Northeastern University
360 Huntington Avenue
170 Cullinane Hall
Boston, MA 02115-5000
phone: 617.373.2769
fax: 617.373.7622
Phone Numbers are under construction
Record of Amendments is under construction
Table of Contents is under construction
Radiation Safety Handbook is under construction
NORTHEASTERN UNIVERSITY RADIATION SAFETY OFFICE
GENERAL SAFETY INSTRUCTIONS AND PRECAUTIONS FOR RADIONUCLIDE USERS
All individuals working with radioactive materials will adhere to the following minimum safety requirements:
NORTHEASTERN UNIVERSITY RADIATION SAFETY OFFICE
AREA SURVEY PROGRAM
Individual users of unsealed radioactive materials are expected to perform routine area surveys of the work places and laboratories to insure that working surfaces, floor, equipment, etc. are free of removable contaminations and that external radiation exposures are maintained at a minimum. Each Principal Investigator shall be required to obtain a suitable survey instrument in the initial review of their application.
In addition to self-evaluation, the Radiation Safety Office will perform area surveys of radiation work areas at appropriate intervals to insure that external and internal exposure of personnel to radiation is maintained as low as possible.
AREA SURVEY PROCEDURES
HOW TO COMPLETE THE AREA SURVEY RECORD FORM
Please refer to the attached Area Survey Record Form.
The purpose of this form is to standardize the format for recording the results of routine area surveys. These surveys are specified in both the Handbook and in the Conditions of Approval for each Authorization to Possess and use Radioactive Materials at Northeastern University.
1) Geiger-Mueller count rate meters, liquid scintillation and solid scintillation counters are all potential survey instruments.
2) For persons using sealed sources only and which do not create a radiation field due to permanent shielding, low activity or give off non-penetrating radiations (alpha or low-energy beta), completion of the Area Survey Record is unnecessary. In these cases, radiation safety is assured through routine leakage testing and inventory taking to assure security of sources.
For persons using sealed sources (except as above), high-energy beta and gamma radiation fields need to be measured and recorded in mr/hr.
For persons using unsealed sources, sources in a dispersible physical state such as solid, liquid or gas and give off non-penetrating radiations only (alpha or low energy beta), representative samples of all potentially contaminated areas must be wiped with filter paper or equivalent and results recorded in dpm removable.
For persons using unsealed or sealed sources which give off penetrating X, high-energy beta or gamma radiations, all radiation fields need to be measured and recorded in mr/hr. Additionally, representative samples of all potentially contaminated areas must be wiped with filter paper or equivalent and results recorded in dpm removable.
3) How to calculate dpm removable (dpm = disintegrations per minute).
4) Step 1: Determine counting efficiency of instrument used.
5) Step 2: The decay of individual atoms of a radionuclide is subject to the laws of probability. Basic statistics reveal that the distribution of random events can be approximated as the Poisson distribution. The standard deviation (s) of an observed number of counts (N) is:
S = (N)½ One standard deviation from the mean represents a confidence level of 68%, while 2 standard deviations represent a confidence level of 95%.Hence, the net sample rate, NSR, is as follows:
NSR = GROSS SAMPLE RATE (GSR) - BACKGROUND RATE (BR)
The standard deviation of the net sample is: S = (GSR/t2 + BR/t2)½, where t is the related counting time.
For example, if GSR = 530 counts in 10 minutes and the background count is 50 CPM; at the 95% confidence level (CL), is the sample radioactive?
GSR = 530/10 = 53 cpm
NSR = 53-50 = 3 cpm
s = (530/100 + 50/1)½ = 7.4, at 95%CL 1.96, s = 14.6
The net sample is 53 and the background sample rate is 50. The difference is less than 14.6, hence there is no detectable radioactivity in the sample.
However, if the net sample rate is greater than 2 standard deviations, then calculate DPM.
DPM = CPM x efficiency factor.
Is your counting system 10, 20, 50, or 100% efficient? You must determine the counting efficiency for each radionuclide for each counting system experimentally.
For example, with a 20 % counting efficiency and a 200 cpm result,
DPM = 200/0.20 = 1000 DPM
6) Re-Test Data
All radiation fields in the laboratory must be reduced to as low as reasonably achievable (ALARA) using shielding, or other methods.
