YY/T 0796.1-2010Medical electrical equipment—Exposure index of digital X-ray imaging systems - Part 1: Definitions and requirements for general radiography (English PDF)

Foreword

This section is a standard YY/T 0796 "Medical electrical equipment - Digital X-ray imaging system exposure index" Part 1.

This part of IEC 62494-1:2008 "Exposure Index Medical electrical equipment - Part 1 digital X-ray imaging systems. Normal X Radiography of definitions and requirements, "the degree of consistency is identical with, the main difference is the reference to IEC standards has been converted to a national or Industry standards, replaced by the corresponding national or industry standards.

This part of the National Medical X-ray equipment and utensils Standardization Technical Committee (SAC/TC10/SC1) centralized.

This section is drafted. Beijing Wandong Medical Equipment Co., Ltd., General Electric (China) Co., Ltd. Medical Systems.

Introduction

In screen film X-ray imaging system, the detection surface of the received radiation exposure, and the optical density of the film has been established to direct

Should the relationship, but this does not apply to digital X-ray imaging system. In the digital X-ray photography often use automated image processing techniques to obtain

Constant imaging features, it can not determine the amount of exposure deviation (such as overexposure and underexposure) according to the brightness of the image deviation. usually Case, underexposure can cause digital image noise level increases, more noteworthy is (from the radiation protection point of view) in the number of overexposed Word image can not be easily identified.

Therefore, different digital X-ray imaging system manufacturers are proposed different concept of "exposure index." These indicators are the root of exposure According to the original image data obtained by numerical calculation, to judge exposure level detector. However, different manufacturers of X-ray imaging system EC, the exposure indicator to define and measure its provisions are different. Therefore, it is necessary to unify the exposure to all the provisions of the digital X-ray imaging system Index and simplify its application, to facilitate the establishment of appropriate exposure guidelines. Especially different manufacturers photography system in the same department When this uniform exposure index more necessary.

This section defines the concept of exposure index, proposed definitions, scope and general requirements for exposure index. Arithmetic processing details (software shipped Algorithm is) not considered in this section to avoid restricting the technological progress.

Exposure Index enables the operator to determine. the image on the detector exposure level is appropriate to obtain the desired level of image quality. value It is noteworthy that, defined in this part of the exposure index is calculated based on the image signal, and thus the energy absorbed by the detector related. Since the The quality of a radiation detector using a predetermined calibration only, so the air exposure index detector surface kerma no direct contact. Therefore, this part of the definition of exposure index suitable for the image quality of digital photography, the image quality is mainly determined by the level of signal to noise ratio, The signal to noise ratio is determined by the level and energy absorption detector.

Appendix A provides basic principle concerning exposure index, details about the characteristics and use.

In order to obtain a suitable image quality, the detector exposure level (ie, corresponding exposure index) may be based on examination of a body part, side view Or a different type of X-ray systems change. This section describes the second parameter, the deviation index for the quantitative description of the actual exposure Index with a suitable exposure index (target exposure index) bias. This parameter can not be used to accurately measure the amount of exposure detectors acceptable and Is to provide a simple way for the operator to check whether the appropriate amount of exposure.

Appendix B provides basic principle concerning deviation index, details about the characteristics and use.

Exposure Index (index and offset) may be recorded in the tag field of DICOM files to facilitate the image detector dose level documents Records and communications.

Exposure index does not limit the use of patient radiation dose parameters describe a method of exposure, such as the reference air kerma or kerma Kinetic Area product. Because the relationship between the exposure of patients and the detector exposure amount is determined by many factors, and these factors are usually in clinical status We can not know, so the exposure index can not be used to calculate or estimate patient doses.

1 Scope

YY/T 0796 This section specifies the definitions and requirements to obtain images from the digital X-ray imaging system exposure index.

This section applies to digital X-ray imaging system under ordinary photography for routine applications produce a projected X-ray image, for example, but Are not limited to.

- PSL X-radiography (CR) imaging plate imaging systems;

- flat-panel detector system;

- Optical coupling device (CCD) system.

It does not include the image intensifier system and applied to the breast or dental imaging system.

This section defines the exposure index applies only to single-exposure image generated. Images generated by irradiation many times (for example, fault Fusion Movies Like, dual energy subtraction image or CR veneer Multiple imaging) are not included in this section.

2 Normative references

The following documents for the application of this document is essential. For dated references, only the dated version suitable for use herein Member. For undated references, the latest edition (including any amendments) applies to this document. Medical electrical equipment IEC TR60788 terms, definitions compilation

3 Terms and Definitions

IEC 60788 and defined by the following terms and definitions apply to this document.