RADT 1085 Unit 1 Test Questions and Answers All Correct
5 views 0 purchase
Module
RADT 1085
Institution
RADT 1085
RADT 1085 Unit 1 Test Questions and Answers All Correct
When increased OID is unavoidable, SID should be - Answer-increased slightly to compensate.
In Computed radiography - Resolving power determined by - Answer-PSP and scanning system frequency (sampling); the greater the frequency the gre...
RADT 1085 Unit 1 Test Questions
and Answers All Correct
When increased OID is unavoidable, SID should be - Answer-increased slightly to
compensate.
In Computed radiography - Resolving power determined by - Answer-PSP and scanning
system frequency (sampling); the greater the frequency the greater the resolution
In Direct radiography - Resolving power determined primarily by - Answer-the detector
element size (DEL), but detector system can influence too
- (Cesium Iodide/Amorphous Silicon vs. Amorphous Selenium)
Amorphous Selenium = better resolution (no light)
What is the purpose of tube filtration? - Answer-to absorb longwavelength photons
before they reach patient
How does tube filtration affect the x-ray beam? - Answer-filtration increases average
energy of the x-ray beam and reduces the dose to the patient by as much as 80%
Tube Filtration has the ability to ... - Answer-...alter beam intensity and alter IR
exposure.
• IR exposure decreases when tube filtration
is increased.
There is an _____ relationship between tissue thickness/type and image receptor
exposure. - Answer-inverse;
- Thick anatomic part decreases IR exposure.
- Thin anatomic part increases IR exposure.
pixel size is determined by - Answer-DEL size; smaller DEL size = smaller pixel pitch =
greater spatial resolution
Quantum Mottle (Noise) - Affects spatial resolution - Answer-when extremely low mAs is
used.
• CR & DR with low exposure index
• If exposure index is low, we must always check for quantum mottle.
- Low Signal to Noise Ratio (SNR) - Answer-Not enough signal (transmitted photons) to
over
take the inherent noise produced by the type of IR
magnification factor formula - Answer-MF = SID/SOD
, Image Size formula - Answer-image size = object size/MF
pixel size formula - Answer-pixel size = FOV/matrix size
Grid ration formula - Answer-Grid Ratio = height/distance between strips
Exposure maintenance formula - Answer-mAs1/mAs2 = D1 squared/D2 squared
- to maintain exposure when distance changes
- also called Direct Square Law
Radiographic distortion - Answer-The misrepresentation of the size or shape of a
structure recorded in the radiographic image.
• A geometric property affecting the radiographic quality.
• Geometric Integrity
2 types of distortion - Answer-size - influenced by OID and SID
shape - influenced by alignment of the CR, part or image receptor and angulation
degree and direction
Magnification - Answer-• Generally, decreases the spatial resolution of the image...
• However, it can be used to image very small structures • Must be used with a small
focal spot size
Exposure - Answer-the amount of radiation that reaches a particular area of the image
receptor
What is the primary controller of image receptor exposure? - Answer-mAs (intensity)
(mGy or mR) - As mAs increases, x-ray exposure increases (intensity) proportionally
Reciprocity law - Answer-Exposure at the IR should remain unchanged as long as
intensity and duration of xray exposure (controlled by mAs) remain unchanged
30% rule: - Answer-minimum change in mAs necessary to cause a significant change in
IR exposure.
As a General rule, make mAs changes ... - Answer-in doubles or halves
How does kVp influence receptor exposure? - Answer-alters intensity of the beam
reaching image receptor - higher kVp levels produce
higher-energy photons that will pass more easily through the body
As kVp increases, the number of primary photons does too,
why? - Answer-because tube current's kinetic energy is more efficiently converted into
x-rays
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Scholarsstudyguide. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £9.35. You're not tied to anything after your purchase.
