DHS 157.03(360)
(360) “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.
DHS 157.03(361)
(361) “Storage area" means any secure location, facility or vehicle that is used to store and secure a radiographic exposure device, a radiation machine, a storage container or a sealed source, when it is not in use.
DHS 157.03(362)
(362) “Storage container" means a device in which sealed sources or radiation machines are secured and stored.
DHS 157.03(363)
(363) “Stray radiation" means the sum of leakage and scattered radiation.
DHS 157.03(364)
(364) “Structured educational program" means an educational program designed to impart particular knowledge and practical education through interrelated studies and supervised training.
DHS 157.03(365)
(365) “S-tube" means a tube through which the radioactive source travels when inside a radiographic exposure device.
DHS 157.03(367)
(367) “Subsurface tracer study" means the release of a substance tagged with radioactive material to trace the movement or position of the tagged substance in the well-bore or adjacent formation.
DHS 157.03(368)
(368) “Supplied-air respirator" or “SAR" means an atmosphere-supplying respirator for which the source of breathing air is not designed to be carried by the user.
DHS 157.03(369)
(369) “Surface casing for protecting fresh water aquifers" means a pipe or tube used as a lining in a well to isolate fresh water aquifers from the well.
DHS 157.03(370)
(370) “Surface contaminated object" or “SCO" means a solid object that is not itself classed as radioactive material, but which has radioactive material distributed on any of its surfaces.
DHS 157.03(371)
(371) “Survey" means an evaluation of the radiological conditions and potential hazards incident to the production, use, transfer, release, disposal or presence of sources of radiation. When appropriate, an evaluation includes tests, physical examinations and measurements of levels of radiation or concentrations of radioactive material present.
DHS 157.03(371m)
(371m) “Tailing" means the residual material resulting from the extraction of minerals from the earth.
DHS 157.03(372)
(372) “Target" means that part of an x-ray tube or accelerator onto which a beam of accelerated particles is directed to produce ionizing radiation or other particles.
DHS 157.03(373)
(373) “Target-skin distance" or “TSD" means the distance measured along the beam axis from the center of the front surface of the x-ray target or electron virtual source to the surface of the irradiated object or patient.
DHS 157.03(374)
(374) “Technique factors" means the following conditions of operation:
DHS 157.03(374)(a)
(a) For capacitor energy storage equipment, peak tube potential in kV and quantity of charge in mAs.
DHS 157.03(374)(b)
(b) For field emission equipment rated for pulsed operation, peak tube potential in kV and number of x-ray pulses.
DHS 157.03(374)(c)
(c) For CT equipment designed for pulsed operation, peak tube potential in kV, scan time in seconds, and either tube current in milliamperes (mA), x-ray pulse width in milliseconds, and the number of x-ray pulses per scan; or the product of tube current, x-ray pulse width, and the number of x-ray pulses per scan expressed as mAs.
DHS 157.03(374)(d)
(d) For CT x-ray equipment not designed for pulsed operation, peak tube potential in kV, and either tube current in mA and scan time in seconds, or the product of tube current and exposure time in mAs and the scan time when the scan time and exposure time are equivalent.
DHS 157.03(374)(e)
(e) For all other equipment, peak tube potential in kV and either tube current in mA and exposure time in seconds or the product of tube current and exposure time in mAs.
DHS 157.03(374m)
(374m) “Telemetric position monitoring system" means a data transfer system that captures information by instrumentation or measuring devices about the location and status of a transport vehicle or package between the departure and destination locations.
DHS 157.03(375)
(375) “Teletherapy" means a method of radiation therapy in which collimated gamma rays are delivered from a source at a distance from the patient or human research subject.
DHS 157.03(376)
(376) “Temporary job site" means a location where any of the following occur:
DHS 157.03(376)(a)
(a) Radiographic operations are performed and sources of radiation may be stored other than at the location or locations of use authorized on the license or registration.
DHS 157.03(376)(b)
(b) Radioactive materials are present for the purpose of performing well logging or subsurface tracer studies.
DHS 157.03(377)
(377) “Tenth-value layer" or “TVL" means the thickness of a specified material that attenuates x-radiation or gamma radiation to an extent that the air kerma rate; exposure rate or absorbed dose rate is reduced to one-tenth of the value measured without the material at the same point.
DHS 157.03(378)
(378) “Termination of irradiation" means the stopping of irradiation in a fashion that will not permit continuance of irradiation without the resetting of operating conditions at the control panel.
DHS 157.03(379)
(379) “Test" means the process of verifying compliance with an applicable regulation.
