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04. Safety of sources and design of facilities (2,935 KB)

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  • These are some examples of the sealed sources used in a nuclear medicine department
  • This is an example of classification of radionuclides according to their radiotoxicity
  • Note that there different types of generators. This illustrates a dry type with a separate container of saline solution that is changed every time a new elution will be made. In the wet type of generator there is a built in container with enough volume of saline solution for all elutions
  • Example of a transport container for a Tc generator
  • This image shows that extra shielding of the generator should be used.as well as shielding of the elution vial
  • This is a closer look at the top of the generator with the needles where the elution vial and the saline solution vial are placed
  • The shielded elution vial
  • The image can be used for a short explanation of a radiopharmaceutical. The same radioactive substance can be used in labeling of different compunds resulting in radiopharmaceuticals with different properties
  • This image and the follwing images are illustrations to the different types of work performed in nuclear medicine. They should be used to explain the need to have different requirements for different types of facilities.
  • These images are examples of bad storage. The image to the left shows an equipment for ventilation studies that is stored in an office
  • The image illustrates how the security of sources must be considered during their lifetime in the hospital
  • The main messages are already dealt with in part XIV of the Material
  • This is a central message - the lecturer should ensure the participants grasp its importance. The documentation must be verified and easily accessible for updates.
  • This is to illustrate the concept of defense in depth. A source is contained in a shield to prevent from external exposure. If contamination occur it should be kept within the work area, the laboratory, the department or at least in the hospital. Weak points? Identify situations where the defense in depth will fail, meaning that we have to introduce a different safety concept or special requirements. Weak points are exhaust of volatile radionuclides through the fume hood directly out in the air and disposal of sources via the sewage system. Another weak point is the living source (patient) leaving the hospital.
  • This is an introduction to the ICRP concept of categorization of hazard which should be used to define some basic building requirements.
  • This is an example of a calculation of the weighted activity. In this case the room for administration of an iodine therapy is a high hazard room
  • These are examples of categorization of hazard for different rooms in a typical nuclear medicine department handling quite large amounts of Tc99m
  • This image should be used to illustrate that categorization of hazard and safety assessments not solely should used to determine the furnishing of a room but also its use.
  • The lecturer can ask the students if there is something wrong in the design of the lead shields although the image basically is an illustration of the possible need of reinforcement of the bench.
  • Rooms where work with unsealed sources are taken place should be under negative pressure to minimize the risk of airborne radionuclides to be spread, The sterile environment that might be necessary in preparation of radiopharmaceuticals is achieved in a laminar air flow bench.
  • If there are regulations about air pressure gradients they should be continously monitored and an alarm system introduced
  • This illustartion is from a Nuclear Medicine department in India. Does it follow the general rule to separate high activity areas from low activity areas and to separate working areas from patient areas?
  • It is important that the radioactive waste be segregated at the point of origin. In a big nuclear medicine department this means that several types of waste containers must be available. In a small department it may be enough with one container for paper, gloves etc and one container for glass, needle and syringes.
  • The image of the gamma camera is to point out that without the collimator it can be used as a whole body counter

04. Safety of sources and design of facilities (2,935 KB) 04. Safety of sources and design of facilities (2,935 KB) Presentation Transcript

  • Part 4 Safety of Sources Design of facilities IAEA Training Material on Radiation Protection in Nuclear Medicine
  • OBJECTIVE To become familiar with the types of sources used in nuclear medicine. To become aware of how the basic principles of defence in depth, safety of sources and optimization are applied to the design of a nuclear medicine facility. To get basic information about shielding calculations.
  • Content
    • Sources
    • Work with sources
    • Security of sources
    • Defense in depth
    • Categorization of hazard
    • Building requirements
    • Safety equipment
  • Part 4. Design of facilities Safety of Sources Module 4.1. Sources IAEA Training Material on Radiation Protection in Nuclear Medicine
  • Sealed sources in nuclear medicine Sealed sources used for calibration and quality control of equipment (Na-22, Mn-54, Co57, Co-60, Cs137, Cd-109, I-129, Ba-133, Am-241). Point sources and anatomical markers (Co-57, Au-195). The activities are in the range 1 kBq-1GBq .
