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Specification for testing of quality control in dental X-ray equipment
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WS 581-2017
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Basic data | Standard ID | WS 581-2017 (WS581-2017) | | Description (Translated English) | Specification for testing of quality control in dental X-ray equipment | | Sector / Industry | Health Industry Standard | | Classification of Chinese Standard | C57 | | Date of Issue | 2017-10-27 | | Date of Implementation | 2018-05-01 | | Regulation (derived from) | State-Health-Communication (2017) 22 | | Issuing agency(ies) | National Health and Family Planning Commission of the People's Republic of China | WS 581-2017: Specification for testing of quality control in dental X-ray equipment---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Specification for testing of quality control in dental X-ray equipment
ICS 13.280
C 57
WS
People's Republic of China Health Industry Standard
Specification for quality control and testing of dental X-ray equipment
2017-10-27 released
2018-05-01 implementation
Issued by the National Health and Family Planning Commission of the People's Republic of China
Foreword
4.1~4.7 of this standard are mandatory, and the rest are recommended.
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
Drafting organizations of this standard. Institute of Radiation Protection and Nuclear Safety Medicine, Chinese Center for Disease Control and Prevention, Beijing Center for Disease Control and Prevention, Beijing
Beijing University Stomatological Hospital, Fujian Provincial Occupational Diseases and Chemical Poisoning Prevention and Control Center, Beijing Chaoyang District Center for Disease Control and Prevention.
The main drafters of this standard. Xu Hui, Yue Baorong, Fan Yaohua, Wei Kedao, Wang Jianchao, Huang Zhuo, Lou Yun, Feng Zechen, Wang Xiaoyan, Wei
Weiqi, Zhao Hongfeng, Li Gang.
Specification for quality control and testing of dental X-ray equipment
1 Scope
This standard specifies the requirements and methods for quality control testing of dental X-ray equipment.
This standard applies to dental X-ray equipment with intraoral X-ray image receivers and dental X-ray image receivers with extra-oral X-ray image receivers.
Quality control inspection of X-ray equipment.
This standard does not apply to the quality control testing of oral CT.
2 Normative references
The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this document.
For undated references, the latest version (including all amendments) applies to this document.
GB 9706.12 Medical Electrical Equipment Part 1.General Requirements for Safety 3.Parallel Standard Diagnostic X-ray Equipment Radiation Protection
General requirements
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Dental X-ray equipment
X-ray equipment dedicated to dental imaging.
3.2
Dental intra-oral X-ray equipment
Intraoral machine
An X-ray machine with an intraoral X-ray image receiver for taking X-ray images of teeth.
3.3
Dental extra-oral X-ray equipment
Extra-oral machine
An X-ray machine with an extraoral X-ray image receiver for taking X-ray images of teeth and jaws.
Note. Extraoral machines generally include panoramic X-ray photography functions and head photography functions.
4 General requirements for quality control testing
4.1 After installation and overhaul of dental X-ray equipment, acceptance inspection shall be carried out in accordance with this standard or the technical requirements agreed in the purchase contract
Test; dental X-ray equipment in normal use should be tested as required, and the status should be tested once a year. Using
For dental X-ray equipment, the stability test should be carried out on a regular basis. The stability test cycle is shown in Table A.1 in Appendix A. Stability test results and
When the deviation of the baseline value is greater than the control standard, and the cause cannot be judged, the status inspection should be performed.
4.2 Acceptance testing should be entrusted to a qualified testing agency. The legal entity, the manufacturer and the testing agency cooperate to complete the work. State detection should
Entrust a qualified testing agency to carry out. The stability test should be carried out by the medical unit itself or by a competent institution.
4.3 The acceptance test results of newly installed dental X-ray equipment should meet the product performance indicators listed in the random document, and the contract or agreement between the two parties
Technical terms, but not lower than the requirements of this standard. Items not specified by the supplier shall meet the requirements of this standard.
4.4 The quality control test items of dental X-ray equipment should cover the items specified in this standard.
The corresponding test items of the inspected equipment under the conditions shall be stated in the test report.
