Basic principles and measures for radiation health protection:
（1） Purpose and principle of radiation protection
Objective: to prevent deterministic effect and control random effect
Basic principles of radiation protection:
1. Justification of radiation events: also known as rationality judgment. After demonstration (cost and benefit analysis), the benefit of a certain radiation event outweighs the harm, which is the principle of justification of ionizing radiation events.
2. Optimization of radiation protection: the principle of the lowest possible that can be reasonably achieved, that is, to obtain the maximum net benefit at the least cost.
3. Personal dose limit: the lower limit of the unacceptable dose range, that is, the personal exposure dose shall not exceed the specified corresponding limit.
In terms of medical irradiation, it is necessary to give the most appropriate dose on the premise of ensuring the curative effect or diagnostic results, select the best conditions and the most appropriate operating technology, and reduce the irradiated dose to the lowest level.
（2） Basic radiological protection measures
1. Strictly implement the notice of the general office of the Ministry of health on standardizing the application of radiation examination technology in health examination (No. [2012] 148) issued by the health office of the Ministry of health:
Radiation examination shall not be included in the physical examination of children and infants.
Generally, the application of radiation examination technology in physical examination shall not exceed once a year.
For physical examination, ordinary X-ray photography and Cr shall be given priority; If conditions permit, Dr is recommended to replace conventional radiography and Cr examination. Direct fluorescent screen fluoroscopy shall not be used for physical examination; Unless there is a clear indication of disease risk (e.g. over 50 years old, long-term heavy smoking, cardiovascular disease risk assessment as medium and high risk, etc.), CT should not be used; Pet, pet/ct, SPECT and spect/ct shall not be used.
A medical institution shall provide the subject with necessary radiation protection articles and take necessary protective measures for the non irradiated parts; Strictly control the range of the irradiation field to avoid direct irradiation of sensitive organs or tissues adjacent to the irradiation field; Before the X-ray examination of the abdomen or pelvis of a woman of childbearing age, it shall be determined whether she is pregnant, and it is not allowed to carry out radiographic examination of the abdomen or pelvis of a pregnant woman. During the inspection, no other personnel shall be allowed to stay in the machine room except the examinee. When the examinee needs help or close care, corresponding protective measures shall also be taken for the help or caregiver.
2. Strictly comply with gb130-2013 radiological protection requirements for medical X-ray diagnosis:
The layout in the machine room shall be reasonable, and the harness shall not be used to directly illuminate the positions of shot, window and pipeline port; Do not stack sundries irrelevant to the diagnosis of the equipment; The machine room shall be equipped with power exhaust device and maintain good ventilation.
Ionizing radiation warning signs, radiation protection precautions and eye-catching working status indicator lights shall be applied outside the door of the machine room, and warning statements shall be set at the light box; The machine room door shall be equipped with a door closing device, and the working status indicator and the door connected with the machine room can be effectively linked.
Patients and subjects should not wait in the computer room; Under no special circumstances, the person who has inspected the seeds shall not stay in the machine room.
According to the work content, each X-ray equipment shall be equipped with at least the protective articles and auxiliary protective equipment for staff, patients and examinees required by the basic categories in Table 4. The quantity shall meet the work needs, and the accompanying examinees shall be equipped with protective clothing at least; The lead equivalent of protective articles and auxiliary protective facilities shall not be less than 0.25mmpb; For different examinations of children of different ages, protective articles for protecting corresponding tissues and organs shall be provided. The lead equivalent of protective articles and auxiliary protective facilities shall not be less than 0.5mmpb.
Table 4 configuration requirements for personal protective equipment and auxiliary protective facilities
Requirements for safe operation of X-ray equipment for dental photography
The oral film should be fixed at the appropriate position, otherwise it should be supported by the examinee.
Mobile equipment can only be used when X-ray inspection is conducted and fixed equipment cannot be implemented; During exposure, the trunk of the staff shall avoid the main ray direction and be more than 1.5m away from the focus.
