GB 16352-1996 Standard for gamma ray sterilization of disposable medical supplies
Some standard content:
National Standard of the People's Republic of China
Standards for Y-rays radiation sterilization of disposable medical appliances1 Subject content and scope of application
GB16352—1996
This standard specifies the process, quality assurance and treatment of medical appliances after radiation sterilization. This standard applies to the radiation sterilization of disposable medical appliances by Y-rays. It is not applicable to the radiation sterilization of medicines or other materials. 2 Referenced standards
GB10252 Radiation protection regulations for cobalt-60 irradiation devices for radiation processing 3 Terms
3.1 Initial contamination bioburden
The total number of viable microorganisms on medical appliances and packaging materials before sterilization. 3.2 Biological indicatorbiological indicatorA test piece with a calibrated number of viable microorganisms. 3.3 Cycle timercycle timer
A device that controls the time it takes for an irradiated container to pass through each position in the irradiation device. 3.4 Dose distribution test dosemapping In the irradiation device, the dose distribution of the articles arranged in a certain way in the irradiation container or the simulated articles with a density similar to that of the articles is measured to determine the dose distribution.
3.5 Dose nonuniformity dose nonuniformity The ratio of the maximum and minimum doses determined in the measured dose distribution diagram. The dose nonuniformity may vary depending on the type of articles.
3.6 Good manufacturing practice, GMP The assurance measures and procedures that need to be taken to ensure the quality of the articles in the process of article manufacturing. 3.7 Good radiation practice, GRP The measures and procedures taken to ensure the provision of appropriate sterilization doses according to the process characteristics of the irradiation device. 3.8 Irradiation container irradiation container The container (such as a container, a vehicle or a pallet) used to load the article unit and transport it through the irradiation device. 3.9 Irradiator irradiator
The irradiation device consists of a radiation source, a transmission device, a control system, safety facilities and an irradiation room. It can be used to achieve a safe and reliable radiation sterilization process.
3.10 Medical devices
Supplies, equipment, tools, machinery, transplant dressings, or other similar items specifically used for human treatment, diagnosis, and contraception. These do not include items that achieve a specified purpose through biochemical or chemical effects in the human body (such as medicines, etc.). Approved by the State Administration of Technical Supervision on May 23, 1996 and implemented on December 1, 1996
3.11 Process validation GB16352---1996
Activities that provide evidence that the radiation sterilization process for supplies has achieved the required sterilization assurance level. 3.12 Product unit
The smallest entity that can be treated as a unit in radiation sterilization. Such as a box, carton, or container. 3.13 Reference dosimeter Reference dosimeter A dosimeter with excellent metrological performance, whose measurement values can be traced back to national reference values. 3.14 Routine dosimeter Routine dosimeter A dosimeter used for routine dose measurement in irradiation field that has been calibrated with reference dosimeters or national standard dosimeters. 3.15 Sterility assurance level, SAL The maximum probability that the supplies have not reached sterilization after effective sterilization. 3.16 Sterilizing dose sterilizing dose
The absorbed dose (in Gy) required to reach or exceed the required sterilization assurance level. 3.17 Sterilizing dose auditing Inspection measures taken to determine the changes in the sterilization dose of the natural microbial community on the supplies. 4 Production management of sterilization of medical supplies
4.1 The production of medical supplies must comply with the relevant provisions of the "Pharmaceutical Production Management Standards", "Pharmaceutical Production Quality Management Standards" and "Disposable Medical Device Production Management Standards" formulated by the State Drug Administration and health departments. 4.2 Radiation sterilization of medical supplies must comply with the requirements of the "Disinfection Technical Specifications" issued by the Ministry of Health. 4.3 The initial manufacturer of medical supplies and radiation sterilization operators must assume their respective responsibilities to ensure the quality of radiation sterilization of medical supplies.
