Some standard content:
ICS13.100
National Occupational Health Standard of the People's Republic of China GBZ/T146-2002
Terminology on radiological protection protectionofmedicalexposure
Published on April 8, 2002
Ministry of Health of the People's Republic of China
Implemented on June 1, 2002
1 Foreword
2 Scope
3 Basic terms
4 Radiology
5 Nuclear medicine
Radiation oncology (radiotherapy)
Appendix A (Informative Appendix) Chinese Index
Appendix B (Informative Appendix) English Index
This standard is formulated in accordance with the "Law of the People's Republic of China on the Prevention and Control of Occupational Diseases" With the continuous development and increasing popularity of the application of ionizing radiation technology in medicine, medical radiation workers are the largest group of occupational exposure, and medical exposure has become the largest source of artificial ionizing radiation exposure. Therefore, radiation protection of medical exposure is the most important branch in the field of radiation health with the widest impact, and it involves multiple professions that overlap with each other. Therefore, the standardization and unification of radiation protection terminology for medical exposure is very important, and this demand is becoming more and more urgent. Therefore, this standard is formulated based on the characteristics of medical exposure and with reference to relevant international standards and national standards of my country. This terminology standard is arranged in chapters and clauses according to the concept system. For the convenience of retrieval, according to the provisions of the terminology standard compilation, this standard is accompanied by a Chinese index in the order of Chinese phonetic letters and an English index in the order of English letters. Appendix A and Appendix B of this standard are informative appendices. This standard is proposed and managed by the Ministry of Health.
The drafting unit of this standard: Institute of Radiation Protection and Nuclear Safety Medicine, Chinese Center for Disease Control and Prevention, Institute of Radiation Medicine, Chinese Academy of Medical Sciences.
The main drafters of this standard: Zheng Junzheng, Lu Zhengfu. This standard is interpreted by the Ministry of Health.
Terminology of Radiation Protection of Medical Exposure
1 Scope
This standard defines the main terms and definitions related to radiation protection of medical exposure. This standard applies to relevant fields involving radiation protection of medical exposure. 2 Basic terms
2.1 Medical radiation medical uses of ionizing radiation GBZ/T146-2002
A general term for ionizing radiation used in medicine. The application of ionizing radiation in medicine has formed branch disciplines such as X-ray diagnostics (also known as radiology), nuclear medicine, and radiation oncology (radiotherapy). 2.2 Radiological protection radiological protection radiation protection
An applied discipline that studies the protection of humans (which can refer to all humans, a part or individual members of the human race, and their offspring) from or as little as possible from the hazards of ionizing radiation. Sometimes it also refers to the requirements, measures, means and methods used to protect humans from or as little as possible from the hazards of ionizing radiation. The term radiation can include non-ionizing radiation in a broad sense, but is usually synonymous with radiation in a narrow sense and refers only to ionizing radiation. Radiation protection in this standard refers specifically to ionizing radiation protection.
2.3 Protection and safety Protection and safety Protecting personnel from or reducing exposure to ionizing radiation and maintaining the safety of radiation sources, including measures to achieve such protection and safety, such as various methods and equipment to keep personnel exposure doses and risks below the specified constraints at the lowest level that can be reasonably achieved, as well as various measures to prevent accidents and mitigate the consequences of accidents. Justification of practice 2.4
One of the three principles of radiation protection proposed by the International Commission on Radiological Protection (ICRP). That is, the practice of radiation exposure should not be adopted unless the benefits brought to the exposed individuals or society are sufficient to compensate for the radiation hazards (including health and non-health hazards) that may be caused. 2.5 Optimization of radiation protection One of the three principles of radiation protection. That is, when conducting radiation practices, after considering economic and social factors, it should be ensured that radiation exposure is kept at the lowest level that can be reasonably achieved. 2.6 As Low As Reasonably Achievable (ALARA) principle The principle of using radiation protection optimization methods to keep the size of individual exposure doses, the number of people exposed, and the potential exposure risks in practices that have been determined to be justified and permitted to be carried out as low as reasonably achievable. Usually referred to as the ALARA principle. 2.7 Personal dose limit personal dose limit One of the three principles of radiation protection. That is, the selected personal dose limit for the exposure generated by all related practices combined. The purpose of setting personal dose limits is to prevent deterministic effects and limit random effects to an acceptable level. Personal dose limits do not apply to medical exposure.