  • Unsealed sources in nuclear medicine
  • Unsealed sources in nuclear medicine
  • Unsealed sources in nuclear medicine
  • RADIOTOXICITY Class A. Very high e.g. Am-241, Cf-252 Class B. High e.g. Na-22, Ca-45, Mn-54, Co-60, Sr-89, I-125, I-131 Class C. Medium e.g. C-14, F-18, P-32, Cr-51, Co-57, Ga-67, Se-75, Mo-99, In-111, I-123, Au-198, Tl-201 Class D. Low e.g. H-3, C-11, N-13, O-15, Tc-99m, Xe-133
  • Nuclear medicine application according to type of radionuclide Radionuclide
    • Pure  emitter  (  )
    • e.g. ; Tc99m, In111, Ga67, I123
    • Positron emitters (ß + )  
    • e.g. : F-18
    •  , ß - emitters  
    • e.g. : I131, Sm153
    • Pure ß - emitters  
    • e.g. : Sr89, Y90, Er169
    •  emitters  
    • e.g. : At211, Bi213
    Diagnostics Therapy
  • 99 Mo- 99m Tc GENERATOR 99 Mo 87.6% 99m Tc  140 keV T½ = 6.02 h 99 Tc ß - 292 keV T½ = 2*10 5 y 99 Ru stable 12.4% ß - 442 keV  739 keV T½ = 2.75 d
  • Technetium generator Mo-99 Tc-99m Tc-99 66 h 6h NaCl AlO 2 Mo-99 +Tc-99m Tc-99m
  • Technetium generator
  • Technetium generator
  • Technetium generator
  • Technetium generator
  • Technetium generator
  • Radiopharmaceuticals Radionuclide Pharmaceutical Organ Parameter + colloid Liver RES Tc-99m + MAA Lungs Regional perfusion + DTPA Kidneys Kidney function
  • RADIOPHARMACEUTICALS
    • Radiopharmaceuticals used in nuclear medicine can be classified as follows:
    • ready-to-use radiopharmaceuticals
    • e.g. 131 I- MIBG, 131 I- iodide , 201 Tl- chloride , 111 In- DTPA
    • instant kits for preparation of products
    • e.g. 99m Tc-MDP, 99m Tc-MAA, 99m Tc-HIDA, 111 In-Octreotide
    • kits requiring heating
    • e.g. 99m Tc-MAG3, 99m Tc-MIBI
    • products requiring significant manipulation
    • e.g. labelling of blood cells, synthesis and labelling of radiopharmaceuticals produced in house
  • RADIOPHARMACEUTICALS
    • Radiopharmaceutical labeling must be performed in accordance with :
    • Radiation safety regulations
    • GMP requirements
    • Requirements of these respective regulations are sometimes conflicting :
    • Manipulation of radioactive material must be performed in closed area under negative air pressure
    • Manufacturing of sterile injectable preparation must be performed under filtered positive air pressure (laminar flow)
  • Part 4. Design of facilities Safety of Sources Module 4.2. Work with sources IAEA Training Material on Radiation Protection in Nuclear Medicine
  • Production of radionuclides Medical cyclotron Industrial cyclotron
  • Preparation and dispensation of radiopharmaceuticals
  • Laboratory work with radionuclides
  • Administration of radiopharmaceuticals
  • Patient examinations
  • Animal experiments
  • CARE OF RADIOACTIVE PATIENTS
  • Storage of radionuclides
  • Part 4. Design of facilities Safety of Sources Module 4.3. Security of sources IAEA Training Material on Radiation Protection in Nuclear Medicine
  • LOCATION AND SITING OF SOURCES (BSS)
    • “ IV.13. Account shall be taken in choosing the location for any small
    • source within installations and facilities such as hospitals and
    • manufacturing plants of:
    • Factors that could affect the safety and security of the source;
    • Factors that could affect occupational exposure and public
    • exposure caused by the source, including features such as
    • ventilation, shielding and distance from occupied areas; and
    • The feasibility in engineering design of taking into account the
    • foregoing factors.”
  • Requirements for the Safety of Sources
    • General Responsibilities
      • Licensees shall ensure safety of the sources
      • A multilevel system of provisions for
        • preventing accidents
        • mitigating consequences
        • restoring sources to safe conditions
      • Use of sound engineering practice on all operations with sources
  • Security of sources
    • BSS 2.34: “Sources shall be kept secure so as to prevent theft or damage and to prevent any unauthorized legal person from carrying out any of the actions specified in the General Obligations for practices of the Standards (see para’s 2.7-2.9),
  • Requirements
    • Accountability and security of sources
      • Records of source inventory (source characteristics, locations)
      • Periodic inventory of sources
      • Records of receipt, transfer and disposal
      • Transfers only to receiver holding a license
      • Prompt communication of information to the Regulatory Authority regarding decontrolled, lost, stolen or missing sources
  • SECURITY OF SOURCES Use Storage of waste Transport (in house) Storage before use Receipt The security of sources shall be taken into account in the different steps of the lifetime of a source in a hospital
  • RECEIPT PROCEDURE
    • Local rules should specify
    • Persons authorized to order radionuclides
    • Routines for delivering radioactive material to the department
    • Routines for check and unpacking of shipment
    • Routines in case of damaged package
    • Routines for check of radionuclide and activity
    • Records to be kept
  • Source Storage
    • Source stores must:
    • provide protection against environmental conditions
    • be only for radioactive materials
    • provide sufficient shielding
    • be resistant to fire
    • be secure
  • STORAGE OF SOURCES
    • locked to prevent unauthorized use
    • and theft
    • warning sign
    • shielded to <2 µ Sv/h at 1m
    • (permanently occupied areas)
    • alternatively <20 µ Sv/h at 1 m
    • (temporarily occupied areas)
    • inventory record
  • Source transport
    • In house transport, according to local rules.
