Quality Assurance in Radiotherapy and Dosimetry

Quality Assurance in Radiotherapy and Dosimetry
Md. Shakilur Rahman, PhD
Bangladesh Atomic Energy Commission
“Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC”
Training Institute, Savar, Dhaka
26 October 2021

Radiation is classified as being either non-ionizing or ionizing. Non-ionizing radiation is longer wavelength/lower
frequency lower energy. While ionizing radiation is short wavelength/high frequency higher energy. Ionizing
Radiation has sufficient energy to produce ions in matter at the molecular level.
Radiation
26 October 2021

- Energy in the form of particles or waves
- Emitted by nucleus of atom or orbital
electron or Coulomb Field of the nucleus
- Released in the form of electromagnetic
waves or particles
Concept of Ionizing Radiation
1896 Henri Becquerel discovered natural radiation - Uranium energy captured by phosphorus and X-Ray film, Marie Curie - student of
Henri, determined the emissions were radiation and found the radioactive element - Radium and Polonium. She won two Nobel Prizes in two
fields (1903 and 1911) one with HB and one with her husband
 1895 X Rays discovered by Roentgen
 1896 First skin burns reported
 1896 Becquerel: Discovery of radioactivity
 1897 First cases of skin damage reported
 1998 First use of X Rays in the treatment of cancer
 1902 First report of X Ray induced cancer
 1911 First report of leukaemia in humans and lung cancer from
occupational exposure
 1911 94 cases of tumour reported in Germany (50 being
radiologists)
α ray Nucleus of Helium (He)
β ray High Energy Electron
γ ray
Photon
(Electromagnetic Ray)
X ray
Photon (Electromagnetic Ray)
n ray Particle Beam
26 October 2021

Applications of Radiation in Medicine
Diagnostic & Nuclear Medicine
 X-rays
 Mammography
 CT
 PET
 Fluoroscopy etc.
Radiation Therapy
 Teletherapy
 Deeptherapy X-ray
 Linac
 Proton Therapy
 BNCT
 Brachytherapy etc.
26 October 2021

 In the 1960’s almost 25% of the global cancer burden
was diagnosed in low-income and lower-middle income
countries.
 In 2010 nearly 55% of the global cancer burden is found
in these countries.
 In 2020 it will rise to around 70%.
The developing world will suffer the most.
 By 2030 over 13 million people will die from cancer
every year. Almost 9 million of these deaths will be in
developing countries.
 By 2050 at present growth rates, your chances of
contracting cancer in your lifetime will be 50 to 60%. The
cancer rate will rise from 0.6 to 2.2 million per year.
 Cancer kills more people globally than tuberculosis, HIV,
and malaria combined.
 85 million people will die of cancer over the next 10
years unless nations take action to prevent these deaths. Low
and middle income countries will be hit the hardest.
Cancer is an important health issue and be a major determinant of the
human and economic wealth in a country
Background: Cancer
26 October 2021

BACKGROUND : CANCER IN BANGLADESH
 In Bangladesh, it is estimated incidence of
cancer is 1.6 million which would be 2.1 million by
2030.
 According to the BBS, cancer is the sixth leading
cause of death.
 International Agency for Research on Cancer has
estimated cancer-related death rates in Bangladesh
to be 7.5% in 2005 and 13% in 2030.
Bangladesh has developed a National Cancer Control Strategy and Action
Plan with the aim of delivering a universal, quality-based and timely service.
Cancer prevention through tobacco control, health promotion and vaccination
program, cancer early detection program for oral cavity, breast and cervix has
initiated.
Cancer site % Cancer site %
Lungs 25.5 Breast 25.6
Lymph
node
7.4 Cervix 21.5
esophagus 5.9 Lung 5.6
Larynx 5.4 Lymph
node
4.1
Stomach 5.1 esophagus 3.4
Liver 3.3 Ovary 3.3
Tongue 2.6 Gall
bladder
2.7
Skin 2.5 Stomach 2.6
Rectum 2.3 Rectum 1.8
Others 40 Others 29.4
Top Malignancies in Bangladesh
26 October 2021

26 October 2021

Treatment of Cancer
 Surgery
 Chemotherapy
 Radiotherapy (60-70%)
 Cell based Immunotherapy
 Gene Therapy
26 October 2021

