REDUCES LEAKAGE TO LESS THAN 100 mR PER HOUR AT A DISTANCE OF ONE METER FROM HOUSING

One meter is 3.3 feet

Body parts should not rest on tube housing

Condition of exposure

When x-ray tube is being energized

kVp, mA or mAs

Visible or audible signal of exposure

Tape measure or laser lights indicate the distance

Must be accurate with 2% of the indicated SID

X-ray beam and light should be within 2% of SID

PBL not required anymore

Beam should line up with image receptor

Proper alignment of beam to film (indicator light)

2.5 mm @70 kVp

1.5 mm between 50-70 kVp

.5 mm below 50 kVp (mammo)

See question on page 532 (refer to chart 31-3 on page 430)

Reproducibility

Linearity

Operator shield

Lead apron assigned to portable

Exposure switch should allow operator to be 2 meter from tube (6+)feet

Source to skin distance – 38 cm

Mobile SSD – 30 cm

When intensifier is in parked position—no fluoro

Intensifier serves as a primary protective barrier and must be 2 mm Pb equivalent.

Filtration should be at least 2.5 mm Al equivalent—Tabletop, patient cradle or other material factored in for total filtration

Collimation—unexposed border should be visible on TV monitor

Dead man type exposure switch

Bucky opening covered automatically by .25 mm lead

Protective curtain -- .25 mm Pb equivalent

Timer (audible) when fluoro time has exceeded 5 minutes

Intensity (R ) should not exceed 2.1 R per minute for each mA at 80 kVp

Location of x-ray table

Where is the primary beam directed?

Surrounding environment (controlled area vs. uncontrolled area)

RF room

Dedicated room

Use factor

# of exams in a room

Anywhere the primary beam is directed ( dedicated chest rooms)

Lead bonded to sheet rock of wood paneling

Concrete, concrete block, brick

4 inches of masonry = 1/16 inch of lead

Image intensifier considered a primary protective barrier

Secondary radiation (scatter, leakage)

Patient is source of scatter

Barrier does not have to be leaded

gypsum board 4 thicknesses of 5/8^th inch drywall

glass ½ to 1 inch thickness

lead acrylic

Control booth

Lead aprons (5mm of lead attenuates____%_at _____kVp

Distance

Occupancy

Control

Use factor

Amount of time x-ray beam is directed at wall/floor

Wall given a use factor of ¼

Floor given a factor of 1

Secondary barrier use factor of 1

Dedicated chest room-use factor of 1

Barriers are designed with 75-100 kVp usage in mind so most barriers are thicker than needed

Exposure to outside of room is calculated to result in a DL of 100mrem per week but do not factor in patient and image receptor interception. DL is actually 1/10^th of the recommended DL

Mounted of fixed to control panel

No long cords