    • External transport, according to international standards and requirements.
  • RADIOACTIVE WASTE
    • Radioactive waste should be handled, stored and disposed of according to local rules that are based on national regulations.
  • Accountability of sources
    • Receipt, storage, use and all movements of a source must be recorded
  • Accountability of Sources
    • Source accountancy records should contain:
      • radionuclide and activity of sources
      • location and description of sources
      • disposal details
    • The records should be updated regularly, and the location of the sources checked.
  • Safety Assessment
    • Identification of the mechanisms for exposure (both routine and accidents)
    • Realistic estimate of doses and likelihood of occurring
    • Identification of possible safety system failures
    • Identification of protection measures needed
  • Safe use of sources
    • Key elements
    • classification of areas
    • local rules
    • supervision arrangements
    • individual monitoring arrangements
    • workplace monitoring arrangements
    • training arrangements
    • emergency plans
  • How do we transfer the requirements of BSS regarding safety and security of sources into the design of a nuclear medicine facility? ??
  • The role of RPO The radiation protection officer (RPO) should be consulted as soon as the planning process commences for construction or renovation of a nuclear medicine facility or other hospital radioisotope laboratory.
  • Facilities The design of the facility should take into consideration the type of work and the radionuclides and their activities intended to be used. The concept of ‘categorization of hazard’ should be used in order to determine the special needs concerning ventilation, plumbing, materials used in walls, floors and work benches.
  • Part 4. Safety of Sources Design of facilities Module 4.4. Defense in depth IAEA Training Material on Radiation Protection in Nuclear Medicine
  • DEFENSE IN DEPTH (BSS)
    • “ 2.35. A multilayer (defense in depth) system of provisions for protection and safety commensurate with the magnitude and likelihood of the potential exposures involved should be applied to sources such that a failure at one layer is compensated for or corrected by subsequent layers, for the purposes of:
    • (a) preventing accidents that may cause exposure;
    • mitigating the consequences of any such accident that does
    • occur; and
    • (c) restoring sources to safe conditions after any such accident.”
  • Defense in depth
    • Nuclear medicine:
    • Source
    • Shielded container
    • Work area
    • Laboratory
    • Department
    • Hospital
    Weak points?
  • Part 4. Design of facilities Safety of Sources Module 4.5. Categorisation of hazard IAEA Training Material on Radiation Protection in Nuclear Medicine
  • Categorization of hazard Based on calculation of a weighted activity using weighting factors according to radionuclide used and the type of operation performed. Weighted activity Category < 50 MBq Low hazard 50-50000 MBq Medium hazard >50000 MBq High hazard
  • Categorization of hazard Weighting factors according to radionuclide Class Radionuclide Weighting factor A 75 Se, 89 Sr, 125 I, 131 I 100 B 11 C, 13 N, 15 O, 18 F, 51 Cr, 67 Ga, 99m Tc, 111 In, 113m In, 123 I, 201 Tl 1.00 C 3 H, 14 C, 81m Kr 127 Xe, 133 Xe 0.01
  • Categorization of hazard Weighting factors according to type of operation Type of operation or area Weighting factor Storage 0.01 Waste handling, imaging room (no inj), waiting area, patient bed area (diagnostic) 0.10 Local dispensing, radionuclide administration, imaging room (inj.), simple preparation, patient bed area (therapy) 1.00 Complex preparation 10.0
  • Categorization of hazard Administration of 11 GBq I-131 Weighting factor, radionuclide 100 Weighting factor, operation 1 Total weighted activity 1100 GBq Weighted activity Category < 50 MBq Low hazard 50-50000 MBq Medium hazard >50000 MBq High hazard
  • Categorization of hazard Patient examination, 400 MBq Tc-99m Weighting factor, radionuclide 1 Weighting factor, operation 1 Total weighted activity 400 MBq Weighted activity Category < 50 MBq Low hazard 50-50000 MBq Medium hazard >50000 MBq High hazard
  • Categorization of hazard Patients waiting, 8 patients, 400 MBq Tc-99m per patient Weighting factor, radionuclide 1 Weighting factor, operation 0.1 Total weighted activity 320 MBq Weighted activity Category < 50 MBq Low hazard 50-50000 MBq Medium hazard >50000 MBq High hazard
