Radiation protection in radiotherapy
Download
1 / 54

Radiation Protection in Radiotherapy - PowerPoint PPT Presentation


  • 178 Views
  • Updated On :

Radiation Protection in Radiotherapy. IAEA Training Material on Radiation Protection in Radiotherapy. Part 15 Security of sources, and disposal of disused sources. BSS glossary:. A source is:

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Radiation Protection in Radiotherapy' - tova


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Radiation protection in radiotherapy l.jpg

Radiation Protection inRadiotherapy

IAEA Training Material on Radiation Protection in Radiotherapy

Part 15

Security of sources, and disposal of disused sources


Bss glossary l.jpg
BSS glossary:

  • A source is:

    “Anything that may cause radiation exposure, such as by emitting ionizing radiation or releasing radioactive substances or materials. For example, materials emitting radon are sources in the environment, a sterilization gamma irradiation unit is a source for the practice of radiation preservation of food, an X ray unit may be a source for the practice of radiodiagnosis, and a nuclear power plant is a source for the practice of generating electricity by nuclear power. A complex or multiple installation situated at one location or site may, as appropriate, be considered a single source for the purposes of application of the Standards.”

Part 15: Security and disposal of sources


Objectives l.jpg
Objectives

  • Be able to apply the concept of a radiation source to radiotherapy

  • Understand how sources in radiotherapy can be made secure

  • Be familiar with appropriate ways to dispose of sources in radiotherapy

Part 15: Security and disposal of sources


Contents l.jpg
Contents

1. Sources in radiotherapy

2. Security of sources

3. Disposal of disused sources

Part 15: Security and disposal of sources


1 sources in radiotherapy l.jpg
1. Sources in radiotherapy

  • X Ray equipment

  • Radioactive sources for external beam radiotherapy

  • Radioactive sources for brachytherapy

  • Other sources

Part 15: Security and disposal of sources


A note on exempted sources l.jpg

Radiotherapy sources are HOT!

A note on exempted sources

  • In general radioactive sources used in radiotherapy will NOT qualify for exemption according to BSS schedule I

Part 15: Security and disposal of sources


X ray equipment l.jpg
X Ray equipment

  • Very common source of radiation in radiotherapy

  • Not of major concern for security of sources and disposal because no radiation is produced when the unit is turned off...

Courtesy of Siemens Medical

Part 15: Security and disposal of sources


Radioactive sources for external beam radiotherapy l.jpg
Radioactive sources for external beam radiotherapy

  • In practice 137-Cs and more importantly 60-Co units need to be considered

MDS Nordion

Part 15: Security and disposal of sources


Radioactive sources for ebt l.jpg
Radioactive sources for EBT

  • High activity (>100TBq (3000 Ci))

  • Small (height and diameter a few centimeters)

  • Relatively long half life of 5.26 years for 60-Co and 30 years for 137-Cs

  • Has been source of a major radiation accident in the past… (Goiânia)

Part 15: Security and disposal of sources


A teletherapy 60 co source l.jpg
A teletherapy 60-Co source

120TBq

5cm

Part 15: Security and disposal of sources


Radiation accident in goi nia l.jpg
Radiation accident in Goiânia

  • End 1985 in Brazil

  • Private radiotherapy unit moved location leaving a 137-Cs unit in former premises

  • Authorities were not notified

  • Cs unit was scavenged as scrap metal

Part 15: Security and disposal of sources


Goi nia accident l.jpg
Goiânia accident

  • Source assembly sold to scrap yard

  • ‘Glow in the dark’ caused attraction

  • Parts of the source distributed widely...

Part 15: Security and disposal of sources


Goiania accident l.jpg
Goiania accident

  • Several persons showed gastrointestinal symptoms due to irradiation

  • One affected person contacted public health department

  • A local physicist was involved in determining the extent of the accident and initiated evacuation of affected areas

Part 15: Security and disposal of sources


Large scale accident l.jpg
Large scale accident

Human Costs

  • 249 people contaminated

  • Four people died within 4 weeks

Part 15: Security and disposal of sources


Environmental and financial costs l.jpg
Environmental and financial costs

  • Lots of work

  • Lots of costs

  • Lots of waste

Part 15: Security and disposal of sources


Radioactive sources for brachytherapy l.jpg
Radioactive sources for brachytherapy

  • Many different isotopes and forms as discussed in part 6 of the course

  • Brachytherapy isotopes are in radiotherapy practice the most likely cause of concern for security and disposal of sources

Part 15: Security and disposal of sources


Other sources l.jpg
Other sources

Part 15: Security and disposal of sources


Other sources18 l.jpg
Other sources

  • Check sources for dosimetric equipment

  • Check sources for shielding

  • Except for sources for unsealed source radiotherapy (dealt with in the course on nuclear medicine) all sources can be considered sealed

In practice a small part of the radioactive inventory

of a radiotherapy department - the considerations

in regards to security and disposal for these sources

are similar to brachytherapy sources

Part 15: Security and disposal of sources


2 security of sources l.jpg
2. 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 paras 2.7-2.9), by ensuring that:

    (a) control of a source not be relinquished without compliance with all relevant requirements specified in the registration or licence and without immediate communication to the Regulatory Authority, and when applicable to the relevant Sponsoring Organization, of information regarding any decontrolled, lost, stolen or missing source;” ...

