This standard applies to optoelectronic X-ray image intensifiers as components of medical diagnostic X-ray equipment and describes a method for determining the brightness distribution and non-uniformity of X-ray image intensifiers under X-ray radiation conditions on the incident surface. YY/T 0457.3-2003 Characteristics of optoelectronic X-ray image intensifiers for medical electrical equipment Part 3: Determination of brightness distribution and non-uniformity YY/T0457.3-2003 Standard download decompression password: www.bzxz.net

YY/T 0457.3-2003/IEC 61262-3: 1994YY/T0457 "Characteristics of optoelectronic X-ray image intensifiers for medical electrical equipment" is divided into seven parts: Part 1: Determination of human radiation field; Part 2: Determination of conversion coefficient; Part 3: Determination of brightness distribution and brightness non-uniformity, Part 4: Determination of image distortion, Part 5: Determination of detection quantum efficiency; Part 6: Determination of contrast and glare coefficient; Part 7: Determination of modulation transfer function. This part is the third part of YY/T0457. The consistency of this part is equivalent to IEC61262-3:1994 "Medical electrical equipment - Characteristics of optoelectronic X-ray image intensifiers - Part 3: Determination of brightness distribution and brightness non-uniformity" (English version). The main differences are as follows:
Some formatting formats have been modified according to Chinese habits, and some expressions applicable to international standards have been changed to expressions applicable to Chinese standards; - The preface of international standards has been deleted;
IEC788 has been changed to IEC60788.
Appendix A of this part is an informative appendix.
This part was proposed by the State Food and Drug Administration. This part is under the jurisdiction of the National Technical Committee for Standardization of Medical Document Equipment and Utensils. The drafting unit of this part is: Liaoning Medical Device Product Quality Supervision and Inspection Institute. The main drafters of this part are: Wang Jianjun and Mu Li. YY/T0457.3-2003/IEC61262-3:1994 Introduction
The brightness distribution and non-uniformity of the characteristics of an optoelectronic X-ray image intensifier are determined by measuring the brightness of the entire output screen under conditions of uniform X-ray radiation on the input surface of the X-ray image intensifier. This method is only used to evaluate relatively large-scale non-uniformities. Local non-uniformities, such as "structural spots", are not considered in this part. 1 Scope
Medical electrical equipment
YY/T 0457.3--2003/IEC 61262-3 : 1994 Characteristics of optoelectronic X-ray color image intensifiers
Part 3: Determination of brightness distribution and non-uniformity This part of YY/T0457 applies to optoelectronic X-ray image intensifiers as components of medical diagnostic X-ray equipment. This part describes a method for determining the brightness distribution and non-uniformity of X-ray image intensifiers under conditions of uniform X-ray radiation on the input surface.
2 Normative references
The clauses in the following documents become the clauses of this part through the application of this part of YY/T0457. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this part. However, parties to an agreement based on this part are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version applies to this part.
IEC60788:1984 Medical Radiology Terminology 3 Terminology
3.1 Definition of terms
For the purpose of this part, the following definitions and the definitions given in IEC60788 are applicable. When there is a difference between the given definition and the definition in IEC60788, this definition shall be considered first. 3.1.1
English abbreviation for photoelectric X-ray image intensifier. 3.1.2www.bzxz.net
Entrance plane
The plane perpendicular to the axis of symmetry of the XRII and tangent to the most protruding part of the XRII in the direction of the radiation source (including the protective shell of the XRII).
Entrance field
For XRII, the area in the entrance plane that can be used for the transmission of X-ray patterns under specific conditions. 3.1.4
Entrance field sizeFor XRII, the diameter of the area in the entrance plane that can be used for the transmission of X-ray patterns at a specified source plane distance (SED). For XRII with more than one magnification mode, the corresponding output image diameter for each magnification mode should be consistent with the output image diameter of the XRII at the maximum entrance plane size. 3.1.5
E source to entrance plane distance(SED)Source plane distance
The distance between the focus of the X-ray tube and the entrance plane of the XRII. YY/T 0457.3—2003/IEC 61262-3 : 19943.1.6
centre of the output imagecentre of the smallest circle circumscribing the output image. 3.1.7
centre of the entrance fieldcentre of the point on the entrance plane imaged at the centre of the output image. 3.1.8
central axiscentral axis
a straight line passing through the centre of the entrance field and perpendicular to the entrance plane. 3.1.9
Not used.
luminance non-uniformityFor a given XRI, it is the difference in luminance between the centre of its output image and the edge of its output image under specified conditions, expressed as a percentage of the luminance at the centre of the output image.
