Radiography Flashcards
As high speed electrons strike the target in an x-ray tube, ________ are produced
Bremsstrahlung and characteristic x-rays
The inherent filtration in a diagnostic x-ray tube results from ___________ and is usually specified in terms of ________.
Components of the x-ray tube itself;
mm Al equivalent
Typical x-ray transformers for general radiography have a power rating of about _______.
100 kW
What is the relationship between the mean free path (MFP) and the half-value layer (HVL)?
MFP = 1.44 x HVL
The increase in x-ray beam intensity from the target end to the filament end of an x-ray tube is due to ___________.
The heel effect
What design feature(s) is(are) used in x-ray tubes to manage the potentially excessive heat production in the anode?
Angled anode, rotating anode, and use of materials with high heat-storage capacity like tungsten
How does adding filtration affect patient dose?
Patient dose is reduced since lower energy x-rays (which may not penetrate the patient) are removed.
** This applies to fixed technique and AEC
The heel effect can be reduced by ______.
Increasing the source to image distance (SID)
How do you calculate the grid ratio?
= height of the septa divided by the width of the interspace material
Common values for grid ratios for radiographic units are ____
8-12
What is the nyquist spatial frequency of a detector?
1 / (2 * detector element size)
**Note: the spacing between detector elements is sometimes referred to as the pitch