2.8 Safety culture literacy safetyculture The sum of various characteristics and attitudes of organizations and personnel in establishing the concept of safety first, to ensure that protection and safety issues are given full attention due to their importance.
2.9 Occupational exposure occupational exposure All exposures to which workers are exposed in the course of their work, except for exposures excluded by relevant national laws and regulations and standards, and exposures from practices or sources exempted in accordance with regulations. 2.10 Medical exposure medical exposure
Exposure to which examinees and patients are exposed when undergoing medical examinations or treatments involving ionizing radiation. It also includes exposures to which examinees and patients are exposed through voluntary support given with knowledge, and exposures to which volunteers are exposed in biomedical research. 2.11 Public exposure public exposure
Exposure to which other members of society, except occupational radiation workers, are exposed to ionizing radiation, including exposures from approved sources and practices and exposures received in intervention situations, but excluding occupational exposure, medical exposure, and exposures from normal local natural background radiation. -1
2.12 Potential exposure potential exposure A type of exposure that can be expected to occur but cannot be confirmed to occur. Such exposure may be caused by an accident of a radiation source, an event or sequence of events of a probabilistic nature (including equipment failure and operating errors). 2.13 Accidental exposure An abnormal exposure received in an accident situation, specifically referring to involuntary accidental exposure. 2.14 External exposure external exposure
Exposure to the human body from an external radiation source.
2.15 Internal exposure internal exposure
Exposure to the human body from radioactive nuclides that enter the human body as a radiation source. 2.16 Assessment of radiation protection Assessment of the quality and effectiveness of radiation protection based on the basic principles and standards of radiation protection. 2.17 Dose constraint dose constraint
An upper limit value for the personal dose that may be caused by a source. It is source-related and is used as a constraint for optimizing the protection and safety of the source under consideration. The corresponding dose constraints can be specifically applied to occupational exposure, public exposure, and medical exposure. 2.18 Frequency of medical exposure The number of people who receive various medical exposures per thousand people each year. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) uses it to investigate, analyze and uniformly compare the development trends of the medical application of ionizing radiation in various countries and regions around the world, and can estimate the collective dose caused by medical exposure.
2.19 Guidance level for medical exposure Guidance level for medical exposure The quantitative levels of dose, dose rate or activity selected after consultation with relevant departments for the exposure of subjects in various diagnostic medical exposures, to guide relevant practitioners to improve the optimization of medical exposure protection. This is a specific manifestation of the application of dose constraints in the optimization of medical exposure protection, which is equivalent to the survey level.
2.20 Medical practitioner A professional medical staff member who obtains qualifications and practices through registration in accordance with the law. Practitioners who perform medical exposures should meet the corresponding training requirements stipulated by the state.
2.21 Qualified expert qualifiedexpert
An expert who is recognized as competent in relevant professional fields (such as medical physics, radiation protection, occupational health, quality assurance or related engineering and safety professions) based on certificates issued by relevant institutions or professional licenses held, or based on academic qualifications and work experience. 2.22 Ethical review ethicalreview
A special review of biomedical research work involving humans based on the maintenance of human dignity, protection of human life and health, compliance with basic ethical principles, and promotion of biomedical development. In medical exposure practice, the exposure conditions and procedures for medical exposure to volunteers in biomedical research who do not directly benefit themselves should be carefully reviewed, and corresponding dose constraints should be proposed according to the principle of optimal protection. 2.23 Deterministic effect deterministic effect A type of ionizing radiation biological effect with a dose threshold, the severity of which depends on the size of the exposure dose. Before the publication of ICRP Publication No. 60 (1991), such effects were called non-stochastic effects. 2.24 Stochastic effect A type of radiation biological effect whose probability of occurrence (rather than its severity) is related to the size of the exposure dose. It is assumed that the probability of occurrence of such effects is proportional to the dose and that there is no dose reading in the low-dose range of interest for radiation protection. 2.25 Radiosensitivity The relative sensitivity of cells, tissues, organs, organisms or any organisms to radiation effects. Also known as radiation sensitivity. 2.26 Tissue equivalent material Tissue equivalent material A material whose absorption and scattering characteristics of a given radiation are similar to those of a certain biological tissue (such as soft tissue, muscle, bone or fat). 2.27 Phantom
An object that absorbs or scatters ionizing radiation in a way that is basically the same as that of human tissue and can be used to simulate actual conditions in various measurements. Depending on different needs, a human body simulation made of tissue equivalent material or a geometric model with agreed dimensions can represent both the entire human body and a specific part of the human body.
