RADIOLOGIC TECHNOLOGY BASICS AND FUNDAMENTALS

RAD PHYSICS X-RAY
INTERACTION IN MATTER

5 INTERACTION IN MATTER


COHERENT SCATTERING
BELOW 10 KEV
ENERGY
low energy x-rays

CLASSICAL SCATTERING
AKA: THOMSON SCATTERING


INTERACTION LOCATION: TARGET ATOM

By means of atom excitation


immediately releases it energy as
SCATTER


changes in direction without change in
HOW ? energy


No energy transfer


no ionization




IMAGE NOISE
Contribution:
REDUCE IMAGE CONTRAST


COMPTON SCATTERING
energy low energy


compton and x-ray energy: INVERSELY




RAD PHYSICS X-RAY INTERACTION IN MATTER 1

, RELATED




COMPTON ELECTRON= EJECTED
ELECTRON
AKA
BACKSCATTER RADIATION: x-ray
scattered back in direction of incident x-
rays

INTERACTION LOCATION OUTER SHELL ELECTRON

X-ray interacts in outer shell electron,
reduces its enery by means of ejecting
electron from the orbits of atom causing
ionization

HOW ?
produces 2 producs:
compton electron
scatter radiation


PARTIALLY ABSORBED

Diagnostic
reduces image contrast
Contribution:
fluoro: greater hazard: greater scattering
radiography: less hazard


PHOTOELECTRIC EFFECT
HIGH ENERGY
- xrays are not scattered but absorbed


ENERGY
total x-ray absorption


produces: characteristic x-rays

INTERACTION LOCATION INNER SHELL ELECTRON

By
Albert Einstein 1912
AKA

ejected electron: PHOTOELECTRON




RAD PHYSICS X-RAY INTERACTION IN MATTER 2