rad 102 ch 23/24/29

what is data drop?

when parts of the anatomy are so overexposed that they don’t show up on the final image

what is detector saturation?

data drop that involves specific areas or regions of the detector

what is electronic masking?

also known as “cropping,” a post-processing function that removes undesirable information from a data set to improve image quality; has no effect on resolution

what is electronic annotation?

post-processing function that labels the image conditions; pt position, pt info, etc

what is dose creep?

when radiologists overtime gradually increase exposure techniques to decrease image noise

what is the variable kVp formula?

(2*Part cm) + 30 kVp= new kVp

what is diagnostic yield?

the amount of clinically significant information produced

what is diagnostic efficacy?

the faithful representation of the patient on a medical radiograph; also called image fidelity

what are LCR artifacts?

things that can be seen on images such as clothing artifacts, bandaged, tattoos, etc

list examples of digital artifacts

phantom images, scratches/tears, light spots, white line, dropout artifacts, fogging, quantam mottle, laser film transport artifacts, histogram analysis error, non-parallel collimation, poor grid alignment, random electronic artifacts

what causes detector saturation and data drop?

extreme overexposure

what is optimal kVp?

used by fixed kVp systems, the max kVp level that will produce images with appropriate contrast consistently in acceptance limits

what is the fixed kVp system?

double or half the mAs for every 5cm of subject thickness; kVp remains the same; better for digital IRs

what is the only step of the process of establishing a technique system that you need to know?

test exposure are first done using a phantom

what does a DI value of +2 mean?

exposure was 50% above recommended target

what does a DI value of -2 mean?

exposure was 50% below recommended target

what are DI values of +3 or greater considered?

an ALARA violation

what is photon starvation?

underexposure to the detector

what are the 6 tenets of radiologic images?

1. legal document

2. pictorial record

3. single moment in patient’s medical timeline

4. accurate and optimal techniques used

5. department routines and procedures are followed

6. ALARA compliant

how can you correct data drop?

post-processing and pixel recovery, collimation, tissue bolusing, compensating filtration

what is distortion?

the misrepresentation of the size and/or shape of the anatomical part being imaged

what is size distortion?

magnification; minification is impossible due to the divergent properties of x-ray photons

what is the most important thing to remember in regards to setting kVp for digital systems?

when higher kVp is used, width of the acquired date becomes narrower, which is desirable because it displays more anatomical data while reducing patient dose

what causes distortion?

it’s always present due to the divergent x-ray photons

how does SID affect magnification?

they’re indirectly proportional to each other

how does OID affect magnification?

they are directly proportional to each other

what’s the most effective way to control magnification?

maximize SID and minimize OID

how do you calculate magnification?

M= SID/SOD

SID = ?

SOD + OID

how do you find the object size?

O= I/M

what is shape distortion?

the misrepresentation by unequal magnification across the dimension of the object

what are the two types of shape distortion?

elongation and foreshortening

what is elongation?

when the object projects to be longer than it really is

what is foreshortening?

when the object projects to be shorter than it really is

what causes elongation?

when the tube or IR is improperly aligned

what causes foreshortening

when the part is improperly aligned

what does tube angulation cause?

elongation

why does shape distortion occur?

because structures lie normally at different levels within the body and because of the divergence of the x ray beam

what is informatics?

organizational theory all motivated by the need for new solutions to enhance the quality and safety of patient care

what does BMI stand for?

biomedical informatics

what is BMI?

an interdisciplinary field of platforms used for medical purposes such as patient care and clinical research

name the 5 subspecialities of BMI

1. translational

2. clinical research

3. clinical

4. consumer health

5. public health

name the 4 BMI platforms

1. PACS

2. HIS

3. RIS

4. EMR/EHR

what does PACS stand for?

picture archiving and communication system

what is PACS?

a networked group of computers, servers, and archives to manage digital images that are configured in a manner that facilitates storing, retrieving, and distributing medical images

what is clinical informatics?

utilizes data and information technology to deliver healthcare services

what does HIS and RIS stand for?

hospital/radiology information systems

what is HIS?

database containing all patient medical record information except for radiology

what is RIS?

radiology specific database

what does EHR/EMR stand for?

electronic health/medical record

what is EMR/EHR?

an electronic version of an individual patient’s collection of medical documents; took place of paper medical chart

what does DICOM stand for?

digital imaging and communication in medicine

what is dicom?

standard format for communicating imaging files around the world

what are the main components of informatics platforms and applications?

hardware and software

what is hardware?

mainframe, CPU, memory, input devices, output devices, and the bus (connects motherboard components and CPU/allows for data transfer)

what is software?

computer programs, applications, and operating systems

what is LAN?

network common for serving computers in small geographical areas

what is WAN?

2 or mORE LANs serving a large geographical network

what is intranet?

connections inside of an organization/controlled by a single authority (ex. inside of a specific hospital)

what is extranet?

private network controlled by organization that creates connections outside of it (ex. hospital supply manufacturers, laundry, etc.)

what is cloud computing?

allows for virtual access of shared resources/storage while maintaining location and device independence

how many bits=1 byte?

8

what is the formula for determining image file size?

XY (B/8)

what is a hardcopy display?

images on film, produced using laser printers and dry processors

what is a softcopy display?

flat screen monitors

how long are images typically archived for?

5-7yrs; pediatric and litigation stored indefinitely

what is a typical storage requirement?

terabyte storage; 1Tb=10,000Gb=10,000,000Mb

what is the relationship between image resolution and data size?

directly proportional

what is lossless compression?

it allows all of the original information in the image to be retained the loss of any information

what is lossy compression?

it loses data once the image is compressed and the uncompressed, which can cause a loss of resolution (bad)

what are examples of short term storage?

local hard drive, PACS server and redundant display of independent discs (RAID)

what are examples of long term storage?

jukebox of discs or tapes

what are examples of short term storage?

jukebox of discs or tapes

what does HIPPA stand for?

health insurance portability and accountability act of 1996

what is a network?

allows computer to exchange data and share resources

what is bandwidth?

describes how much data can be moved, measured in bps