Radiotherapy and Cancer
 Radiotherapy is the procedure by which intentionally high radiation dose is delivered to the tumor
 This is main mode of treatment of cancer patients about 60-70% of the cancer patients are treated with
radiotherapy
 Radiotherapy is the clinical use of ionizing radiation for cancer treatment to control malignant cells.
 Radiotherapy is the treatment modality where intentionally high radiation dose delivered to the patients. It works by
damaging the DNA within cancer cells and destroying their ability to reproduce.
target
Critical
organs
Beam
directions
Patient
Radiation therapy is used two different ways :
 To cure cancer:
– Destroy tumors that have not spread to other body
parts.
– Reduce the risk that cancer will return after
surgery or chemotherapy.
 To reduce symptoms:
– Shrink tumors affecting quality of life, like a lung
tumor that is causing shortness of breath.
– Alleviate pain by reducing the size of a tumor.
26 October 2021

Types of Radiotherapy
Radiation therapy can be delivered two ways;
externally and internally.
External beam radiation therapy delivers radiation using
a linear accelerator, 60Co or radiation beam from source
outside the body.
Internal radiation therapy, called brachytherapy or seed
implants, involves placing radioactive sources inside the
patient.
26 October 2021

Radiotherapy Equipment
Deep-therapy X-ray, IMRT based Cobalt unit and Linear Accelerator
True Beam Accelerator, Proton beam, Cyber-Knife

Basic Concept of Biological Effects of Ionizing Radiation
Stochastic Effects
o Where the severity of the result is the same but the probability of occurrence increases with radiation dose,
e.g., development of cancer
o There is no threshold for stochastic effects
o Examples: cancer, hereditary effects
o Hereditary: (genetic) - assumed stochastic incidence, however, manifests itself in future generations
Deterministic Effects
o Where the severity depends upon the radiation dose, e.g., skin burns
o The higher the dose, the greater the effect
o There is a threshold for deterministic effects
o Examples: skin burns, cataract
 Due to cell changes (DNA) and proliferation towards a
malignant disease
 Severity (example cancer) independent of the dose
 No dose threshold - applicable also to very small doses
 Probability of effect increases with dose
Generally occurs with a single cell
e.g. Cancer, genetic effects Dose
Probability of effect
Stochastic Effects of Ionizing Radiation
26 October 2021

Thresholds for Deterministic Effects (Single exposure)
Tissue or Organ and effect Thresholds (Sv)
Testis: Temporal Sterility
Permanent Sterility
0.15
3.5 ~ 6.0
Ovary: Permanent Sterility 2.5 ~ 6.0
Lens of eyes: Detectable opacity
Cataract (Visual impairment)
0.5 ~ 2.0
5.0
Bone marrow: Depression of hematopoiesis 0.5
Effect Region Exposed
Leukemia red bone marrow
Lung Cancer trachea, bronchial tubes, alveoli
Breast Tumor mammary gland
Sterility reproductive gland （ovary, testis）
Hereditary Effect reproductive gland （ovary, testis）
Embryonic Malformation 2~8 weeks embryo
Region Exposed vs. Arising Effects
26 October 2021

Radiation Burn
Skin graft
13wk >21wk
3 wk 4wk 11wk
26 October 2021

Ionizing radiation interacts at the cellular level:
 Ionization
 Chemical changes
 Biological effect
 Stochastic effects develop due to mutation effect of low
dose radiation; it is observed that cancer of different
location appears above different dose ranges, the severity
of the effect does not depend on the dose.
 Genetic effects might result in lesions of chromosomes in
the germinal lineage
 Deterministic effects develop due to cell killing by high
dose radiation, appear above a given threshold dose,
which is considerably higher than doses from natural
radiation or from occupational exposure at normal
operation
Radiation effects
H-O-H  H+ + OH- (ionization)
H-O-H  H0+OH0 (free radicals)
26 October 2021

The main mechanism of radiotherapy
The radiations produce ionization of the tissues along its path while passing through the human body.
 When the cells are ionized, free radicals and reactive oxygen species (ROS) form. Free radicals are simply
atoms, molecules, or ions with unpaired electrons, and ROS is a subset of free radicals that involve oxygen.
 These agents are very chemically reactive due to their free electron. Due to this high reactivity, free radicals
and ROS are likely to attack the covalent bonds of the DNA and typically occur in chains. Enough injury in
the cell will result in cell death. At the same time, if enough DNA is damaged, the cells will be unable to
replicate.
 Thus, when the radiation targets the tumor cells, the affected cells will die or be unable to proliferate;
effectively reducing or eliminating the cancer. These radiation damages can be repaired efficiently in
normal cells by the presence of enzyme ribonuclease, but the same enzyme is deficient in cancer cells.
 direct ionization of the DNA, ≈ 15%
 indirect ionization of the DNA, ≈ 85%
1 Gy of RT causes approximately
 105 ionizations
 >1000 damages to DNA bases
 1000 single strand breaks
 20-40 double strand breaks (DSBs)
 Kills approximately 30% of human cells, as a consequence of efficient DNA repair
26 October 2021

