Code of Massachusetts Regulations › 105 CMR - DEPARTMENT OF PUBLIC HEALTH › Title 105 CMR 120.000 - The Control of Radiation › RECORDS › Section 120.203 - Definitions

Current through Register 1525, July 5, 2024
As used in
				  105 CMR
				  120.200, the following definitions
				  apply:
Annual Limit on Intake (ALI)
means
				  the derived limit for the amount of radioactive material taken into the body of
				  an adult worker by inhalation or ingestion in one year. ALI is the smaller
				  value of intake of a given radionuclide in one year by Reference Man that would
				  result in a committed effective dose equivalent of 0.05 sievert (5 rem) or a
				  committed dose equivalent of 0.5 sievert (50 rems) to any individual organ or
				  tissue. ALI values for intake by ingestion and by inhalation of selected
				  radionuclides are given in
				  105
				  CMR 120.296:
Appendix B
,
				  Table I, Columns 1 and 2.
Class
means a classification scheme
				  for inhaled material according to its rate of clearance from the pulmonary
				  region of the lung. Materials are classified as D, W, or Y, which applies to a
				  range of clearance half-times: for Class D, Days, of less than ten days, for
				  Class W, Weeks, from ten to 100 days, and for Class Y, Years, of greater than
				  100 days. For purposes of
				  105
				  CMR 120.000, "lung class" and "inhalation class" are
				  equivalent terms.
Declared Pregnant Woman
means a
				  woman who has voluntarily informed the licensee or registrant, in writing, of
				  her pregnancy and the estimated date of conception. The declaration remains in
				  effect until the declared pregnant woman withdraws the declaration in writing
				  or is no longer pregnant.
Derived Air Concentration (DAC)
means the concentration of a given radionuclide in air which, if breathed by
				  Reference Man for a working year of 2,000 hours under conditions of light work,
				  results in an intake of one ALI. For purposes of
				  105
				  CMR 120.000, the condition of light work is an
				  inhalation rate of 1.2 cubic meters of air per hour for 2,000 hours in a year.
				  DAC values are given in
				  105
				  CMR 120.296:
Appendix B
,
				  Table I, Column 3.
Derived Air Concentration-hour
				  (DAC-hour)
means the product of the concentration of radioactive
				  material in air, expressed as a fraction or multiple of the derived air
				  concentration for each radionuclide, and the time of exposure to that
				  radionuclide, in hours. A licensee may take 2,000 DAC-hours to represent one
				  ALI, equivalent to a committed effective dose equivalent of 0.05 sievert (5
				  rems).
Dosimetry Processor
means an
				  individual or an organization that processes and evaluates individual
				  monitoring equipment in order to determine the radiation dose delivered to the
				  monitoring equipment.
Inhalation Class
see
Class
.
Lung Class
see
Class
.
Nationally Tracked Source
means a
				  sealed source containing a quantity equal to or greater than Category 1 or
				  Category 2 levels of any radioactive material listed in
				  105 CMR
				  120.298:
Appendix D
. In this
				  context a sealed source is defined as radioactive material that is sealed in a
				  capsule or closely bonded, in a solid form and which is not exempt from
				  regulatory control. It does not mean material encapsulated solely for disposal,
				  or nuclear material contained in any fuel assembly, subassembly, fuel rod, or
				  fuel pellet. Category 1 nationally tracked sources are those containing
				  radioactive material at a quantity equal to or greater than the Category 1
				  threshold. Category 2 nationally tracked sources are those containing
				  radioactive material at a quantity equal to or greater than the Category 2
				  threshold but less than the Category 1 threshold.
Nonstochastic Effect
means a health
				  effect, the severity of which varies with the dose and for which a threshold is
				  believed to exist. Radiation-induced cataract formation is an example of a
				  nonstochastic effect. For purposes of
				  105
				  CMR 120.000:
Deterministic
				  Effect
is an equivalent term.
Planned Special Exposure
means an
				  infrequent exposure to radiation, separate from and in addition to the annual
				  occupational dose limits.
Quarter
means a period of time equal
				  to ¼ of the year observed by the licensee or registrant, approximately
				  13 consecutive weeks, providing that the beginning of the first quarter in a
				  year coincides with the starting date of the year and that no day is omitted or
				  duplicated in consecutive quarters.
Reference Man
means a hypothetical
				  aggregation of human physical and physiological characteristics determined by
				  international consensus. These characteristics may be used by researchers and
				  public health employees to standardize results of experiments and to relate
				  biological insult to a common base. A description of Reference Man is contained
				  in the International Commission on Radiological Protection report, ICRP
				  Publication 23,
Report of the Task Group on Reference
				  Man
.
Respiratory Protective Device
means
				  an apparatus, such as a respirator, used to reduce an individual's intake of
				  airborne radioactive materials.
Sanitary Sewerage
means a system of
				  public sewers for carrying off waste water and refuse, but excluding sewage
				  treatment facilities, septic tanks, and leach fields owned or operated by the
				  licensee or registrant.
Stochastic Effect
means a health
				  effect that occurs randomly and for which the probability of the effect
				  occurring, rather than its severity, is assumed to be a linear function of dose
				  without threshold. Hereditary effects and cancer incidence are examples of
				  stochastic effects. For purposes of
				  105
				  CMR 120.000:
Probabilistic
				  Effect
is an equivalent term.
Very High Radiation Area
means an
				  area, accessible to individuals, in which radiation levels from radiation
				  sources external to the body could result in an individual receiving an
				  absorbed dose in excess of 500 rads (five grays) in one hour at one meter from
				  a source of radiation or from any surface that the radiation penetrates. (At
				  very high doses received at high dose rates, units of absorbed dose, gray and
				  rad, are appropriate, rather than units of dose equivalent, sievert and
				  rem.)
Weighting Factor W for an Organ or Tissue
				  (T)
means the proportion of the risk of stochastic effects
				  resulting from irradiation of that organ or tissue to the total risk of
				  stochastic effects when the whole body is irradiated uniformly. For calculating
				  the effective dose equivalent, the values of WT
				  are:
ORGAN DOSE WEIGHTING FACTORS
Organ or Tissue
wT
Gonads
0.25
Breast
0.15
Red bone marrow
0.12
Lung
0.12
Thyroid
0.03
Bone surfaces
0.03
Remainder
0.30*
Whole Body
1.00**
* 0.30 results from 0.06 for each
				  of 5 "remainder" organs, excluding the skin and the lens of the eye, that
				  receive the highest doses.
** For the purpose of weighting
				  the external whole body dose, for adding it to the internal dose, a single
				  weighting factor, wT = 1.0, has been specified. The use
				  of other weighting factors for external exposure will be approved on a
				  case-by-case basis until such time as specific guidance is issued.