Requirements for safe operation of mammography X-ray equipment protection
The thyroid parts of patients and subjects shall be well protected.
Select the appropriate target / filter material combination according to the breast type and compression thickness, and use the automatic exposure control function of the camera to obtain a stable acquisition effect and achieve the optimal protection requirements.
Requirements for safe operation of mobile and portable X-ray equipment protection
Mobile equipment can only be used when fixed equipment cannot be used and X-ray examination is really required.
When mobile equipment is used for X-ray examination in the ward, protective measures shall be taken for patients adjacent to the bed (within 2m), and the useful harness shall not be oriented towards other patients.
Other auxiliary measures
(1) Personal protection and safe operation
(2) Health monitoring and personal dose monitoring
(3) Utilization decay (external irradiation from unsealed source)
Machine room area and protection thickness
(1) Area of machine room: 200mA X-ray machine room with single tube head shall not be less than 24m2, and that with double tube heads shall not be less than 36m2; The X-ray machine room with single tube head larger than 200mA shall be appropriately expanded, with a recommended area of 30 ㎡, and that with double tube heads shall not be less than 36 ㎡; X machine room for interventional diagnosis and treatment shall be no less than 30 ㎡; CT room: 36 ㎡. Dental machines shall have a separate machine room.
(2) Protective thickness: the protective thickness of the wall and ceiling of the machine room shall be calculated and determined according to the type of X-ray equipment, estimated working load, adjacent rooms and surrounding conditions.
1. the main protective wall (the wall facing the useful harness) shall have 2mm lead equivalent protective thickness, and other side walls (auxiliary protective wall), ceiling and perspective machine room shall have 1mm lead equivalent protective thickness. At present, the commonly used brick wall plus cement is approved as arsenic. If the building quality is guaranteed, the thickness of 25cm (30cm of the main wall) can meet the protection requirements; The walls around the CT machine room shall reach 30cm.
2. the protective thickness of doors and observation of various irradiation rooms is the same as that of side walls, i.e. at least 0.5-1mm lead equivalent protective thickness; The door panel (with lead sheet) is overlapped with the door frame for 2-3cm, and the lead glass of the observation window is embedded into the wall for 2cm to prevent ray leakage.
Health supervision and management of radiation diagnosis and treatment
Supervision and management: national supervision is combined with unit self-discipline, and hierarchical management is combined with territorial management.
Objective: to prevent and control radioactive hazards, ensure health and safety, and reduce or reduce the occurrence of radioactive accidents.
1、 Basis for supervision and management
（1） Laws: Law on the prevention and control of occupational diseases, law on the prevention and control of radioactive pollution, law on licensed doctors, etc.
（2） Administrative regulations: Regulations on the safety and protection of radioisotopes and radiation devices, regulations on the administration of medical institutions, etc.
（3） Administrative regulations: Measures for the classified management of occupational disease hazards in construction projects, provisions on the management of radiation diagnosis and treatment, measures for the management of occupational supervision of radiation workers, etc.
（4） Normative documents and standards
1. basic standard for radiation protection: basic standard for ionizing radiation protection and radiation source safety (GB18871-2002).
2. technical specifications and standards for protection against various types of radiation
Including more than 40 mandatory and recommended standards (specifications), such as health protection standard for medical X-ray diagnosis, health protection monitoring specification for medical X-ray diagnosis, etc.
Standard category crown number
category
mandatory
Recommendability
national standards
GB
Gb/t
National occupational health standards
GBZ
Health industry standards
WS
Ws/t
3. diagnostic criteria for radiation diseases
There are 19 items in total, including 18 mandatory items and 1 recommended item.
2、 Main contents of supervision and management
（1） Health review of construction project (radiation diagnosis and treatment)
1. examination institution: the health administrative department above the county level (determined according to the items of radiation diagnosis and treatment), which shall be handled by each health supervision office.
