Physics Flashcards
Who discovered Xray? and when?
Dr. Wilhelm Conrad Roentgen
November 8th 1895
Velocity
V=D/T
Roentgen (R)
is used to quantify radiation intensity
Rad/ Grey
is used to quantify the biologic effects of radiation on humans and animals. aka absorbed dose.
1rad= 10^-2Gy (.01 Gy)
Rem
this is used to quantify occupational exposure or dos equivalent
1rem=10^-2Sv (.01Sv)
Curie
is used to quantify radioactivity
Anode
is the positive electrode in the X-ray tube. this part is over the head of the table
cathode
is the negative electrode in the X-ray tube. this section is usually at the foot of the table.
Atom
basic building block of matter
consists of protons, neutrons, electrons and the nucleus
Effective focal spot
the X-ray beam area as seen from the perspective of the patient
electromagnetic radiation
an electric and magnetic disturbance traveling through space at the speed of light
emulsion
the radiation-sensitive and light sensitive layer of the film
Remnant radiation
aka exit radiation: the attenuated X-ray beam leave the patient and is composed of both transmitted and scattered radiation.
Fluorescence
refers to the ability of phosphors to emit visible light only while exposed to X-rays
Flux Gain
an expression of the ratio of the number of light photons to the number of light photons emitted input phosphor
Focal Plane
same as the object plane, the plane where the area of interest lies at the level of the fulcrum
what will impact the viability
the anode heel effect
SID and IR size
inverse square law
I1/I2=(D2)^2/(D1)^2
Pixel Pitch
Pixel size and spacing determine the spatial resolution of the digital image. This is known as:
acute radiation syndrome
a whole-body dose in a short period of time, certain symptoms will occur; these are referred to as
Backscatter on a digital image can cause an artifact called a?
Phantom image artifact
To eject a K-shell electron from a tungsten atom, the incoming electron must have an energy of at least
70 KeV
The tabletop exposure rate during fluoroscopy shall not exceed
10 R/min
Bremsstrahlung Radiation
Bremsstrahlung (Brems) or “braking” x-ray production, a high-speed electron, accelerated toward a tungsten atom, is attracted (and “braked,” that is, slowed down) by the positively charged nucleus and therefore is deflected from its original course with a resulting loss of energy. This energy loss is given up in the form of an x-ray photon
A star pattern is used to measure
focal spot resolution
15% rule
Increase density= kvp x 1.15
Decrease density= kvp x .85
Maintain density= kvp x 1.15 and mAs/2
densitometer.
The instrument that is used frequently in quality-control programs to measure varying degrees of x-ray exposure
An exposed image plate will retain its original image quality for about…?
8 hours
Most common used types of AEC devices
Ion chamber and photomultiplier tube
Light sensitive AEC devices are known as
Phototimers
