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In India, cyclotron-produced radionuclides are gaining importance in molecular imaging in Nuclear Medicine (NM) departments. The importance of this modality among others is due to the fact that it provides valuable clinical information, which was lacking in other available modalities. Presently, every well-established hospital would like to procure Medical Cyclotron or positron emission tomography-computed tomography (PET-CT) facility in their NM department. Because cyclotron-produced radionuclides have higher energy than the other routinely used radionuclides for diagnosis, it becomes essential for the user to know about the regulatory requirement and radiation safety precautions that one has to take for the installation of this new modality in their premises. The various stages of approval of PET-CT facility by the Atomic Energy Regulatory Board (AERB) and important steps that one has to know/follow before planning for this new facility are summarized in the following sections.
The user has to submit to AERB two copies each of the proposed layout plan, site plan, and elevation drawing of the facility indicating the floor, nature of occupancy around, above and below, if any, has to be submitted in “B3” size paper (353×500 mm2) along with the application form AERB/RSD/NMF/SLA (downloadable from www.aerb.gov.in). The user has to clearly indicate the dimension of each of the rooms associated with the facility in the proposed layout plan of the NM department. When the user has to plan the laboratory, it is required that the arrangement of the various rooms associated with the facility has to follow the principle of low active area to high active area, that is, entrance of the facility should have reception/general waiting area, and at the end hot laboratory cum radiopharmacy/radioactive waste storage area is to be planned. The typical layout plans for the facility given in Figures Figures11 and and22 may be referred to design the PET-CT facility alone or PET-CT facility along with the gamma camera facility with respect to the arrangement/allocation of rooms and area requirement. The above documents have to be submitted to the Head, Radiological Safety Division (RSD), AERB. On scrutinizing the plans from radiologic safety point of view, necessary approval of facility will be granted.
The user has to submit the details of the completion of the construction work as per the approved plan, installation of equipments, procurement of radiologic protection accessories, enrollment of radiation workers in Personal Monitoring Services and availability of qualified staff as per AERB Safety Code AERB/SC/MED-IV (Rev-1 2001), shall be intimated to Head, RSD, AERB, by submitting the Regulatory Consent form no. AERB/444-NM/RC-FORM (downloadable from www.aerb.gov.in). The Radiological Safety Officer (RSO) as per the qualification mentioned in the AERB Safety Code AERB/SC/MED-IV (Rev-1 2001) has to be nominated by the employer for the NM facility by submitting the application form no. AERB/441/RSOM-II/III (downloadable from www.aerb.gov.in).
In this stage, the precommissioning inspection of the facility will be carried out by AERB official(s) to ensure that the construction of NM facility is as per the approved plan and also to verify the information provided in stage “2” mentioned above.
On ensuring the compliance of the requirement as specified in AERB safety Code SC/MED-IV (Rev.1. 2001) for the safe handling of radioactive material in the approved NM facility, the authorization for the procurement of radioactive material indigenously or no objection certificate (NOC) for procurement of radioactive material from abroad will be issued for the stipulated time period. The renewal for the same is done only after receipt and review of the Annual Status Report AERB/NM/Radiation Safety/02 (downloadable from www.aerb.gov.in) by AERB.
In NM facility, the radiopharmaceutic formulation should be prepared, handled, administered to the patients, and disposed of in a safe manner taking into account adequate radiation protection measures. Radioisotopes should be stored, used, and transported safely and securely all the time. Any unusual event that has resulted or has the potential to result in overexposure to the workers or public should be reported to the AERB. Annual Safety Status report of the facility should reach the AERB in the prescribed format at the end of each calendar year. Any change in the qualified person or design of the facility shall be reported to the AERB. Cooperation should be extended to the authorized inspectors from the AERB during inspection of the facility. Failure of compliance to radiation safety procedures may attract enforcement action by the AERB.
In India, radioactive waste management is governed by the Atomic Energy (Safe Disposal of Radioactive Wastes) Rules, 1987, GSR-125 issued under the Atomic Energy Act, 1962. Chairman, AERB is the competent authority. Implementation of the Rules is primarily to ensure safety of the public and the environment.
Radioactive waste needs to be managed safely because it is potentially hazardous to human health and the environment. Through good practices in the production and use of radionuclides, the amount of waste may be significantly reduced but not fully eliminated. It is important that safe waste management, in compliance with all relevant regulations is considered and planned for at the early stages of any projects involving radioactive materials. The radioactive waste in hospitals comprises different types of waste. It may be in solid, liquid, or gaseous form. The radioactive material may be mixed with different chemicals, which in itself would be hazardous or flammable. Moreover, some of the waste is mixed with biological substances, such as blood and may be infectious. Also, special precautions must be taken for disposing items, such as needles used for injection. All these aspects must be accounted for in the planning of waste treatment in a hospital. In NM, having PET-CT facility, mostly short-lived radioisotopes C-11, N-13, O-15, F-18, and others are used in unsealed form. The half-lives of these radioisotopes range from few minutes to few hours. In a typical NM department, there may be certain sealed sources used for calibration of dose calibrators, survey instruments; these sources may end up as spent sources after their useful life or during the decommissioning of the department. Gaseous radioactive waste arising from the PET-CT department may be very rare.