Provincial level: radiotherapy, nuclear medicine
Municipal level: interventional radiology
County level: ordinary X-ray diagnosis
2. object of review: newly built, reconstructed and expanded radiation diagnosis and treatment construction projects (collectively referred to as construction projects)
3. review contents:
(1) Pre assessment and review of radiation occupational hazards;
(2) Design review (serious hazard project);
(3) Evaluation and acceptance of radiation hazard control effect.
Pre evaluation and control effect evaluation shall be carried out by legally qualified service institutions. After obtaining the corresponding evaluation report, they shall apply to the health administrative department for review, review or filing.
（2） Licensing management of Radiology Diagnosis and treatment
1. Licensing and registration
Apply to the health administrative department with jurisdiction before carrying out radiation diagnosis and treatment (equivalent to the review of construction projects, and apply to the health administrative department with high jurisdiction if carrying out multiple diagnosis and treatment businesses at the same time). The specific offices are set up in the health supervision centers at all levels.
Licensing procedure: application - acceptance - Review - issuance
After obtaining the radiation diagnosis and treatment license, the applicant shall go through the registration formalities with the local health administrative department according to the territorial management principle. After the radiation diagnosis and treatment license is obtained, the applicant shall go through the registration formalities with the local health administrative department according to the territorial management principle (approve the secondary diagnosis and treatment subjects), and then the diagnosis and treatment business can be carried out.
2. Verification, change and cancellation of license
Verification: it shall be verified at the same time as the medical institution practice license, and the duplicate of the license shall be endorsed.
Change: if the radiology diagnosis and treatment items are changed, the change procedures shall be handled with the original issuing authority before the change, and the change shall not be made without approval.
Cancellation: in case of any of the circumstances listed in Article 18 of the provisions on the administration of radiation diagnosis and treatment, the original issuing unit shall cancel it.
（3） Daily management of site, equipment and supplies
1. The protective facilities in various places shall be kept intact, used normally and comply with relevant regulations; Repair and replace the damaged parts in time.
2. All kinds of diagnosis and treatment equipment and protective articles shall have standing books or lists, and maintenance and overhaul records; Large equipment shall have configuration certificate.
3. Carry out monitoring as required to ensure the quality of the site and equipment.
Site protection monitoring: not less than once a year.
monitor
Equipment performance test: installation test and regular test
Instrument verification: belonging to measuring instruments.
Monitoring and testing institutions: service institutions with legal qualifications (27 in the province by the end of 2012)
（4） Management of radiation workers
1. Working conditions: hold the radiation worker certificate.
Basic conditions: at least 18 years old; The occupational health examination meets the requirements; Qualified in radiation protection and relevant legal knowledge training; Comply with laws and regulations, and accept health monitoring and personal dose monitoring.
Issuance of radiation worker certificate: the person who issues the radiation diagnosis and treatment certificate shall issue the radiation worker certificate.
Procedure: application → acceptance → review → issuance
2. Daily management: training, health monitoring, personal dose monitoring.
(1) Training: pre employment training and regular post employment training (once every two years in principle).
(2) Occupational health monitoring: including occupational physical examination, establishment of personal health monitoring files (one file for each person), etc.
Occupational physical examination: pre post physical examination, regular physical examination during on-the-job, off-the-job physical examination and emergency physical examination. The physical examination institution shall have professional physical examination qualification.
Treatment of physical examination results: inform the person, store in the health file, and record in the radiation worker certificate
Occupational contraindications: hemogram decline and taboo diseases, it is not suitable to engage in radioactive work, and the on-the-job personnel shall be transferred from their original posts.
Blood Meridian protein: Male
Hemogram leukocyte: before work
Platelets: before work
Other diseases: such as severe respiratory, circulatory, digestive, blood, endocrine, urinary, immune, nerve, skin, visual impairment, malignant tumor, disability, deformity, genetic disease, other organic or functional diseases, uncontrolled bacterial or viral infection.
Occupational radiation sickness
Legal radiation diseases: external radiation acute radiation disease, external radiation subacute radiation disease, external radiation chronic radiation disease, internal radiation disease, radiation skin disease, radiation bone injury, radiation thyroid disease, radiation combined injury, and other radiation injuries.