3.2 Degree of requirement
Auxiliary verbs in this part:
“shall” indicates that compliance with a requirement is necessary. "Should" indicates that compliance with a requirement is strongly recommended but not mandatory. "May" indicates that compliance with a requirement is permitted to be achieved in a special way in order to comply with this standard. The following words have the following meanings:
"specific" when used with a parameter or condition: refers to a particular value or standardized arrangement, usually those required by IEC standards or laws; see IEC 60788, RM-74-01. "specified" when used with a parameter or condition: a value or arrangement usually indicated in the accompanying documents or selected for the purpose under consideration; see IEC 60788, RM-74-02. "designed for" when used in a standard to describe the characteristics of equipment, devices, components or arrangements: indicates the intended and usually obvious application or use of the product. 4 Requirements
4.1 Test setup
a) SED shall be 100 cm ± 1 cm;
b) The X-ray tube focus shall be on the central axis; c) The distance between the X-ray tube focus and any additional filtering shall not exceed 33 cm; d) The X-ray field shall completely cover the human field, but the area beyond shall not exceed 10% of the incident field area. A diaphragm placed directly in front of the incident field will control the X-ray field. Use the X-ray source's beam limiting device to limit the X-ray beam at this diaphragm, and the diaphragm's attenuation rate for the air kerma rate shall be at least 100. 4.2 X-ray image intensifier operating conditions
a) The XRII shall operate under the normal operating conditions specified by the manufacturer; b) Anti-scatter grids or protective covers shall not be used; c) For multi-field X-ray image intensifiers, the specified maximum human field size shall be measured, and other field sizes may be measured optionally. 4.3 Input Radiation a) The total filtration of the incident X-ray beam shall be 22.5 mm ± 0.5 mm of aluminum equivalent, of which at least 20 mm shall be aluminum (purity 99.9%). The half-value layer corresponding to the center of the incident field shall be 7.0 mm ± 0.2 mm of lead (purity 99.9%). This condition corresponds to an X-ray tube voltage of approximately 75 kV; YY/T 0457.3—2003/1IEC 61262-3: 1994 b) The air kerma rate of the incident surface shall ensure the working linearity of the XRII and detector used in the measurement. The recommended air kerma rate is 1 μGy s-1 to 100 μGys-1; c) The measurement uncertainty caused by instantaneous fluctuations in the air kerma rate shall not exceed 2%. If the air kerma rate measurement or brightness measurement is carried out at different time periods, the output of the X-ray tube should be monitored and the measurement results should be calibrated to meet the needs;
d) The air kerma rate at any position of the human radiation field should not be less than 70% of the maximum value of the air kerma rate of the human radiation field. 4.4 Test device
Not used.
4.5 Measurement equipment
4.5.1 X-ray field uniformity measurement device
a) Any device that measures a quantity with a known correspondence to the relative air kerma rate may be used, such as a photomultiplier tube coupled to a scintillator or a screenless film with known sensitivity characteristics. The accuracy of this device should ensure that the relative error in its measurement of the air kerma rate is no more than 2%. There are no special technical requirements for the absolute accuracy of these measurements;
b) The maximum diagonal of the effective measurement area of ​​the device should not exceed 10% of the human field size. 4.5.2 Output screen brightness measurement device
a) Any device that measures a quantity with a known correspondence to the relative brightness may be used. The accuracy of this device should ensure that the relative error in its measurement is no more than 2%. There are no special technical requirements for the absolute accuracy of these measurements;
The device should measure the relative brightness in the direction perpendicular to the output screen. To avoid measurement errors near the edge of darkness, b)
The detector's receiving cone angle should be small enough; the diagonal of the effective area of ​​the measurement field should be at least 0.1 mm and should not exceed 5% of the output image diameter; c)
d) If the brightness is measured by a one-dimensional or two-dimensional image detector through a lens at a fixed position, the lens vignetting, non-uniformity and non-linearity of the detector response should be corrected.
5 Determination of brightness distribution and non-uniformity
5.1 Preparation
a) The requirements of the measurement setup given in 4.1 should be met; b) According to 4.3a), the total filtration of the radiation and the X-ray tube voltage are adjusted to obtain the required half-value layer at the equivalent position of the center of the human radiation field (set according to 4.1).
