Rad Study Guide (Ch. 14, 17, and 18)

Recorded detail/Spatial Resolution

What’s the analog and digital term for the ability to image small objects that have high subject contrast

Recorded detail

What’s the analog term for spatial resolution

Focal spot, SID, OID

What primarily controls recorded detail in analog?

Spatial frequency

This is expressed in line pairs/mm (lp/mm)

Higher

Imaging systems with _________ (higher or lower) spatial frequency have better spatial resolution

Pixel size; System Modulation Transfer Function (MTF)

What is spatial resolution primarily limited by?

What is it determined by?

Smaller

_________ (Smaller or Larger) pixels result in increased spatial resolution

Modulation Transfer Function (MTF)

Mathematical procedure for measuring resolution; determines spatial resolution

Gamma Camera; Digital Mammography (DM)

Which type of imaging has the lowest spatial resolution and can be found in nuclear medicine?

Which type of imaging has the highest spatial resolution?

Contrast resolution

Ability to distinguish between and to image similar tissues

True

True/False: All digital imaging systems have better contrast resolution than analog systems.

Contrast/Grayscale or Dynamic Range

What’s the analog AND digital terms (2) for the number of gray shades that an imaging system can produce

Grayscale/Dynamic Range

What’s the digital term for analog’s scale of contrast (2 terms)

30; 16,000; 65,000

How many shades of gray can humans see?

How many shades of gray can digital radiography demonstrate?

How many shades of gray can digital mammography demonstrate?

Noise/Low SNR

What is contrast resolution limited by?

CT, beam collimation

What imaging modality has the best contrast resolution and why?

Pre and Post-processing; Can help visualize all shades of gray

What’s the principal advantage of digital imaging and why is it important?

Contrast; Brightness

The post-processing function of window width is for __________

The post-processing function of leveling is for __________

High; mAs; increased

Do you want the signal to noise ratio (SNR) to be as high or as low as possible for the best image obtainable?

What part of technique should be adjusted to improve SNR? Should this technique be increased/decreased?

ALARA

When needing to increase mAs to improve SNR, what principle should you always keep in mind?

Dose Creep

This can result from overexposing patient/IR and not checking exposure indicator after each image

True

True/False: Digital image contrast is unrelated to patient dose, so you can increase the kVp to decrease patients dose without worrying about decreasing contrast due to post-processing.

kVp

What should you increase in digital radiography if you want to decrease the patient’s dose and aren’t worried about image contrast

Detective Quantum Efficiency (DQE)

This is the percentage of x-rays absorbed by the IR

Higher; Lower

Does digital radiography have higher or lower DQE compared to analog?

Because of its DQE, does digital radiography require a higher or lower patient dose compared to analog?

Rod; Cone; Cone

What’s the type of vision used in dim lighting?

What’s the type of vision used in bright lighting?

Which type of vision provides better visual acuity?

Lumen

Basic photometric unit

Photometry

science of response of human eye to light

Luminance intensity

Luminous flux that is emitted into entire viewing area; property of the source of light; measured in candela

Luminous flux

Total intensity of light from a source

Candela

What is luminance intensity measured in?

Cosine Law

This states that the best viewing of a digital display device is straight on due to luminous intensity

Hard; soft

Images on film are called __________ copies while images viewed on digital display device/monitor are called __________ copies

Maximum

According to the Cosine Law, when viewing a monitor straight on, luminous intensity is at its __________

Cathode Ray Tube (CRT) or Active Matrix Liquid Crystal Display (AMLCD)

What are the two types of display monitors/devices that can be used to view soft copies of images?

AMLCDs

Better contrast resolution and less glare

Angular dependence of viewing - goes against Cosine Law

Which is more frequently used: Active Matrix Liquid Crystal Displays (AMLCDs) OR Cathode Ray Tubes (CRTs)?

Why?

What is the disadvantage of the AMLCDs?

1,000 × 1,000; 2,000 × 2,500; 5-megapixel

What is the pixel arrangement for a 1-megapixel display?

