FREE RADIOLOGY AND STUDY GAMES ABOUT RAD 122 -

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FREE RADIOLOGY AND STUDY GAMES ABOUT RAD 122 -

PP UNIT 1 EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -120 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: What are pros and cons of NO FAULT technique?

Answer:

wide dynamic range, fewer repeats tech can get lazy with technique, increase patient dose, tech can edit image before it's saved to patient record (PACS)

Question 2: What is field of view?

Answer:

FOV - Display monitor (can only change if you change monitor size) FOV - image including anatomy

Question 3: Increase CONTRAST RESOLUTION.

Answer:

High grayscale - ability to distinguish many shades of gray; dependent on the pixel bit depth (higher bit depth = increased contrast resolution)

Question 4: describe CCD

Answer:

Orth p 273 small, highly adaptive light sensitive devices must have SCINTILLATOR to function (solid state device looks like a sim card) Question 5: What happens to contrast resolution if we increase the pixel bit depth?

Answer:

Allows us to increase contrast resolution because of more shades of gray are available with increased pixel bit depth

Question 6: What is brightness?

Answer:

amount of luminance coming from display monitor PROPERTY of the MONITOR brightness is based upon a pixel value which is determined by xray attenuation (differential absorption) secondary - pathology, patient factors (thin or dense, etc)

Question 7: Describe types of PSP plates (indirect DR)

Answer:

Orth p 266 have SCINTILLATORs Turbid phosphors Structured phosphors

Question 8: What are the types of digital detectors?

Answer:

DR - digital radiography (anytime you use a computer to process or view images) CR - computed radiography (PSP) plate DR - flat panel display (FPD)

Question 9: What are differences in film screen and digital processing?

Answer:

Film screen uses chemicals DR uses CR reader or FPD

Question 10: CONS of digital system

Answer:

spatial resolution (Orth p251) dependent upon processing algorithm and display characteristics (monitor); dose creep

Question 11: Describe turbid phosphors.

Answer:

Orth p 266 scattered and random (like a fruitcake) spreads light results in lower spatial resolution

Question 12: Explain the FPD AMA.

Answer:

Active Matrix Array matrix of pixels Each pixel has a light sensitive face painted with A-Si (amorphous Silicon), also has TFT embedded in DEL or dexel.

Question 13: What influences subject contrast?

Answer:

• Internal factors (tissue densities within part/pathology)
• External factors like radiation quality, scatter, contrast agents

Question 14: What is pixel pitch/size dependent on?

Answer:

matrix size OR Image receptor size OR Field of view

Question 15: Computer operations

Input

Answer:

Input - 2 types - Programs - govern acquisition, manipulation and output of data Data - input for processing by computer (arrange into table, spreadsheet etc)

Question 16: Describe fill factor

Answer:

the percentage of the dexel face that is devoted to semiconductor detection area approx 80%, remaining 20% (TFT and capacitor)

Question 17: What is AMA?

Answer:

Active matrix array array of DELs or dexels that contain TFTs (all electrical components) that will take info from plate for processing same as TFT array

Question 18: What are tech responsibilities in evaluating images?

Answer:

ensure anatomy is visible and EI# or S# within range

Question 19: What is digital imaging?

Answer:

the acquisition of images to a computer rather than directly to film

Question 20: Describe how pixel value is determined

Answer:

The value assigned to each pixel is relative to signal intensity received by detector (xray photon), GOVERNED by bit depth of system Question 21: What happens with spatial resolution and appearance of digital images when matrix is increased from 32x32 to 1024x1024?

Answer:

Orth p 251 fig 19.5 more information is displayed with improved spatial resolution as you increase quantity of pixels Can see individual pixels in 32x32 image, cannot see individual pixels in 1024x1024

Question 22: What kind of contrast resolution does an 8 bit system have?

Answer:

256 shades of gray; high contrast resolution LOW contrast; think more bits means more shades of gray available.