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Chapter V
Radiation Protection Program

  1. General

    Radioactive material under license by either State or Federal agencies must be used under an approved radiation protection program. This program is designed to protect the health and safety of workers and public from potentially harmful effects of radiation by maintaining both external and internal exposures As Low As Reasonably Achievable (ALARA).

    The Radiation Safety Officer, and the Radiation Safety Committee (at UM), has the responsibility to implement the radiation protection program. UM's program includes:

    1. Authorization of individuals and work areas for use of radioactive materials or radiation producing equipment.

    2. Assuring the safe use of radioactive material and radiation producing equipment.

    3. Approval of all purchases of radioactive material.

    4. Receives all radioactive materials coming to UM Campus.

    5. Maintaining an inventory of all radioactive material received.

    6. Assuring that all required surveys and records are maintained.

    7. Certifying the proper disposal of radioactive waste.

    8. Providing external and internal radiation exposure monitoring.

    9. Leak testing of sealed radioactive sources.

    10. Analysis and testing for radioactive materials.

    11. Assisting users in the design and implementation of laboratory experiments, safety equipment, etc.

    12. Surveys of radiation producing equipment.

    13. Calibration of radiation detection instruments.

    14. Responding to radiation emergencies.

    15. Providing training to personnel who use radioactive materials or radiation producing equipment.

    Routine and unannounced inspections of laboratories and other use areas for compliance with applicable rules and regulations are performed by radiation safety personnel. Those working with radioactive materials and radiation producing equipment have the responsibility to report promptly to authorities any condition which may lead to or cause a violation of radiation safety regulations or cause unnecessary exposure to radiation or radioactive material. Thus, workers must be familiar with the conditions of their radioactive materials authorization, applicable State or Federal regulations.

  2. UM Radiation Protection Program

    1. Regulatory Agency

      2. Possession and use of radioactive materials at the University of Maryland at College Park is authorized under a license issued by the Maryland Department of the Environment, Center for Radiological Control as specified in Title 26 of the Official Annotated Code of Maryland, Chapter 26.12.01 - Ionizing Radiation Protection. Selected Sections of the State Code are shown below:
      PartTitle
      AGeneral Provisions

      Section A.1 - Scope
      Section A.2 - Definitions
      Section A.3 - Exemptions
      Section A.4 - Records
      Section A.5 - Inspections
      Section A.10 - Prohibited Users

      BRegistration of Radiation Machine Facilities and Services
      CLicensing of Radioactive Material

      Section C.1 - Purpose and Scope
      Section C.3 - Source Material
      Section C.20 - Types of Licenses

      DStandards for Protection Against Radiation

      Section D.1 - Purpose and Scope
      Section D.101 - Radiation Dose to Individuals in Restricted Areas
      Section D.102 - Determination of Accumulated Dose
      Section D.103 - Exposure of Individuals to Concentrations of Radioactive Material in Restricted Areas
      Section D.104 - Exposure to Minors
      Section D.201 - Surveys
      Section D.202 - Personnel Monitoring
      Section D.203 - Caution Signs, Labels, and Signals
      Section D.204 - Exceptions from Posting and Labeling Requirements
      Section D.205 - Instruction of Personnel

      IRadiation Safety Requirements for Particle Accelerators
      JNotices, Instructions and Reports to Workers and Inspections

    2. Radiation Protection Services

      3. At the University of Maryland, the Radiation Safety Officer has the responsibility to develop and implement the radiation safety program in order to assure compliance with the provisions of the State Code and the University's radio-active materials license. This program is outlined in the "Radiation Safety Manual". This manual is available to all users and includes instructions for:

      1. Obtaining authorization for use of radioactive material.

      2. Ordering and receiving radioactive material.

      3. Basic radiation protection techniques.

      4. Survey techniques and contamination limits.

      5. Personnel monitoring.

      6. Radioactive waste disposal.

      The Safety Manual also includes a description of the administrative organization of the safety program and other useful information applicable to the safe use of radioactive materials on Campus. Each user must become familiar with the requirements in the appropriate sections of the manual.

