Maintaining Process Effectiveness

Regular Testing and Calibration

Regularly test and calibrate

Process equipments

Characterizing the magnitude, distribution, and reproducibility of the dose absorbed in a material of homogeneous density

Analytical equipments

Dosimetry systems

Dosimetry System Calibration

Calibrate

New batch of dosimeters

Calibration verification should be performed periodically at the facility

Analytical instruments

Measurement traceable to national standard

Dosimeters in a conditions similar to those in the actual production irradiator

Routine dosimeters

The level of measurement uncertainty at a specified confidence level should be known

Documented Procedure

Orientation of the product with diagrams

Product handling before, during and after irradiation

Documented procedure

Routine dosimetry

Required activities and functions for the irradiation of the products

Documentation for Dosimetry system

Type and batch number

Dosimeter manufacturer Dosimetry

system selected

Instruments used for analysis

Reference standard or transfer standard

Date

Dosimeter Calibration

Reference the calibration facility used

Documentation for Dosimetry performance

Dose rate

Temperature, Humidity. lightEffect of environmental conditions on dosimeter during irradiation and measurement

Energy spectrum

Measurement quality assurance plan used for the routine dosimetry

Measurements

Uncertainty associated with the measurement

Reference the method used to convert dosimetry measurements to absorbed-dose values in water

Records

Fulfill obligations to and requirements of the authorities

Provide documentary evidence showing that the product received correct treatment

The main purpose of Records

To settle disputes (if any)

Product Process record

Storage environment

Unique code identifying each product

Loading the product onto the irradiator system

Reception and inspection of product

Record of

Unloading the irradiated product from the system

Scheduling the irradiation

Inspection

checking of routine dosimetry, process parameters

Sign-off of any non-conformances

Approval for release and dispatch to the customer

Daily shift maintenance record

Record of

Shut downdetails

System Condition

Date & shift Personnel on duty - time in &out with signature

Record shutdown details with time. Record reason for shut downRecord action taken

Record various operational parameters such as Conveyor speed, cycle time, running time of the irradiator, total number of packages transferred

Technical details of each equipments employed for operation (exhaust fan, hydraulic motor, recirculation pump, etc) and values of other monitoring instruments such as survey meters, contamination monitors, conductivity, hydraulic pressure recirculation water temperature, pH, etc

Product log record

Record of

Requireddose

Details of product

ProductCustomer name,Unique ID of the box, Package number, Carrier no. If any,

Cycle timeConveyor speed

Dosimeter Dosimeter number

ProductProcessing

Package inDate and time

Package out Date & time

Irradiation Control record

Product type

Time

Absorbed doses for products processed

Date

Record ofLoading diagrams

Process parameters of specific production runs

Reference the calibration of processing equipment

Reference the calibration of dosimetry systems and other analytical instruments

Dosimetry record

Calibration of Dosimetry equipments

Calibration of dosimeters

Absorbed dose for each specific production runs

Record of

Maintenance of the dosimetry equipment

Facility record

Any special conditions of the facility that could affect the absorbed dose to the product

Date the product is processed and the starting and the ending times of the irradiation

Each lot of product that is processed with unique identification number

Record of

Name of the operator

Record for Review and Approval

Periodic audit of all documentation

Names of authorized personnel who issued the certificate

Certificate for delivery of the dose to the product for each production run.

Record of

Retention of Records at the facility

Certificate of irradiation

Time specified by relevant authorities

Dose calibration documents

Copies of shipping documents

Copies of receiving documents.

Routine Dosimetry data

Irradiation control records

For each production run, retain record at the facility for inspection

Retain the records for a period

References

Guidelines for the Development, Validation and Routine Control of Industrial Radiation Process.IAEA Radiation Technology Series No.4 (2013)

ISO 11137:2006 “Sterilization of Healthcare Products – Radiation”Part 1: Requirements for development, validation and routine control of a sterilization process for medical devicesPart 3: Guidance on dosimetric aspects

Trends in radiation Sterilization of Health Care Products. IAEA, STI/PUB/1313 (2008)

ISO/ASTM 51649 “Standard Practice for Dosimetry in an Electron BeamFacility for Radiation Processing at Energies Between 300 keV and 25MeV”

ISO/ASTM 51702 “Standard Practice for Dosimetry in Gamma Irradiation Facilities for Radiation Processing”

ISO/ASTM 51261 “Standard Guide for Selection and Calibration of Dosimetry Systems for Radiation Processing”

Worked example

Example. 1: The sterilization dose specified for a product is 25 kGy and maximum dose is specified as 40 kGy. Data from a dose mapping exercise at the irradiation facility for the product shows dose at Reference position - 30.5 kGyminimum position - 26.5 kGymaximum position - 37.0 kGyFind out the minimum and maximum reading that is permissible for the routine dosimeter during routine processing of the product at the facility?

