ASTM E2303

Radiation processing is carried out under fixed path conditions where (a) a process load is automatically moved through the radiation field by mechanical means or (b) a process load is irradiated statically by manually placing product at predetermined positions before the process is started. In both cases the process is controlled in such a manner that the process load position(s) and orientation(s) are reproducible within specified limits.

Some radiation processing facilities that utilize a fixed conveyor path for routine processing may also characterize a region within the radiation field for static radiation processing, sometimes referred to as “Off Carrier” processing.

Radiation processing may require a minimum absorbed dose (to achieve a desired effect or to fulfill a legal requirement), and a maximum dose that can be tolerated (while the product, material or substance still meets functional specifications or to fulfill a legal requirement).

Dose mapping is used to characterize the radiation process and assess the reproducibility of absorbed-dose results, which may be used as part of operational qualification and performance qualification.

Dose mapping is used to determine the spatial distribution of absorbed doses and the zone(s) of maximum and minimum absorbed doses throughout a process load, which may consist of an actual or simulated product.

Dose mapping is used to establish the relationship between the dose at a reference position and the dose within the minimum and maximum dose zones established for a process load.

Dose mapping is used to verify mathematical dose calculation methods. See Guide E 2232.

Dose mapping is used to determine the process shutdown and startup transit dose effect on the distribution of absorbed dose and the magnitude of the minimum and maximum doses.

Dose mapping is used to assess the impact on the distribution of absorbed dose and the magnitude of the minimum and maximum doses resulting from the transition from one process load to another where changes, for example, in density or product loading pattern may occur.

1. Scope

1.1 This document provides guidance in determining absorbed-dose distributions in products, materials or substances irradiated in gamma, X-ray (bremsstrahlung) and electron beam facilities.

Note 1—For irradiation of food and the radiation sterilization of health care products, other specific ISO and ISO/ASTM standards containing dose mapping requirements exist. For food irradiation, see ISO/ASTM 51204, Practice for Dosimetry in Gamma Irradiation Facilities for Food Processing and ISO/ASTM 51431, Practice for Dosimetry in Electron and Bremsstrahlung Irradiation Facilities for Food Processing. For the radiation sterilization of health care products, see ISO 11137: 1995, Sterilization of Health Care Products Requirements for Validation and Routine Control Radiation Sterilization. In those areas covered by ISO 11137, that standard takes precedence. ISO/ASTM Practice 51608, ISO/ASTM Practice 51649, and ISO/ASTM Practice 51702 also contain dose mapping requirements.

1.2 Methods of analyzing the dose map data are described. Examples are provided of statistical methods that may be used to analyze dose map data.

1.3 Dose mapping for bulk flow processing and fluid streams is not discussed.

1.4 Dosimetry is only one component of a total quality program for an irradiation facility. Other controls besides dosimetry may be required for specific applications such as medical device sterilization and food preservation.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.

2. Referenced Documents

E1026 Practice for Using the Fricke Reference Standard Dosimetry System
E170 Terminology Relating to Radiation Measurements and Dosimetry
E177 Practice for the Use of the Terms Precision and Accuracy Applied to Measurement of a Property of Material
E178 Practice for Dealing with Outlying Observations
E2232 Guide for Selection and Use of Mathematical Methods for Calculating Absorbed Dose in Radiation Processing Applications
E666 Practice for Calculating Absorbed Dose from Gamma or X Radiation
E668 Practice for the Application of Thermoluminescence-Dosimetry (TLD) Systems for Determining Absorbed Dose in Radiation-Hardness Testing of Electronic Devices
ISO/ASTM 51204 Practice for Dosimetry in Gamma Irradiation Facilities for Food Processing
ISO/ASTM 51205 Practice for Use of a Ceric-Cerous Sulfate Dosimetry System
ISO/ASTM 51261 Guide for Selection and Calibration of Dosimetry Systems for Radiation Processing
ISO/ASTM 51275 Practice for Use of a Radiochromic Film Dosimetry System
ISO/ASTM 51276 Practice for Use of a Polymethylmethacrylate Dosimetry System
ISO/ASTM 51310 Practice for Use of a Radiochromic Optical Waveguide Dosimetry System
ISO/ASTM 51400 Practice for Characterization and Performance of a High-Dose Radiation Dosimetry Calibration Laboratory
ISO/ASTM 51401 Practice for Use of a Dichromate Dosimetry System
ISO/ASTM 51431 Practice for Dosimetry in Electron and Bremsstrahlung Irradiation Facilities for Food Processing
ISO/ASTM 51538 Practice for Use of the Ethanol-Chlorobenzene Dosimetry System
ISO/ASTM 51540 Practice for Use of a Radiochromic Liquid Dosimetry System
ISO/ASTM 51607 Practice for Use of the Alanine-EPR Dosimetry System
ISO/ASTM 51608 Practice for Dosimetry in an X-ray (Bremsstrahlung) Facility for Radiation Processing
ISO/ASTM 51631 Practice for Use of Calorimetric Dosimetry Systems for Electron Beam Dose Measurements and Dosimeter Calibrations
ISO/ASTM 51649 Practice for Dosimetry in an Electron beam Facility for Radiation Processing at Energies between 300 keV and 25 MeV
ISO/ASTM 51650 Practice for Use of Cellulose Acetate Dosimetry Systems
ISO/ASTM 51702 Practice for Dosimetry in a Gamma Irradiation Facility for Radiation Processing
ISO/ASTM 51707 Guide for Estimating Uncertainties in Dosimetry for Radiation Processing
ISO/ASTM 51818 Practice for Dosimetry in an Electron Beam Facility for Radiation Processing at Energies between 80 and 300 keV
ICRU Report 14 Radiation Dosimetry: X-Rays and Gamma Rays with Maximum Photon Energies Between 0.6 and 50 MeV
ICRU Report 17 Radiation Dosimetry: X-Rays Generated at Potentials of 5 to 150 kV
ICRU Report 34 The Dosimetry of Pulsed Radiation
ICRU Report 35 Radiation Dosimetry: Electron Beams with Energies Between 1 and 50 MeV
ICRU Report 37 Stopping Powers for Electrons and Positrons
ICRU Report 60 Fundamental Quantities and Units for Ionizing Radiation
ISO 11137 Sterilization of Health Care Products-Requirements for Validation and Routine Control-Radiation Sterilization

Index Terms

absorbed dose; Bremsstrahlung; dose distribution; dose mapping; dose zone; dosimetry; electron beam; gamma rays; irradiator characterization; maximum dose; minimum dose; operational qualification; performance qualification; radiation processing; reference monitoring; sterilization; uncertainty; X-rays; ICS Number Code 13.280

Citing ASTM Standards

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