Harmful Effects of Exposure to Radiation
The staff, the patients and many others in the vicinity, may be exposed to the hazards of radiation which may be Somatic, Teratogenic or Genetic.
Somatic Effects (affecting the body of the irradiated person) such as Radiation Erythematic, Leukemia, Hypo plastic Anemia, Sterility (reproductive organs have the highest sensitivity to radiation hazards), Malignancy.
A teratogenic effect (birth defects in the new born) of exposure to ionizing radiation during pregnancy is a known radiation hazard.
Genetic effects (hereditary disorders in the progeny) of exposure of reproductive organs to radiation such as hereditary disorders or birth defects
The Radiation Effects on Patients and Public can be prevented by:
i. Safe facilities
ii. Compliance with statutory requirements
iii. Credentialing and privileging of technical staff
iv. Safe handling and storage of radioactive materials
v. Safe handling and disposal of radioactive waste
vi. Appointment of a radiation safety officer
vii. Specific measures for protection of patients from undesirable exposure to radiation
viii.General safety measures.
1. Safe Facilities:
The buildings housing the radio diagnosis or radiotherapy services must be constructed in compliance with the Radiation Safety Regulations.
The designs have to be approved by the AERB and after installation of the equipment and before commissioning; the facilities have to be again approved by the AERB. Some of the important aspects are discussed below.
a. Location, Accommodation, Space, Layout and Design:
i. The department should be sited so as to be near the OPD/A & E services and yet convenient for the inpatient areas
ii. The machine rooms, especially the X-ray, CT and MRI should be away from the public traffic
iii. The design should be as per the Radiation Safety norms and approval of AERB to ensure the safety of patients, staff and the passersby from radiation hazards
iv. The flooring in the machine rooms should be nonconductive
v. Windows should be 2 m above the ground outside if standard glass is used. The glass partition between X-ray room and the control panel room should be of see through lead glass of at least 2 mm thickness.
b. Size of the Equipment Rooms:
5 m X 4 m (as per the BARC Rules, depending upon the equipment) CT scan unit: 110 to 120 sq m
Mammography unit: 15-20 sq m, if located next to CT unit
110-120 Sq M. It is a highly sensitive department as it has to accommodate a “Hot lab” also which houses radioactive nuclides which are potentially hazardous and require extra care in receiving, storing and disposal.
c. Wall Thickness of the Equipment Rooms:
The material and thickness of walls of the equipment rooms is of crucial importance. Radiation spreads horizontally (chest X-rays) as well as through scatter effect.
Though 1 mm lead thickness may suffice up to 30 exposures a day, a wall thickness of 2 mm lead equivalent should be ideal (1 mm of lead = 8-10 cm of poured standard concrete of density 2.35 G/cm3 = 1 cm of plate glass or 5 mm thick steel sheeting), especially against the direction of the beam (as in chest X-rays).
d. Positioning of Equipment:
Thickness of wall between the X-ray room and the dark room should be at least 10 cm brick/concrete. If beam is pointed towards that wall then the thickness should be at least 20 cm of poured standard concrete otherwise fogging of films will take place.
The entry doors of the machine rooms should be reinforced suitably to be radiation proof. The beam should not be pointed towards the entry door.
2. Compliance with Statutory Requirements for Safe Operation of Medical X-ray Machines:
AERB has laid down the safety code on ‘Medical Diagnostic X-ray Equipment and Installation (No. AERB/SC/MED-2 (Rev.1) for ensuring safety in the operation of medical X-ray machines. The responsibility for ensuring compliance with the statutory provisions rests with the owner/employer of medical X-ray installation.
It is mandatory that all medical X-ray installations in India get registered with AERB, (Niyamak Bhavan, Anushakti Nagar, and Mumbai 400094) and comply with the following rules:
i. Only the X-ray machines approved by AERB shall be installed for use
ii. It shall be ensured that only the technicians duly qualified, as prescribed in the safety code, are permitted to operate the X-ray machines
iii. Safety accessories, equipment and other materials required as per the safety code shall be procured in sufficient quantity and used by the radiation workers
iv. Personnel associated with the operation of X-ray machines shall be provided with individual radiation monitoring badges
v. Medical X-ray installations will be subjected to periodic inspections by persons authorized under Section 17 of the Atomic Energy Act, by the chairman AERB/his representatives
vi. Quality assurance performance tests of the X-ray machines shall be carried out by the supplier/manufacture of the equipment. The owner may seek the advice from Radiological Physics and Advisory Division, Bhaba Atomic Research center, CT and CRS Building, Anushakti Nagar, Mumbai in this regard.
3. Credentialing and Privileging of Staff:
In view of the seriousness of hazards, it is imperative for the hospital management to verify the credentials and proficiency of the staff in safe operations of equipment and radiation safety rules before putting them on duty.