DHS 157.03(380)
(380) “Therapeutic dosage" means a dosage of an unsealed radioactive material that is intended to deliver a radiation dose to a patient or human research subject for palliative or curative treatment.
DHS 157.03(381)
(381) “Therapeutic dose" means a radiation dose delivered from a sealed source containing radioactive material to a patient or human research subject for palliative or curative treatment.
DHS 157.03(382)
(382) “Therapeutic radiation machine" means x-ray, gamma ray or electron-producing equipment designed and used for external beam or internal radiation therapy.
DHS 157.03(383)
(383) “Thermoluminescent dosimeter" or “TLD" means a dosimeter containing a crystalline solid for measuring radiation dose, plus filters to help characterize the types of radiation encountered. When heated, TLD crystals that have been exposed to ionizing radiation give off light proportional to the energy they received from the radiation.
DHS 157.03(384)
(384) “Tight-fitting facepiece" means a respiratory inlet covering that forms a complete seal with the face.
DHS 157.03(385)
(385) “Tomogram" means the depiction of the x-ray attenuation properties of a section through the body.
DHS 157.03(386)
(386) “Tomographic plane" means that geometric plane which is identified as corresponding to the output tomogram.
DHS 157.03(387)
(387) “Tomographic section" means the volume of an object whose x-ray attenuation properties are imaged in a tomogram.
DHS 157.03(388)
(388) “Total effective dose equivalent" or “TEDE" means the sum of the effective dose equivalent for external exposures and the committed effective dose equivalent for internal exposures.
DHS 157.03(389)
(389) “Total organ dose equivalent" or “TODE" means the sum of the deep dose equivalent and the committed dose equivalent to the organ receiving the highest dose.
DHS 157.03(390)
(390) “Transport index" or “TI" means the dimensionless number, rounded up to the next tenth, placed on the label of a package to designate the degree of control to be exercised by the carrier during transportation. The transport index is the number is determined by multiplying the maximum radiation level in millisievert (mSv) per hour at one meter (3.3 feet) from the external surface of the package by 100, which is equivalent to the maximum radiation level in millirem per hour at one meter (3.3 ft).
DHS 157.03(391)
(391) “Transuranic waste" means waste containing elements having an atomic number greater than 92, a half-life greater than 5 years and in quantities greater than 3.7 kBq/g (100 nCi/g).
DHS 157.03(392)
(392) “Treatment site" means the anatomical description of the tissue intended to receive a radiation dose, as described in a written directive.
DHS 157.03(392m)
(392m) “Tribal official” means the highest ranking individual that represents Tribal leadership, such as the Chief, President, or Tribal Council leadership.
DHS 157.03(393)
(393) “Tritium neutron generator target source" means a tritium target source used within a neutron generator tube to produce neutrons for use in well logging applications.
DHS 157.03(393m)
(393m) “Trustworthiness and reliability" means the characteristics of an individual considered dependable in judgment, character, and performance, such that unescorted access to category 1 or category 2 quantities of radioactive material by that individual does not constitute an unreasonable risk to the public health and safety or security. A determination of trustworthiness and reliability for this purpose is based upon the results from a background investigation.
DHS 157.03(394)
(394) “Tube housing assembly" means the tube housing with tube installed. It includes high-voltage, filament transformers and other appropriate elements which are contained within the tube housing.
DHS 157.03(395)
(395) “Tube" means an x-ray tube, unless otherwise specified.
DHS 157.03(396)
(396) “Type A package" means a packaging that, together with its radioactive contents limited to A
1 or A
2 as appropriate, meets the requirements of
49 CFR 173.410 and
173.412 and is designed to retain the integrity of containment and shielding required under normal conditions of transport as demonstrated by the tests set forth in
49 CFR 173.465 or
173.466, as appropriate.
DHS 157.03(397)
(397) “Type A quantity" means a quantity of radioactive material, the aggregate radioactivity of which does not exceed A
1 for special form radioactive material or A
2 for normal form radioactive material, where A
1 and A
2 are given in ch.
DHS 157 Appendix O or may be determined by procedures described in ch.
DHS 157 Appendix O.
DHS 157.03(398)
(398) “Type B package" means a packaging that, together with its radioactive contents, is designed to retain the integrity of containment and shielding required by
49 CFR 173 when subjected to the normal conditions of transport and hypothetical accident test conditions set forth in
10 CFR 71.
DHS 157.03 Note
Note: A Type B package design is designated as B(U) or B(M). B(U) refers to the need for unilateral approval of international shipments; B(M) refers to the need for multilateral approval. No distinction is made in how packages with these designations may be used in domestic transportation. To determine their distinction for international transportation, refer to
49 CFR Part 173. A Type B package approved prior to September 6, 1983 was designated only as Type B.
DHS 157.03(399)
(399) “Type B quantity" means a quantity of radioactive material greater than a type A quantity.