The solid waste generated in NM includes cover papers, gloves, contaminated items, empty vials, and syringes. The liquid waste may comprise unused or leftover radiopharmaceutic solutions, radioactive spills, decontamination effluents, laboratory washings, and so on.
All the labels on the containers having contaminated radioactive material should be removed defaced prior to disposal. There are 2 main approaches to the disposal of radioactive waste. One is characterized as “dilute and disperse” and the other as “confine and contain.” By the “dilute and disperse” concept, radioactive material, in aqueous or gaseous form, is released into the environment in such a way that the material is diluted and distributed over a large volume so that the final concentration of radionuclides is acceptably low. In the “confine and contain” approach, the waste is collected and converted into a form such that, when placed in a repository, it will retain the radionuclides until the activity has decayed, or at least will ensure that the leakage of radionuclides from the repository does not give rise to unacceptable concentrations anywhere in the environment. This approach is always used for longer-lived solid radioactive waste and spent sources, which are negligible in the PET-CT facility.
When the NM facility is no longer to be used, the permission for decommissioning should be obtained from the AERB.
NM facility with PET-CT employs relatively large activities of high-energy photon emitting radioisotopes. This coupled with the current dose limits for members of the public, can result in a shielding requirement. Even modest reductions in the radiation levels at 511 keV require significant amounts of shielding. A thorough and site-specific evaluation has to be made for each facility.
Presently, AAPM task group report no. 108 on PET and PET-CT shielding requirements are being used for carrying out the shielding calculations. In outline, the sequence of steps similar to any other shielding calculation is as follows:
Vendors are providing specialized equipment to reduce exposure to operating personnel in the PET-CT facility and to improve instrument performance in the higher radiation background found in the hot laboratory. The equipment include:
Transporting and positioning the patient are the operations that deliver significant exposure to the technologist. Maximize separation from the patient after injection and minimize the time spent with them. Patient instruction should be completed before injection, as should the completion of any forms or questionnaires. If the patient is ambulatory, allow as much separation as feasible when they are escorted to the scanner room. Minimize the time spent near the patient in the scanner room. Use of unit dose will reduce technologist exposure compared with the use of bulk distribution radiopharmaceutics. In the hot laboratory, particular attention should be paid to minimize the time required to handle the dose during the assay and verification steps.
It is always better to have the IV access with a butterfly infusion set before the dose is taken out of the shield to reduce the handling time of the syringe. Use of cart to transport the dose from the hot laboratory to the injection room will increase the separation between the technologist and the syringe and reduce the dose if the transport time is significant.
Every staff member, involved in radioactive work, such as radiopharmacy, radiochemistry, dispensing of radioactivity, radiopharmaceutic dose administration, patient imaging, and others, should be covered with personnel monitoring services. For availing this facility, one may approach the Head, CDandR Section, RP and AD, BARC, Anushakti Nagar, Mumbai – 400 094, or the respective accredited laboratory in their zone for the service. Presently, 3 such laboratories are accredited as given below.
In the NM department having the Medical Cyclotron and PET facilities, following are the monitoring equipments required:
Since the quantity of radionuclide that is being handled is significant and the energy of associated radiation is high, it is absolutely necessary to have an automatic smaller dosage dispensing unit, fume hood, and L-Bench to handle smaller dose for quality assurance tests, lead bricks, shielding devices made of tungsten (syringe shield, source container, transport container, and others), remote handling devices (de-capper, cap sealer, long vial holder, pair of tongs, and others)
A facility to be approved by the AERB should have the following staff/personnel. The responsibilities that these personnel have to carry out are also given below.
The NM physician shall
The NM technologist shall
A candidate with the following qualification is eligible to appear in the RSO Certification Examination conducted by the AERB.
ensure urgent processing of personnel dosimeters in cases of suspected overexposure; and display advisory notices in the NM departments to avoid unintentional exposures to pregnant women/lactating mothers.
PET-CT facilities involve somewhat different design requirements than conventional NM facilities and are more likely to require additional shielding. By providing good handling facilities and following good work practices, radiation dose to the staff, public, and environment can be maintained well below the acceptable limit.
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Conflict of Interest: None declared.