MOD 11 - Facility and Equipment Requirements

main priority when planning for xray images

to ensure that persons in the vicinity of the facility are not exposed to levels of radiations which surpass the regulatory exposure limits

adequate shielding that must be present to meet the following requirements

1. controlled areas for MRTs = 20 mSv per year

2. uncontrolled areas for all = 1mSv per year

three steps to ensure adequate shielding

1. preparation of facility plans

2. considerations for room design and layout

3. determination of parameters governing shielding requirements

radiation workers’ dose limits in controlled areas

20mSv per year

non-radiation workers’ dose limits in uncontrolled areas

1mSv per year

pediatric ward uncontrolled area dose limit

0.30 mSv per year

X-ray Workload

a measure of the operational time or the amount of use of the X-ray equipment

occupancy factor (T)

the fraction of time that an area is occupied by an individual who spends the most time there while the X-ray equipment is operating

use factor (U)

the fraction of the workload during which the X-ray beam is pointed in the direction under consideration

Primary Protective Barriers

• provide radiation shielding from the direct x-ray beam

• eg: gonadal shielding, wall behind the upright bucky or the floor under the table bucky

Secondary Protective Barriers

• provide shielding only from scattered and leakage x-rays

• eg: ceiling, doors

control booth protective barrier type

a secondary barrier and the xray tube should NEVER be directed towards the control booth

Primary and secondary barriers must be provided when

where the x-ray tube can be moved

Angiographic and radioscopic equipment requires what type of protective barrier

secondary shielding throughout the room

All radiographic, radioscopic, and computed tomography (CT) equipment requirements

• Indicators of radiation danger that include warning signs

• Specific markings

• Mechanical stability

• Indicator lights

• Indication of loading factors

• Irradiation control

• Controlling timers

• X-ray tube shield

  • X-ray beam filter

in CR and DR systems the electronic display devices must be assessed how often

daily

Tests to measure geometric distortion, luminance and resolutions should be performed how often

monthly

lens of the eyes annual dose limit

• MRT

• public

• radiation workers: 20mSv

• public: 15mSv

skin annual dose limit

• MRT

• public

• radiation workers: 500mSv

• public: 50mSv

hands and feet annual dose limit

radiation workers: 500mSv

minimum of lead for certain kV

• 0.25mm lead → <100kV

• 0.35mm lead → 100kV<kV<150kV

• 0.50mm lead → >150kV