Reference: What is Free Radical?
Nucleus Electron
Unpaired Electron
Unpaired Electron
Strong
Oxidizing
Power
Free Radical
Radiation
Water (H2O)
Hydroxyl Radical
To be stable, a Free
Radical takes an electron
from other molecules.
A Free Radical has strong oxidizing power since it takes an electron from other molecules.
(Oxidizing Other Substance)
Super Oxide Radical (Active Oxygen), Hydroxyl Radical (OH’)
26 October 2021

Effect of radiation : DNA Level
Ionization by radiation
DNA strand break
DNA repair
complete incomplete
Recovery of
normal function
Possibility to future somatic or
hereditary effect

High resolution IMRT
Multileaf Collimator
Dynamic MLC
and IMRT
1960’s 1970’s
1980’s 1990’s 2000’s
Cerrobend Blocking
Electron Blocking
Blocks were used to
reduce the dose to
normal tissues
MLC leads to 3D
conformal therapy
which allows the first
dose escalation trials.
Computerized IMRT
introduced which
allowed escalation of
dose and reduced
compilations
Functional
Imaging
IMRT Evolution
evolves to smaller
and smaller
subfields and high
resolution IMRT
along with the
introduction of new
imaging
technologies
The First Clinac
Computerized 3D CT
Treatment Planning
Standard Collimator
The linac reduced
complications
compared to Co-60
Evolution of Radiotherapy
26 October 2021

60Co Tele-therapy Machine
26 October 2021

A linear accelerator is a device that uses high Radio‐Frequency (RF) electromagnetic waves to accelerate charged
particles (i.e. electrons) to high energies in a linear path, inside a tube like structure called the accelerator waveguide.
 The x-rays are generated by a linear accelerator
(linac).
 The linac fires high energy electrons at a metal target
and when the electrons strike the target, x-rays are
produced.
 The x-rays produced are shaped into a narrow beam
by movable metal shutters.
Linear Accelerator
26 October 2021

23
Proton Beam Radiotherapy
 Proton are produced from ion source, positively charged
particle from cyclotron
 It has Bragg peak due to cross-section increases energy decreases
 Works as pencil beam scanning or narrow beam
 Very complex type of tumor can be irradiated with high precision

Boron Neutron Capture Therapy (BNCT)
1. Inject boron-10 non toxic compound known as Boronophenylalanine (BPA)
2. Cancer cell has high demand on amino acid, BPA works as amino acid transporter
3. Epithelial neutron (0.3 eV-10 keV) from cyclotron by proton-Be reaction or from
nuclear reactor
BNCT: Brain, Head-neck and Melanoma
26 October 2021

Types of external beam radiation therapy
Three-dimensional conformal radiation therapy (3DCRT)
 Common type of EBRT
 The radiation therapy team use CT scans to map out the precise location of the
cancer and the normal organs that need to be protected.
 The radiation beam is then shaped (conformed) so that the cancer receives most
of the radiation, and surrounding tissues receive much less.
 Used to treat many different types of cancer.
Intensity-modulated radiation therapy (IMRT)
 Highly accurate type of conformal radiation therapy.
 Shapes and divides multiple beams of radiation into tiny beams (beamlets) that vary
in dose.
 Used for most cancer types, especially for curative treatment.
 Volumetric modulated arc therapy (VMAT) is the specialized forms of IMRT that
deliver radiation continuously as the treatment machine rotates around the body
26 October 2021

Image-guided radiation therapy (IGRT)
 Uses a treatment machine that takes x-rays or CT scans at the start of
each session to check that you are in the correct position for treatment.
 Markers (usually grains of gold) may have been inserted into or near the
cancer so they can be seen in the x-rays or scans and used to guide
positioning.
 Positioning can be very finely adjusted to deliver treatments with
millimetres accuracy.
 Commonly used with many types of radiation therapy to any area of the
body.
 May also be recommended for areas likely to be affected by movement,
such as the lungs from breathing.
Stereotactic radiosurgery (SRS) and stereotactic radiation
therapy (SRT)
 Specialized type of radiation therapy.
 Combines many small radiation fields to give precisely targeted radiation.
 SRS is delivered as one high dose and SRT is delivered as a small number
of high doses.
 Used to treat small cancers in the brain while minimizing the radiation
reaching healthy brain tissue.
 A custom mask is worn to keep the head still.
 Despite the name, SRS is not surgery and does not involve any surgical
cuts.

