ALARA Policies and Reporting


MU has set ALARA levels for occupational exposures from any source of radiation, including X-Ray and RAM exposures. The ALARA levels are derived from the NRC's dose limits in 10 CFR 20 which can also be found in the table NRC Dose Limits. Even though radioactive materials and x-ray producing equipment are regulated by different entities, ALARA levels for both exposures have been derived using the NRC limits.

Additional information regarding Missouri's regulations on radiation protection for x-ray uses can be found on the Department of Health & Senior Services Website.

 

MU is committed to the ALARA philosophy and therefore sets forth the following ALARA policy:

  • ALARA is the acronym for "As Low As Reasonably Achievable." The ALARA philosophy applied to radiation safety programs is to maintain minimal levels of occupational radiation exposures and releases of radioactive effluents to the environment. The ALARA concepts are extensions of the radiation protection guides in that any unnecessary radiation exposures are considered excessive. The Radiation Safety Program (RSP) at MU is committed to the ALARA principles for reasonably reducing radiation exposures.
  • The ALARA principle is practiced throughout the RSP. The Radiation Safety Committee (RSC) reviews and audits the ALARA program.  All requests for use of radioactive materials are considered by the Radiation Safety Staff (RSS) and the RSC to insure that operations are conducted in an efficient manner by properly trained personnel. Continued radiation safety surveillance and inspection by the RSP insures that proper procedures are being used. Records of the inspections, surveys and personnel dosimetry are maintained and compared to evaluate the success of the ALARA program. Action levels are established at values well below the allowable dose limits and investigations are conducted when the action levels are exceeded. Radiation users must contribute to the ALARA programs by providing continuous reviews and improvements of their radiation protection procedures.
  • The ALARA program is the responsibility of all persons involved in the use of radiation at MU. Administrators, faculty, staff, RSS, and radiation users participate and cooperate in the development and improvement of the ALARA concepts as applied to the RSP. 
  • The management of MU is committed to maintaining its RSP for materials licenses consistent with the ALARA philosophy. 
  • All individuals who have radiation safety responsibilities of any nature for a material license (e.g., administrative, operational, procedural, and/or ancillary responsibilities) will be instructed in the ALARA Policy. 
  • The RSC will review quarterly ALARA reports prepared by the RSS.  Appropriate actions will be taken on external and internal radiation doses that exceed the investigational levels listed in the “ALARA INVESTIGATIONAL LEVELS” table below. 
  • Radiation dose investigational levels and reporting frequencies different than those listed may be established by the RSS for an individual worker or a group of workers. Justification for new action levels will be documented and must be consistent with good ALARA practices. The RSC will review the justification for and must approve or disapprove all revisions to the investigational levels.

 

ALARA Investigational Levels

Exposure Type
Quarterly (mrem)
Level 1
(notification only)
Level 2
(requires investigation)
Deep Dose Equivalent (DDE) or Effective Dose Equivalent (EDE)*
125
375
Lens Dose Equivalent (LDE)
375
1250
Shallow Dose Equivalent (SDE)
1250
3750
Committed Dose Equivalent (CDE)
1250
3750

 

Definitions

Deep Dose Equivalent (DDE): External whole body exposure at a tissue depth of 1 cm

Lens Dose Equivalent (LDE): External exposure to the lens of the eye at a tissue depth of 0.3 cm

Shallow Dose Equivalent: (SDE) or Shallow Dose Equivalent Maximum Extremity (SDE_ME): External Exposure at a tissue depth of 0.007 cm or to any extremity.

Committed Dose Equivalent (CDE): Exposure to organs or tissue that will be received from an intake of radioactive material by an individual during the 50-year period following the intake.

*Webster Calculation (Effective Dose Equivalent: EDE) may be used to account for DDE doses when wearing a lead apron.

 

 

ALARA REPORTING

The ALARA program sets personnel dose levels well below the annual regulatory limits. Doses exceeding these Level 2 will trigger an investigation to determine the cause of the dose and assess methods for dose reduction. Persons who receive a dose greater than Level 1 but less than Level 2 will only receive a notification. 

 

ALARA INVESTIGATIONAL LEVELS

The ALARA investigational levels are listed above in ALARA investigational Levels.  The NRC dose limits are presented below for comparison. Doses reported by the dosimetry vendor are used to determine if ALARA levels have been exceeded. Contact the RSS for the establishment of different ALARA levels for a new group.

 

REPORTS AND INVESTIGATIONS

A Quarterly Report of all individuals who have exceeded quarterly ALARA Levels is provided to the RSC. An ALARA Level 1 Notice will be sent to individuals who only exceed an ALARA Level 1 limit. An ALARA Level 2 Investigational Report will be sent to individuals who exceed an ALARA Level 2 limit. The individual is asked to complete the ALARA Report describing the type of work that was performed during the monitoring period and, if possible, to identify ways to reduce future exposure. This report is to be signed by the individual and the RSS person who conducted the investigation. The returned reports are then filed with the individual's exposure records.

 

NRC Dose Limits (10 CFR 20)

Area of Dose
Occupational Dose Limits (mrem/yr)
Public Dose Limits (mrem/yr)
Total Effective Dose Equivalent (or Whole Body: external + internal)
5000
100
Committed Dose Equivalent (or any organ dose)
50000
N/A
Eye Dose Equivalent (or lens of eye)
15000
N/A
Shallow Dose Equivalent (or skin dose)
50000
N/A
Extremity Dose (or shallow dose to any extremity)
15000
N/A
Minor (less than 18 years of age)
10% of Occupational Limits
N/A
Embryo/Fetus of Declared Pregnant Woman (limit taken over time of pregnancy)
500
N/A

 

Page last updated on September 22, 2021.