      The Radiation Safety Office staff performs periodic inspections of laboratories using radioisotopes and radiation installations to assure compliance with the safety manual, license and State Code. Violations of established rules, regulations and procedures may results in the loss of privilege to use radioactive material as well as cause an undue hazard to both the user and the people in the surrounding work area. Therefore, radiation safety can only succeed when each user follows both the spirit and actual rules described by the Radiation Safety Manual and this Training Manual and Study Guide.

Bibliography

Casarett, A.P., "Radiation Biology", Englewood Cliffs, NJ: Prentice-Hall Inc., 1968.

Cember, H., "Introduction to Health Physics", New York: Pergamon Press Inc., 1969. Second Edition, 1983.

Eisenbud, M., "Environmental Radioactivity", New York: Academic Press, 1973.

Faires, R. and Parks, B., "Radioisotope Laboratory Techniques", New York: John Wiley and Sons, 1973.

Grosch, D.S. and Hopwood, L.E., "Biological Effects of Radiations", New York: Academic Press, 1979.

Jaeger, R.G., editor, "Engineering Compendium on Radiation Shielding":, New York: Springer-Verlag, 1970.

Joe, H.J., "Radiation Safety Technical Training Course":, Argonne, IL: Argonne National Lab (ANL-7291 Rev 1), 1972.

Knoll, G.F., "Radiation Detection and Measurement:", New York: John Wiley and Sons, 1979.

Kobayashi, Y. and Maudsley, D., "Biological Applications of Liquid Scintillation Counting:", New York: Academic Press, 1974.

Martin, A. and Harbison, S., "An Introduction to Radiation Protection:", New; York: John Wiley and Sons, 1972.

National Academy of Sciences, "The Effects on Populations of Exposure to Low Levels of Ionizing Radiation: (BEIR III Report)", Washington, D.C.: National Academy Press, 1980.

National Council on Radiation Protection and Measurements (NCRP)) Reports, Washington D.C.:

# 22 Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and Water for Occupational Exposure (NBS Handbook 69), 1959.
# 39 Basic Radiation Protection Criteria, 1971.
# 45 Natural Background Radiation in the United States, 1975.
# 56 Radiation Exposure from Consumer Products and Miscellaneous Sources, 1977.
# 58 Handbook of Radioactivity Measurement Procedures, 1978, Second Edition, 1985.

Packard Prias Liquid Scintillation Operation Manual, Packard Instrument Co., Downers Grove, IL, 1977.

Shapiro, J., "Radiation Protection", Cambridge, MA.: Harvard University Press, 1972.

Snyder, W.S., Ford, M.R., Warner, G.G., Watson, S.B., "Dose Per Unit Cumulated Activity for Selected Radionuclides and Organs", (MIRD Pamphlet No. 11) Maryville, TN.: MIRD Committee, 1975.

State of Maryland, "COMAR 26.12.01 - Ionization Radiation Protection".

Taylor, L.S., "Protection Standards"Cleveland, OH.: The Chemical Rubber Company, 1971

United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), "Sources and Effects of Ionizing Radiation", New York: 1977 Report to the General Assembly.

United States Public Health Service, Bureau of Radiological Health, "Radiological Health Handbook"US Government Printing Office, January, 1970.

United States Department of Transportation, "and Regulations, Title 49: Subchapter C, Hazardous Materials Transportation", US Government Printing Office, as amended.

United States Nuclear Regulatory Commission, "Rules and Regulations", Title 10, Chapter 1: Code of Federal Regulations, Part 20 - Standards for Protection Against Radiation:, US Government Printing Office, as amended.

Wang, Y., editor, "CRC Handbook of Radioactive Nuclides", Cleveland, OH.: The Chemical Rubber Company, 1969.

Wang, C., Willis, D., Loveland, W., "Radiotracer Methodology in the Biological, Environmental, and Physical Sciences"Englewood Cliffs, NJ.: Prentice-Hall, Inc., 1975

Chart of the Nuclides

The information contained herein is being made available by the General Electric Company in the interest of promoting the dissemination of technical knowledged. The Company assumes no responsibility for liability or damage which may result from the use of any of this information.