History of radiotherapy in Bangladesh
 The first radiotherapy in Bangladesh was introduced in 1947 by a 300 kV x-ray machine that was installed for
the treatment of cancer patient at Kumudini Hospital in Mirzapur, Tangail
 The second 60Co machine was installed in 1959 at DMCH.
 A deep therapy x-ray machine was installed at CMCH in 1964.
 Beside the radiotherapy units, few manual Ra-226 are installed
26 October 2021

Radiotherapy Facilities in Bangladesh: Government Oncology Centers
Sl. No Radiotherapy center 60Co LINAC B’therapy Simulator
1. National Institute of Cancer Research & Hospital 02 04 01 02
2. Dhaka Medical College and Hospital 01 01 01 01
3. Bangabandhu Sheikh Mujib Medical University - 01 01 -
4. Chittagong Medical College and Hospital 01 - 01 01
5. Rajshahi Medical College and Hospital 01 - 01 -
6. Rangpur Medical College and Hospital 01 - - -
7. Sylhet MAG Osmani Medical College & Hospital 01 - - -
8. Sher-e-Bangla Medical College and Hospital 01 - 01 -
9. Mymensingh Medical College and Hospital 01 - - -
10. Shaheed Ziaur Rahman Medical College & Hosp. - 01 01 -
11. Bangladesh Atomic Energy Commission, Dhaka - 01 - 01
12. Combined Military Hospital, Dhaka - 01 01 01
Total 09 09 08 07
26 October 2021

Sl. No. Name of Center 60Co LINAC B’therapy Simulator
1 Delta Hospital Limited 02 03 01 01
2 United Hospital Ltd. - 02 01 01
3 Khawja Yunus Medical College and Hospital - 03 01 02
4 Square Medical College and Hospital - 01 - 01
5 Ahsania Mission Cancer and General Hospital 01 02 01 01
6 North-East Medical College and Hospital - 01 01 01
7 Enam Medical College & Hospital - 01 01 01
8 Apollo Hospital Ltd. - 01 01 01
Total 03 14 07 09
Private Oncology Centers
26 October 2021

Meet the Radiotherapy Treatment Team
 Radiation Oncologist
The doctors who oversee the radiation treatment therapy
 Medical Radiation Physicist
Ensures the treatment plans are properly tailored for each patient
 Dosimetrist
Works with the radiation oncologist and medical physicist to calculate the proper dose of
radiation given to the tumor
 Radiation Therapist
Administers the daily radiation under the doctor’s prescription and supervision
 Radiation Technologist
Deliver the dose to patient as per prescription and planning
 Radiation Oncology Nurse
Cares for the patient and family to provide education, emotional support and tips for
managing side effects
26 October 2021

Interaction of Photon with Tissue
26 October 2021

Management of QA Program
Radiation oncologists:
 consultations,
 dose prescriptions,
 on-treatment supervision and evaluations,
 treatment summary reports,
 follow-up monitoring and evaluation of treatment outcome and morbidity.
Medical physicists
 specification, acceptance, commissioning, calibration and quality assurance of all radiotherapy equipment.
 measurements of beam data, calculate doses and plan the treatment.
 take care of radiation safety and radiation protection in the radiotherapy department.
Radiotherapy technologists:
 Clinical operation of simulators, computed tomography (CT) scanners, treatment units, etc.; Patient set-up and dose
delivery;
 Documenting treatment and observing the clinical progress of the patient and any signs of complication.
 Undertaking daily quality assurance of treatment equipment in accordance with physics quality assurance procedures
and protocols;
 Construction of immobilization devices, etc.
Dosimetrists:
 Accurate patient data acquisition;
 Radiotherapy treatment planning;
 Dose calculation;
 Patient measurements.
26 October 2021

