Segurança e Protecção Radiológica em Aplicações Médicasde Fontes de Radiação

Radiological Protection, Safety and Security Issues in the Medical Applications of Radiation Sources

Pedro Vaz

Centro de Ciências e Tecnologias Nucleares

Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal

XX Congresso Brasileiro de Física Médica e

Simpósio Internacional de Proteção Radiológica em Medicina

Rio de Janeiro, Brasil, 13 de Agosto de 2015

About Radioactive Sourcestrivial thoughts...

They are ubiquitous, in medical, industrial, research, lifestyle, etc. applications, etc.

They can pose hazards to individuals´health if undue exposure to the ionizong radiation they emmit occurs

They are usually small-sized

Even high activity radioactive sources can occupy small volumes

They are easily transportable

Easily stolen, diverted

They are... radioactive !

trigger specific psychological and emotional reactions in the citizens (members of the public)

About the word“Segurança”…

Security/Securité

Safety/Sûreté

English/French Portuguese

Segurança

Outline

• Use of radioactive sources for medical and industrial applications –facts and numbers - an (historical) overview

• Radiation Protection issues

• Safety versus Security issues

• DSRS and Orphan Sources: Risk, Hazards, Accidents, Malicious acts

– “Where are we and where do we go from here ?”

• Security of Radiation Sources in the Medical Applications - example

• Conclusions

IAEA Conferences

Use of radioactive sources for

medical and industrial applications

facts and numbers - an (historical) overview

Radioactive sources are used worldwide for peaceful applications

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Radioactive sources are used worldwide for peaceful applications

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Radioactive SourcesApplications, Activity, Quantities

Source: J. Conca (2006)

Activity

“Quantity”(number of sources)

Radioactive sealed sources in medical applications

Co-60 is (still) used for treating cancer (~45,000 treatments/day in more than 50 countries)

Cs-137 is used in blood irradiation to prevent GVHD following transfusions (over 750 units installed in 50 countries)

Brachytherapy techniques in novel treatment applications employ

Ir-192, I-125, Pd-103, Sr-90, etc.

Co-60 is depended upon to sterilize some 45% of all single-use medical supplies and devices in the world:

sutures, catheters, syringes, heart valves, artificial joints and an estimated 80% of all surgeons’ gloves

Data from P. Gray, Chairman, International Source Suppliers and Producers Association (ISSPA) – October 2013

Types of Radioactive SourcesUSA @ 2008

Extracted from report “Radiation Source Use and Replacement”, U.S. National Research Council, National Academy Press (2008)

HASSEuropean Union @ 2014

Extracted from European Commission report “RADIATION PROTECTION N° 179”

30700 High Activity Sealed Sources (HASS)

50%

Radioactive sourcesProduction (@ 2008)

Extracted from report “Radiation Source Use and Replacement”, U.S. National Research Council, National Academy Press (2008)

Radioactive SourcesFrom the 1950s to 1980s

• The “Golden Era” ?

• Utilization of Radioactive Sources promoted for their benefits, particulary in developping countries

• Regulations still being developed

• Concerns: Radiological Protection and Safety

– focusing on not exceeding the regulatory limits for workers

Radioactive SourcesFrom 1987 to 2001

• Era of Safety Concerns

• 1987: Radiological accident in Goiânia

– A landmark !

• Awakening of international consciousness

• Orphan sources:

– The global nature of the problem is recognised

• Dijon Conference (1998)

• IAEA Action Plan & Code of Conduct (2000-2001)

• Concerns: Radiological Protection, Radiation Safety (mainly)

Radioactive SourcesSince 2001 (> 11th September)

• Era of Security Concerns

• Deliberate malicious use becomes a major source of concern

• Security becomes a top priority for some countries

– Illicit trafficking of radioactive materials

– Special Nuclear Materials (SNM)

– Regulatory control of sources, “from cradle to grave”

– Transport issues

• Revision of IAEA Action Plan

• Code of Conduct (2003, under IAEA´s umbrella)

– Guidance on Import/Export (2005)

• Other international Action Plans (EU), Conventions, UN resolutions, etc.

Radioactive SourcesSince 2001 (> 11th September)

• Era of Alternatives

• Replacement of

137CsCl sources ?

241AmBe sources ?

60Co sources ?

192Ir sources ?

• ~ 99% of Categories 1 & 2 radioactive sources

• Golden era for X-rays ?

Radioactive Sources

Radiation Protection (and Safety) issues

Protect the

environment

Protect the public

Protect the

workers

Safety culture Security culture

Categorization of Radioactive Sources (D-values)

• Based on the potential for radioactive sources to cause deterministic health effects

• Stochastic health effects not considered

• If sources are not managed appropriately, as in the case of accidents, malicious use or orphan sources, they can cause

a range of deterministic health effects resulting in

– Acute radiation sickness,

– Erythema,

– Amputation of limbs and organs,

– Damage of organs and tissues,

– Death

Categorization of Radioactive Sources (D-values)

• D-values are given in terms of an activity above which a radioactive source is considered to be “a dangerous source” as it has a significant potential to cause severe deterministic effects if not managed safely and securely

• D-values: quantify “how dangerous” a source is/may become

• The following exposure scenarios were considered:

– An unshielded source being

Carried in the hand for one hour,

Carried in a pocket for 10 hours, or

In a room for days to weeks.

