Chapter 1 Procedures 1

ALARA

As Low As Reasonably Achievable

What do you use to clean objects to kill pathogenic bacteria?

Disinfectants

What inhibits the growth of pathogenic microorganisms without killing them?

Antiseptics

What is the easiest & most convenient method of preventing the spread of microorganisms?

Handwashing

Standard Precautions are designed …

to reduce the spread of pathogens (blood, all body fluids, secretions & excretions, nonintact skin, mucus membranes

What is worn when coming in contact with blood or body fluids, secretions, excretions, contaminated items, mucous membranes, nonintact skin?

Gloves

What is worn to protect the mucus membranes of the eyes, nose, and mouth?

Mask & Eye protection/ Face Shield protects

Protects skin and prevents soiling of clothing during procedures & Pt. care activities likely to generate splashes or sprays of blood or body fluids

Gown

Needles are placed

\-in a puncture-proof container

\-on a short-stop needle holder

\-use a safety need cap

Procedure Book

\-covers examination procedure by category

\-outlines supplies, duties, required images

Obtaining the Hx is the responsibility of

radiographer

Pt. Instructions

Make sure the pt. knows what is going to happen and why in a clear and concise way (saves on time & pt. exposure

Diagnosing is the responsibility of the

radiologist

How are pt. bowels cleaned before the radiologic exam? (barium enema, exams of the urinary system)

\-limited diet

\-laxatives

\-cleansing enema

Pt’s attire should NOT consist of

starch (radiopaque), limit folds, zippers, necklaces, snaps, thick elastic bands, buttons, diapers, dentures, partial plates, hair pins, earrings

Surgical Dressings

\-need permission to remove

\-leave a thin layer to protect the open wound

Involuntary motion is primarily controlled by

the length of exposure time

Ways to control voluntary motion:

\-clear communication/instructions

\-make patient comfortable (table pad)

\-support devices

\-immobilization

Voluntary motion

breathing, nervousness, discomfort, excitability, fear, age

Involuntary motion

peristalsis, heart pulsation, chill, tremor, spasm, pain,

Conditions which require a decrease in kVp (exposure factors)

\-old age

\-pneumothorax

\-emphysema

\-emaciation

\-deg. arthritis

\-atrophy

Conditions which require an increase in kVp (exposure factors)

\-pneumonia

\-pleural effusion

\-hydrocephalus

\-enlarged heart

\-edema

\-ascites

Inspiration ____ the diaphragm

depresses (lowers)

Expiration _____ the diaphragm

elevates

Types of Image Receptors

\-cassette with film

\-photostimulable storage phosphor (PSP) image plate used for CR (computed radiography), similar looking outside to cassette

\-solid-state detectors - used for DR (digital radiography) - cassette less

\-fluoroscopic screen

Contrast (film)

differences in densities between areas on radiograph (kVp)

Low contrast (technical factor)

more gray tones (low = lots)

High Contrast (technical factor)

few gray tones with greater differences between them (black + white)

Contrast Resolution (Digital)

controlled by bit depth, the number of brightness values possible for each pixel

Optical Density

degree of blackening of the film (mAs)

Special Resolution (recorded detail)

ability to see small structures

Magnification

enlarges an image, always some degree of mag.

Shape Distortion

change in the overall shape of a structure

What is the policy for gonadal shielding?

All patients must be shielded unless it compromises the exam, questions females of childbearing age as to the possibility of pregnancy

Guidelines to Gonadal Shielding

\-if gonads lie within or close to (5cm) the primary beam

\- if the clinical objective isn’t compromised

\-if- if the pt. has a reasonable reproductive potential

How should the IR (image receptor) be placed?

The long axis of the pt.’s anatomy of interest is parallel to the IR

Portrait/Lengthwise IR position

Landscape/Crosswise IR Position

Diagonal IR position

Central Ray (CR)

The central portion of the X-ray beam

SID

source-to-IR distance, the distance from the anode in the x-ray tube to the IR

Collimation

the act of configuring the x-ray beam to a determined field size

What does collimation do for an x-ray?

\-reduces pt. Exposure dose by limiting the tissue irradiated

\-reduces amt. of scatter radiation, reducing the image quality

\-improves image quality (recorded detail & improves contrast)

Shuttering

A post-processing electronic technique that reduces the background light outside the collimated (beam restricted) border

\*DOES NOT restrict exposure to only the area of interest

4 Identifications of Radiographs

1. pt. name or ID #
2. Date of procedure
3. Institution
4. Right/left anatomical side marker

Evaluate the image to ensure proper Dx by any ..