5.2 Measurement
5.2.1 Measurement of X-ray field uniformity
a) After the human radiation surface and the center of the human radiation field are determined, remove the X-ray image intensifier from the X-ray beam. According to 4.1, there should be no objects that may cause X-ray scattering in the X-ray beam at a distance of no more than 50 cm from the incident surface; for the measurement of uniformity, the effective area of ​​the measuring device is on the incident surface and parallel to it, and XRII should not be in the line beam; b)
Measure the air kerma rate at the position corresponding to the subsequent measurement of the output screen brightness; d)'If the air kerma rate at different positions is measured at different time periods, the output of the X-ray tube should be monitored. 5.2.2
Measurement of the brightness of the output screen
Locate XRII according to 4.1;
When measuring the brightness distribution, the relative brightness of the output screen should be measured along two orthogonal diameters of the output screen, at least over the range of b)
corresponding to 90% of the size of the covered human field. The distance between adjacent measurement points should not exceed 10% of the corresponding incident field size. When measuring brightness non-uniformity, the relative brightness of the output screen should be measured at the center of the output image and at four positions on two orthogonal diameters of the output screen at a distance equivalent to 90% of the radius from the center of the output image. c) If the brightness measurements at different positions are made at different time periods, the output of the X-ray tube should be monitored. Note: The output of the X-ray tube can be monitored by monitoring the brightness of a fixed area of ​​the output screen. d) When correcting the relative brightness measurements for X-ray beam non-uniformity, the relative position of the incident surface and the output image should be determined; e) The device for measuring the air kerma rate should be removed. 5.3 Correction
If the relative brightness or relative air kerma rate measurements at different positions are obtained at different time periods, they should be corrected based on the short-term fluctuations of the air kerma rate and the relative stability of the air kerma rate. If X-ray field non-uniformity occurs, the relative brightness value shall be divided by the corresponding air kerma rate at the corresponding position of the incident surface to correct the spatial non-uniformity of the X-ray field if it exceeds 2% of the maximum air kerma rate as determined in accordance with 5.2.1. 5.4 Determine the non-uniformity of the brightness by the following formula: Z (L. - LI / L
L = 100% × 1/4 ×
Where L. is the brightness at the center of the output image, and L (i - 1 to 4) is the brightness of the four points near the edge of the output image. See 5.2.2b). 6 Representation of results
6.1 Representation of brightness distribution
The representation of brightness distribution shall include the following: Identification of the X-ray image intensifier, for example, type, model name or number, and the distribution of brightness may be represented by a curve or a table of a set of numerical values. The relative brightness is expressed as a function of distance along one or two diameters through the output image and should be scaled relative to the distance from the incident surface, and the maximum percentage of relative brightness should be given; the resulting representation should cover at least 90% of the size of the incident field. If only one diameter is chosen to describe the state of the brightness distribution, it should be the diameter that shows the maximum deviation in output image brightness.
b) Unless otherwise specified,
"the size of the incident field.
6.2 Description of milli-degree non-uniformity
a) The description of brightness non-uniformity shall include the following: - Identification of the X-ray image intensifier, for example, type, model name or number; Brightness non-uniformity measured according to 5.4 and expressed as a percentage. b) Unless otherwise specified,
the size of the incident field.
7 Declaration of conformity
a) If it is to be declared that the measurement results of the brightness distribution of the X-ray image intensifier comply with the requirements of this standard, it shall be stated as follows: - Brightness distribution: YY/T0457.3-2003; b) If it is to be declared that the measurement results of the brightness distribution of the X-ray image intensifier comply with the requirements of this standard, it shall be stated as follows: n
Brightness non-uniformity: YY/T0457.3--2003. IEC 60788
Unit names in the International Units
Undefined derived terms
Undefined terms
Early unit names·
Abbreviations·
3.1 in YY/T0457.3--2003
accompanying documents
random documents
added filter
air kerma rate
anti-scatter grid attenuation ratio
beam lirniting device
Appendix A
(Informative)
centre of theentrance field ·.centre of the output imagecentral axis
diaphragm
YY/T 0457.3--2003/IEC 61262-3 : 19943.1
rm-82-01
rm-35-02
. rm-13-11 and rm-13-13
rm-32-06
rm-13-40
rm-37-28
electro-optical X-ray image intensifierelectro-optical X-ray image intensifierentrance field
entrance field size
entrance plane
focal spot
half-value layer
luminance distributionluminance non-uniformitynon-screen film
Screenless film
Normal use
normal use
Output image
Output screen
Radiation beam
Radiation source
Source surface distance
output image
output screen
radiation beam.
radiation source
forward
electricity
source to entrance plane distancetest device
test device
total filtration
X-ray irradiation
X-ray radiation
X-ray beam
X-irradiation
X-radiation
X-ray beam
.3.1.8
rm-37-29
rm-32-40
m-20-13s
.rm-13-42
rm-32-45
rm-32-35
rm- 82-04
rm-32-49
rm-32-48
rm-37-05
rm-20-01
rm-71-04
m-13-48
rm-12-09--
rm-11-01-
rm-37-05+
YY/T 0457.3—2003/IEC 61262-3:1994X-ray equipment
X-ray field
X-ray image intensifierX-ray pattern
X-ray source assemblyX-ray tube
X-ray tube voltagePhotoelectric X-ray image intensifier
rm-20-20
rm-37-07+
rm-32-39
rm-32-01
rm-20-05+
rm-22-03
·rm-36-02
...................................................... 3.1.1
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