• Also considered: dispersal of a source, for example by fire, explosion or human action, resulting in a dose from inhalation, ingestion and/or skin contamination.

Category boundaries(based on A/D ratios)

• A/D = 1000 (Category 1: A/D 1000)

Permanent injury: handled/in contact with for more than a few minutes.

Fatal: to be close ,for a period of a few minutes to an hour.

• A/D = 10 (Category 2: 10 A/D < 1000)

Permanent injury: handled /in contact with for minutes to hours.

Fatal: to be close , for a period of hours to days.

• A/D = 1 (Category 3: 1 A/D < 10)

Permanent injury: handled/in contact with for some hours.

It might be fatal to be close, for a period of days to weeks.

• A/D = 0.01 (Category 4: 0.01 A/D < 1)

Temporary injury

A/D < 0.01 (Category 5)

Activity of a radionuclide that is considered to be “exempt” from regulatory control

Categories of sources(@ IAEA Tec Doc 1344)

Categories of sources(1 TBq = 27 Ci)

60 TBq(A/D = 1000)

0.6 TBq(A/D = 10)

0.06 TBq(A/D = 1)

0.0006 TBq(A/D = 0.01)

Category 5 Category 4 Category 3 Category 2 Category 1

Am-241Activity

30 TBq(A/D = 1000)

0.3 TBq(A/D = 10)

0.03 TBq(A/D = 1)

0.0003 TBq(A/D = 0.01)

Category 5 Category 4 Category 3 Category 2 Category 1

Co-60Activity

100 TBq(A/D = 1000)

1 TBq(A/D = 10)

0.1 TBq(A/D = 1)

0.001 TBq(A/D = 0.01)

Category 5 Category 4 Category 3 Category 2 Category 1

Cs-137Activity

Gamma point sourceEquivalent Dose rate

H 2

AH

r

Units:

2

H

mSv m

h GBq

Dose rate of a point source (with negligible absorption) is proportional to the activity and inversly proportional to the square of the distance

r

“Point” source (activity A)

Teletherapy and blood irradiators

Radioative (point) sources and dose rates

Nuclide Activity

(TBq)

mSv/h

(at 1m)

137Cs 74 5632

60Co 37 11336

Radioactive Sources

Safety versus Security issues

Radioactive SourcesSafety and Security

• Safety & Security are distinguishable terms in English, but the same word is used in other major languages CONFUSION

• Safety - “means” to prevent harm from radiation

• Security – “means” to inhibit unauthorized and unlawful use of radioactivesources by ensuring that control over radioactive materials is notrelinquished or improperly acquired

• Safety Accidents/incidents

• Security Terrorist threats/malevolent acts

• A radioactive source that is secure (namely radioactive material is kept under proper control, physically protected) is not necessarily a safe radiation source (namely, a source unlikely to produce radiation harm)

• A radioactive source cannot be safe if its radioactive material(s) are not secure.

After “9/11”

Priority on:

remediation,

collection of disused sources

securing high-risk sources

Security after the events of September 11, 2001

• Radioactive sources, primarily a safety concern in the past, become considered a security risk

• A “Radiation Dispersal Device” (aka “dirty bomb”) could

incite widespread panic and terror

cause illness and increase cancer risk

contaminate large areas

result in evacuations

severely disrupt the economy

have huge decontamination costs

WMD – Weapon of Massive Disruption

• Shift in international nuclear security efforts to include radioactive materials and special nuclear materials (SNM)

IAEA Code of Conduct (2003)Non-legally binding

• In 2002-2003, the IAEA carried out a number of technical meetings to revise the Code of Conduct (CoC) to more adequately address security concerns

• Code contains non-legally binding guidance for life-cycle control of radioactive sources

• Revised Code was approved by the IAEA Board of Governors in 2003 and published in 2004.

IAEA Code of ConductObjectives & requirements

• Through the development, harmonization and implementation of national policies, laws and regulations, and through the fostering of international co-operation, aims at:

Achieving and maintaining a high level of safety and security;

Preventing unauthorized access or damage to, and loss, theft or unauthorized transfer of, radioactive sources, so as to reduce the likelihood of accidental harmful exposure to such sources or the malicious use of such sources to cause harm to individuals, society or the environment; and

Mitigating or minimizing the radiological consequences of any accident or malicious act involving a radioactive source

• Requires every Member State to take appropriate measures necessary to ensure that radioactive sources are safely managed and securely protected during their useful lives and at the end of their useful lives

International EffortsUN, IAEA, European Union, etc.