  • Category of hazard (premises not frequented by patients) Typical results of hazard calculations High hazard Room for preparation and dispensing radiopharmaceuticals Temporary storage of waste Medium hazard Room for storage of radionuclides Low hazard Room for measuring samples Radiochemical work (RIA) Offices
  • Category of hazard ( premises frequented by patients) Typical results of hazard calculations High hazard Room for administration of radiopharmaceuticals Examination room Isolation ward Medium hazard Waiting room Patient toilet Low hazard Reception
  • Building requirements Category Structural shielding Floors Worktop surfaces of hazard walls, ceiling Low no cleanable cleanable Medium no continuous cleanable sheet High possibly continuous cleanable one sheet folded to walls What the room is used for should be taken into account e.g. waiting room
  • Building requirements Category Fume hood Ventilation Plumbing First aid of hazard Low no normal standard washing Medium yes good standard washing & decontamination facilities High yes may need may need washing & special forced special decontamination ventilation plumbing facilities facilities facilities
  • Design Objectives
    • Safety of sources
    • Optimize exposure of staff, patients and general public
    • Maintain low background where most needed
    • Fulfil requirements regarding pharmaceutical work
    • Prevent uncontrolled spread of contamination
  • Part 4. Design of facilities Safety of Sources Module 4.6. Building requirements IAEA Training Material on Radiation Protection in Nuclear Medicine
  • Floors
    • Impervious material
    • Washable
    • Chemical-resistant
    • Curved to the walls
    • All joints sealed
    • Glued to the floor
    No carpet!
  • Walls and ceiling Should be finished in a smooth and washable surface with joints being sealed, wherever practicable. Walls should be painted with washable, non-porous paint (e.g. gloss paint). What the room is used for should be taken into account e.g. waiting room
  • Worktop surfaces
        • Worktop surfaces must be finished in a smooth, washable and chemical-resistant surface with all joints sealed. Some laminates do not resist certain chemicals, and the supplier should be consulted with regard to the specific chemicals to be used in the laboratory.
        • Open shelving should be kept to a minimum to prevent dust accumulation.
        • Services (e.g. gas, electricity, vacuum) should not be mounted on top of the bench, but on walls or upstands.
        • Light fixtures should be easy to clean and of an enclosed type in order to minimize dust accumulation.
  • Worktop surfaces
        • Structural reinforcement may be necessary, since a considerable weight of lead shielding may be placed on counter tops.
  • Worktop surfaces Cover the surface with absorbing paper
  • VENTILATION
        • Laboratories in which unsealed sources, especially radioactive aerosols or gases, may be produced or handled should have an appropriate ventilation system that includes a fume hood, laminar air flow cabinet or glove box.
        • The ventilation system should be designed such
        • that the laboratory is at negative pressure relative to surrounding areas. The airflow should be from areas
        • of minimal likelihood of airborne contamination to areas where such contamination is likely.
        • All air from the laboratory should be vented through a fume hood and must not be recirculated either directly,
        • in combination with incoming fresh air in a mixing system, or indirectly, as a result of proximity of the exhaust to a fresh air intake.
  • VENTILATION Sterile room negative pressure filtered air Dispensation negative pressure Corridor Injection room Fume hood Laminar air flow cabinets Passage Work bench
  • Continuous monitoring of air pressure gradients Alarm system
  • Fume hood The fume hood must be constructed of smooth, impervious, washable and chemical-resistant material. The working surface should have a slightly raised lip to contain any spills and must be strong enough to bear the weight of any lead shielding that may be required. The air-handling capacity of the fume hood should be such that the linear face velocity is between 0.5 and 1.0 metres/second with the sash in the normal working position. This should be checked regularly.
  • PLUMBING
    • sinks
    • washing facilities
    • patient toilets
  • Sinks
        • If the Regulatory Authority allows the release of aqueous waste to the sewer a special sink shall be used. Local rules for the discharge shall be available. The sink shall be easy to decontaminate. Special flushing units are available for diluting the waste and minimizing contamination of the sink.