Chart Unavailable

Note: Due to space limitations the General Electric Company Chart of the Nuclides is unavailable on the web. Below is a link to a chart of the nuclides courtesy of the Korea Atomic Energy Research Institute. Chart of the Nuclides

Solutions to Problem Set 1

1) d          2) c          3) a,c	4) a,b	5) b,c,d	6) c	
7) b          8) d          9) c	

10) Alpha - U-238, Ra-226:  Beta  - C-14, H-3, P-32
    Positron - Na-22, Zn-65

11) Nuclear Transition (gamma) - Co-57, Mn-54
    Electron Capture - I-125, Cr-51

12) a.  λ = 0.693    = 0.693  = 0.0231 min-1 
                   T1/2 min  30 min

    b.  A = λN, therefore N =   A   =   10,000 dpm  = 432,900 atoms
                    λ    0.0231 min-1

    c.  A = Ao e-λt , where t = 90 minutes and Ao = 10,000 dpm

          = (10,000 dpm)e[(0.0231 min-1)(90 min)]

          = (10,000)(0.125) = 1,250 dpm


13)  A  = e-λt  ;  3,885 dpm   = 0.259 = e-λt
     Ao                 15,000 dpm 

     ln 0.259  =  ln e-λt ; (ln e-λt = -λt)

     ln 0.259  = -λt

      1.35  = 0.693 (t),  T1/2  = 0.693 (24 hrs) = 12.32 hrs
	      T1/2                1.35

The isotope is potassium-42, determined by the half-life from Appendix IV.

14)  A  = e-λt  ; 6 dpm  =  0.6667 = e-λt
     Ao                 9 dpm

     0.4054 = 0.693   (t),  t =   0.4054    = 3,352 years old
              5730 yr           0.000121 y-1


15) Ao =A      =             2mCi                 =       101.4mCi
       e-γt     e-[0.693/12.71 hrs x 72 hours]

Solutions To Problem Set 2

	1) a,b,d          2) a          3) b

	4) a) GM;   b) Ion Chamber;  c) Liquid Scintillation;  d) Liquid Scintillation;
	   e) NaI;  f) NaI;          g) Ion Chamber 

	5) c          6) d           7) c           8) a,b,c

	9) 1,000 cpm  = 10,000 cpm  = 40,000 dpm
	       0.1          0.25 c/d

       10) a) Sgross - Sbkg = Snet Therefore 15,575 - 250cpm = 15,550
                                                     10 min

           b) (0.1µCi)(2.22 x 106dpm/µCi) = 2.22 x 104 dpm

              15,550 cpm x 100 = E = .70 x 100 = 70%
              2.22 x 104dpm

           c) 300 cpm = 429 dpm
               0.70

           d) (429 dpm)(1) = 4290 dpm 

           Therefore 4290 dpm = 0.0019µCi
                     2.22 x 10 6dpm/µCi

           e) MDA = 3 x 2501/2 = 4.74 cpm = 6.8 dpm (10 min count)
                        10 min   0.70 c/d

Solutions To Problem Set 3

	1) b          2) d          3) c          4) a          5) b          6) a,b,d
	8) d          9)a

    10)  Rate of cell division
	 State  of cell division
         Metabolic rate
	 State of nourishment
	 Oxygen levels
	 Enzyme levels associated with the repair process

    11) Rems per Year

          Whole Body      5.0
          Skin           50.0 
          Extremities    50.0

    12)  50 Rem 

    13)  As long as the total accumulated whole body dose does not exceed 50 Rem.

    14)  0.5 Rem
	 
    15)  0.10 Rem

    16)  10%

    17)  5 Rem

18)  Primary and secondary cosmic rays; naturally occurring radioactive materials in the earths crust; naturally 
     occurring radioactive materials in the body.

19)  Buildings made from materials containing Uranium, Thorium, Radium, and Potassium-40 can increase the 
     natural background external exposure.  If the ventilation rate is poor, radon gas and its decay products 
     can build up and increase internal exposures. 

