BTEC Applied science level 3 - Unit 21 - Assignment A

Unit 21: Medical Physics Applications

Assignment 1- Radiation use in medical diagnosis and
treatment



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,P1/P2

Introduction to ionising radiation




Ionising ra diation is a type of rad iation tha t is m ade up of pa rticles or w aves that ha ve en ough
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energ y to remo ve ele ctrons fro m ato ms, th us crea ting ions. In t erms of par ticle ph ysics,
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ionisi ng radi ation is ma de up of par ticles su ch as alpha par ticles, bet a partic les, gam ma ra ys,
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and X-rays.

Al pha parti cles a re mad e u p of tw o pr otons a nd tw o neu trons an d are em itted fro m the nuclei
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of cer tain radio active a toms. The y ar e rel atively lar ge a nd slo w-moving, an d as a r esult, th ey
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can be stop ped by a f ew centi metres o f air or a few sh eets of pa per.
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Be ta parti cles ar e high -ener gy elect rons that are em itted from the nu cleus of a rad ioactive
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at om. The y are much smal ler and fas ter than alp ha parti cles, an d as a r esult, the y can
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penetra te furth er into m aterials. i i i




Gam ma ra ys are hig h-en ergy electro magnetic wa ves th at are em itted from the nu cleus of a
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radio active a tom. They are mu ch s maller and fa ster than al pha and bet a pa rticles, and a s a
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resu lt, they can pe netrate fur ther into ma terials.
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X-ra ys are high-e nergy elect romagnetic wav es th at are em itted from the el ectron she lls of
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ato ms. They are m uch smal ler and fa ster than alph a, beta, and gamm a particle s, a nd as a
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result, they can penet rate furt her into mate rials. i i i

, Wh en th ese pa rticles and w aves int eract with m atter, they can ca use ionisat ion, whi ch is the
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proc ess of rem oving elec trons from a toms. Th is can cause d amage to liv ing cell s and ca n le ad
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to t he devel opment of c ancer.
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