What is the pixel arrangement for a 5-megapixel display?

Which display has higher spatial resolution?

Ambient Light

What should be reduced to near darkness for best viewing conditions of soft copies on a monitor?

Pre; Post

__________ (Pre or Post) Processing of digital images is largely automatic while __________ (pre or post) processing requires operator manipulation

Signal interpolation

This process in pre-processing function corrects defective pixels by averaging value of surrounding pixels

Offset and Gain

__________ images and __________ images are designed to make response of IR uniform; Flatfielding

Flatfielding

In this image pre-processing function, offset and gain images are designed to make response of IR uniform

Annotation

Post-processing function; labels the image

Window & Level

Post-processing function; expand digital grayscale to better visualize image

Magnification

Post-processing function; used to enlarge area of image to improve spatial resolution

image flip

Post-processing function; reorient image presentation

Image inversion

Post-processing function; flips typical colors of x-ray so that bones appear black while soft tissue appears white; typically used in fluoro

Subtraction (Digital Subtraction Angiography (DSA))

Post-processing function; improve image contrast; typically used to subtract bones from an image; can be used to compare images taken months apart

Pixel Shift

Post-processing function; can be used to re-register image to correct for patient motion during serial image acquisition

Region of interest (ROI)

Post-processing function; determines the average pixel value for use in quantitative imaging that can be use to help diagnose pathology

Edge enhancement

Post-processing function; useful for fractures and small, high-contrast tissues

Picture Archiving and Communication System (PACS)

Previously used to store radiographic images; Electronic file room that consists of image acquisition system, display system, network, and storage system

image acquisition system, display system, network, and storage system

What 4 things does PACS consist of?

Teleradiology

Process of remote transmission and viewing of images

Radiology information system (RIS)

This is the information management and database portion of PACS/MIMPS

Client

All the devices used in the radiography department that allow for storage, retrieval, and viewing of images; includes PACS Workstations, Department Mainframe, Secretarial workstations, etc

Digital Imaging and Communications in Medicine (DICOM)

This is the standard imaging and interface format that allows various manufacturers’ equipment to work together

Pre-Fetching

Process of recovering archived records in RIS to be made available upon patient arrival to RAD department

Offsite

__________ image storage is extremely important in case of a catastrophic event

Electronic Health Record (EHR)

Contains all of patient’s medical information

Health Level Seven (HL7)

Set of standards, formats, and definitions for exchanging and developing electronic health records (EHRs)

Lexicon

Standardization of vocabulary in medical imaging electronic programs

Ontology

Standardization of term relationships in medical imaging electronic programs

Medical Image Management and Processing System (MIMPS); April 19, 2021

Replaced PACS due to 21st Century Cures Act

When did this system replace PACS?

21st Century Cures Act

This resulted in PACS being switched over to MIMPS as it stated that software functions related to image and information storage or archiving are NO longer regulated by the FDA

2; Short-term and long-term

How many storage facilities does MIMPS require for images in case something catastrophic happens?

What are the types of storage?

Hospital Information System (HIS)

The main hospital computer that can review patient ID, billing, accounting, and interaction with other departments

Electronic Medical Record (EMR)

When a patient checks into a HC facility, a document is prepared to properly identify the patient, and this is incorporated with the HIS for information transfer and storage

Electronic Health Record (EHR)

EMRs are filed within this system to provide a comprehensive list of patient’s visits at the organization

Server; Cloud

__________-based systems consist of MIMPS Servers and MIMPS reading stations

__________-based systems consist of MIMPS Servers and MIMPS reading stations and can be accessed by any computer with internet

Local Area Network (LAN); Wide Area Network (WAN)

Type of network that has stronger security as it can only be accessed in a small region of people

Type of network with reduced security as it can be accessed by a larger collection of people

Network

Infrastructure that handles information between multiple parties; Used to connect computers so they can interact with one another; can be a local or wide area

Acquisition Devices, Workstation, Network, Archive Servers

What are the 4 things that make up MIMPS?

Brightness/Receptor Exposure

The 2 digital terms for density are