4.3.1 The initial manufacturer of medical supplies shall provide information on the radiation adaptability and average initial contamination count of medical supplies and packaging materials, and propose the sterilization assurance level and the minimum sterilization dose. 4.3.2 Radiation sterilization operators shall be subject to assessment and obtain a certificate of qualification before they can engage in radiation sterilization work, and shall be responsible for determining the sterilization dose range. 4.4 The provisions of the "Regulations on the Hygiene Protection Management of Large Radiation Processing Equipment" must be implemented. 5 Acceptance and maintenance of irradiation equipment
5.1 The irradiation equipment must be inspected and accepted before it is officially put into operation. This is to verify the absorbed dose and its distribution received by uniform materials within the typical density range under normal operating conditions and the reproducibility of irradiation. 5.2 The electronic and mechanical system of the irradiation equipment must operate reliably and meet the requirements of GB10252. 5.3 The dose distribution must be measured during the initial acceptance. Actual measurements are performed after filling the upper and lower limits of the density range of the irradiated supplies with real objects or simulants with densities similar to the real objects. This is to determine the dose non-uniformity of supplies with different densities under different irradiation methods. The dose non-uniformity should not be greater than 2.
5.4 One or more conventional dosimeters should be used to measure the dose distribution. Dosimeters should be placed at pre-selected reference positions throughout the supply load, and reference dosimeters should be placed at representative reference positions for comparative measurements. See Appendix A (reference). 5.5 The dose deviation of conventional dosimeters and their measurement systems should be less than ±10% (at a 95% confidence level). The dose measurement accuracy of reference dosimeters and their measurement systems should be less than ±4% (at a 95% confidence level). 5.6 The irradiation device must be monitored for extraordinary events (such as mechanical failures, etc.) to determine the impact of these events on dose distribution and sterilization.
5.7 Re-acceptance must be carried out when the activity of the radiation source increases or the operating parameters change. When the structure of the source remains unchanged, it is only necessary to measure the dose distribution in the maximum and minimum dose areas and their surroundings to determine whether the initial acceptance is still valid. When the structure of the source changes, the dose distribution map must be remeasured.
5.8 The equipment must be strictly inspected and maintained in accordance with the routine and preventive maintenance procedures recommended by the equipment supplier to ensure the safe and reliable operation of the irradiation device, and maintenance records must be kept.
GB16352—1996
5.9 If the maintenance does not affect the performance of the irradiation device, there is no need to re-verify the radiation sterilization cycle. When the maintenance may affect the structure of the radiation source, the loading mode of the supplies or the operating parameters of the irradiation device, re-acceptance must be carried out. 6 Process Confirmation
6.1 The radiation sterilization process of a certain medical supply must be confirmed. To determine the suitability of the material, select the required minimum sterilization dose, establish the supply loading mode, measure the dose distribution map, and set the irradiation cycle timer. 6.2 Suitability of materials
6.2.1 Medical supplies and packaging materials used for radiation sterilization must be tested at the maximum dose expected during routine radiation sterilization to evaluate the radiation physical and chemical stability and bioapplicability of the materials, with particular attention to the high molecular depolymerization effect caused by radiation. 6.2.2 Medical supplies after radiation sterilization must be fully functionally tested and qualified according to their final use. 6.3 Determination of sterilization dose
6.3.1 The minimum sterilization dose should be determined based on the number of natural microbial communities on the medical supplies to be sterilized, their radiation resistance and the sterilization assurance level. See Appendix B (reference).
6.3.2 When the number and radiation resistance of the natural microbial communities on the supplies are unknown, and it is confirmed that the supplies are produced in accordance with the provisions of the medical supplies production management specifications, and the initial contamination is low, 25kGy should be used as the minimum sterilization dose (which can provide a sterilization assurance level of 10-6). 6.4 Supplies loading pattern
6.4.1 A loading pattern should be established for each type of supplies unit. The number and position of supply units in the irradiation container should be stated in the loading pattern instructions.
6.4.2 The design of the supplies loading pattern should use the supplies to fill the container space to the maximum extent within the allowable weight range of the irradiation container and distribute them as evenly as possible to minimize the dose variation. 6.5 Dose distribution calibration
6.5.1 After the supply loading mode is established, actual supplies or simulants with approximate supply density should be used for loading to measure their dose distribution. When there are several transmission channels available in the irradiator, the dose distribution should be calibrated for each channel. 6.5.2 For static stacking irradiation mode, the spatial dose distribution must be measured in advance and the isodose curve must be drawn. 6.5.3 A sufficient number of dosimeters should be placed in the irradiation container or in the supply load in the stack to determine the minimum and maximum dose areas, and then select the dose monitoring position. 6.5.4 When the radiation source structure changes, the dose distribution calibration should be performed again. 6.6 Cycle timer setting
6.6.1 For irradiation devices with determined source loading, the cycle timer must be set or the stacking supply flipping and shifting time must be determined based on the dose distribution calibration results, the supply loading mode and the required minimum sterilization dose to control the time the supplies pass through or stay in the irradiator and the dose received.