2.28 Primary radiation Ionizing radiation emitted directly by a target or radiation source. -2-
2.29 Secondary radiation secondaryradiation Ionizing radiation produced by the interaction of primary radiation with matter. 2.30 Useful radiation usefulradiation
Radiation beam emitted from the radiation source for use after being limited by a beam-limiting device. Also called useful beam or useful ray. 2.31 Residual radiation residualradiation In radiology, it is the remaining part of the useful beam after passing through the image receptor and radiation measuring device, or the remaining part emitted through the irradiated part of the human body in radiotherapy.
2.32 Scattered radiation scatteredradiation Radiation with reduced radiation energy and (or) changed radiation direction due to the interaction between ionizing radiation and matter. 2.33 Leakage radiation leakageradiation Unwanted radiation that escapes through the protective shielding of the radiation source and through the gaps in the protective shielding of the radiation source. 2.34 Stray radiation strayradiation
A general term for leakage radiation, scattered radiation and residual radiation. 2.35 narrow beam narrowbeam
In order to measure the ideal radiation dose, a radiation beam with the smallest possible solid angle is used. Under this condition, the influence of scattered radiation tends to a minimum and, if necessary, lateral electron balance is ensured.
2.36 broad beam broadbeam
A radiation beam condition in radiation dose measurement. When the solid angle of the radiation beam increases, the measured radiation dose does not increase significantly, but there is a scattering effect.
2.37 scattering scattering
The process of changing the direction or energy of the incident particle or incident radiation due to collision with other particles or particle systems. 2.38 back-scattering back-scattering
Scattering caused by matter that makes the angle between the direction of travel of radiation or particles and the original direction greater than 90 degrees. 2.39 energy absorption energyabsorption The phenomenon that all or part of the energy of the incident radiation is transferred to the material it passes through. Scattering accompanied by energy loss (such as Compton scattering and neutron deceleration) is also considered energy absorption.
2.40 Attenuation
The process in which the radiation decreases due to various interactions with matter when passing through it. It does not include the geometric reduction of radiation caused by increasing the distance from the radiation source.
2.41 Filtration
The change in the characteristics of ionizing radiation when passing through matter. It can be: selective absorption of certain components of multi-energy X-ray radiation or ray radiation, and attenuation at the same time; or the change in the radiation intensity distribution on the cross section of the radiation beam. 2.42 Attenuation equivalent The thickness of the reference material. In a beam of specified radiation mass and under specified geometric conditions, when the reference material replaces the material under consideration, there is the same degree of attenuation. It is expressed in appropriate approximate units of meters, and the reference material and incident beam radiation mass are given at the same time. 2.43 Lead equivalent
The attenuation equivalent expressed as the thickness of lead when lead is used as the reference material. 2.44 Aluminum equivalentaluminiumequivalentThe attenuation equivalent expressed as the thickness of aluminum when aluminum is used as the reference material. 2.45 Half-value layerhalf-valuelayer
When a narrow beam of X-ray radiation or gamma-ray radiation of a specific radiation energy or energy spectrum passes through a specified material, the kerma rate, exposure rate or absorbed dose rate is reduced to half of the measured value when the material is not present. Expressed in appropriate approximate units of meters, and specifying the material used.
2.46 Tenth-value layertenth-valuelayerWhen a narrow beam of X-ray radiation or gamma-ray radiation of a specific radiation energy or energy spectrum passes through a specified material, the kerma rate, exposure rate or absorbed dose rate is reduced to one-tenth of the measured value when the material is not present. Expressed in appropriate approximate units of meters, and specifying the material used.
2.47 Equivalent energyequivalentenergyThe energy of a single-energy radiation that has the same specified effect as the multi-energy radiation under consideration. -3-
2.48 Shielding
A method of reducing the radiation level in a certain area by using materials that can reduce radiation. 2.49 Shield
A physical barrier made of materials that can reduce radiation and placed between the radiation source and people, equipment or other objects to reduce the radiation level in a certain area.