All removable contamination must be reduced to background levels in all areas that are not clearly posted, "CAUTION RADIOACTIVE MATERIALS", such as absorbent paper on benches.
7) Principal Investigator
Regardless of who in the lab conducts the Area Survey, all results should be recorded and initialed by the surveyor at the end of each workday on which radioactive materials are used. Principle Investigators must review and approve survey results by initialing the record on a weekly basis, at a minimum, regardless of work activity if radioactive materials are used or stored in the laboratory.
8.) Laboratory/Area Diagram
A diagram must be made of all areas in which radioactive materials or radiation sources are used. For large or complex areas more than one Area Survey Record form may be used. For example, if there are more than 11 areas to be surveyed in any given area, more than one sheet must be used.
[PLACE AREA SURVEY RECORD FORM HERE]
BIOASSAY PROGRAM FOR INTERNAL RADIATION MONITORING
Appropriate internal radiation monitoring shall be conducted on any individual working with unsealed radioactive materials where a potential exists for receiving radiation doses and/or body burdens in excess of the limits established in 10 CFR 20. All records of such bioassays will be maintained by the Radiation Safety Office.
A) All individuals routinely working with greater than 1 millicurie quantities of iodine-125 and iodine-131 shall participate in the in-vivo thyroid counting program conducted by the Radiation Safety Office.
B) The Radiation Safety Office will arrange for routine monthly thyroid measurements for persons exposed as in (A) above. If the quantity handled exceeds 10 mCi, measurements will be performed weekly.
C) In addition to routine monthly thyroid monitoring, personnel involved in so-called "iodination" procedures will receive thyroid measurement preferably within 48 hours of performing the iodination procedure but in any case within one work-week.
D) The maximum permissible weekly increase of iodine-125 or iodine-131 in the thyroid is established as 0.05 microcurie based upon the 40 hour per week maximum permissible air concentration.
E) If a thyroid measurement indicates the presence of greater than 25% of the maximum permissible burden of either iodine-125 or iodine-131 in the thyroid, the Radiation Safety Office shall initiate an immediate investigation of the work place, local exhaust system, work practices, procedures, etc. to determine the cause of the increased iodine uptake. The investigation may include area and personal air monitoring and wipe testing of surfaces as well as visual observation of techniques. Depending on the actual thyroid level of radioiodine, the individual may also be temporarily restricted from further radioiodine work.
A) All individuals routinely working with unsealed quantities of P-32 or H-3 in excess of 10 mCi will participate in the urinalysis program conducted by the Radiation Safety Office.
B) The Radiation Safety Office will arrange for routine monthly urinalysis on all such individuals. Should the quantity handled by any individual exceed 100 mCi of either radionuclide, the urinalysis frequency shall be increased to weekly.
C) As with the radioiodine bioassy program, if radioassay indicates the presence of greater than 25% of the urinary MPC, the Radiation Safety office will initiate an immediate investigation of the work place, local exhaust system, work practices, procedures, etc., to determine the cause of increased H-3 or P-32 uptake. Where appropriate, air samples and wipe tests of surfaces will be taken. Depending on the actual level of H-3 and/or P-32 in the urine, the individual may also be temporarily restricted from further exposure.
EMERGENCY PROCEDURES
Minor Spills
Major Spills
RADIATION SAFETY OFFICER: John M. Price
ASSISTANT RADIATION SAFETY OFFICER: Rebecca O'Donnell
OFFICE PHONE: x2769
HOME PHONE: request assistance from the Public Safety Division (x3333) so that on-call personnel can be paged
ALTERNATE NAMES AND TELEPHONE NUMBERS DESIGNATED BY RADIATION SAFETY OFFICER:
F.X. MASSE ASSOCIATES (978) 283-4888 (24 hour coverage)
Steven Brehio Office: x2769
Under Construction
NORTHEASTERN UNIVERSITY RADIATION SAFETY OFFICE
CONDITIONS FOR THE USE OF ANIMALS CONTAINING RADIOACTIVE MATERIALS