Answer.Minimum reading of the routine dosimeter

= Dose at the reference position X sterilization dose Dose at the minimum position= 30.5 x 25 kGy = 28.8 kGy 26.5

Maximum reading of the routine dosimeter= Dose at the reference position X sterilization dose Dose at the maximum position

= 30.5 x 40 kGy = 33.0 kGy 37.0

Therefore the minimum and maximum permissible reading of the routine dosimeter to register for the load to meet the specification are 28.8 kGy and 33 kGy respectively.

Worked example

Example. 2: The sterilization dose specified for a product is 25 kGy and maximum dose is specified as 40 kGy. If the routine permissible range is from 27 kGy to 35 kGy, find out the absorbed dose at minimum and maximum dose position in the product if the routine dosimeter registers a reading of 31 kGy?

Answer.Absorbed dose at the minimum dose position

= Sterilization dose X Routine dosimeter reading Minimum routine permissible reading= 25 x 31 kGy = 28.7 kGy 27

Absorbed dose at the maximum dose position= Maximum specified dose X Routine dosimeter reading maximum routine permissible reading= 25 x 31 kGy = 35.4 kGy 35

Therefore the minimum and maximum absorbed dose corresponds to the above routine dosimeter reading are 28.7 kGy and 35.4 kGy respectively.

Questions

Multiple Choice 1. Penetration of electrons depends on:

A. Current of electron beam, B. Electron energy, C. Speed of conveyor.

2. Radiation sterilization is performed according to: A. ISO 11134, B. ISO 11137, C. ISO 11135.

3. What does “dose mapping” mean? A. Determination of minimum dose B. Determination of maximum C. Measurement of dose distribution

4. Which dosimeter is used for monitoring of radiation processing of products? A. Reference dosimeter B. Routine dosimeter C. Transfer standard dosimeters

5. In radiation processing application, calorimeter is used as A. Primary dosimeter B. Transfer standard dosimeter C. Routine dosimeter

6. For absorbed dose measurements for radiation sterilization, dose is referred in A. Water B. Air C. Graphite

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Questions

1. Which standard do you follow for the sterilization of health care products?

2. Which standard do you follow for the selection of dosimetry systems?

3. Which standard do you follow for the calibration of dosimetry systems?

4. Which standard do you follow for estimating uncertainty in your dosimetry systems?

5. Name few reference standard dosimeters for calibration gamma irradiation facilities

6. What are the differences between reference standard and routine dosimeters?

7. What are the required procedures to validate the radiation processing of products?

8. How do you achieve measurement traceability for your dosimetry systems?

9. What are the roles of dosimetry in the validation of radiation processing?

10. How do you ensure quality assurance during routine production of radiation

processed product?

11. Name few routine dosimeters used in the range of 400 Gy to 1 kGy dose range for

food irradiation facilities.

12. How do you calibrate 10 MeV electron beams?

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Questions

13. Name few routine dosimeters used in electron beam irradiators.

14. What are important differences between the dosimetry of electron beam facility and

gamma irradiation facility?

15. What are the main aims of carrying out dose mapping in IQ, OQ and PQ?

16. Why do you require different dosimeters during different stages of validation process?

17. What are the important environmental conditions that affect the performance of the

dosimeters during its applications?

18. How do you ensure accuracy of measurement?

19. How do you correct systematic error in your dosimetric measurement?

20. What are operational and performance qualifications?

21. How is dose mapping in operational qualification is different from performance

qualification?

22. Which standard do you follow for dose mapping during validation?

23. Which standard do you follow for the validation of radiation processing gamma

irradiator?

24. What standard do you follow for the validation of electron beam irradiator?

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