2.50 Structural shield Structural shield A shield made of materials that can reduce radiation and incorporated into the building structure. 2.51 Area residence factor Areaoccupancy factor In shielding calculations, when calculating the shield required for the radiation source to irradiate the location under consideration, the coefficient used to correct the dose rate or fluence rate according to the length of time the personnel stay in the relevant area. 2.52 Build-up factor
When a wide beam of radiation passes through a medium, the ratio of the total value of a specific radiation at any point to the value produced by the radiation that reaches that point without any collision.
2.53 Workload
Refers to the measurement of the degree of use of equipment that produces ionizing radiation in corresponding units. It is generally determined by the average value of the product of the X-ray tube current and the corresponding on-time within a week. For X-ray diagnostic equipment, it is usually expressed in coulombs per week (C), milliampere seconds per week (mA·s) or milliampere minutes per week (mA-min). For X-ray therapeutic equipment, it is generally expressed in the kerma of the radiation beam at a distance of one meter from the radiation source within a week.
2.54 Defense in depth
A variety of protective measures taken for a given safety goal. These protective measures ensure that the safety goal can be achieved even if one of the protective measures fails.
2.55 Quality assurance quality assurance All planned and systematic activities necessary to ensure that items or services meet the specified quality requirements and provide sufficient confidence. 2.56 Quality control quality control
Operational techniques and activities taken to achieve the specified quality requirements 2.57 Acceptance test acceptance test
After the equipment is installed or undergoes major repairs, a quality control test is conducted to determine whether its performance indicators meet the agreed values. 2.58 Status test statustest
Periodic quality control test of running equipment to evaluate whether its performance indicators meet the requirements. 2.59 Stability test constancytest
Quality control test to determine whether the change of performance of equipment in use relative to an initial state meets the control standard. 2.60 Baseline value baselinevalue
Reference value of equipment performance parameters. Usually obtained from the initial stability test after the acceptance test is qualified, or given by corresponding standards. 2.61 Type inspection typeinspection
Also known as routine inspection, it is a comprehensive inspection of various performance indicators of the product to assess whether the product quality meets all standards and design requirements.
2.62 Factory inspection exfactory inspection The final inspection that must be carried out when the product leaves the factory to assess whether the product that has passed the type inspection meets the quality confirmed by the type inspection when leaving the factory. The factory inspection with the participation of the ordering party is called delivery inspection. 2.63 Accompanying documents Documents accompanying devices, equipment, auxiliary equipment or accessories, including important information provided for the assembler, installer and user of the equipment, especially information related to safety. 2.64 Instructions for use The part of the accompanying documents that provides information for the user to use the equipment correctly and operate safely. 2.65 Installation information The part of the accompanying documents that provides the installer with necessary precautions for the safety and operating performance when installing the equipment, equipment components or parts according to their respective specified purposes. 2.66 Radioactivity radioactivity
The property of certain nuclides to spontaneously emit particles or rays, or emit X-rays after orbital electron capture, or undergo spontaneous fission.
2.67 Radioactive decay radioactive decay A spontaneous nuclear transition process in which the nucleus emits particles or rays, or undergoes orbital electron capture and subsequent emission of X-rays, or undergoes spontaneous nuclear fission.
2.68 decay constant decayconstant; disintegrationconstant The probability that a nucleus of a certain radioactive nuclide decays spontaneously per unit time. The decay constant λ is given by the following formula: λ=(-1/N)(dN/dt), where λ is the decay constant; N is the number of nuclei of the nuclide existing at time t. 2.69 radionuclide radionuclide
A radioactive nuclide. A nuclide is a type of atom with a specific mass number, atomic number, and nuclear energy state, whose average lifespan is long enough to be observed.
2.70 half-life half-life
The time required for the radioactivity to drop to half of its original value during a single radioactive decay process. Also called the physical half-life. 2.71 Biological half-life biological half-life When the excretion rate of a certain radionuclide in a biological system approximately obeys an exponential law, the time required for the total amount of the nuclide in the system to be reduced to half due to biological processes. 2.72 Effective half-life effective half-life The time required for the total amount of a certain radionuclide after entering the human body to be reduced by half in the whole body or a certain organ due to the combined effects of radioactive decay and biological excretion. 2.73 Radioactivity activity
At a given moment, the radioactivity A of a certain amount of a certain radionuclide in a specific energy state is the quotient obtained by dividing the expected value dN of the number of spontaneous nuclear transitions of the nuclide from this energy state by the time interval dt: A=dN/dt, also known as activity. 2.74 Specific activity
Mass activity
The radioactivity of a substance per unit mass, i.e. the quotient (Sm) obtained by dividing the radioactivity A of a substance by the mass m of the substance, i.e.: Sm=A/m.