• Several United Nations´Resolutions

• IAEA Nuclear Security Plans (2002+)

– Binding instruments

• Convention on the Physical Protection of Nuclear Material (CPPNM)

• UN Convention for the Suppression of Acts of Nuclear Terrorism

– Non-Binding instruments

• IAEA Code of Conduct on the Safety and Security of Radioactive Sources

• Guidance on the Import & Export of Radioactive Sources

– IAEA Nuclear Security Series Documents

• INFCIRC/225/Rev.5 -> The Physical Protection of Nuclear Material and Nuclear Facilities (recommendations)

• European Union´s Action Plan on Chemical, Biological, Radiological and Nuclear (CBRN) Security

• USA/UK Global Threat Reduction Initiative/Programme

DSRS and Orphan Sources

Risk, Hazards, Accidents, Malicious acts

“Where are we and where do we go from here ?”

Radioactive sealed sourcesLife cycle

DSRS & orphan sources

• DSRS – Disused Sealed Radioactive Source

– A radioactive source becomes DSRS if:

it is no longer used because its use is not needed anymore,

or because its activity has decreased to a value that is not useful for the utilization initially foreseen

– When a radioactive source becomes disused:

The risk of future loss of control is increased

The source may remain dangerous for many years

Safety, security and radiological protection are at stake

• Orphan source – source that is out of regulatory control:

Lost

Stolen

Abandoned (deliberately or by unwareness)

Misplaced

Transferred without propoer authorization

Safety and Security issuesDSRS

• DSRS exist in virtually all countries – millions in use and disused around the world.

• Some sources not properly controlled – lack of safe, secure, and sustainable management options for the long-term

• Loss of control and theft are plausible scenario

• Common accidental/emergency scenario - dangerous source is obtained by someone who is unaware of the hazard.

• Possibility of malicious/malevolent use

• Radiation emergencies/accidents can occur anywhere !!! Involving serious injuries and deaths

About Risk

From L. Castle (ARPANSA) @ IAEA Conference, Abu Dhabi, 27-31 October 2013

Radiological accidents

And several others...

Radiological accidents/incidentsCommon causes

Lack of / poor regulatory structure

Poor or no Education & TrainingNo safety programmeNot following safety proceduresEquipment failureFailure to use survey meter / dosemetersEtc.

Lack of regulations´awarenessImproper storage / disposalSocio-economic and financial issuesPoor education and trainingNo safety programmeDisassembling equipmentEtc.

TheftLossDeliberate abondonmentMisplacementIgnoranceUnawareness / ignoranceEtc.

DSRS

RDD hazardTerrorism

RDD – Radiological Dispersal Device

IncidentsIAEA Incident & Trafficking DataBase

Extracted from: IAEA Incident and Trafficking DatabaseIAEA Bulletin 48/1 (2006)

IncidentsIAEA Incident and Trafick DataBase

Unauthorized possession (1993-2013)

424 incidents

Theft or loss (1993-2013)

664 incidents

Unauthorized disposal(RS entering scrap metal industry) +

Unauthorized shipment(contaminated scrap metal) +

Discovery of radioactive material(uncontrolled RS)

1337 incidents

Security of Radiation Sources in theMedical Applications – example

Security of radioactive sources@ hospital / medical center

• Radioactive sources:

Nuclear Medicine (unsealed)

Radiotherapy (sealed)

• LDR brachytherapy

– Thousands of I-125 “seeds”

• PDR brachytherapy

– Tens of GBq Iridium-192

– Security risk level: low

• HDR brachytherapy

– ~TBq Iridium-192

– Security risk level: intermediate

Blood irradiators (self-shielded)

• Tens of TBq Cesium-137

• Security risk level: high

Few tens up to a few hundreds of persons authorized to “handle” these sources !

Security requirements

• During use or storage Deter Don’t be interesting

Monitor & Detect

Cameras

ID card with security technology

Biometric access control

Digital locks

Assess

Decision systems on monitoring of alarms

Training of security & staff

Delay Make it hard

Anchoring therapy units

Motion sensors

Balanced magnetic switch

Response Adequate reactions of staff

• Portable and mobile devices an issue

Security and Safety of SourcesInventory, Accountability, Storage

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 out of control, lost, stolen or missing sources

Proper storage of sources

– Security

– Radiation shielding

– Provide physical protection (envinronmental, fire, etc.)

Security and Safety of SourcesTransport

Transport of sources

– Receipt of sources – well defined rules

• 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

– In house transport, according to local rules

– External transport, according to international standards and requirements

Conclusions and Outlook(1)

• Radiation Protection and Safety-related concerns about the use of radioactive sources have evolved towards Security-related concerns, due to potential malevolent/malicious use and associated threats and accident scenarios such as:

RDD (Radiological Dispersal Devices)

IND (Improvised Nuclear Devices)

RED (Radiation Exposure Devices)

• Effective – from cradle to grave - control of high activity sealed sources (HASS IAEA Categories 1, 2 and 3) can only be obtained through adequate:

Control over high-activity sources in use

Management of disused sources (DSRS)

Strategies for handling orphan sources

Conclusions and Outlook(2)

• Medical facilities will face or are already experiencing the trend ofhardening the physical security and protection of radiation sourcesand radioactive sources, to:

Deter,

Monitor and detect,

Assess,

Delay,

Respond,

To attempts of illegal access or manipulation (including theft)

• The role of the Radiation Protection Officer/Expert in interfacingsafety and security aspects associated to the manipulation ofradiation and radioactive sources is of cornerstone importance !