  • Washing facilities
        • The wash-up sink should be located in a low-traffic area adjacent to the work area.
        • Taps should be operable without direct hand contact and disposable towels or hot air dryer should be available.
        • An emergency eye-wash should be installed near the hand-washing sink and there should be access to an emergency shower in or near the laboratory.
  • Patient toilet
        • A separate toilet room for the exclusive use of injected patients is recommended.
        • A sign requesting patients to flush the toilet well and wash their hands should be displayed to ensure adequate dilution of excreted radioactive materials and minimise contamination.
        • The facilities shall include a wash-up sink as a normal hygiene measure.
        • Washrooms designated for use by nuclear medicine patients should be finished in materials that are easily decontaminated.
        • The patient washing facilities should not be used by hospital staff as it is likely that the floor, toilet seat and sink faucet handles will be contaminated frequently.
  • Pipes
        • Drain-pipes from the radioisotope laboratory sink should go as directly as possible to the main building sewer, and should not connect with other drains within the building, unless those other drains also carry radioactive material. This is to minimize the possibility of a &quot;back up&quot; contaminating other, non-controlled areas. and the final plans of the drainage system which are supplied to maintenance personnel must show which drains are from radioisotope laboratories.
        • Note: Some countries require that drain-pipes from the nuclear medicine department and especially from isolation wards for patients undergoing radionuclide therapy shall end up in a delay tank.
  • Shielding Much cheaper and more convenient to shield the source, where possible, rather than the room or the person. Structural shielding is generally not necessary in a nuclear medicine department. However, the need for wall shielding should be assessed e.g. in the design of a therapy ward (to protect other patients and staff) and in the design of a laboratory housing sensitive instruments (to keep a low background in a well counter, gamma camera, etc)
  • Layout of a nuclear medicine department From high to low activity
  • Part 4. Design of facilities Safety of Sources Module 4.7. Safety equipment IAEA Training Material on Radiation Protection in Nuclear Medicine
  • Safety equipment
    • Shields
    • Protective clothing
    • Tools for remote handling
    • of radioactive material
    • Containers for radioactive waste
    • Dose rate monitor with alarm
    • Contamination monitor
    • Decontamination kit
    • Signs, labels and records
  • SHIELDING Bench top shield Vial shields Syringe shields Structural shielding
  • FORCEPS AND TONGS
  • Containers for radioactive waste Several containers should be available in order to segregate the waste at the point of origin (radionuclides, half-lives, glass, paper, syringes etc.)
  • MONITORING EQUIPMENT Personal (effective dose, extremity dose & contamination) Workplace (external dose rate & contamination)
  • EMERGENCY KIT
    • Should be kept readily available for use in an emergency. It may include the following:
    •  
    • protective clothing e.g. overshoes, gloves
    • decontamination materials for the affected areas including absorbent materials for wiping up spills,
    • decontamination materials for persons
    • warning notices,
    • portable monitoring equipment
    • bags for waste, tape, labels, pencils .
  • Signs, labels and records Activity:4312 MBq Volume:12 ml Activity concentration; 359 MBq/ml Date: 2001-10-18 Time: 07.45 Signature:SC Tc99m-MDP Tc.generator no: A2376 Reference activity: 30 GBq Reference date: Oct 12 12.00 GMT SC 15 ml 22572 MBq 07.30 Oct 15 Signature Volume Activity Time Date
  • Questions?
  • DISCUSSION A hospital is setting up a new nuclear medicine practice with 2 gamma cameras. Discuss the layout, furnishing , safety equipment etc. required in the imaging room.
  • DISCUSSION Discuss a programme for daily cleaning of the department. When, where and how? Local rules?
  • DISCUSSION A laboratory is performing only preparation and measurements of plasma samples containing Cr-51. What safety equipment is needed?
  • Where to Get More Information
    • Practical session
      • Visit to a Nuclear Medicine Department, Simulated inspection of facilities
    • Other sessions
      • Part 5 . Occupational exposure
      • Part 8. Medical exposure. Therapy
      • Part 10. Radioactive waste
      • Part 11. Protection of general public
      • Part 12. Potential exposure
    • Further readings
      • IAEA, International Basic Safety Standards for Protection Against Ionizing Radiation and for the Safety of Radiation Sources Safety Series No.115, (1996)
      • IAEA/WHO Manual on Radiation Protection in Hospital and General Practice, Volume 4, Nuclear Medicine . (draft)
      • Saha GB, Fundamentals of Nuclear Pharmacy. 4 th edition . Springer Verlag, 1998. ISBN 0-387-98341-4.