2.75 Becquerel
The special name of the SI unit of radioactivity, which can be abbreviated as becquerel, symbol Bq. 1Bq-1/s. 2.76 Curie
The old special unit of radioactivity used before the adoption of the SI, symbol Ci. Its conversion relationship with the current legal SI unit becquerel is: 1Ci-3.7×10l°Bq. 2.77 Absorbed dose absorbeddose
The quotient (D) obtained by dividing the average energy ds given by ionizing radiation to a substance in a volume element with a mass of dm by the mass dm of the substance in the volume element, that is: D=de/dm.
2.78 Organ dose organdose
The average absorbed dose DT in a specific tissue or organ T of the human body, that is: Dr=（1/mT）Ddm, where mr is the mass of the tissue or organ T; D is the absorbed dose in the mass element dm. Dr can also be expressed as: Dr=&T/mT, where εT is the total energy given to the tissue or organ T.
2.79 Kerma
The quotient (K) obtained by dividing the sum of the initial kinetic energies dEtr of all charged particles released by uncharged ionizing particles in a substance with a mass of dm by the mass dm of the substance, that is: K=dEu/dm. 2.80 Gray gray
The SI unit name for absorbed dose, kerma, etc., symbol Gy. 1Gy=1J/kg-100rad. 2.81 Rad rad
The old special unit for absorbed dose, kerma, etc. used before the adoption of the SI system. The conversion relationship between it and the current legal SI unit gray is: 1rad-0.01Gy.
2.82 Exposure exposure
When all the electrons (negative electrons and positrons) released by photons in air with a mass of dm are completely blocked by the air, the absolute value dQ of the total charge of ions of any sign generated in the air, divided by the mass of the air dm, the quotient (X), that is: X=dQ/dm. The SI unit of exposure is coulomb/kilogram (C/kg). 2.83 Roentgen roentgen
The old special unit for exposure used before the adoption of the SI system, symbol R. 1R=2.58×104C/kg. 2.84 Radiation weighting factor radiationweightingfactor For the purpose of radiation protection, the factor by which the absorbed dose is multiplied considering the relative harmful effects of different types of radiation R, symbol WR 2.85 Tissue weighting factor tissueweightingfactor For the purpose of radiation protection, the factor by which the equivalent dose of an organ or tissue is multiplied considering the different sensitivities of different organs or tissues T to the random effects of radiation, symbol WT.
2.86 Equivalent dose equivalentdose
The equivalent dose Hr produced by radiation R in an organ or tissue T, R is the average absorbed dose DT in the organ or tissue T, the product of R and the radiation weighting factor Wr, that is, HT.R=WRDr:R. When the radiation field is composed of multiple types of radiation with different Wr values, EWRDTR.
2.87 Effective dose effectivedose
When the effect under consideration is a stochastic effect, in the case of non-uniform irradiation of the whole body, the weighted sum of equivalent doses of all tissues or organs of the human body (E), that is, E=ZWHT, where HT is the equivalent dose received by tissue or organ T; Wr is the weight factor of tissue T. 2.88 Quality factor qualityfactor
The coefficient (Q) used to represent the influence of the microscopic distribution of absorbed dose on the hazard. Its value is determined according to the value of the linear energy transfer density in water. For radiation with energy spectrum distribution, the effective value Q of Q can be calculated. In actual radiation protection, the approximate value of Q can be used according to the type of primary radiation.
2.89 Linear energy transfer density linearenergytransfer (LET) When a charged particle travels a distance dI in a substance, the energy loss dε caused by the collision with an electron whose energy loss is less than △ is divided by d/, which is the quotient of the linear energy transfer density L= (de/d/)A. LET is also called restricted linear collision stopping power.
2.90 Dose equivalent doseequivalent
The dose equivalent H at a certain point in the tissue is the product of the absorbed dose D at that point, the quality factor Q of the radiation and other correction factors N, that is, H-DQN.