\-Superimposition

\-Adjacent structures

An anatomical marker should always mark

the side closes to the IR

Should a marker be placed anterior or posterior to the anatomy?

anterior

AP, PA, or Obl. Chest images are marked where?

the upper-outer corner

An image is to be oriented on monitor or view box so that the person viewing the image sees the body part in …

anatomic position

Computed Radiography (CR)

A special image receptor with a phosphor material plate inside the closed cassette (imaging plate), after exposure the plate is scanned by a laser in a reader

Digital Imaging (DR)

no cassette, use a solid state flat panel or CCD detector that receives the image in the table or wall unit (17'“ x 17’ IR)

Can operate at the higher end of KVP range as to reduce patient exposure by …

reducing mAs accordingly

Too high of a kVp will …

over penetrate & change the scale of subject

What is wrong with this image?

extraneous line patters caused by noise in the IP reader electronics

mAs affects …

the amount of radiation dose

What does this image have?

shape distortion (elongated cervical spine), it is an oblique image

Why is this image grainy?

insufficient light produced on IP (under exposure)

Difference between CR and DR

DR, only one exposure is made prior to processing, CR allows for multiple images

This is an example of …

Shuttering (applying a black surround)

Image Lag

When the detector is unable to eliminate all of the signal from the previous image

Working with an obese patient a radiographer needs?

\-equipment and transportation for the correct weight

\-to be sensitive & show compassion (remains the same)

\-imperative to cent pt. Bony skeleton is the same

What is AEC and what does it do?

Automatic exposure control is a device for the automatic termination of the exposure once the radiation penetrates the part & reaches the ionization detector

APR

anatomically programmed radiography

Define image receptor (IR)

a device that receives the energy of the xray beam and forms the image of the body part

Brightness

Digital imaging term equivalent to OD

Spatial resolution

The ability to visualize small structures

Describe how hand and foot radiographs should be displayed

with the digits pointing upward and as viewed from the perspective of the xray tube

When the radiologist is unable to see the patient who is responsible for ensuring that an adequate clinical history accompanies the radiographs?

the radiographer

According to the Centers for Disease Control and Prevention, all human blood and certain bodily fluids should be treated as if they contain \_____ ?

Pathogenic Microorganisms

Sterilization

destruction of all microorganisms

Which term (antiseptic or disinfectant) classifies isopropyl alcohol?

Antiseptic

The rhythmic motion of smooth muscle structures is called \____.

peristalsis

what body system controls the movement of voluntary muscles?

central nervous system

why is it necessary to ensure that any folds in cloth gowns are straightened out before making the radiographic exposure?

to prevent confusing shadows

before beginning a radiographic examination what should the radiographer do to gain the cooperation of a coherent patient?

give an example of the procedure to be performed

what is the minimum number of personnel that should be used to transfer a helpless patient from a gurney to the radiographic table?

four

some examinations require an additional marker to indicate the \__________ after the introduction of a contrast medium.

cumulative time

from the following list indicate which of the following is not recommended or unacceptable for right and left side marker placement:

a) use of electronic insertion of the

b) placement of the marker in the anatomy of interest side marker in digital imaging \n c) placement of the marker on the border of the collimated field

d) writing the side marker on the hard copy images

a b d

what adjustment can be made by the radiographer to compensate for an increase in OID?

increase the SID

T/F in direct digital image the field size or collimation must be manually adjusted

True

T/F creating an image using a larger than required (necessary) field size is a violation of the ASRT Code of Ethics

True

T/F Shuttering of direct digital images is an acceptable substitution for proper collimation

False

what are the two phases of respiration?

Inspiration (inhalation) & Expiration (exhalation)

what respiration procedure provides for lung motion but not rib motion?

slow deep breathing

how have equipment manufacturers responded to the growing obesity problem in the United States?

radiographic and fluoroscopic table weight limits have doubled to 700lb CT and MRI table weights and aperture openings have also increased

what is the major risk factor in transportation and transfer of obese patients?

risk of injury to radiographers other health care workers and the patient

From the following list circle the factors that mAs affect in digital imaging:

a) OD b) Contrast c) image noise d) Spatial resolution e) patient dose

a c e

From the following list circle the six factors that control spatial resolution:

a) IP phosphor (digital) b) flat panel detector c) motion d) distance e) exposure f) geometry g) focal spot size h) mA i) kVp

a b c d f g

From the following list circle the two factors that control radiographic magnification:

a) time in seconds b) mA c) kVp d) Object to image receptor distance (OID) e) Source to image receptor distance (SID)

d e

T/F All radiographs yield some degree of magnification

True

From the following list circle the five factors that control or affect shape distortion of a body part:
a) alignment
b) angulation
c) central ray
d) IR
e) anatomic part
f) OID
g) SID

a b c d e

Describe how hand and foot radiographs should be displayed

with the digits pointing upward and as viewed from the perspective of the xray tube

Identify the three types of muscular tissue and state the type of motion (voluntary or involuntary) associated with each

smooth, involuntary (peristalsis) \n cardiac involuntary (systole) \n striated voluntary

PA skull
(matching best choice for how side markers should be used)

R marker typically used

AP cervical spine
(matching best choice for how side markers should be used)

R marker typically used

Lateral Lumbar Spine
(matching best choice for how side markers should be used)

mark side closer to the IR

AP Oblique Lumbar Spine
(matching best choice for how side markers should be used)

mark side closer to the IR

Bilateral AP Knees (side by side on one IR)
(matching best choice for how side markers should be used)

use both R and L marker to identify both sides

list four reasons why it would become necessary to angle the central ray

-to avoid the superimposition of overlying or underlying structures
-to avoid superimposing a curved structure on itself
-to project through angled joints
-to project through angled structures without foreshortening or elongation