Part 15: Security and disposal of sources


Slide20 l.jpg
...and...

(b) a source not be transferred unless the receiver possesses a valid authorization; and

(c) a periodic inventory of movable sources be conducted at appropriate intervals to confirm that they are in their assigned locations and are secure.”

Part 15: Security and disposal of sources


Security of sources l.jpg
Security of sources

  • Not a problem for X Ray equipment if one assumes that

    • they are properly designed and maintained (compare part 10 of the course)

    • only authorized persons are able to operate the equipment

    • unit cannot be accessed by un-authorized persons

Part 15: Security and disposal of sources


Linac console l.jpg
Linac Console

Key required for operation

Part 15: Security and disposal of sources


Security of sources23 l.jpg
Security of sources

  • All radiation equipment must be locked when not in use...

Part 15: Security and disposal of sources


Security of 60 co sources l.jpg
Security of 60-Co sources

  • In teletherapy units:

    • Mainly a feature of equipment design

    • Treatment rooms must be locked

    • Source transfer only be done by qualified persons

    • Great care must be taken when disposing the source - it MUST be returned to an authorized person or company!!!

Part 15: Security and disposal of sources


Must know the source housing and exposure mechanism design l.jpg
Must know the source housing and exposure mechanism design

Source

Exposure mechanism

Hg pumped

in and out

Part 15: Security and disposal of sources


Security of brachytherapy sources l.jpg
Security of brachytherapy sources

  • Some info in part 6 on sources

  • May affect all aspects of source utilization:

    • receipt of sources

    • storage

    • handling

    • use on patients

    • disposal

125-I seeds - Courtesy Mentor

Part 15: Security and disposal of sources


Safety assessment l.jpg
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

Part 15: Security and disposal of sources


Source storage l.jpg
Source Storage

Source stores must:

  • provide protection against environmental conditions

  • be only for radioactive materials

  • provide sufficient shielding

  • be resistant to fire

  • be secure

Part 15: Security and disposal of sources


Features of source storage l.jpg
Features of source storage

  • Secure (lock and key)

  • Labels

  • Different compartments

  • Shielding

  • Easy access

  • Well organized

Part 15: Security and disposal of sources


Important to keep a good log book l.jpg
Important to keep a good log book

  • Update with every source movement

  • Clear labels

  • Identify all sources

  • A drawing of the safe outline may be useful

Part 15: Security and disposal of sources


Source transport l.jpg
Source transport

  • Always accompanied by qualified person

  • Details in part 14 of the course

Part 15: Security and disposal of sources


Accountability of sources l.jpg
Accountability of sources

  • Receipt, storage, use and all movements of a source must be recorded

Part 15: Security and disposal of sources


Accountability of sources33 l.jpg
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.

Part 15: Security and disposal of sources


Testing and maintenance l.jpg
Testing and Maintenance

  • Testing of safety systems

  • Calibration and testing of radiation monitors

  • Leak tests of sealed sources

  • Periodic examination of safety critical components

Part 15: Security and disposal of sources


Testing and maintenance35 l.jpg
Testing and Maintenance

  • Documentation must exist for all procedures:

    • How to be done

    • Who is responsible

    • How often to be done

      Records of results must be kept

Part 15: Security and disposal of sources


A lost source l.jpg
A lost source...

  • A major concern for radiation protection

  • Possible in case of:

    • Discharge of patients with temporary implants not completely removed

    • In theatre during implant of radioactive seeds

Seeds are small

Part 15: Security and disposal of sources


A lost source37 l.jpg
A lost source

  • In theatre a physicist should be present to identify a lost source immediately

  • Can be located often best using a radiation detector

Part 15: Security and disposal of sources


A lost source in the ward l.jpg
A lost source in the ward

  • Notify physicist or radiation safety officer immediately

  • Have a plan for the search...

Part 15: Security and disposal of sources


A lost source39 l.jpg
A lost source?