6.6.2 After the initial cycle timer is set for each product, the radiation source should be adjusted for decay compensation in subsequent radiation sterilization operations.
7 Routine sterilization treatment
7.1 Sterilization requirements
The original manufacturer of medical products and the radiation sterilizer should jointly propose the sterilization requirements for the products in written form, and determine the sterilization process and treatment methods that should be adopted for each type of product before, during and after sterilization. 7.2 Pre-irradiation treatment of products
7.2.1 A detailed inventory record must be made for the products to be sterilized. The record should include the exact number of product units received, and any discrepancy with the number on the shipping document should be verified and noted.
7.2.2 Products to be sterilized should be stored in a special storage area designed for non-sterile products. When necessary, a color-changing indicator can be used to identify irradiated and non-irradiated products.
7.3 Irradiation of Supplies
7.3.1 Dosimeter Arrangement
GB16352—1996
7.3.1.1 Conventional dosimeters must be selected in accordance with the requirements of Article 4.5. The number of dosimeters to be used shall be determined according to the style of the irradiation device, the type of supplies, and the requirements for dose measurement accuracy. 7.3.1.2 Dosimeters shall be placed in the minimum dose area in the irradiation container, or in an easily placed position with a known quantitative relationship with the minimum dose area. In addition, some dosimeters shall be placed in the maximum dose area to monitor the maximum dose received by the supplies. 7.3.2 Loading of Supplies
Supplies shall be loaded into the irradiation container or stacked in the irradiation device according to the designed loading pattern of supplies, and the total number of supplies shall be verified and recorded.
7.3.3 Monitoring of the Irradiation Process
7.3.3.1 The radiation source shall be monitored to ensure its correct irradiation position. 7.3.3.2 The cycle timer should be equipped with an appropriate auxiliary timer to monitor whether the timer is working properly. 7.3.3.3 Records of cycle time, transfer equipment operation, radiation source location and arrangement of supplies in the irradiation container should be established and should be part of the radiation sterilization documentation.
7.3.3.4 The cycle timer should be calibrated regularly by the statutory metrology and verification department in accordance with relevant standards. 7.3.4 Unloading of supplies
7.3.4.1 When the supplies are taken out of the irradiation container after sterilization, the total number of supplies should be verified again and recorded. 7.3.4.2 When all dose meters are retrieved, it should be checked that all dosimeters are indeed placed in the designated location and then sent to the laboratory for measurement and calculation. 7.4 Post-irradiation processing of supplies
7.4.1 The supplies unloaded after irradiation should be stored in a special storage area designed for sterilized supplies. 7.4.2 Before the irradiated supplies are shipped from the storage area, they must be released by a dedicated person. When the supplies are shipped, the supply code, batch number and unit number should be checked and must be consistent with the receipt record. 7.5 Sterilization Records
The requirements and conditions for sterilization should be recorded and kept by a designated person and filed for future reference. The sterilization record shall include the following contents: a.
Name, code, batch number and number of units of the radiation sterilized supplies delivered, date of manufacture and date of receipt; b.
Loading mode of supplies in the irradiation container or irradiation device; type, quantity and location of dosimeters in the irradiation container or irradiation device; c.
Sterilization batch number and quantity;
Radiation sterilization dose (and maximum dose); cycle timer setting;
Verified name, code, batch number and number of units of supplies loaded into the irradiation container; sterilization date,
Verified name, code, batch number and number of units of supplies unloaded from the irradiation container or irradiation device; j.
Dosimeter monitoring results;
Name, code, batch number and number of units of the supplies issued; k.
Transmission equipment operation and source location, and the transmission channel used in the sterilization of supplies; 1.
m. Sterilization process interruption and measures taken; n. Signature of the sterilization operator.
