Radiation Protection for Radiotherapy - E. Aird (ESTRO) - European ...

ESTRO Activities: Radiation
Protection for Radiotherapy
Edwin Aird
RPA/ESTRO Teacher

ESTRO Mission ( education)
• The ESTRO School of Radiotherapy and
Oncology is an international school that aims to
improve, professionalise and standardise
knowledge and practice in radiation oncology
and associated professions in Europe and
beyond. Our guiding principles are set out in our
mission statement which was approved by the
ESTRO Board on 14th September, 2008
• To organise courses; workshops; large scientific
meetings (all professions and researchers)
together with the manufacturers.

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Recent ESTRO Activity
NUMBER OF COURSES AND PARTICIPANTS
2000-2011
Courses
Participants
1
0
1
3
1
2
1
1
1
2
1
4
1
6
1
9
2
3
2
8
3
0
3
1
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

ESTRO LIVE COURSES:
ROADMAP

Aim of Radiotherapy (and the meaning of
radiation protection in Radiotherapy)
• To sterilise the tumour (e.g 74Gy)with
minimum damage to the surrounding
normal tissues and critical structures
• Best practice requires: optimal planning in
3D on CT; dose prescription includes
dose/fraction and overall time AND critical
structure tolerances (dose/volume criteria);
full reporting of all these factors (ICRU 50
ICRU 62; ICRU ## etc)

TISSUE EFFECTS FOR
RADIOTHERAPY: Tumour Control
Probability can increase without
increasing NTCP if CTV-PTV
margins are reduced
Dose
Escalation
Moves to the
right as
margin
reduced

ICRU volumes
for Breast
Internal Target
Volume

Radiotherapy Process
• Pre-planning diagnostic images
• Planning Images: CT/MRI/PET/US etc
• Transfer of 3D Patient Image to Treatment
Planning System
• Planning: 3D Conformal; IMRT etc
• Transfer actual patient to linac (or other) and
correctly and accurately position
• Verification Radiographs/CBCT
• Treat/Follow-up

General Knowledge for R/T
• Physics of the atom
• Sources: High Energy 6-20MV + Diagnostic; Sealed and
unsealed sources (e.g. Ir-192; I-125; I-131)
• Radiation Physics
– Interaction; geometry of beams etc
• Radiobiology
– Time/dose/fractionation; models etc
• Concomitant Imaging for Radiotherapy ([For Image
Guided Radiotherapy (IGRT)]
• Second Cancer: imaging doses and out-of-beam doses
• Protection Legislation

Modern Linac with the addition of kV
On-Board-Imaging (Includes CBCT)

100000
Dose in
mGy
10000
Rectum
Bone-
Marrow
R/T doses (mGy)
for Prostate 74Gy
(15MV) vs distance
ALLEGRO
EU Project
1000
100
Colon
Stomach
Lung
CT doses
for daily
CBCT
R/T
C/T
Liver
10
Thyroid
1
0 20 40 60 80
Distance
Distance cm
from centre
from of fields centre

ESTRO and European Curricula
European Core Curricula have been developed for the training
of medical specialists in radiotherapy (radiation oncology),
medical physicists in the field of radiotherapy
and radiotherapy technologists.
In 2002, these were endorsed by representatives
from 35 European countries. In 2008 the school was created
to bring together the established teaching
Courses into a coherent structure. In 2011 the 3 Core Curricula
have been updated

Basic Science for Oncologists (Part of
ESTRO Core Curricula)
• Radiobiology:
– Describes the interaction of radiation on molecular
level (knowledge)
– Discusses DNA damage (comprehension)
– Describes cellular effects, mechanisms of cell death
(knowledge)
– Describes repair of radiation damage (knowledge)
– Discusses cell survival curves (comprehension)
– Describes normal tissue systems (knowledge)

Basic Sciences (oncologists)
• Basic radiation physics
– Describes atomic and nuclear structure
(knowledge)
– Describes radioactive decay (knowledge)
– Contrasts the properties of particle and
electromagnetic radiation (analysis)
– Defines and describes radioisotopes
(knowledge)

Eg Part of ESTRO Training Course
• Physics of teletherapy beams:
– Energy of X-ray beams
– Build-up and skin sparing
– PDD and Isodose curves
– Principles of wedges
– Output factors
– Beam geometry/penumbra etc

Isodoses
• Depth dose penetrates further
into tissue through thin end
• Dynamic wedges give “pointier”
isodoses
• Slope reduces with depth due to
scatter
• Used in oblique incidence to
shift isodoses by angle of
incidence

Wedged pair
• For head region
• e.g. maxillary antrum or floor of the mouth
• [NB What about Monitor Units?]