QA parameters of a Medical Linac

Traceability to international standards
26 October 2021

 5% too low - may result in clinically detectable
reduction in tumour control (e.g. Head and neck cancer:
15%)
To normal tissues:
 5% too high - may lead to significant increase in
normal tissue complication probability = morbidity =
unacceptable side effects
The outcome of radiotherapy highly depends on how precisional dose deliver to the tumor
Sources of uncertainty:
 Absolute dosimetry/calibration
 Relative dosimetry (%depth dose, profiles, output
factors)
 Treatment planning (estimated uncertainty of the order
of  2%)
 Machine performance on the day ( 2%)
 Patient set-up and movement ( 3%)
 Medical linear accelerator (LINAC) and Teletherapy (60Co) is a potential source of photon beam in curative and
palliative treatment modality for a variety of cancers.
 The effectiveness of the output of treatment is highly dependent on the radiation dose being delivered to the
treatment site.
 Clinical data consideration lead to generally agreed recommendations, ICRU report-24 (1976) for at least accuracy
of ±5%. This requirement implies that dose measurement should be accurate with ±3.5%.
Importance of Radiotherapy Dosimetry
26 October 2021

IAEA 277: Absorbed Dose Determination in External Beam
Radiotherapy (1987) based on air kerma
IAEA 398: Absorbed Dose Determination in External Beam
Radiotherapy (2000)
DIN 6800-2: German Protocol for High Energy Photon and Electron
Beam for Therapy level Dosimetry
AAPM TG-51: Protocol for clinical reference dosimetry of high-
energy photon and electron beams (1999)
 Dosimetry protocols or codes of practice state the procedures to be followed when calibrating a clinical photon or
electron beam.
 The choice of which protocol to use is left to individual radiotherapy departments or jurisdictions.
 Dosimetry protocols are generally issued by national, regional, or international organizations.
Dosimetry Protocols
26 October 2021

QA of Dosimetry : Intercomparison Program
IAEA/WHO TLD INTERCOMPARISON PROGRAM
Dosimetry intercomparison is designed to establish the accuracy and the precision of dosimetry at given level in
the dosimetry chain and to assess consistency between the centers.
 To investigate the accuracy of output dose used for the treatment of patients at oncology centers
 To reduce uncertainties involved in the measurement of absorbed dose to water
 To build-up the confidence of hospital physicist on QA of dosimetry
 Traceability of national and international standard for absorbed dose measurement
26 October 2021

No.
center
Oncology centers Year Treatment unit No. Center No.
of beam
07
MAG Osmani Medical College & Hospital, Sylhet
2011
FYC-260 60Co
10
Rajshahi Medical College & Hospital, Rajsahi FYC-260 60Co
Rangpur Medical College & Hospital, Rangpur FYC-260 60Co
Square Hospital Ltd., Dhaka Varian 2300CD 6 MV
United Hospital Ltd., Dhaka Varian Clinac
2DMX
6MV, 15 MV
National Institute of Cancer Research Hospital,
Dahka
Varian 2100CD 6MV, 60Co
Khwaja Yunus Ali Medical College & Hospital,
Sirjagonj
Elekta Synergy 6 MV (2)
03 Khwaja Yunus Ali Medical College & Hospital,
Sirajgonj
2013
Elekta Synergy 4 MV, 6 MV (2), 15 MV
10
Dhaka Medical College & Hospital, Dhaka Varian 2100CD,
Elite 80
6 MV, 15 MV, 60Co
Square Hospital Ltd., Dhaka Varian 2300D 6 MV, 10 MV
05 Ahsania Mission Cancer and General Hospital,
Dhaka
2015
Elekta Platform 4 MV, 6 MV, 15 MV
14
Dhaka Medical College & Hospital, Dhaka Varian 2100CD,
Elite 80
6 MV, 15 MV
Khwaja Yunus Ali Medical College & Hospital,
Sirajgonj
Elekta Platform 4 MV, 6 MV , 15 MV
National Institute of Cancer Research Hospital,
Dhaka
Varian 2100CD 6 MV, 10 MV, 15 MV
United Hospital Ltd., Dhaka Varian Clinac DMX,
Varian True Beam
6MV (2), 15 MV
Hospital level intercomparison program