20)  External exposure from K-40, U-238, and Th-232 decay series; Internal exposure from K-40, Radon, and Thorium.

Solutions to Problem Set 4

	1) c          2) b          3) a          4) a,b,c,d	5) c          6) b
	7) c

       8)  Reduce Stay Time; Increase Distance; Provide Shielding   

       9) 
          1. The type and energy of the radiation emitted.
          2. The radiological half-life of the isotope.
          3. The biological half-life of the isotope.
          4. The isotope's distribution in the body.
          5. The solubility of the compound containing the isotope.
	
   Note: No. 2 and 3 are combined to give the "Effective half-life".

10) I1= I2d22 = (5mR/hr)(100)2 =53.82 mR/hr
         d12    (30.48 cm)2

11) I =Ioe-µχ, Where µ= µm x ρ

          = mass attenuation coefficient for Cr-51 gamma (Appendix IV) for 
            lead multiplied by the density of lead

          = (0.369 cm2/gm) x (11.35 gm/cm3)=4.19 cm-1


Io= I          Therefore Io =       2mR/hr       = 8718 mR/hr
   e-µχ'                   e-(4.19 cm -1x 2 cm)

12) For Cs-137: γ=0.33 R/hr/meter/Ci (Appendix IV)
      For 20 mCi: 0.33 x 0.02 Ci = 0.0066 R/hr/m
      (Note: the source must be decay corrected for the true dose rate at present time).

 I1= I2d22 = (0.0066 R/hr)(39.37)2 =.021 R/hr
       d12    (22 inches)2


A Caution - Radiation Area sign must be posted at the point whre the radiation field is 5 mR/hr

13) 21 mR/hr x 0.5 hr = 10.5mR Approximately equals 11mRem

14)

   I2= I1d12 = (5mR/hr)(6 ft)2 =.021 R/hr
        d22    (3 ft)2

   Exposure = 5 mR/hr x 5 hrs = 25 mR;

   Stay time = 50 mR - 25 mR = 1.25 hr
                     20 mR/hr

   (Note: 1 mR approximately equals 1 mRem)

15) Two lead blocks are required for a shield for the vial:

    I = 1/8 = 0.125 = e-µχ
    Io

    (ln 0.125 = -2.0794):(ln e-µχ=µx)

    x=            2.0794            = 3.1 cm
         (0.059 cm2/gm x 11.35 gm/cm3)

    3HVL = 1/8 reduction (2x2x2=8)

    HVL for Co-60 = 1.035 cm x 3 = 3.1 cm

    Since 3.1 cm x 1 inch = 1.22 inches
                        2.54cm

    One block isn't enough shielding. Two blocks are required.

Question 16 answers:

      1)  No.   Gross cpm - Bkg  =  Net cpm ÷  Eff*  =  dpm
	  1        54       50        4       ---      ---
	  2       101       51       51       .50      102
	  3       237       25      212       .85      250
	  4       350       50      300       .55      546
	  5       120       50       70       .20      350
	  6      4025       25     4000       .85     4706
	  7       925       25      900       .90     1000
	  8       525       25      500       .88      569
	  9       225       25      200       .85      236
         10        47       50      ---       ---      ---

	  * Determined off the quench curves for the particular ESR and isotope in question.
2) By observing the distribution of the standard counts in the red and green channels, you can determine which isotopes contributed to the contamination:

Sites 2, 4, 5, are contaminated with H-3.

Sites 3, 6, 7, 8, 9, are contaminated with P-32.

3) Sites 1 and 10 are within the statistical fluctuation of the background counts (501/2 = 7.07; (25)1/2 = 5). Thus, any gross counts that fall between 43 and 57 in the red channel, or 20 and 30 in the green channel can be considered to be due to background. As a general rule of thumb, counts that are twice background counts can be considered to be from radioactivity.

4) Sites 6 and 7 exceed the removable contamination limits of 100 dpm/100 cm2.

5) The waste container should be posted with a "Caution-Radiation Area" sign since an individual could receive an exposure of 5 mr in one hour.

