Radiation Safety and Patient Protection in Medical Imaging

List the ways in which patient exposure can be substantially reduced:

use of motion reduction techniques, proper X-ray beam limitation devices, filtration of X-ray beam, shielding specific areas, suitable technical exposure factors, appropriate digital image processing, and elimination of repeat radiographic exposures

True/False: grids aid in limiting patient dose

false

True/False: treat the whole person, not just the area of interest

true

Holistic patient care begins with effective _____________ between the radiographer and patient

communication

Communication can be accomplished through

verbal messages, body language, and clear, concise instructions

Effective communication reduces _________ and __________ ___________, as well as ___________ ___________

anxiety; emotional stress; repeat exposures

Effective communication enhances the __________ ________ of the radiographer and increases chances for a __________ _______

professional image; successful exam

Patient protection begins with clear and concise/confusing and elaborate instructions

clear and concise

When explaining procedures, use simple/complex terms

simple

If a radiographer stands 6 m away from an x-ray tube and receives an exposure rate dose of 4 mGy_a/hr, what will the exposure rate dose be if the same radiographer moves to stand at a position located 12 m from the X-ray tube

1 mGy_a/hr

Which of the following are methods that can be used by a C-arm operator to reduce their own occupational exposure and that of other personnel?

1. Collimate the x-ray beam to include only the anatomy of interest.

2. Use the foot pedal or the handheld exposure switch with their cables extended away from the machine as far as possible whenever making an exposure.

3. Use magnification whenever possible to visualize body parts better.

1 and 2 only

If the Bucky slot shield and protective curtain or sliding panel were not in the correct position during a routine fluoroscopic examination, what exposure dose rate would the fluoroscopist experience?

Exceed 1 mGy_a/hr at a distance of 0.6 m from the side of the x-ray table

Units of either mAs/wk or mA-min/wk are used to determine the for a specific x-ray room.

workload

For mobile radiographic units, which are not equipped with remote control exposure devices, the cord leading to the exposure switch must be long enough to permit the radiographer to stand at least _____ from the patient, the x-ray tube, and the useful beam to reduce occupational exposure

2 m (6 ft)

Of the following factors, which are specifically considered when determining thickness requirements for protective barriers?

1. Occupancy factor (T)

2. Workload (W)

3. Use factor (U)

4. kVp

1, 2, and 3 only 

Pediatric patients require special consideration and appropriate radiation protection procedures because they are much more vulnerable to which of the following?

The late effects of radiation

Which of the following examinations are considered unnecessary radiologic procedures?

1. Chest x-ray study as part of a preemployment physical

2. Screening mammography

3. Whole-body multislice spiral CT screening

1 and 3 only

If a maximum of 500 people inhabited an island and each person were to receive an equivalent dose (EqD) of 0.005 Sv gonadal radiation, the gross genetic effect would be the effect occurring if 50 individual inhabitants were each to receive 0.05 Sv of gonadal radiation and no equivalent dose were received by other inhabitants.

Identical to

True/False: always answer questions truthfully, even if you have to say "I am not sure, let me find someone who knows"

true

Create a sense of ________ between you and your patient

trust

__________ ___________ are attributed to poor communication

repeat exposures

Blurred images/images with motion have little to no __________ _________ and require repeats

diagnostic value

Voluntary motion is controlled by

will

Voluntary motion can be eliminated through

patient cooperation

Involuntary motion is controlled

unwilfully

Involuntary motion examples may include

digestion or heartbeat

True/False: breathing is an involuntary motion

false; both

How can you minimize involuntary motion

shorten the exposure time

Protective shielding minimizes potential exposure of

radiosensitive organs or tissues

Protective shielding reduces or eliminates ________ harm

biologic

Areas that should be shielded whenever possible

lens of eye, breasts, thyroid gland, and gonads (though gonads are no longer on the textbook publisher's list)

AAPM recommended _______ and _______ shielding be discontinued

gonadal; fetal

NCRP recommends discontinuation of gonadal and fetal shielding during ________ and _______ exams only

abdominal; pelvic

Selection of appropriate technical factors is essential to ensure a _________ image with _________ patient dose

diagnostic; minimal

Gonadal shielding should be used when reproductive organs are within ____ of the x-ray beam

5 cm

True/False: Gonadal shielding is a replacement for collimation

false

Gondal shielding should only be used when the shield will not

compromise the diagnostic value of an image or block the anatomy of interest

Gonadal shielding is a _________ protective measure

secondary

Female reproductive organs receive ___ ______ exposure than males

3x more

Flat contact shield reduces exposure approximately ____ for females and ________ for males

50%; 90-95%

Use the ____________ _________ to locate the pubic symphysis, which is at the level of the testes

greater trochanter

Move the shield 1 inch medial to each _____ to locate the ovaries

ASIS

Shielding ultimately reduces ___________ ____________ gonad dose

cumulative population

Standardization in the processing of digital images, which includes regular monitoring and maintaining of all processing and image display equipment

quality control program

Suspended from above the beam, hangs over the patient and casts a shadow in the primary beam over the reproductive organs

shadow shield

These are made of transparent lead-acrylic material impregnated with approximately 30% lead by weight

clear lead shield

Cup-shaped radiopaque device that encloses the male reproductive organs to protect them from exposure to ionizing radiation

shaped contract shield

Campaign to promote lowering the amount of radiation used in medically necessary imaging procedures and eliminating unnecessary procedures in adult medical imaging

image wisely

The recorded detail in the radiographic image

spatial resolution

Select the four basic types of gonadal shielding devices that can be used during a diagnostic x-ray procedure.