7.6 Interruption of sterilization
7.6.1 For articles that do not multiply bacteria, it is generally not necessary to move the articles in the irradiation container when the sterilization process is interrupted. Such interruptions should be recorded and checked to ensure accurate dose readings and to continue irradiation. 7.6.2 For articles that can multiply bacteria, when the sterilization process is interrupted, the changes in the microorganisms of the articles during the interruption should be investigated, and the possible impact of continued irradiation on the quality of the articles should be considered. Unqualified articles should be discarded. 3 When articles in the irradiation container must be moved during the interruption of sterilization, they must be numbered and returned to their original position and direction. The correct resetting of the articles should be checked and recorded. 87
GB16352—1996
Appendix AwwW.bzxz.Net
Dose measurement for radiation sterilization monitoring of medical supplies (reference)
Dose measurement should be carried out after the irradiation device is accepted, the supply loading mode is established, and during routine radiation sterilization. A1
A2 It is recommended to use the commonly used conventional dosimeters and their measurement systems in Table A1 and the reference dosimeters and their measurement systems in Table A2. Table A1 Examples of commonly used conventional dose measurement systems Agent
Dyed transparent plexiglass
Colorless transparent plexiglass
Fluorobenzene ethanol solution
Cerium sulfate solution
Ferrous-copper solution
Alanine
Cerium sulfate solution
Radiochromic dye Film, liquid, paper, optical waveguide Ferrous sulfate solution (Fricke dosimeter) Reading
Visible spectrophotometer
Ultraviolet spectrophotometer
Calorimetric titrator or HF oscillator
Potentiometer or UV spectrophotometer
UV spectrophotometer
Table A2 Examples of reference dose measurement systems
Readout system
ESR spectrometer
UV spectrophotometer
Visible spectrophotometer or densitometer
UV spectrophotometer
Approximate range of absorbed dose, kGy
1～40
1～100
0. 1~~100
1～300
Approximate range of absorbed dose, kGy
0. 001～100
1～100
0.001~1 000
A3 The relevant technology of dose measurement can be consulted with the metrology department or experienced standard laboratory, or refer to relevant reference books. Dose measurement should be carried out by a dedicated person and professionally trained. A4
A5 The dose measurement system should be regularly calibrated by the metrology standard laboratory and traceable to the national standard. It is not necessary and recommended to use biological indicators to monitor the quality of radiation sterilization in routine sterilization. A6
Radiation color-changing indicators should not be used for dose measurement. They are only used to identify whether the product has been irradiated. A7
Appendix B
Determination and Check of Radiation Sterilization Dose
(Informative)
B1 Terms and Symbols
Number of positive samples when 100 samples are tested for sterility under DDkGy irradiation. B1.2Dio
The dose required to kill 90% of the organisms in a uniformly distributed microbial community. B1.3 d°(kGy)
For each batch of increasing dose tests, d is equal to the minimum of the following (1) and (2). (1) The minimum value of the first incremental dose when 2 consecutive 0/20 positives appear, and the total number of subsequent positives is less than 2; (2) The first incremental dose when 1/20 positives appear, and the immediate preceding and following 0/20 positives are all present, and the total number of subsequent positives is less than 2.88
B1.4 D* (kGy)
GB16352--1996
Initial estimate of the irradiation dose required to achieve a sterility assurance level of 10-2 for the sample. B1.5DD\(kGy)
The delivered dose in experiment 2 where CD* has been determined. B1.6 D**(kGy)
Treatment dose at which the number of non-sterile samples is expected to be no more than 1 in 100 samples. B1.7 DS (kGy)
Effective D1o value of the microbial community irradiated with DD*, kGy. DSkGy is determined by the conservation formula of radiation dose defined by FNP-FFPkGy.
B1.8 A (kGy)
Radiation dose less than or equal to 2.0kGy, used for standardization of FFPkGy dose. B1.9 Fraction Positive The quotient obtained by taking the number of positive sterility test samples as the numerator and the total number of samples as the denominator. B1.10 First fraction positive dose (initial value) first fraction positive, fft For a batch of supplies, sampling and processing, at least one of the 20 samples reaches the minimum incremental dose used for sterilization. B1.11 First Fraction Positive Dose (Processing Value) First Fraction Positive.FFP The middle value of three FFP minus AkGy.