There are no areas in which an individual is likely to receive 100 mr in one hour. Even though the exposure rate is 125 mr/hr inside the freezer, one is not likely to stand there floor one hour. Therefore, a "Caution-High Radiation Area" sign is not required anywhere in the lab.

6) Opening the freezer with contaminated gloves is the most probable way the handle became contaminated. Since the handle is metal, soap and water should remove contamination. Other commercially prepared decontaminating solutions such as count-off or lift-away can be used if soap and water fail.

7) The person or persons using P-32 have contaminated the floor.

8) Recommendations:

  1. Keep articles like laboratory notebooks out of radioactive materials work areas; areas should be maintained as neat and as clean as possible to aid in controlling the spread of any contamination.
  2. Shield the radioactive waste container by placing it in another container made out of plastic or steel or move it to an area where there is little or no traffic.
  3. Shield the isotope storage area in the freezer by using plastic bins or shields since the high exposure rate is due to the P-32 beta radiation.
  4. A GM survey meter should be available whenever P-32 is being used so that areas of contamination can be instantly identified, limited, and decontaminated as appropriate. For areas of H-3 use, smears should be taken and evaluated as soon as possible after the manipulations have occurred. Equipment, surfaces, etc. should be treated as potentially contaminated until proven otherwise.
  5. More attention should be afforded to changing gloves given the probable instance by which the refrigerator handle and the cover of the liquid waste container were contaminated.
  6. Minimize and localize all items which may be used in procedures involving the use of radioactive materials. Contamination control effectiveness can be of crucial importance to the success of experimental data and results.
  7. Persons manipulating materials should be directly responsible for the monitoring and cleanup after they have worked, rather than having someone else find out how careless they may have been days after the occurrence. This is especially true in laboratory settings in which space is limited, people are numerous, and much time is spent in close quarters.
  8. The person working with P-32 received a pipette bulb from the person working with H-3 which was contaminated. This is not only poor safety practice, but could interfere with accuracy of the P-32 worker's experimental results.

Appendix III

(Penetration Ability of Beta Radiation)

Beta Radiation

Appendix IV

Rules of Thumb and Useful Equations

Alpha Particles

Alpha particles of at least 7.5 MeV are required to penetrate the protective layer of the skin.

Beta Particles

Beta particles of at least 70 keV are required to penetrate the protective layer of the skin.

The average energy of a beta-ray spectrum is approximately one-third the maximum energy.

The range of beta particles in air is about 12 ft/MeV. Thus, the maximum range of P-32 is: 1.71 MeV x 12 ft/MeV = 20 Ft.

The dose rate in rads per hour in a solution by a beta emitter is 2.12 EC/ρ, where E is the average beta energy per disintegration in MeV, C is the concentration in microcuries per cubic centimeter, and ρ is the density of the medium in grams per cubic centimeter. The dose rate at the surface of the solution is one-half the value given by the relation. Example: For P-32 average energy of approximately 0.7 MeV, the dose rate from 1 µCi/cc (in water) is 1.48 rads/hr.

The surface dose rate through the nominal protective layer of skin from a uniform thin deposition of 1 µCi/cm2 is about 9 rads/hour for energies above about 0.6 MeV.

For a point source of beta radiation (neglecting self and air absorption) of millicurie strength, the dose rate at 1 cm is approximately equal to 200 x mCi = rads/hour and varies only slowly with beta energy. Example: The dose rate for 1 mCi P-32 at 1 cm is : 200 x 1 mCi = approximately 200 rads/hour at one centimeter.

Gamma Rays

The dose rate to tissue in rads per hour in an infinite medium uniformly contaminated by a gamma emitter is 2.12 EC/ρ, where C is the number of microcuries per cubic cen..1675 (100) 11 .01 --- --- --- --- --- Whole Body 44.3 (400);Testes(90) Zinc-65 243.9 d 0.329 + (1.5) 30 .03 0.27 1.115(50.8) .925 0.066 Whole Body 193.2 (60) I = Intensity h = hours d = days y = years G = rem/hour at one meter per Curie

Appendix V Reference Data for Selected Radioisotopes

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