2.91 Personal dose equivalent personaldoseequivalent The dose equivalent Hp (d) in the soft tissue at an appropriate depth d below a specified point on the human body. It can be applied to strong penetrating radiation (recommended d=10mm) or weak penetrating radiation (recommended d=0.07mm). 2.92 Effective dose equivalent effectivedoseequivalent When the effect considered is a random effect, in the case of non-uniform irradiation of the whole body, the sum of the dose equivalents of the organs and tissues at risk and the corresponding weighting factors (He), that is, He=WrHr, where W is the tissue weighting factor: Hr is the dose equivalent received by the organ or tissue T. This is the amount recommended for use in ICRP Publication No. 26 (1977). ICRP Publication No. 60 (1991) uses effective dose instead.
2.93 Sievertsievert
SI unit name for dose equivalent, equivalent dose, etc., symbol Sv. 1Sv=1J/kg. 2.94 Rem
Old special unit of dose equivalent used before the adoption of the SI unit. Its conversion relationship with the current legal SI unit sievert is: Irem=0.01Sv
2.95 Committed equivalent dose Committed equivalent dose H:(t) is defined as:
. Where to is the time of ingestion of radioactive material; H(t)0+
H(t)=H(t)dt
is the equivalent dose rate of organ or tissue T at the moment; T is the time after ingestion of radioactive material. If it is not specified, T is taken as 50 years for adults and 70 years for children. -6-
2.96 Committed effective dose Committed effective dose E(t) is defined as:
E(t)=」E(t)dt
. Where to is the time of ingestion of radioactive material; E(t) is the effective dose rate at time t; T is the time elapsed after the ingestion of radioactive material. When T is not specified, T is 50 years for adults and up to 70 years for children.
2.97 Collective dose collective dose
For a given group, the product of the average dose of each member of the group and the number of members of the group, where the organ used to determine the dose must be specified. The unit of collective dose is usually: person·Sv. 2.98 Genetically significant dose (GSD) is a quantity used to evaluate the genetic risk of a group caused by medical exposure, etc. If the genetic risk caused by the gonadal dose actually received by all members of the group is equal to the genetic risk caused by a certain dose received by each member, then this dose is called a genetically significant dose. 3 Radiology
3.1 Radioscopywww.bzxz.net
The technology of obtaining a series of continuous or intermittent X-ray images and displaying them continuously as visible images. Indirect radioscopy3.2
X-ray fluoroscopy in which the image is displayed after information conversion and can be observed indirectly outside the radiation beam. Fluoroscopy
Traditional X-ray fluoroscopy using a fluorescent screen. 3.4 Radiography
The technology of acquiring, recording and selectively processing the information contained in the X-ray image on the image receiving surface directly or after conversion. 3.5 Direct radiography direct radiography A type of X-ray photography that can be recorded on the image receiving surface. Indirect radiography indirect radiography3.6
X-ray photography in which the information obtained on the image receiving surface is converted and recorded. Fluorography
Indirect X-ray photography with the aid of a fluorescent screen. 3.8 Kymography
Direct X-ray photography that obtains images of moving contours of objects. 3.9 Cineradiography Rapid and continuous indirect X-ray photography of moving objects on film. 3.10 Dental panoramic radiography Direct X-ray photography of part or all teeth using a dental X-ray machine. This type of photography, which is different from ordinary dental intraoral films, is also called dental panoramic photography.
3.11 Tomography X-ray photography of one or several selected layers in an object. 3.12 Indirect tomography Indirect tomography that converts the signal obtained on the image receiving surface and then records the image of a certain layer of the object. 3.13 Radiopaqueagent X-ray contrast agent A substance that can be injected into the human body to make the injected site and the surrounding tissue show a clear contrast on the X-ray image. 3.14 X-ray tube X-raytube
High vacuum device that generates X-ray radiation by bombarding the anode target with electrons generated by the cathode through electric field acceleration. 3.15 X-ray tube housing X-ray tube housing Container with radiation window that can prevent electric shock and X-ray radiation and holds the X-ray tube. 3.16 X-ray tube assembly X-ray tube assembly-7-
Component that contains the X-ray tube in the X-ray tube housing. 3.17 X-ray source assembly X-ray source assembly Component that consists of the X-ray tube assembly and the beam limiting system. 3.18 Actual focal spot actualfocalspot
Area on the anode target surface of the X-ray tube that blocks and stops the accelerated particle beam 3.19 Effective focal spot effectivefocalspot The vertical projection of the actual focal spot on the reference plane. 3.2o Nominal focal spot value nominalfocalspot value A dimensionless value that is measured under specified conditions and has a specific ratio to the effective focal spot size of the X-ray tube. 3.21 High-voltage generator A combination of all components in an X-ray generator that controls and generates electrical energy for feeding X-rays, usually consisting of a high-voltage transformer assembly and a controller assembly.