B1.12 First No Positive, FNP The minimum dose at which 100 samples of a batch of supplies reach sterility in a series of increasing dose sterilization experiments. B1.13 Incremental Dose The irradiation dose given in increments of 1.0 or 2.0 kGy within the range of 1.0~～18.0 kGy. B1.14 Screening Dose, X kGy The minimum increasing dose at which the positive score of each batch of three batches of supplies does not exceed 10/20. B1.15 Sample Item Proportion, SIP The proportion of samples taken for irradiation and testing to determine the dose. When sampling small parts such as sutures, the entire piece (SIP=1) should be tested, while when sampling large parts such as surgical gowns, only a portion (such as 1%, SIP=0.01) should be selected. The sampling ratio selection, processing and packaging should be completed before irradiation.
B2 Determination of radiation sterilization dose
The radiation sterilization dose should be determined using a reasonable and accurate method, that is, based on the number of natural microbial communities on the sterilized supplies and their radiation resistance and the required sterilization assurance level. B3 Basic principles and requirements for selecting sterilization dose methods B4, B5, B6 and B7 recommend four methods for selecting sterilization doses. The basic principles and requirements for using these methods are: a. A Co radiation source that can give an accurate dose in the range of 1.0~18kGy should be used. b. Sterilization tests should be performed on complete samples or sampling ratios of supplies. These tests must be performed in a sterile laboratory without sterilization factors.
c. It is assumed that a single culture medium is used for the sterilization test, which should be suitable for the growth of aerobic and anaerobic viable bacteria. The culture temperature is room temperature and 35℃, and the culture period is 1 to 7 days. d. Based on the probability model of the deactivation of microbial communities, the model requires that the initial contamination is a mixture of uniform communities, and the behavior of each community is expressed in the form of \D1. \. B4 Determination of dose using initial contamination
B4.1 Dose determination is divided into the following two steps:89
B4.1.1 Determination of initial contamination
GB 16352--1996
Before sterilization of supplies, at least 10 samples are randomly selected from each of every three batches of supplies. It can be a complete sample of supplies or a sampling ratio (SIP). Determine the average initial contamination of each sample in each batch and the total average initial contamination of all samples. The sterilization dose is calculated using the total average of the initial contamination of the supplies. If the average of one batch is more than twice the total average, the average of the largest batch should be used for calculation.
B4.1.2 Check the radiation resistance of the initial contamination through experiments with a sterilization assurance level (SAL) of 10-2. Find the verification dose in Table B1. The amplitude of the verification dose can exceed 5% of the dose value in the table or 0.5kGy.
Irradiate the sample with the verification dose. If there are no more than 2 positive results in 100 test samples, the treatment dose that reaches the required SAL can be found in Table B2. If there are more than 2 positive results, it is necessary to change to other sterilization dose determination methods. Table B1 Radiation sterilization verification dose determination table
Find the verification dose (kGy) when the sterilization assurance level is 10-2 according to the average initial contamination of each supply and the sampling ratio (SIP). Verification dose for all samples with different total average initial contamination (DB), kGySIP
Note: 1) For verification doses not recommended, other methods should be used to determine the dose. 103
5×103
Table B2 Radiation treatment dose determination table
5×10+
5×105
Based on the verification dose test, find the treatment dose (kGy) according to the total average initial contamination of each sample and the required sterilization assurance level (SAL). logSAL
Treatment dose for all supplies with different total average initial contamination (DB), kGy50
Note: 1) No dose is specified, other methods should be used to determine the dose. 500
B4.2 Application of Table B1 and Table B2 when interpolation is not required103
5×103
5×10*
5×105
When the average initial contamination of each sample and the SIP of the sample are within 20% of the values listed in Table B1 and Table B2, the verification dose and sterilization treatment dose can be directly found from the parameters listed in the table without interpolation. Perform a verification dose test to confirm that the selected treatment dose can achieve the required sterilization assurance level. For specific application, see Example 1: Example 1: No interpolation required.
Sterilization Assurance Level - SAL
Initial contamination
Treatment dose
Sampling ratio SIP
Verification dose
Verification dose actually given
Verification dose irradiation test results
Acceptable
GB 16352—1996
End-use requirements for sterilization assurance level of 10-6 The initial contamination counts of the first, second and third batches of samples were 700, 840 and 890 respectively, and the total average was 810. No batch average exceeded the total average by more than one time. Therefore, the total average was used because the total average of 810 was within 20% of 1000 in Table B1, and the SAL dose associated with 1000 was acceptable. The SAL dose was 24.9 kGy and SIP was selected to facilitate sterilization testing. 0.12 is within 20% of Table B10.1 and can be used to identify the verification dose.