flat contact shield, shaped contact shield, shadow shield, and clear lead shield

The air-gap technique reduces the amount of scatter reaching the IR by increasing the

OID (object to image receptor distance)

An interaction that produces a satisfying result through an exchange of information

communication

A campaign to change long-established practice by raising awareness about methods for lowering radiation dose during pediatric medical imaging exams

image gently

Areas on the patient that can be used to guide placement of a testicular or ovarian shield

external anatomic landmarks

Primary function of the epidermis

to protect underlying tissues and structures

Alternative to the use of a grid for reducing scattered radiation during certain exams

air-gap technique

Individual responsible for ordering radiologic exams

referring physician

The decision to order a radiologic examination by a physician should depend upon whether

the benefit of the exam outweighs the risk

Which of the following can be used to specify the amount of radiation a patient receives from exposure to x-rays? 1. Gonadal dose 2. Entrance skin exposure 3. Bone marrow dose

1, 2, and 3

Why can an accurate determination of a patient's skin dose be made with a thermoluminescent dosimeter (TLD)?

Because the lithium fluoride detector reacts similarly to human tissue when exposed to ionizing radiation

Unconscious actions, or nonverbal messages, that if understood as intended will promote effective communication between radiographer and patient

body language

Devices used on patients during diagnostic x-ray procedures to protect reproductive organs from exposure when these organs are within 5 cm of a properly collimated beam

gonadal shielding

Most commonly reported and simplest way to specify the amount of radiation received by a patient from a diagnostic imaging procedures

entrance skin exposure

Radiation exposure received by the male and female reproductive organs

gonadal dose

The practice of using fluoroscopy to determine the exact location of the central ray before taking a radiographic exposure

fluoroscopically guided positioning

Which shield is not suited for non-recumbent positions or projections other than AP or PA

flat contact shield

The EqD to the reproductive organs that, if received by every human, would be expected to bring about an identical gross genetic injury to the total population, as does the sum of the actual doses received by exposed individual members of the population

Genetically significant dose (GSD)

________ is of great importance because it contains large numbers of stem cells that could be either depleted or even eliminated by substantial exposure to ionizing radiation

bone marrow

Which members of a population would be excluded from the genetically significant dose?

Individuals beyond reproductive years (post-menopausal)

The NCRP recommends that radiologic exams be performed during ___________________ to minimize the possibility of irradiating an embryo

the first few days of menses

Shaped shields can be used for

AP, oblique, and lateral (upright or recumbent) projections

What shield is used for scoliosis exams

clear lead shields

What shield is commonly used in sterile fields

shadow shields

True/False: there is a correct way to shield, and you must do it as such

true

There is no harm in shielding a patient upon request if the shield is

not in the primary beam or does not obscure any anatomy of interest

True/False: SID and filtration contribute to determining technical exposure factors

true

What are artifacts

unwanted densities in image that aren't part of the patient's anatomy

True/False: artifacts can be produced by IR, software, or the patient

true

True/False: technique charts replace the need for critical thinking

false

The use of a higher kVp permits a ______ mAs setting

lower

Advantage of the Air Gap technique

improves image contrast

Disadvantage of the air gap technique

increased magnification

Any image that must be performed more than once because of human or mechanical error

repeat images

During a repeat image, the patients' skin and gonads receive _______ dose (or more if the technical factors increase)

double

Reduce the need for repeats by

correctly positioning the patient and selecting appropriate technical factors

Digital radiography changed the _____ of repeats

cause

5-17% of digital repeats are due to

positioning errors

True/False: patient mispositioning, motion, external foreign bodies/artifacts, or clipping of anatomy are reasons for unacceptable images

true

True/False: striving for perfection is a good reason to repeat an image

false

True/False: radiographers are more careful when they know images are being reviewed and analyzed

true

Values of a repeat analysis program include

process improvement, minimizing patient exposure, increasing awareness, and improving overall performance

Nonessential radiologic exams are performed in the absence of

definite medical indications

Who determines if the benefit of an exam justifies the risk of exposure

the ordering physician

True/False: some RTs believe FGP results in less dose to the patient than does a repeat radiograph

true

True/False: ESE can be converted to skin dose

true

How is ESE estimated in fluoroscopy

measuring exposure rate at the tabletop and multiplying it by the exposure time

True/False: the GSD includes the number of children who may be expected to be conceived by members of the exposed population each year

true

The ____ does not believe abdominal exams should be postponed or selectively scheduled

ACR

True/False: bone marrow dose cannot be accurately measured; it can only be estimated

true

True/False: The ASRT views fluoroscopy-guided positioning as an ethical practice since it double checks the work of the rad tech

false; it increases patient dose and should never be used in place of appropriate skills required of a competent rad tech