3.22 Constant potential high-voltage generator A high-voltage generator whose output voltage ripple rate does not exceed the specified value. 3.23 Capacitor discharge high-voltage generator A high-voltage generator that can store electrical energy in a high-voltage capacitor and supply its energy to a X-ray tube through discharge during a single load. 3.24 Deadman switch deadman control
A switch that meets the needs of protection and safety. It is a device that can keep the high-voltage circuit of the X-ray device turned on only when the operator continuously presses the switch, and the circuit is disconnected once it is released.
3.25 Beam limiting system All components that limit the geometry of the radiation beam. 3.26 Diaphragm
A beam limiting component with a fixed or adjustable window in a plane. 3.27 Inherent filtration inherentfiltration The equivalent filtration produced by a non-removable material before the radiation beam is emitted from the X-ray source assembly or its components. 3.28 Additional filtration additionalfiltration The equivalent filtration produced by additional filter plates and other removable materials between the X-ray source and the patient or specified plane in the radiation beam. 3.29 Total filtration totalfiltration
The sum of inherent filtration and additional filtration.
3.30 Irradiation field radiationfield
The area whose radiation intensity exceeds a certain or specified level on the plane orthogonal to the radiation beam 3.31 Light field indicator lightfieldindicator In X-ray equipment, a device that projects the range of the irradiation field through visible light. 3.32 Focal spot to skin distance focal spot to skin distance The closest distance from the center of the effective focus to the surface of the subject's skin. 3.33 focal spot to image receptor distance refers to the distance from the effective focal reference plane to the intersection of the reference axis and the image receiving plane. 3.34 X-ray diagnostic table X-ray diagnostic table is a patient support system for X-ray fluoroscopy and photography. It is also called a diagnostic bed. 3.35 serial changer
A device that performs continuous photography on a single or multiple films by manually or (and) automatically operating the transfer mechanism of photographic films or cassettes. 3.36 filmspot device
In X-ray fluoroscopy, a device that takes one or more X-ray photos of the examined part immediately after selection. 3.37 X-ray photographic film is a transparent carrier material coated with radiation sensitizer on one or both sides for X-ray photography. 3.38 non-screen film
X-ray photographic film that does not require an intensifying screen for direct X-ray photography. 3.39 screenfilm
X-ray film with a relatively high sensitivity to the radiation emitted by the intensifying screen during direct X-ray photography. 3.40 intensifying screen used in direct X-ray photography to convert incident X-rays into an emulsion screen more suitable for the photosensitivity of photographic film. 3.41 anti-scatter grid a device placed in front of the image receiving surface to reduce the scattered radiation incident on the image receiving surface, thereby improving the contrast of the X-ray image.
3.42 stationary grid stationarygrid an anti-scatter grid that does not move relative to the radiation beam when in use. 3.43 moving grid movinggrid an anti-scatter grid that can move the grid when the radiation beam passes through it to avoid imaging of the absorption bars and causing signal loss. 3.44 fluorescent screen fluorescent screen
a carrier layer that can emit fluorescence when irradiated by ionizing radiation. 3.45 Radioscopic screen A fluorescent screen used directly for X-ray fluoroscopy.