Refer to Table B1, the average number of initial contamination is 1000, SIP is 0.1, and the verification dose is 8.0kGy. The actual verification dose is not more than 5% of the specified verification dose or 0.5kGy, so the experimental dose is qualified.
100 samples were treated with a dose of 8.2kGy. There were 2 positive results (SAL is 10-6) and the dose of 24.9kGy was verified. Note: If the verification dose test has more than 2 positive results, the B6 method can be used to determine the sterilization dose. B4.3 Application of Tables B1 and B2 when interpolation is required When the average number of initial contamination or SIP of each sample is not within 20% of the values listed in Tables B1 and B2, the interpolation method should be used to derive the corresponding verification dose and treatment dose.
B4.3.1 Initial contamination interpolation method
When the SIP of the sample is within 20% of the value listed in Table B1, and the average initial contamination value of each sample is not within 20% of the value listed in Tables B1 and B2, the initial contamination value interpolation method should be used to determine the verification dose and treatment dose. See Example 2 for specific application.
Example 2:
The SIP is 0.012.
The average initial contamination value of all samples is 3000. SAL is 10-3.
Step 1: Determine verification dose (DVD) (kGy) General formula:
Initial bacterial count
Verification dose
Initial bacterial count
Verification dose for SIP of 0.01
log(DB)-log(B1)
log(B2)-log(B1)
DVD BEF(VD12-VD11)+VD11
log(3 000)-log(1 000)
log(5 000)-log(1 000)
DVD=0.683(7.1-5.2)+5.2-6.5 kGyStep 2:Determine the treatment dose (DD)
General formula:
（B1）
（B2）
Initial bacterial contamination number
Treatment dose
Initial bacterial contamination number
GB16352—1996
DD-BEF(D2-D1)+D1
Treatment dose
DD=0.683(16.6-14.2)+14.2=15.84 kGy5000
（B3）)
By interpolation, SIP is 0.012, the initial bacterial contamination number is 3000, the verification dose is 6.5kGy, and the treatment dose for SAL10~3 is 15.8kGy.
General formula:
B1--less than the initial bacterial contamination number of all samples and closest to the initial bacterial contamination number listed in Table B1; B2--
-greater than the initial bacterial contamination number of all samples and closest to the initial bacterial contamination number listed in Table B1; - initial bacterial contamination number of all samples;
greater than the SIP of the sample and closest to the SIP listed in Table B1; less than the SIP of the sample and closest to the SIP listed in Table B1; SIP2--
DSIP--SIP of a medical sample;
Verification dose for SIP1 and B1;
Verification dose for a pair of SIP1 and B2;
VD12---
Verification dose for SIP2 and B1;
VD22--Verification dose for SIP2 and B2; IVD1
Interpolation verification dose 1. The dose is between VD11 and VD12; interpolation verification dose 2. The dose is between VD21 and VD22; - sample verification dose;
D1 - treatment dose for initial bacterial count B1; D2 - treatment dose for initial bacterial count B2; DD - treatment dose for initial bacterial count DB; BEF - initial bacterial count extrapolation factor;
SEF - SIP extrapolation factor.
B4.3.2 SIP interpolation method
When the initial bacterial count of each sample is within 20% of the values listed in Tables B1 and B2, and the SIP of the sample is not within 20% of the values listed in Table B1, the SIP value interpolation method should be used to determine the verification dose. See Example 3 for specific application.
Example 3:
SIP is 0.40.
The initial bacterial count of all samples is 105.
SAL is 10-'.