4.5 The quality control test items and test methods of dental X-ray equipment are shown in Chapter 5.The evaluation should meet the requirements of Table A.1 in Appendix A. Check
The test result is equal to or better than the index value specified in this standard as qualified.
4.6 Quality control inspections should have inspection records, and acceptance inspections and status inspections should also issue inspection reports. The basic content of the test report should include
Including. basic information and equipment information of the inspected unit, test items and test methods, necessary test conditions, test results and corresponding standard requirements
begging.
4.7 Refer to Appendix B for the schematic diagram of quality control inspection and testing of dental X-ray equipment.
4.8 Refer to Appendix C for examples of dental X-ray equipment quality control test phantoms.
4.9 Refer to Table D.1 in Appendix D for the equipment and utensils required for quality control and testing of dental X-ray equipment.
5 Quality control testing methods
5.1 Requirements for testing equipment and phantom
5.1.1 Testing instruments should be verified or calibrated in accordance with relevant regulations, and the results should be traceable.
5.1.2 When detecting the tube voltage, use a digital high-voltage measuring instrument and use a non-intrusive method for detection.
5.1.3 For the standard aluminum absorbing sheet used for testing the half-value layer, the purity of aluminum should not be less than 99.5%, and the thickness error should be within ±0.1mm.
The size of the aluminum sheet should at least fully cover the sensitive area of the dosimeter detector.
5.1.4 The midline pair range of the high-contrast resolution test phantom must at least meet. digital imaging dental X-ray equipment 1.6 lp/mm~3.0
lp/mm.
5.1.5 The low-contrast resolution test phantom should include at least 0.5mm thick aluminum plates with diameters of 1.0mm, 1.5mm, 2.0mm and
2.5mm round hole.
5.2 Deviation of tube voltage indication
5.2.1 The digital high-voltage measuring instrument should be set accordingly according to the type of high-voltage generator and testing parameters of the tested equipment.
5.2.2 For the intraoral machine, place the kV detector near the exit of the beam limiting tube, and its effective measurement point is located on the central axis of the main beam and make the detection
The surface of the detector is perpendicular to the central axis of the main beam to ensure that the X-ray beam completely covers the detector. The test diagram is shown in Figure B.1.
5.2.3 For the panoramic photography function of the extra-oral camera, you can first find the position of the shooting field on the image receiver with a no-processing film, and set the kV detector
On the surface of the image receiver housing, the effective measurement point is located on the central axis of the main beam and the detector surface is perpendicular to the central axis of the main beam. Test shows
The intent is shown in Figure B.2.
5.2.4 For the head photography function of the extraoral camera, you can use the no-wash film to find the position of the field outside the secondary diaphragm, and set the kV detector
Outside the secondary diaphragm, the effective measurement point is located on the central axis of the main beam and the detector surface is perpendicular to the central axis of the main beam. See the test diagram
Figure B.3.
5.2.5 During the acceptance test, set the lowest, middle and highest three tube voltages of adjustable tube voltage equipment; during the state inspection, the available equipment
Use gear to detect. Repeat the exposure at least 3 times, record each tube voltage measurement, and calculate the average value.
5.2.6 Calculate the relative deviation of the tube voltage indication value according to formula (1), and compare it with the requirements of Table A.1 in Appendix A.
5.3 Repeatability of output
5.3.1 For the intraoral machine, place the dose detector close to the exit of the beam limiting tube, and its effective measuring point is located on the central axis of the main beam and make the detector
The surface of the detector is perpendicular to the central axis of the main beam to ensure that the X-ray beam completely covers the detector. The test diagram is shown in Figure B.1.
5.3.2 Expose under the usual adult exposure conditions of the equipment, expose continuously for 5 times, record the dose value of each time, and calculate the radiation using formula (2)
Repeatability of output.
5.4 Load time deviation
5.4.1 The test geometry conditions are the same as 5.2.1~5.2.4.
5.4.2 Under the usual adult exposure conditions of the equipment, expose continuously for 3 times, record the measurement time displayed by the dosimeter after each exposure, and calculate the average
value.
