CT Registry Review exam 2024 with 100% correct answers
14 views 0 purchase
Course
Computed Tomography
Institution
Computed Tomography
What is the smallest component of a digital image - correct answer pixel
How many CT numbers are assigned to each pixel in the image matrix? - correct answer One
In a CT image, the CT number - correct answer Of a material is dependent on its linear attenuation coefficient
Each two-di...
CT Registry Review exam 2024 with 100% correct answers
What is the smallest component of a digital image - correct answer pixel
How many CT numbers are assigned to each pixel in the image matrix? - correct answer One
In a CT image, the CT number - correct answer Of a material is dependent on its linear attenuation coefficient
Each two-dimensional square of data that make up the CT image is called a - correct answer pixel
What is an element of the digital image - correct answer pixel
Which of the following influences the spatial resolution in cardiac CT imaging - correct answer *detector size
*reconstruction interval
*pitch
As patient motion increases spatial resolution decreases - correct answer TRUE
Which is an advantage of using a small focal spot - correct answer increased spatial resolution
Increasing the CT image matrix from 256x256 to 512x512 will likely improve? - correct answer High-
contrast spatial resolution
The practical limiting spatial resolution of a CT scanner is 3.6 lp/cm. What size object does this correspond to? - correct answer 1.4 mm Use of a bone filter, as opposed to a soft tissue filter, to reconstruct CT images would likely improve? - correct answer Spatial resolution
The spatial resolution of a typical CT scanner is on the order of? - correct answer 1 mm
A 512 x 512 matrix CT image over a 30-cm field of view could show a spatial resolution of no better than ? lp/cm? - correct answer 8.5
When comparing a 512x512 matrix to a 1024x1024 matrix, the 1024x1024 matrix? - correct answer Contains four times as many pixels: 1024 x 1024 =1048576 then 512 x 512= 262144...then divide 1048576 /262144 = 4
High contrast spatial resolution and low contrast resolution are typically measured baseline and ? thereafter - correct answer Biannually
To improve the high contrast spatial resolution of a CT study, one would increase _____ while keeping all other factors the same. - correct answer Matrix size (128x128 to 512x512)
A radiologist wants to improve the high-contrast spatial resolution of anatomy which he/she is examining by CT. The change which would best lead to this improvement is - correct answer Increase the matrix size
To improve the high-contrast spatial resolution of a CT study, one could increase ? while keeping all other factors the same? - correct answer Matrix size
A voxel contains 25% air, 50% water and 25% bone. The CT number for this voxel would be expected to be _____ HU? - correct answer 0
How many pixels are contained in a 1,024 matrix image? - correct answer D. 1,048,576 MATH 1024 X1024 It is located in a matrix and is a two dimensional representation of a voxel - correct answer pixel
When CT numbers are calculated for voxels (volume elements) of tissue what is assigned the calculated number and a subsequent shade of gray - correct answer pixel
What is defined as a picture element or the smallest component of the digital image - correct answer pixel
A CT scan produces a 512x512 matrix transverse image of a 30 cm diameter FOV. Each pixel is approximately _____ mm on a side. - correct answer 0.6 equation: 30cm/512= .058cm convert to mm and its .58 which is approximately 0.6
The ability of a system to define small objects distinctly is referred to as which of the following? - correct answer spatial resolution
Which of the following terms is/are commonly used to describe a CT scanner's ability to differentiate objects with similar linear attenuation coeffiecents - correct answer *spatial resolution
*sensitivity
Which of the following factors have an affect on contrast resolution - correct answer *patient size
*slice thickness
*pixel size
*mAs/dose
As mAs/dose increases contrast resolution decreases - correct answer FALSE
As mAs/dose increases contrast resolution INCREASES - correct answer TRUE
The ability of a CT scanner to accurately image objects with similar densities is termed - correct answer *contrast resolution *sensitivity Which of the following has a direct relationship on increasing contrast resolution - correct answer *mAs/dose increase
*Slice thickness
For a particular CT scanner's beam quality, the linear attenuation coefficient for water is 0.20 cm-1 and for a certain tumor is 0.21 cm-1. What is the CT number of the tumor? - correct answer 50. Equation (.21-.20/.21) × 1000= 50
A CT scanner with poor contrast resolution or low sensitivity has difficulty separating - correct answer tissues whose linear attenuation coefficients are nearly equal
What is the basic physical quantity being measured by a CT system - correct answer Linear attenuation coefficient
Assume the linear attenuation coefficient is 0.20 cm-1 for water and 0.40 cm-1 for tissue within a given voxel. What is the CT number in Hounsfield units for the pixel representing this voxel? - correct answer +1,000....Equation { (.4-.2) /.2} x 1000
What fraction of monoenergetic x-rays will be absorbed by a 20-cm thick material having a linear attenuation coefficient of 0.05 cm-1? - correct answer 0.63
The contrast resolution of CT is approximately ? % - correct answer 0.3 to 0.6
This term describes the ability CT scanner to differentiate objects with MINIMAL differences in attenuation coefficients - correct answer contrast resolution
What is the term for resolution of a CT scanner referred to as the system's ability to differentiate objects
with SIMILAR densities. - correct answer contrast resolution
In order to pass ACR CT accreditation, the CT scanner's adult head protocol must be within - correct answer 1.0
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 or Stuvia-credit 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 YANCHY. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $15.49. You're not tied to anything after your purchase.
