Additional Equipment and Quality Control

What is defined as a program used to systematically monitor and evaluate the quality of services within an imaging department

quality assurance program

T/F: Continuous Quality Improvement (CQI) is part of the Quality Assurance (QA) process?

True

____ ____ focuses specifically on imaging equipment, acessories, and the images produced

quality control

T/F: equipment is routinely tested to make sure it is functioning properly

True

What do we use to help maintain image quality while keeping repeat exams and unnecessary patient exposure as low as possible

quality control

What are the 3 steps of the quality control program?

1. Acceptance testing

2. Routine performance monitoring

3. Maintenance

This part of quality control occurs when equipment is installed to make sure it is operating properly

acceptance testing

This part of quality control occurs when there is routine testing to make sure equipment continues to function properly over time

routine performance monitoring

This part of quality control is performed to prevent problems

preventative maintenance

This part of quality control is performed after a probelm occurs

repair/error maintenance

____ removes low-energy photons that would be absorbed by the patient without contributing useful information to the image

filtration

What is an important patient-protection feature of the imaging system?

filtration

What are the 3 types of filtration?

1. inherent - already in the tube housing and collimator

2. added - aluminum placed in the path of the beam

3. total - inherent + added

T/F: filtration can directly be measured

False, it cannot be measured directly

_____ is the thickness of absorbing material needed to reduce the intensity of the beam to one-half of its original value

HVL (half value layer)

How often is filtration and HVL evaluated?

annually or when changed to the tube or housing are made

T/F: the light field should accurately represent the area that will be exposed by the x-ray beam

True

This is referred to as an automatic collimation system

PBL (positive beam limitation)

T/F: PBL senses the size of the IR and adjusts the collimator shutters to match it

true

What is light field-radiation field congruence?

it determines whether the area shown by the positioning light matches the area exposed

How do we test for congruence?

• a collimator test tool

• the 8-penny test

How often should collimation be evaluated?

semiannually

_____ provides a simple method of evaluating collimator accuracy without a specialized collimation test tool

8-penny test

What type of equipment is transportable to the patients bedside or the operating room?

mobile equipment

What are the different types of mobile x-ray units?

• direct

• battery

• Capacitor-discharge

• High-frequency

T/F: C-arm mobile units have the ability to do fluoroscopy

True

T/F: when using a fluoroscopic unit, the tube is under the patient and the image intensifier is above the patient

True

Why is the tube under the patient in fluroscopy?

to reduce operator exposure

This type of x-ray unit is designed to image curved surfaces by moving around a stationary patient (ex. mandible)

panoramic

Where is a panoramic x-ray unit typically used?

in dentistry

_____ evaluates patients bone mineral density and mass for evidence of osteoporosis

bone densitometry

What is the most common procedure?

DEXA

T/F: the beam should be parallel when the tube is positioned perpendicular

False, the beam should be perpendicular

What can improper beam alignment cause?

• image distortion

• clipped anatomy

• grid cutoff

Imaging systems must have a minimum filtration of ___ mm Al

2.5 mm Al

The light field must ve congruent within ___% of the SID

2%

Beam alignment must be within __% of the SID

1%

Distance indicator must be within ___% of the actual SID

2%

Centering must be accurate within ___% of the SID

1%

Spatial resolution is determined by the ____

FSS

Which produces better spatial resolution a small or large focal spot

small focal spot

How often should FSS be evaluated?

when new equipment is installed, a tube is replaced, or annually

Pinhole camera, star pattern, and slit camera are tools used to measure ___

FSS

This way to measure FSS is difficult to use and requires excessive exposure times

Pinhole camera

This way to measure FSS is easiest to use but is limited in size

star pattern

This way to measure FSS is considered the gold standard

slit camera

This is an example of what tool used to measure FSS?

Pinhole

This is an example of what tool used to measure FSS?