Step 1: Determine the verification dose (DVD)
General formula:
Verification dose
(kGy）
log(DSIP)—log(SIP2)
)—log(SIP2)
log(SIP1)
DVD=SEF(VD11 -VD21)+VD11
（B5）
Verification dose for SIP of 0.40
GB 16352--1996
log(0.40) -log(0.1)
log(1.0)-log(0.1)
DVD0.602(8.0—5.2) +5.2-6. 89Step 2: Determine the treatment dose (DD) (kGy) -0.602
When the average initial bacterial count of the sample is within 20% of the value in Table B2, the treatment dose can be found in the table. For example, when the initial bacterial count is 105 and the SAL is required to be 10-6, the treatment dose should be 21.2kGy. By interpolation, the verification dose is 6.89kGy. For SIP of 0.40, initial bacterial count of 105, and SAL of 10-6, the treatment dose is 21.2kGy. B4.3.3 Interpolation method for SIP and initial bacterial count
When both SIP and initial bacterial count are not within 20% of the values listed in Table B1 and Table B2, the interpolation method should be used to first select two verification doses that are less than and greater than and closest to SIP, and interpolate the SIP verification dose from these two dose values; then determine the treatment dose according to B4.3.1.
For specific application, see Example 4.
Example 4:
SIP is 0.05.
Initial bacterial count is 3000.
SAL is 10-.
Step 1: Determine the verification dose (DVD) (kGy) To find the verification dose with an initial bacterial count of 3000 and a SIP of 0.05, you must first find two adjacent doses with an initial bacterial count of 3000 and a SIP in Table B1. From these two adjacent doses IVD1 and IVD2, use the interpolation method to determine the verification dose of the sample. Verification dose (kGy) for different initial contamination average values of each sample SIP
Step 1.1: Determine IVD1
General formula for calculating IVD1:
Initial contamination number
Verification dose
Initial contamination number
log(DB)—log(B1)
log(B2)-log(B1)
IVD1=BEF(VD12-VD11)+VD11
Verification dose for SIP of 0.1
log(3000)-log(1000)
log(5000)-log(1000)
IVD1=0.683(10.0—8.0)+8.0=9.37 kGyStep 1. 2: Determine IVD2
General formula for calculating IVD2:
Initial bacterial count
Verification dose
.(BI)
(B2)
Initial bacterial count
GB 16352
2—1996
IVD2=BEF(VD22- VD21)+VD21
Verification dose for SIP of 0.01
IVD2=0.683(7.1—5.2)+5.2=6.50kGyStep 1.3: Determine DVD
General formula for DVD:
Verification dose
Verification dose
log(DSIP)—log(SIP2)
log(SIP1)-log(SIP2)
DVD-SEF(IVD1-IVD2)+IVD2
log(0. 05)-log(0. 01)
log(0. 1)-log(0. 01)
DVD0.70(9.37-6.50)+6.50=8.51kGyStep 2: Determine the treatment dose (DD) (kGy)General formula:
Initial bacterial contamination number
Treatment dose
Initial bacterial contamination number
DD=BEF(D2-D1)+D1 ..
DD=0.683(16.6-14.2)+14.2=15.84kGy5000
（B6）
（B4）
（B7)
（B3）
According to the interpolation method, the verification dose (DVD) for SIP of 0.05 is 8.51kGy, and the treatment dose required for SAL of 103 and initial bacterial infection number of 3000 is 15.8kGy.
B5 Determine the dose using the positive fraction, extrapolation factor and DS (kGy) of irradiation with increasing doses B5.1 Formula for determining the dose
Use formula (B8) to determine the treatment dose expected to achieve the specified sterilization assurance level: Treatment dose (kGy) = D* * + [—log(SAL)log(SIP)—2] (DS) Where: D.*----The treatment dose estimated to make the test sample reach 10-2SAL, kGy; SAL The sterilization assurance level required for medical samples; (B8)
SIP-the proportion of the sample taken in the test to the complete supplies, the size of SIP should be based on the ability to provide effective sterilization test results. If possible, SIP should be 1 (i.e. complete sample); DS-similar to D. Value (kGy), it is the estimated dose required to kill 90% of microorganisms at 10-2SAI, kGy. DS should be determined from the increasing dose experimental data (FFP and FNP). If the sterilization test is not conducted on intact samples (SIP is 1), an appropriate correction factor should be proposed for log(SIP) in the formula. B5.2 Steps to determine the dose
Randomly sample from three independent batches of supplies. a.
b. Conduct an increasing dose test to determine the lowest dose for sterilization of certain samples. This dose is called the first positive fractional dose (FFP, kGy). This test can also be used to preliminarily estimate the dose D\ (kGy),c. The second dose test is conducted with 100 samples at D* (kGy). This test gives the lowest dose estimate, i.e., the first no positive dose 9.1
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