Radiation Safety Requirements for Particle Accelerators Used for Medical Services - Assignment Example

Radiation Safety Requirements for Particle Accelerators used for Medical Services Scope and Purpose This document will delineate various safety related requirements that need to be practised by establishments authorised to use particle accelerators for medical purposes. The purpose of this document is to limit unintended harmful exposure to radioactive sources to professionals, patients and visitors in the vicinity of particle accelerators used for medical services. 2. Administrative Requirements a. Authorization No particle accelerators can be installed, operated, maintained or dealt with in any way without prior authorization of the regulatory body. Authorization both includes license and registration with the regulatory body. All forms of authorization shall be renewed with a frequency of six months. Requirements for authorization include: The applicant’s operators for the particle accelerator are trained, experienced and qualified such that danger to public health and safety is minimised; The applicant’s equipment, facilities, operating and emergency procedures warrant the safety and health of public at large; The applicant has a complete management structure to deal with radiation dangers; The applicant’s radiation management structure is capable of dealing with radiation during operation and emergency as per applicable guidelines, rules and laws; The applicant must at least be a practising physician with prior training, experience and qualification in dealing with particle accelerators for medical practice; Under no circumstances can the applicant be a non medical personnel except for the purposes of research which is approved under applicable laws and displays a proposition and commitment to mitigate radiation hazards to public at large. b. Accreditation All and any personnel operating on the particle accelerator must be qualified appropriately and must possess requisite experience before dealing any such equipment. Personnel will include operators, maintenance technicians and any other trades that come in contact with the particle accelerator for operational and emergency aspects. Failure to comply may result in legal penalties. Moreover accredited personnel must comply with the following limitations under all circumstances. The accredited operator has been instructed as per radiation safety and demonstrates acute understanding of related concepts; The accredited operator has been given copies of this document, of licenses and registrations, of applicable operating and emergency procedures, of applicable guidelines, rules and laws; The accredited operator has demonstrated a deep understanding for the documents listed above. Professional testing may be carried out to assess the state of understanding developed thereof; The accredited operator has prior training, experience and qualification along with demonstrated skills that warrant his operation of the particle accelerator, auxiliary equipment, survey devices and other related equipment; The accredited operator has not been convicted of or proven to be involved in negligence on a job before. c. Inspection Members of the regulatory body are free to visit the particle accelerator at any point in time and to seek appropriate safety records. Failure to comply may result in cancellation of authorization. 3. Radiation Protection Requirements Radiation protection measures must be adopted to limit the exposure of various audiences to radiation. Three categories of audiences exist, which are: Professionals: people trained to use particle accelerators; Patients: people being treated by particle accelerators; Visitors: people in the vicinity of a particle accelerator who are neither professionals nor patients. The level of acceptable dosage for patients is not prescribed as it would depend on the concerned physician and any prescription may harm the patient’s treatment. Acceptable dosage levels for professionals and visitors are listed in the table below: Professionals Visitors Dose Type 5 year average dose Maximum annual dose 5 year average dose Maximum annual dose Effective dose 20 mSva-1 50 mSv 1 mSva-1 5 mSv Equivalent dose to lens of eye 150 mSva-1 - 15 mSva-1 - Equivalent dose to extremities (hands, feet and skin) 500 mSva-1 - 50 mSva-1 - a. Pregnant Workers Any female workers (who operate or are exposed to the particle accelerator) who become pregnant shall be treated within the visitor category to avoid harmful exposure to the foetus. Their job shall be modified with immediate effect to avoid foetal exposure to radiation. b. Minimisation of Exposure Unnecessary and unauthorised access to the particle accelerator shall not be provided to visitors except for members of the regulatory body. Visitor exposure to the particle accelerators radiation must be minimised under all circumstances. c. Occupational / Professional Exposure The licensee shall ensure that radiation exposure to machine operators and other professionals in the radiation area should meet or exceed applicable guidelines. All personnel exposed to radiation will be monitored with a frequency of one month and the findings will be recorded. Investigation levels of 0.4 to 0.5 mSv effective dose should be utilised for monitoring. For pregnant workers see (a) above. Personnel must be provided with adequate PPEs (Personal Protective Equipment) and their use must be ensured. Personnel should record radiation levels at regular frequency to detect any aberrations such as increasing radiation levels. The local health and safety management may define the frequency but all records should be retained for 12 months. In case of emergencies the exposure of personnel to radiation must be managed to ensure compliance with regularly acceptable radiation levels. Any overdose shall not be acceptable even in case of emergencies. Contingency plans must be available and followed in letter and spirit. Regular rehearsals of emergencies should be used to teach personnel on how to deal with emergencies. d. Medical / Patient Exposure Patients can only be exposed to radiation if prescribed by a certified radiologist / radiation oncologist; Patients should be exposed only to the radiation levels prescribed. No variation in radiation levels is acceptable unless directed by competent authority; Patients can only be delivered radiation therapy for medical healing purposes. Any other utilisation of a particle accelerator on a human being is strictly forbidden; Pregnant females who are in need of radiation therapy must provide a statement of approval in consultation with their radiologist / radiation oncologist for treatment to commence. Care should be taken to avoid unnecessary exposure to the foetus but any damage sustained by the foetus resulting from radiation shall not create any liability. e. Public / Visitors Exposure The