3.46 X-ray image intensifier A device that converts an X-ray image into a corresponding visible light image and uses external energy to enhance the image brightness. 3.47 Electro-optical X-ray image intensifier An X-ray image intensifier equipped with an electro-optical vacuum device. 3.48 Input screen inputscreen
A thin layer that constitutes the image receiving surface in an electro-optical vacuum device. 3.49 Output screen outputscreen
A thin layer that converts an electronic image into a visible light image in an electro-optical vacuum device. 3.50 Output image outputimage
A visible light image produced on the output screen in an electro-optical vacuum device. 3.51 X-ray television system A combination of devices that directly or indirectly converts an X-ray image into an electrical signal and sends it to a display device to obtain an X-ray image. 3.52 loading
In an X-ray generating device, the action of applying electrical energy to the anode of the X-ray tube. 3.53 loading time loadingtime
The time during which the anode input power is applied to the X-ray tube measured by a specified method. 3.54 irradiation time irradiationtime
The duration of irradiation measured by a specified method, usually the time during which the radiation dose rate exceeds a certain specified level. 3.55 X-ray tube voltage X-raytubevoltage The potential difference between the anode and cathode of the X-ray tube. Usually expressed in kilovolts (kV) peak. 3.56 Nominal X-ray tube voltage nominalX-raytubevoltage The maximum X-ray tube voltage allowed under specified conditions. 3.57 Maximum X-ray tube voltage limitedmaximumX-raytubevoltage The maximum limit voltage limited for the X-ray tube in a specific X-ray device. 3.58 Initial X-ray tube voltage initialX-rayvoltage In a capacitor discharge X-ray generating device, the voltage at the beginning of X-ray tube loading. 3.59 Residual X-ray voltage residualX-rayvoltage In a capacitor discharge X-ray generator, the voltage that continues to exist when the X-ray tube is loaded. 3.60 X-ray tube current X-raytubecurrent The electron beam current incident on the X-ray tube target. Usually expressed as an average value of milliamperes (mA). 3.61 Filament current filamentcurrent
The current added to the X-ray tube filament to control the cathode thermal ion emission. 3.62 Ripple percentageripple
For the power supply of the high-voltage generator expressed as a percentage, the difference between the highest and lowest values of the rectified voltage waveform within one cycle is proportional to the highest value.55X-ray tube voltageX-raytubevoltageThe potential difference between the anode and cathode of the X-ray tube. Usually expressed in kilovolts (kV) peak. 3.56Nominal X-ray tube voltagenominalX-raytubevoltageThe maximum X-ray tube voltage allowed under specified conditions. 3.57Maximum X-ray tube voltagelimitedmaximumX-raytubevoltageThe maximum limit voltage limited for the X-ray tube in a specific X-ray device. 3.58Initial X-ray tube voltageinitialX-rayvoltageThe voltage at the beginning of X-ray tube loading in a capacitor discharge X-ray generator. 3.59Residual X-ray tube voltageresidualX-rayvoltageThe voltage that continues to exist at the end of X-ray tube loading in a capacitor discharge X-ray generator. 3.60X-ray tube currentX-raytubecurrentThe electron beam current incident on the X-ray tube target. Usually expressed in milliamperes (mA) average value. 3.61Filament currentfilamentcurrent
The current added to the X-ray tube filament to control cathode thermal ion emission. 3.62 Ripple ratio percentageripple
For the power supply of a high-voltage generator expressed as a percentage, the difference between the highest and lowest values of the rectified voltage waveform within one cycle is proportional to the highest value.55X-ray tube voltageX-raytubevoltageThe potential difference between the anode and cathode of the X-ray tube. Usually expressed in kilovolts (kV) peak. 3.56Nominal X-ray tube voltagenominalX-raytubevoltageThe maximum X-ray tube voltage allowed under specified conditions. 3.57Maximum X-ray tube voltagelimitedmaximumX-raytubevoltageThe maximum limit voltage limited for the X-ray tube in a specific X-ray device. 3.58Initial X-ray tube voltageinitialX-rayvoltageThe voltage at the beginning of X-ray tube loading in a capacitor discharge X-ray generator. 3.59Residual X-ray tube voltageresidualX-rayvoltageThe voltage that continues to exist at the end of X-ray tube loading in a capacitor discharge X-ray generator. 3.60X-ray tube currentX-raytubecurrentThe electron beam current incident on the X-ray tube target. Usually expressed in milliamperes (mA) average value. 3.61Filament currentfilamentcurrent
The current added to the X-ray tube filament to control cathode thermal ion emission. 3.62 Ripple ratio percentageripple
For the power supply of a high-voltage generator expressed as a percentage, the difference between the highest and lowest values of the rectified voltage waveform within one cycle is proportional to the highest value.
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