Slit camera

____ can be used instead of directly measuring FSS when evaluating spatial resolution

line-pair test tool

The _____ test tool shows how well the imaging system can distinguish between small objects that are close together

line-pair

Who checks the accuracy of kVp?

medical physicist

What 3 things does kVp accuracy affect?

• patient dose

• image quality

• radiographic contrast

What are the most common devices used to measure accuracy of kVp

filtered ion chambers or filtered photodiodes

How often should kVp accuracy be evaluted?

annually or after changes to high-voltage generator components

It only takes a ___% change in kVp to affect optical density and radiographic contrast

4%

When testing, the measured kVp should be within ___% of the indicated kVp

10%

Exposure time is the responsibility of who?

the technologist

Exposure time affects both ____ and ___

patient dose and image production

Who evaluated the exposure timer and how often?

medical physicist annually

T/F: regardless of material thickness and exposure time, the exposure of the processed image should be constant

True

___ performance can be evaluated by exposing an image receptor through different thicknesses of aluminum or acrylic

AEC

___ acts as a safety feature if the AEC fails to terminate the exposure.

AEC backup timer

How is the backup timer tested?

by placing a lead filter in the beam

____ describes the ability of the x-ray unit to produce a consistent radiation output using different combinations of mA and exposure time

exposure linearity

A ____ is used to measure radiation output

dosimeter

exposure linearity radiation output for adjacent mA stations should be within ___%

10%

____ the ability of the radiographic unit to replicate an exposure using the same technique

Exposure reproducibility

Exposure reproducibility radiation output should not vary by more than ___%

5%

How often is lead protective apparel evaluated?

annually

What type of damages can occur to protective apperal?

• cracking

• tearing

• bunching

T/F: you should avoid folding lead aprons

true

____ is defined as an undesirable and usually unexpected event caused by medical management rather than the patient’s underlying disease or condition

adverse event

What are some examples of adverse events?

• patient falls

• improper medication administration

• procedure complications

T/F: an adverse event requires there to be permanent damage to the patient

False, it does not have to be permanent

____ is defined as an unexpected occurrence involving death or serious physical or psychological injury, or the risk thereof

sentinel event

What type of events are serious enough to require immediate investigation and response.

Sentinel events

T/F: exposure techniques differ between mobile units

True

T/F: the longer the fluoroscopy time, the greater the radiation exposure

true

What does a DEXA commonly scan?

lower spine and hips

The ___ compares the patients bone density to a young healthy adult

T-score

The ___ compares the patients bone density to adults of similar age

Z-score

T/F: positioning is critical when performing DEXA scans

True

T/F: breast tissue attenuates the x-ray beam similarly

True

What kVp and mAs should be used when imaging the breasts?

low kVp and high mAs since there is not a lot of contrast (24-34 kVp)

Compression during mammography helps to make breast thickness ___, reduce ___, and increase ____

uniform, scatter, spatial resolution

_____ can be used to better visualize very small structures but also causes increased radiation exposure

magnification

____ is a 3D mammography that is similar to CT

DBT (digital breast tomosynthesis)

What is being performed when an x-ray tube moves over the compressed breast from one side to the other creating multiple images from different angles

DBT (digital breast tomosynthesis)

T/F: DBT may improve detection of abnormalities and reduce false-positives

true

Which has a higher breast radiation dose, conventional mammography or digital breast tomosynthesis

digital breast tomosynthesis

____ uses movement to intentionally blur anatomy above and below the plane of interest

linear tomography

Linear tomography has largely been replaced by what imaging modality?

CT

The ____ angle is the arc created by the total movement of the x-ray tube

tomograohic

The ___ lies within the plane of the anatomic area to be imaged (the pivot point of the tomographic movement)

fulcrum

The ___ plane contains the area of interest

object

T/F: exposure time must be increased and a low mA must be used to achieve blurring

true

To achieve maximum blurring in linear tomography, the AOI should be ____ to the direction of movement

perpendicular

When performing linear tomography, structures that are parallel to the motion can appear as _____

streaks

T/F: the fulcrum is fixed

false, it can be fixed or adjustable