Main actions

  • Need an emergency plan

Part 15: Security and disposal of sources


3 disposal of disused sources l.jpg
3. Disposal of disused sources

  • A potential for accidents

  • Disposal routes should already be considered when ordering sources

  • Accounting for sources includes their disposal

  • Responsibility for sources only ends after they have been safely disposed and disposal has been documented

Part 15: Security and disposal of sources


Bss appendix iii public exposure radioactive waste l.jpg
BSS Appendix III: PUBLIC EXPOSURE - Radioactive Waste

  • III.8. “Registrants and licensees shall:

    (a) ensure that the activity and volume of any radioactive waste that results from the sources for which they are responsible be kept to the minimum practicable, and that the waste be managed, i.e. collected, handled, treated, conditioned, transported, stored and disposed of, in accordance with the requirements of the Standards and any other applicable standard; and

    (b) segregate, and treat separately if appropriate, different types of radioactive waste where warranted by differences in factors such as radionuclide content, half-life, concentration, volume and physical and chemical properties, taking into account the available options for waste disposal.

Part 15: Security and disposal of sources


Radiotherapy x ray equipment l.jpg
Radiotherapy X Ray equipment

  • In practice usually not a problem

    • as no parts of the equipment are activated

    • if the unit is properly ‘decommissioned’

    • the unit is disposed off either in a condition which renders it unusable or sold to an appropriately licensed person - this also includes donations

    • the regulatory authority is informed

Part 15: Security and disposal of sources


Disposal of teletherapy sources l.jpg
Disposal of teletherapy sources

  • Due to their high activity (even when not anymore fit for use on patients) the disposal of these sources poses a potential risk for severe accidents…

  • In practice this should not a be major problem if the source is replaced - in this case the manufacturer of the source shall also accept the source to be disposed

Part 15: Security and disposal of sources


Potentially a problem if the teletherapy unit is decommissioned l.jpg
Potentially a problem if the teletherapy unit is decommissioned

  • The source should be disposed to an operator licensed to do so

    • this could be expensive… but is cheaper than an accident

  • Appropriate transport containers must be used

Part 15: Security and disposal of sources


Please note l.jpg
Please note decommissioned

  • A hospital is NOT a suitable place for long term storage of high activity sources

  • The source housing is usually NEITHER suitable for transport NOR for long term storage of the source

Part 15: Security and disposal of sources


Brachytherapy source disposal l.jpg
Brachytherapy source disposal decommissioned

  • Permanent implants ‘walk out with the patient’

    • remaining sources must be disposed of appropriately

  • For temporary implant sources the disposal depends on activity and half life:

    • short/medium half life, low/medium activity (e.g. 192-Ir LDR sources) can be stored until decayed to an activity which is below limit values specified by the regulatory authority

    • this strategy does not work for high activity 192-Ir HDR sources or 137-Cs

Part 15: Security and disposal of sources


192 ir hdr sources l.jpg
192-Ir HDR sources decommissioned

  • Typically exchanged

  • Need trained personal for exchange

  • Storage not recommended

Part 15: Security and disposal of sources


137 cs sources l.jpg
137-Cs sources decommissioned

  • Despite half life of 30 years most manufacturers only specify a useful life of 10years. This is mainly due to:

    • risk of damage to the encapsulation

    • e.g. Cs pellets in Microselectron ‘bump’ into each other during loading of the applicators

  • Wipe tests required

  • Disposal only to person authorized to accept sources

Part 15: Security and disposal of sources


A note on the role of suppliers l.jpg
A note on the role of suppliers decommissioned

  • BSS appendix IV.9. “In addition, and where applicable, registrants and licensees shall make suitable arrangements with suppliers of sources:

    (a) to establish and maintain mechanisms for suppliers to obtain information from the registrants and licensees or other users on the use, maintenance, operating experience, dismantling and disposal of sources, and in any particular normal or abnormal operating conditions that may be important for the protection of individuals or the safety of the source;…”

Safety and security of sources is everyone's responsibility

Part 15: Security and disposal of sources


Summary l.jpg
Summary decommissioned

  • Safety and security must be considered for all sources in radiotherapy

  • Security of sources relies on a system of accounting for sources

  • Disposal of sources is a major responsibility of the licensee - sources must only be disposed to an authorized person or company

Part 15: Security and disposal of sources


Where to get more information l.jpg
Where to Get More Information decommissioned

  • Parts 6, 10 and 11 of the course

Part 15: Security and disposal of sources


Any questions l.jpg

Any questions? decommissioned


Question l.jpg

Question: decommissioned

Please discuss what records should be included in a system for accountability of sources used for external beam radiotherapy


The records should include l.jpg
The records should include: decommissioned

  • Name of authorized person

  • Licensee and license conditions

  • Who ordered the source and when

  • Supplier (including address, license details and contact details)

  • Source specifications (chemical form,

  • Date delivered, received by

  • Source certificate

  • Installed by

  • List of tests performed

  • Name and contact details of person for emergencies (e.g. RSO)

  • Record of ongoing relevant QA (e.g. wipe tests, activity verification)

  • Any incidents (stuck source?)

  • Any changes to licensing conditions

  • Decommissioning details

  • Disposal details (name and license of the person/company the source was disposed to)

Part 15: Security and disposal of sources


ad