Question 1

The contrast ratio of a viewing monitor should be higher than&#10;A)100.&#10;B)170.&#10;C)250.&#10;D)500.

Accepted Answer

The contrast ratio is the ratio of the maximum white level (L_max) to the minimum black level (L_min), OR L_max/L_min, and should be greater than 250 (most will be at least 600 or greater).

Question 2

Going from a 256 &#180; 256 to a 512 &#180; 512 matrix doubles an image's&#10;A)spatial resolution.&#10;B)pixels.&#10;C)gray levels.&#10;D)contrast resolution.

Accepted Answer

Spatial resolution refers to the size of the smallest distinguishable detail in an image, and it is directly proportional to the number of pixels in an image. Therefore, doubling the number of pixels from 256 x 256 to 512 x 512 doubles the spatial resolution of the image.

Question 3

Which of the following uses photostimulable phosphors?&#10;A)Indirect conversion DR system&#10;B)Direct conversion DR system&#10;C)CR systems&#10;D)Flat panel fluoroscopic systems

Accepted Answer

Photostimulable phosphors are used in CR systems. Indirect conversion DR systems use a scintillator material, direct conversion DR systems use a photoconductor material, and flat panel fluoroscopic systems use either amorphous silicon or amorphous selenium as the detecting material.

Question 4

CRT monitors for viewing digital images should have a luminance value higher than ____ nit.&#10;A)100&#10;B)170&#10;C)1500&#10;D)3500

Accepted Answer

The answer of CRT monitors for viewing digital images should...

Question 5

The DICOM standard does not specify an image's&#10;A)matrix depth.&#10;B)bit depth.&#10;C)display settings.&#10;D)examination time.

Accepted Answer

The DICOM standard is the protocol that allows medical imaging devices to communicate with each other electronically and has nothing to do with examination time.

Question 6

Benefits of digital PACS images do not generally include&#10;A)convenient storage.&#10;B)image transmission.&#10;C)computer-aided diagnosis.&#10;D)improved spatial resolution.

Accepted Answer

The benefits of digital PACS images do generally include convenient storage, image transmission, and computer-aided diagnosis, but they do not necessarily lead to improved spatial resolution. In fact, the spatial resolution of a digital image is determined by the imaging system used to acquire it, and digital PACS images can be degraded by factors such as compression or post-processing.

Question 7

Photoconductors convert x-ray energy into&#10;A)light energy.&#10;B)heat energy.&#10;C)radiofrequencies.&#10;D)electric current.

Accepted Answer

Photoconductors are materials that become electrically conductive when exposed to light, in this case, x-ray energy. Therefore, they convert x-ray energy into electric current.

Question 8

The limiting spatial resolution is also known as the&#10;A)modulation transfer function.&#10;B)Nyquist frequency.&#10;C)fill factor.&#10;D)detective quantum efficiency.

Accepted Answer

The limiting spatial resolution is determined by the Nyquist frequency, which is half of the sampling frequency. It represents the highest spatial frequency that can be resolved by the imaging system. The other choices (modulation transfer function, fill factor, detective quantum efficiency) are related to other aspects of image quality.

Question 9

Film utilized in dry laser printers uses silver _____ emulsions.&#10;A)bromide&#10;B)iodide&#10;C)behenate&#10;D)sulfide

Accepted Answer

These devices were introduced in 1996 and require specialized film (photothermographic) that uses silver behenate rather than silver halide to produce the image and that is processed thermally rather than with liquid developer and fixer.

Question 10

The most important component affecting the spatial resolution in digital subtraction angiography is the&#10;A)focal spot size.&#10;B)image intensifier.&#10;C)television camera.&#10;D)computer matrix size.

Accepted Answer

The computer matrix size (i.e., the number of pixels in the matrix) is the most important component affecting spatial resolution.

Deck 9: Digital and Advanced Imaging Equipment