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Radioactive Contamination Surveys

Contamination monitoring is an important element in assessing the effectiveness of the contamination control program at the National Institutes of Health. Routine contamination monitoring at the NIH is recorded and documented on a variety of contamination surveys, which are described below. 

Daily Surveys

A daily contamination survey is required each day unsealed radioactive material (RAM) is used. Daily contamination surveys are NOT required on days when work with RAM is not performed. 

Hand-held radiation survey meters can be used as long as the sensitivity of the instrument allows for efficient detection of the radionuclides handled. Contamination monitoring should be performed on the ungloved hands, lab coat, work area, the floor adjacent to the work area, the top and bottom of shoes, waste storage areas and any potentially contaminated equipment.

  • When using a hand-held survey meter, a count rate of greater than two times the background usually indicates the presence of contamination
  • Any area found to be contaminated must be decontaminated immediately and re-surveyed following appropriate decontamination procedures
  • Contaminated lab equipment that is dedicated for radioactive material work and likely to be re-contaminated should be appropriately labeled and kept separate from non-contaminated equipment


Monthly Surveys

A DRS contractor performs a thorough contamination survey of the lab module, which is required for each calendar month an unsealed form of radioactive material is used after the last monthly survey was conducted. The survey is not required to be performed on an exact day each month, but there should be a consistent pattern when the surveys are performed (e.g. during the third week of each month).  ​​

Guidance on what constitutes a lab module can be found in our  Guidelines for Conducting and Reporting Monthly Surveys


Monthly surveys are conducted in the following manner:  

A minimum of ten or more smear sample locations are collected, including at least two locations on the floor. Swipe or smear locations include areas and equipment that have a higher potential for being contaminated. 

Suggested locations where swipe or smear sampling is performed are:

  • Work areas, lab benches, and desks
  • At least two locations on the floor 
  • ​Floor adjacent to work areas and near hallway entrances
  • Lab equipment used with radioactive materials
  • Sinks in the laboratory
  • Door handles of lab doors, incubators and radionuclide storage refrigerators and freezers
  • Shelves in refrigerators and freezers
  • Incubator shelves
  • ​​Swipes or smears are counted using an appropriate LSC or gamma counter via proper sample labeling techniques and counter settings. 

Survey results will be conveyed to the Authorized User (AU). Any contaminated location identified must be decontaminated and re-surveyed to demonstrate compliance with the removable contamination limits for restricted areas, as listed in the "Surveying for Removable Contamination" section below. 

Reports are to be retained for a minimum of three years for review by the DRS or contract personnel and NRC inspectors.

Comprehensive Surveys​

In addition to daily and monthly surveys, the DRS maintains a staff of contract technicians who perform routine comprehensive surveys of all posted laboratories. The purpose of these surveys is to ensure compliance with NRC regulations and NIH license requirements.​ Survey frequency is determined by the DRS and varies for each lab (i.e., semiannual, quarterly, bimonthly, monthly, or weekly), based on radionuclide usage and activity. 

Like daily and monthly surveys, comprehensive surveys are designed to monitor for contamination. During these surveys, measurements of radiation levels, inspection of lab records, and an evaluation of general compliance with the NIH Radiation Safety Program are also performed. 

Results of a comprehensive survey are reported to the DRS on a Radiation Survey Report or contractor survey report form and include any items of noncompliance. The area health physicist​ reviews each comprehensive survey and determines if corrective action needs to be taken. 

A copy of each comprehensive Radiation Survey Report is furnished to the AU of the lab, along with a set o​f Radiation Survey Information Sheets to describe the survey results and suggest corrective actions.​


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