X-Rays Radiation Application in Medicine IONIZING RADIATION

X-Rays Radiation Application in Medicine

IONIZING RADIATION ELECTROMAGNETIC WAVES WITH WAVELENGTH < 10 n м ( depends on nature : roentgen & γ- rays ) CORPUSCULAR RADIATION α — particles flow Proton radiation Space raysβ — particles flow Neutron radiation Ionizing radiat іо n Electromagnetic waves’ scale

W. Roentgen – is an author of fundamental works in different fields of experimental physics. 1895 he discovered new kind of rays & called them X-Rays. These rays are known now as Roentgen Rays. He made the first roentgen pictures – pictures of his & his wife’s arms. ROENTGEN RADIATION is electromagnetic waves with wavelength 10 е V. hc h. E Wilhelm Roentgen (1845 -1923), germany physicist – experimentalist, Nobel prize laureate (1901) HYSTORY OF X-RAYS DISCOVERY

First roentgen picture of W. Roentgen’s wife’s arm. COMPARE THE FIRST ROENTGEN PICTURE & THE MODERN ONE Modern roentgen picture of an arm

ROENTGEN TUBE CONSTRUCTION

ROENTGEN RADIATION Braking (Bremsstrahlung) characteristic Braking (Bremsstrahlung) radiation U 1 < U 2 < U 3 Ф 123 λUe=hν Bremsstrahlung(from Germanbremsen(to brake) and. Strahlung(radiation)) is X ray radiation (green) emitted by charged particles, such as electrons (yellow), which are braking around other charged particles, such as an atom nucleus (blue)

, BZA А, В= const , Z – element number. CHARACTERISTIC RADIATION When a sample is bombarded by an electron beam, some electrons are knocked out of their shells in a process called inner-shell ionization. About 0. 1% of the electrons produce K-shell vacancies; most produce heat. Outer-shell electrons fall in to fill a vacancy in a process of self-neutralization. The energy required to produce inner-shell ionization is termed the excitation potential or critical ionization potential (E c ). MOZLY LAW

Roentgen radiation interaction with matter COHERENT LENGTHS INCOHERENT DISPERSION (COMPTON EFFECT)PHOTOEFFECT COHERENT DISPERSIONhν hν hν < A и The direction of electro magnetic radiation is change. Used for roentgen structure analysis.

Due tothe phenomenaof diffractionandinterference of. X-rayson a crystalona photographic plate, behind the crystal, symmetricalpatternofspots (Lauegram) appears. German scientist. Maxvon. Laue(1879 -1960)was the first who predicted thepossibility of using. X-raysto determine the structureof bodies. Lauehramreading whenthe structure of crystal is unknown — a difficulttask. If thestructure of thecrystalis known, the. Lauemethodallows todeterminethe wavelengths, to make. Roentgenspectroscopy. Lauehram Letthe distancebetween the twocrystal-planewemarkedbyd. Twoparallelon-me 1 and 2 are fallingat an angleαto theseplanesanddiffractsations. A and B. diffractedrays 1 ‘and 2’interfere, and ifthe beam 2. 2’has relativelybeam 1. 1’path differenceequal tol ora wholemultipleof it, theirintensityyutsyacomplexity. Spot ona photographic plateoccursonly whenstrictlyacorner, whichis performedforconditions of Bragg: , . . . )2, 1(, sin 2 kkd. For this purposeit is better touse the methoddeveloped by father and son. Braggs. Eachcrystalcan be imagined asa set of separateparallellayersof ions oratoms, called thecrystalplanes. COHERENT LENGTHS US

X-RAYS IMAGING SHADOW PROECTIONS

X-RAYS DIAGNOSTICS

COMPUTER TOMOGRAPHY

COMPUTER TOMOGRAPHY

SPIRAL TOMOGRAPHY

MAMMOGRAPHY

X-RAYS IN STOMOTOLOGY

X-RAYS DOSIMETRY