4. Safe Storage and Handling of Radio Active Materials:
The department must have a satisfactory arrangement for safe storage of radioactive materials such as Cobalt 60, Iridium and other radio isotopes used in nuclear medicine such as given in annexure 21.
5. Safe Handling and Disposal of Radioactive Waste:
Improper disposal of radioactive waste can be extremely dangerous as it may affect not only the patients and staff, but even the general public exposed to it.
6. Appointment of a Radiation Safety Officer:
As per rule 12 of the Atomic Energy (Safe Disposal of Radioactive Waste) Rules 1987, the authorized person (MS of hospital with radiotherapy and isotope studies facilities) is required to appoint, with the approval of the competent authority, either himself or a person under his employ as Radiological Safety Officer (RSO).
The RSO should have had training in radiological safety at BARC and one year experience under a qualified RSO and would perform the following functions:
i. To advise the employer regarding the safe handling and disposal of radioactive wastes
ii. To instruct the radiation workers engaged in waste disposal on the hazards of radiation and on suitable measures and work practices aimed at minimizing exposure to radiation and contamination, and to ensure that adequate radiation surveillance is provided for all radiation workers and environment
iii. To ensure that all buildings, laboratories and plants wherein radioactive waste will be handled/produced/stored/discharged from, are designed to provide adequate safety for safe handling and disposal of radioactive waste
iv. To assess the radiation protection equipment/instruments required for an installation and to keep such equipment/instruments in use under proper calibration
v. To help investigate and initiate prompt suitable measures in respect of any situation that could lead to radiation hazards
vi. To ensure that reports on all hazardous situations along with details of any remedial measures that may have been initiated, are made available immediately to his employer and a copy, thereof, to the competent authority
vii. To ensure that provisions of Radiation Protection Rules 1971 are followed properly.
7. Measures for Protection of Patients:
The departmental radiation safety manual must describe in detail, the important measures for safety of patients and public.
The radiation safety procedures, as mentioned below, must be known, understood and implemented by all staff.
a. Specific Measures for Protection of Patients:
i. Avoidance of unnecessary investigations.
ii. A procedure for proper identification of the patient before allowing him in the machine room.
iii. Use of collimaters/cones.
iv. Covering of the other parts of the body by protective shields or other protective covers.
v. Reproductive organs are highly sensitive to radiation effects (nearly 2-4 times more than other tissues).50 The same amount of exposure produces far more serious health effects on gonads than on other issues. Therefore, gonadal/pelvic shielding is a must, wherever indicated.
vi. For every procedure the exposure must be minimum acceptable and as per the instructions in the safety manual.
vii. Pregnant women, because of dangers of teratogenic effects need to be more cautious. X-rays examination (particularly of the abdomen) should be contraindicated in pregnant women unless it is a life-threatening situation for the mother. Other body parts however, may be X-rayed, if unavoidable, after full protection of the rest of the body (especially the abdomen) and with full information and consent of the patient. However, it will be ensured that the woman receives the dose as low as reasonably possible.
viii.As a rule, a notice in the radiology department (prominently displayed) is supposed to advise all female patients to inform the staff in case they are pregnant.
ix. Availability of specialist doctors to handle emergency situations like allergic reactions to the dyes injected during specialized investigations.
b. General Safety Measures for Protection of Patients:
i. Having a departmental manual of policies and procedures for protection against radiation hazards including the actions to be taken for safe handling of accidental radiation leakage or spillage of radioactive materials.
ii. Patients undergoing investigations often have to undress for the investigations. The department must have a proper change room attached to every machine room, where the patients can undress/change in privacy.
iii. A department with more than two machine rooms should have attached toilet facility with at least one machine room for patients’ convenience during some investigations.
iv. It is particularly important to ensure privacy during the investigations by not allowing anyone in. Availability of a female attendant/husband is a must in case of tests (ultra sonography) on female patients.
v. The doors to the X-ray rooms must always be kept closed and the red light on during an exposure, to prevent anyone walking in by mistake.
vi. Reports of investigations are privileged information and confidentiality must be maintained.
8. Measures for Protection of Public:
i. By display of signage warning the public about the radiation hazard in the hazardous area and red light outside the equipment room, when the equipment is on:
ii. Not allowing anyone except patient and staff when the radio diagnosis/therapy equipment is on
iii. Correct storage of radioactive materials and correct disposal of radioactive waste as per the rules
iv. Periodic surveillance of the radiation level by the Radiation Safety Officer in and around the rooms housing the equipment and radioactive stores.
Safety in radiology and radiotherapy departments, unlike other departments, is very important because the damage done cannot be undone by any means.
Prevention of ill effects of radiation is the only effective approach. Therefore, management and staff have to ensure that all radiation safety measures are implemented in letter and spirit.