5.4.3 Compare the average load time test with the device display value.
5.4.4 Calculate the deviation of loading time according to formula (3).
5.5 Useful Harness Half Value Layer
5.5.1 Method 1.Aluminum sheet method
5.5.1.1 The test geometry conditions are the same as 5.2.1~5.2.4.
5.5.1.2 Set the common tube voltage of the equipment from level 1 to level 3 and perform exposure, and record the air kerma rate value.
5.5.1.3 Place the aluminum sheet at the X-ray outlet of the tube, keep the exposure conditions unchanged, and measure the air comma after the aluminum sheet with different thicknesses
Kinetic energy rate value.
5.5.1.4 Gradually increase the thickness of the aluminum sheet until the measured air kerma rate value is less than half of the air kerma rate value when no aluminum sheet is added.
Used as a graph or calculation method to find the half-value layer.
5.5.2 Method 2.Direct measurement method with multifunctional dosimeter
5.5.2.1 The useful harness half-value layer can also be directly measured with a multifunctional digital dosimeter, and the test geometric conditions are the same as 5.2.1~5.2.4.
5.5.2.2 Set the common tube voltage of the equipment in 1-3 gears and perform exposure, and directly record the half-value layer reading displayed by the dosimeter.
5.5.2.3 When there are objections to the results, the aluminum sheet method (5.5.1.1~5.5.1.4) shall be used to re-measure.
5.6 High contrast resolution
5.6.1 The phantom of the test card can be inspected by wire-to-card or embedded wire.
5.6.2 For the intraoral machine, place the wire-pair card or test phantom near the exit of the beam limiting tube, and make its plane perpendicular to the central axis of the main beam.
The test diagram is shown in Figure B.4.
5.6.3 For the panoramic photography function of the out-of-oral camera, place the line-to-card or test phantom at the center of the headrest, the central axis of the main beam and the plane of the test phantom
vertical. Place 0.8mmCu at the outlet of the X-ray tube as an additional attenuation layer. The test diagram is shown in Figure B.5.
5.6.4 For the extraoral camera head photography function, place the line-to-card or test phantom at the position of the clinical subject’s head, and the central axis of the main beam
It is perpendicular to the plane of the test phantom. Place 0.8mmCu at the outlet of the X-ray tube as an additional attenuation layer. The test diagram is shown in Figure B.6.
5.6.5 Perform exposure in accordance with the test steps and methods recommended by the equipment manufacturer, or set the common adult exposure conditions of the equipment.
5.6.6 Read the image on the high-resolution display and observe the number of distinguishable pairs of lines.
5.7 Low contrast resolution
5.7.1 Use a low-contrast resolution phantom for testing.
5.7.2 The test geometry conditions are the same as 5.6.2~5.6.4.
5.7.3 Perform exposure according to the test steps and methods recommended by the equipment manufacturer, or set the common adult exposure conditions of the equipment.
5.7.4 Read the image on a high-resolution display and observe the smallest low-contrast details that can be distinguished.
Appendix A
(Normative appendix)
Quality control test items and technical requirements
A.1 The quality control test items and technical requirements of dental X-ray equipment should meet the requirements of Table A.1.
A.2 The half-value layer of dental X-ray equipment should meet the requirements in GB 9706.12, see Table A.2.
Appendix B
(Normative appendix)
Test schematic
For the test schematic diagram of the intraoral machine and the extraoral machine, see Figure B.1~Figure B.6.
Appendix C
(Informative appendix)
Test phantom example
An example of a dental X-ray equipment quality control test phantom is shown in Figure C.1.A high-resolution test card is embedded in the test phantom, in 0.5mm aluminum
There are circular holes with diameters of 1mm, 1.5mm, 2mm and 2.5mm respectively on the board for low-contrast resolution testing. For measuring equipment image reception
The phantom also adds a 6mm aluminum attenuation layer. The upper part of the phantom is composed of a central ring of different cone sizes and a 6mm aluminum plate
Attenuation layer; the middle part of the phantom is a high-contrast resolution test card and a test aluminum plate with a low-contrast resolution round hole; the lower part of the phantom has
There are sockets for dosimeter detectors or intraoral camera image receivers.
Appendix D
(Informative appendix)
Equipment and utensils required for quality control testing
The equipment and utensils required for quality control and testing of dental X-ray equipment are shown in Table D.1.
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