DHS 157.03(401)
(401) “Underwater irradiator" means an irradiator in which the sources always remain shielded under water and humans do not have access to the sealed sources or the space subject to irradiation without entering the pool.
DHS 157.03(402)
(402) “Underwater radiography" means industrial radiography performed when the radiographic exposure device and related equipment are beneath the surface of the water.
DHS 157.03(402g)
(402g) “Unescorted access" means solitary access to a category 1 or category 2 quantity of radioactive material or the devices that contain the material.
DHS 157.03(402m)
(402m) “Unirradiated uranium" means uranium containing not more than 2 X 10
3 Bq of plutonium per gram of uranium-235, not more than 9 X 10
6 Bq of fission products per gram of uranium-235, and not more than 5 X 10
-3 g of uranium-236 per gram of uranium-235.
DHS 157.03(403)
(403) “Unit dosage" means a quantity of radioactive material that meets all the following criteria:
DHS 157.03(403)(b)
(b) Is to be administered as a single dosage to a patient or human research subject without any further manipulation of the dosage after it is initially prepared, except to adjust the dosage to patient needs.
DHS 157.03(404)
(404) “Unrefined and unprocessed ore" means ore in its natural form prior to any processing, such as grinding, roasting or beneficiating, or refining the ore from its natural state. Processing does not include sieving or encapsulation of ore or preparation of samples for laboratory analysis.
DHS 157.03(405)
(405) “Unrestricted area" or “uncontrolled area" means an area, access to which is neither limited nor controlled by the licensee or registrant.
DHS 157.03(406)
(406) “Uranium sinker bar" means a weight containing depleted uranium used to pull a logging tool down toward the bottom of a well.
DHS 157.03(407)
(407) “Useful beam" means the radiation which passes through the tube housing port and the aperture of the beam-limiting device when the exposure switch or timer is activated.
DHS 157.03(408)
(408) “User seal check" means an action conducted by the respirator user to determine if the respirator is properly seated to the face. Examples include negative pressure check, positive pressure check, irritant smoke check, or isoamyl acetate check.
DHS 157.03(409)
(409) “Variable-aperture beam-limiting device" means a beam-limiting device that has capacity for stepless adjustment of the x-ray field size at a given SID.
DHS 157.03(410)
(410) “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 5 Gy (500 rad) in one hour at one meter from a source of radiation or one meter from any surface that the radiation penetrates.
DHS 157.03(411)
(411) “Virtual source" means a point from which radiation appears to originate.
DHS 157.03(412)
(412) “Visible area" means that portion of the input surface of the image receptor over which incident x-ray photons are producing a visible image.
DHS 157.03(413)
(413) “Waste" means those low-level radioactive wastes containing source, special nuclear, or byproduct material that are acceptable for disposal in a land disposal facility. For the purposes of this definition, “low-level radioactive waste" means radioactive waste not classified as high-level radioactive waste, transuranic waste, spent nuclear fuel, or byproduct material as defined in sub.
(50) (b) to
(e).
DHS 157.03(414)
(414) “Waste handling licensee" mean a person licensed to receive and store radioactive residue prior to disposal and a person licensed to dispose of radioactive residue.
DHS 157.03(415)
(415) “Wedge filter" means a filter which effects continuous change in transmission over all or a part of the useful beam.
DHS 157.03(417)
(417) “Weighting factor" or “w
T" for an organ or tissue 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 w
T 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 0.30a/
Whole Body 1.00b/
a/ 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.
b/ 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 department shall approve the use of other weighting factors for external exposure on a case-by-case basis until such time as specific guidance is issued.
DHS 157.03(418)
(418) “Well" means a drilled hole in which well logging may be performed.
DHS 157.03(419)
(419) “Well logging" means all operations involving the lowering and raising of measuring devices or tools which may contain sources of radiation into wells or cavities for the purpose of obtaining information about the well or adjacent formations which may be used in oil, gas, mineral, groundwater or geological exploration.
DHS 157.03(419m)
(419m) "Well logging assistant" means any individual who, under the personal supervision of a well logging supervisor, handles sources of radiation that are not in logging tools or shipping containers or who performs surveys required by s.
DHS 157.55.