Treating the prostate ( 74Gy in 2Gy per#); avoiding rectum, bladder, etc

Isodose display - can be
complex and 3D

Prostate Intensity Modulated RT plan,
showing some reduction of rectal wall dose

Basic Sciences (oncologists)
• Radioprotection
– Discusses the general philosophy of radioprotection including
ALARA (comprehension)
– Contrasts stochastic and deterministic effects (analysis)
– Discusses the risk of induction of secondary tumours
(comprehension)
– Defines and discusses radiation weighting factor (knowledge)
– Defines and discusses equivalent dose – tissue weighting factor
(comprehension)
– Discusses occupational/public health consequences of radiation
exposure, radioprotection and dose
– limits for occupational and public exposure (comprehension)
– Outlines European and national legislation (knowledge)
– Determines what is evidence based in radioprotection
(knowledge

Cyberknife
Robotic
Radiotherapy
using 6MV x-
rays
ESTRO Physics 2007
ESTRO Physics 2007

Aspects of Radiation protection for
Radiotherapy
• Room Design; staff protection only for
sealed and unsealed sources
• Second Cancer
• Quality Assurance:
– Definitions: QA, QC , QM, QS
– Verification
– Reporting Near misses and errors
– What’s in a prescription…link to legislation

ESTRO Ref
• The updated ESTRO core curricula 2011 for clinicians, medical
physicists and RTTs in radiotherapy/radiation oncology JG Eriksen
et al Radiotherapy & Oncology 103, 103-108 (2012)
• Competencies in radiation oncology: A new approach for education
and training of professionals for radiiotherapy and oncology in
Europe R Potter et al Radiotherapy & Oncology 103, 1-4 (2012)
• Shaping the future; training of professionals for radiotherapy in
Europe M Baumann et al Radiotherapy & Oncology 70, 103 (2004)
• Guidelines for the infrastructure of training institutes and teaching
departments for radiotherapy in Europe E Rottinger et al Radio &
Oncol 70, 123 (2004)

ESTRO
• ESTRO e-learning: EAGLE: ESTRO
Application for Global Learning
• ESTRO web education:
• http://www.estro-education.org

Protection for Brachy HDR
• Well designed room ( which includes antiterrorist
measures) +room GM tube
• Calibration of new source (well chamber)
• Emergency procedures ( especially if
source sticks in patient)
• Security (Environment Agency/Anti-Terror)
• Quality Assurance: daily checks

HDR room design (example)

Layout example

Radiation Protection (ESTRO Physicists)
– They have to be prepared to address the needs of
protecting the patient, personnel and the general
public in the radiotherapy department.
– They have to know the physical and biological effects
of radiation for exposed individuals, the relevant
regulations, methods of compliance and record
keeping.
– This knowledge will allow them to assess the
radiation risk and optimise the medical exposures.
– They will be asked to apply the ALARA and dose
limitation principles in the design of radiation therapy
facilities, treatment and imaging protocols.

Radiation Protection for Physicists
• Competences
• • demonstrate an understanding of the principles of radiation safety procedures;
• • ability to measure effective performance of radiation safety procedures;
• • ability to improve effective performance of radiation safety procedures;
• • ability to investigate and assess risk factors of radiation;
• • ability to optimise medical exposures;
• • ability to verify that the clinical physics program is in compliance with applicable
national radiation safety regulations (e.g., radioactive materials licenses, occupational
dose limits, and review of radiation surveys for any new construction);
• • ability to perform radiation surveys of an area using appropriate dose-rate meters
• • ability to perform design calculations for a linac room, simulator/CT room,
brachytherapy source room;
• • ability to discuss the use of personal dosimeters;
• • ability to prepare the documentation needed for audits by the radiation protection
authorities;

Basic Sciences (oncologists)
• Radiation physics applied in radiation therapy (RT)
• Outlines the design and explains the mechanism of action of an X-
ray tube (comprehension)
• Describes the design and explains the mechanism of action of a
linear accelerators
• (comprehension)
• Describes specialized collimating systems (knowledge)
• Describes brachytherapy systems (knowledge)
• Outlines the design and explains the mechanism of action of a
cyclotron (comprehension)
• Defines, explains and discusses absorbed dose distributions
(comprehension)
• Describes treatment planning including 3D planning, virtual and CT
simulation and applies these
• procedures to plan patients’ treatments (application