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Gamma Knife therapy, like all radiosurgery, uses doses of radiation to kill cancer cells and shrink tumors, delivered precisely to avoid damaging healthy brain tissue. Gamma Knife radiosurgery is able to accurately focus many beams of gamma radiation on one or more tumors.
The chief advantage of proton therapy over other types of external beam radiotherapy (e.g., radiation therapy, or photon therapy) is that the dose of protons is deposited over a narrow range of depth, which results in minimal entry, exit, or scattered radiation dose to healthy nearby tissues. High dose rates are key in cancer treatment ...
The increase is dose dependent, related to the RT's dose strength, volume and location. Use of concomitant chemotherapy, e.g. anthracyclines, is an aggravating risk factor. [34] The occurrence rate of RT induced cardiovascular disease is estimated between 10 and 30%. [34]
Kilovoltage beams do not exhibit a build-up effect and thus deposit their maximum dose at the surface, i.e. d max = 0 or D 0 = 100%. Conversely, megavoltage beams do exhibit the buildup effect deposit; they deposit their maximum dose at some depth below the surface, i.e. d max > 0. The depth of dose maximum is governed by the range of the ...
However, it had a number of problems that limited its appeal. X-ray IORT has a poor uniformity of dose as a function of depth of penetration, the radiation does not stop at a pre-defined depth but continues to deposit radiation to underlying structures, and can do damage to boney structures if too high a dose is delivered.
Recognized effects of higher acute radiation doses are described in more detail in the article on radiation poisoning.Although the International System of Units (SI) defines the sievert (Sv) as the unit of radiation dose equivalent, chronic radiation levels and standards are still often given in units of millirems (mrem), where 1 mrem equals 1/1,000 of a rem and 1 rem equals 0.01 Sv.
Gel dosimeters, also called Fricke gel dosimeters, are manufactured from radiation sensitive chemicals that, upon irradiation with ionising radiation, undergo a fundamental change in their properties as a function of the absorbed radiation dose. Over many years individuals have endeavoured to measure absorbed radiation dose distributions using ...
It is often indicated in micrograys per hour (μGy/h) [1] or as an equivalent dose rate Ḣ T in rems per hour (rem/hr) or sieverts per hour (Sv/h). [ 2 ] [ 3 ] Dose and dose rate are used to measure different quantities [ 1 ] in the same way that distance and speed are used to measure different quantities.
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