Ch. 15 - Management of Imaging Personnel Radiation Dose During Diagnostic X-Ray Procedures

EfD annual limit

50 mSv

CumEfD annual limit

age x 10 msv

Imaging procedures that increase the radiographer's risk

Fluoroscopy, Interventional procedures with HLCF, Mobile radiography, Mobile fluoro

3 basic principles of radiation protection

Time, distance, shielding

Most effective means for radiation protection

distance

Biggest source of scatter

patient

Stand at a ____° angle to the primary x-ray beam at a distance of ____ meter.

90°, 1 meter

Greatest occupational hazard

scattered radiation

True / False: Pregnant women are allowed to be permitted to assist in holding a patient during an exposure.

False

Minimum lead apron thickness

0.25 mm Pb/eq

NCRP recommended lead apron thickness

0.5 mm Pb/eq

Maternity lead aprons should be how thick?

0.5 mm Pb/eq

Fetal dosimeters are worn:

at waist level, under lead apron

Primary protective barrier purpose

protect from direct beam

Primary protective barrier specifications

1.6 mm (1/16") lead, 2.1 m upward from floor

Secondary protective barrier purpose

protect from scatter & leakage radiation

Secondary protective barrier specifications

0.8 mm (1/32") lead, Overlap primary barrier by 1.3 cm (1/2")

Control booth barrier specifications

Extend 2.1 m upward from floor, secured to floor, Diagnostic x-rays should scatter minimum of 2x before reaching any area behind this barrier

Control booth observation window lead thickness

1.5 mm Pb/eq

Control booth exposure cord must be...

short enough to be kept behind the protective barrier

Accessory protective devices

Aprons, Gloves, Thyroid shields, Protective eyeglasses

Protective gloves lead thickness

0.25 mm Pb/eq

Thyroid shield minimum lead thickness

0.5 mm Pb/eq

Protective eyeglasses lenses minimum lead thickness

0.35 mm Pb/eq

What should not be touched while an exposure is in progress?

x-ray tube housing or cables

Fluoroscopic procedures dose-reduction techniques

- Collimation

- Filtration

- Control of technical factors

- Appropriate SSD

- Protective tube housing

Mobile fluoroscopy exposure switch must be at least _______ long.

2 meters (6 ft)

Annual EqD limit to localized areas of the skin & hands

500 mSv

Workload (W)

amount of radiation use in a given room over a specific period of time

Occupancy factor (T)

amount of time a space next to a radiation area is occupied by people

Leakage radiation should not exceed _______ from the tube house.

1 mGy/hr at 1 meter

Radiation warning signage must be present and indicate...

beam is on

The single most important source of scattered radiation in both radiography and fluoroscopy is the:

patient

Which of the following is recommended for the pregnant radiographer?

a) change dosimeters weekly

b) wear a second dosimeter under a lead apron

c) wear two dosimeters and switch their positions appropriately

d) leave radiation areas for the duration of the pregnancy

b

What is the minimum lead requirement for lead aprons, according to the NCRP?

a) 1.0-mm Pb equivalent

b) 0.25-mm Pb equivalent

c) 0.50-mm Pb equivalent

d) 0.05-mm Pb equivalent

b

Any wall that the useful x-ray beam may be directed toward must be a:

primary barrier

What is the significance of the inverse-square law on radiation protection concepts?

intensity of the beam decreases as distance increases

What term defines the gonadal dose that, if received by every member of the population, would be expected to produce the same total genetic effect on that population as the actual doses received by each of the individuals?

genetically significant dose (GSD)

The protective curtain used during fluoroscopic procedures must have a lead equivalent of at least what thickness?

a) 0.15 mm

b) 0.25 mm

c) 0.5 mm

d) 0.7 mm

b

True/False: Shielding is the most effective means of radiation protection.

False