick lead lining. It is important that radiation protective glasses contain a wrap-around side shield. Glasses containing 0.5 mm lead offer four times the protection of regular glasses glasses with photochromic lenses offer two times the protection of regular glasses plastic lenses offer no protection. Eyeglasses made of 0.5 to 0.75 mm lead-equivalent glass, should be worn by personnel exposed to radiation on a daily basis. Select the correct statements in regards to radiation safety devices like lead glasses, lead aprons, and thyroid shields Procedures to check safety of all equipment. Requiring protective equipment to be worn by all personnel. Program to make personnel aware of the risks associated with radiation exposure. Continuing education programs for personnel on radiation safety. Routine monitoring of personnel radiation exposure. Select the concepts, which the cath lab radiation safety policy should include List the difference between fluoroscopy and cineangiography in relation to radiation exposureįluoroscopy generates 1/5th the x-ray exposure of the cineangiography Click here to study/print these flashcards.Ĭreate your own flash cards! Sign up here.
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