licensee is responsible for ensuring that unnecessary public exposure to radiation is not brought about through the use of appropriate shielding and safety devices; All radioactive sources must be kept under lock and key at all times; Visitors accompanying patients should not be admitted to the particle accelerator installation to discourage public exposure; Rooms housing particle accelerators should be well sealed and locked so as to prevent unauthorised entry; The particle accelerators main console should be locked when not in use and the key should reside with a competent authority as decided by local health and safety officials. f. Emergency Response The licensee must have emergency response plans available at all times; The personnel operating the particle accelerator must be well versed in emergency mitigation measures preferably through rehearsals; Emergencies involving maintenance personnel shall be dealt with by appropriately trained and certified technicians only. Technicians merely relevant to servicing electromechanical devices shall not be admissible to serving any particle accelerators in cases of emergency; Ventilation and other transport systems should be turned off with immediate effect as soon as an emergency is declared. 4. Managerial Requirements A culture of safety must be fostered and maintained to ensure that exposure remains minimal. A complete safety policy shall be constituted by the managerial staff. Professionals and visitors in regular contact with the particle accelerator must be made aware of the policy and frequent review is encouraged. a. Reduction of Human Error Human error shall be reduced as much as possible by appropriate capacity building and monitoring of professionals. b. Staffing The facility must provide minimal required numbers of professionals to operate and maintain the particle accelerator. Staffing must meet at least minimum work load requirements. c. Education and Training All professionals dealing with the particle accelerator must be appropriately qualified from professional institutions. Appropriate training and education should be encouraged to upgrade the skills of professionals. 5. Shielding and Safety Design a. A qualified expert registered with the licensing authority shall be consulted in the design of a particle accelerator installation. b. A qualified expert shall perform a radiation survey when the accelerator is first capable of producing radiation to verify that radiation levels and shielding effectiveness meet the applicable requirements. c. Each particle accelerator installation shall be provided with such primary and secondary barriers as are necessary to assure compliance with dose limits specified in the table above 6. Warning Systems a. All facilities possessing a particle accelerator shall display easily observable signs outside particle accelerator rooms. These signs should be automated so that whenever radiation therapy is in progress the signs warn people outside; b. Electronic signs should be integrated with the building’s fire protection system to ensure that fire fighters are aware of the presence of radioactive sources; c. High doses of radiation shall be declared with audio sirens that must go off for at least a minute. The facility can incorporate visual signs as well in order to facilitate disabled individuals; d. The building’s blue prints must be updated after the installation of a particle accelerator in order to ensure that updated information is available to authorities to deal with any emerging situations; e. Local law enforcement and rescue services must be appraised of the presence, quantity and quality of the on hand radiation sources. 7. General Operating Procedures a. The particle accelerators’ will be locked out when not in active use using the attached locking devices; b. The particle accelerators’ main console will be used to switch the machine on or off. Any auxiliary switching or safety interlocks switching will not be allowed for regular use; c. All devices including the safety interlocks will be preventively maintained with a frequency of at least six months. Maintenance records shall be kept for at least five years; d. Electrical diagrams and drawings should be kept handy in order to deal with regular operation and emergencies; e. This policy document, operating instructions and maintenance instructions should be placed near the particle accelerator at all times; f. Secondary copies of the above documents must be placed with the local safety and health management structure for reference. 8. Radiation Monitoring a. Portable / hand held radiation monitoring devices must be used at a particle accelerator facility to determine radiation levels; b. Monitoring devices must be maintained and calibrated every year; c. The licensing authority’s designated agents will carry out radiation surveys when the particle accelerator is installed, when the installation is modified for any reasons and when the installation is decommissioned; d. Radiation levels should be monitored continuously and reported to a monitoring station; e. Audio and visual alarms should be provided in case the radiation levels exceed their threshold; f. Ventilation systems should be monitored at the source and at the exit to determine the amount of airborne radiation; g. All radiation surveys must be recorded and kept in record for at least two years. 9. General Instructions a. Instrumentation All instrumentation on the particle accelerator must be clearly labelled and should be easily accessible for maintenance. Instrumentation must be maintained preventively in order to discern any problems that might occur. Maintenance frequency set by the manufacturer should be followed strictly. b. Controls All controls installed on the particle accelerator must be easily accessible and should be ergonomic in design. c. Interlocking Systems The particle accelerator must possess interlocking devices to enhance safety. No modification of interlocking systems is allowed without prior review and approval of the licensing authorities experts. The interlocking systems must follow the directions listed below: All interlocks should automatically trip when threshold limits are exceeded but interlocks should be reset manually only by virtue of design. Manual resets should exist on the interlock itself and on the main console. All interlocks should be independent of each other during operation. All interlocks should be designed and installed as fail safe devices that prevent the operation of the particle accelerator in the event of a malfunction in the interlock system at any position. Emergency cut off switches should be installed near the operator’s normal operating position, on the main console and anywhere else as per requirement. In the event of an emergency cut off the particle accelerator should be restarted from the manual resets located on the main console only. Read More