No.
center
Oncology centers Year Treatment
unit
No. center Number
of beam
01 North-East Medical College and Hospital,
Sylhet
2016 Varian Clinac iX 6 MV, 15 MV 02
05
Enam Medical College & Hospital, Savar,
Dhaka
2017
Elekta Synergy
#154138
6 MV, 10 MV,
15 MV
14
National Institute of Cancer Research
Hospital, Dhaka
Varian Clinac 2100 C/D #5550
Varian Clinac 2100 C/D#3186
6 MV, 10 MV
15 MV
Khwaja Yunus Ali Medical College &
Hospital, Sirajgonj
Elekta Synergy S
#151836
4 MV, 6 MV,
15 MV
Square Hospital Ltd., Dhaka Varian Clinac DHX#4526 6 MV, 10 MV
United Hospital Ltd., Dhaka Varian True Beam #1519
Varian Clinac DMX#4943
6 MV, 15 MV
6 MV
04
Ahsania Mission Cancer and General
Hospital, Dhaka
2018
Elekta Platform
Uqinox 80
6 MV, 15 MV,
60Co
09
Apollo Hospital Ltd., Dhaka Elekta Versa 6 MV, 15 MV
Square Hospital Ltd., Dhaka Varian Clinac iX #5982 6 MV, 15 MV
United Hospital Ltd., Dhaka Varian Clinac DMX #4943
Varian TrueBeam #1519
6 MV, 15 MV
Hospital level intercomparison program
26 October 2021

Beams Range (1%) Range
(2%)
Range
(3%)
Range
(4%)
Range
(5%)
Range
( 5%)
60Co 1 1 2 1 - -
4 MV - 3 - - - 1
6 MV 5 6 7 3 2 4
10 MV 1 1 2 1 - -
15 MV 6 5 2 1 1 3
Total
59
13 16 13 6 3 8
Intercomparison Program : Result
The acceptance limit (±5%) with an uncertainty of ±1.8% (k=1)
The reason of discrepancies is determined and correction is made by onsite visit by SSDL personnel. The
intercomparison performed is a successful step from the point of view in improving the dosimetry situations in
hospitals.
Discrepancy (large value) :
 Error in calculating absorbed dose
 IC calibration factor
26 October 2021

Reference Study Beam No. Ratio : Mean SD
Wochos et al., 1982 USA 2319 1.00 0.042
Davis and Falr., 1992 Switzerland 25 0.995 0.005
Hanson et al., 1993 Europe 357 1.007 0.040
Dutriex et al.,1993 EC 125 0.970 0.095
Huntley et al., 1994 Australia 30 0.993 0.033
Izewska J. et al., 1995 Poland 22 1.004 0.038
Nisbet A. et al., 1998 Ireland 13 1.002 0.012
Rassiah P. et al., 2004 Malaysia 12 1.027 0.031
Rahman, M. S. et. al., 2019 Bangladesh 59 1.011 0.029
Results : Dose Ratio
Ratio = Measured Mean Dose (IAEA)/User Stated Dose
26 October 2021

Secondary Standard Dosimetry Laboratory (SSDL)
 To provide dosimetry services as per international protocol
 To provide Quality Assurance (QA) services of Dosimetry as per international traceable
system
 To Provide calibration services of dosimetric equipment such as electrometer, ionization
chamber etc.
 Work as a link between field radiotherapy centers and international organization IAEA
and WHO to ensure the quality of radiotherapy treatment
 QA and QC of diagnostic radiology such as X-ray, Mammography, fluoroscopy etc.
 Calibration services of Radiation Protection equipment such as survey meter, pocket
dosimeter, contamination meter, personnel dosimeter etc.
 Dosimetry Services
 Calibration of Ionization chamber
electrometer
 QA/QC of radiotherapy units
 Traceability of radiotherapy unit
according to international system

Reference Standard of SSDL, Bangladesh Atomic Energy Commission
NPL : National Physical Laboratory
PTB: Physikalisch-Technische Bundesanstalt
NIST : National Institute of Standards and Technology
IAEA: International Atomic Energy Commission
26 October 2021

80 Laboratory in 67 member states
 As a link between IAEA and radiotherapy centers for
radiotherapy dosimetry and QA
 Calibration and standardization of radiotherapy
equipment
SSDL, Member of IAEA and WHO
26 October 2021

Objective : IAEA/WHO SSDL Network
The IAEA/WHO SSDL Network is an association of national SSDLs that have agreed
to cooperate in promoting the objectives of that Network under international auspices.
Its objectives are:
Accuracy: to provide dosimetry services and create and distribute knowledge in radiation
dosimetry in order to improve the accuracy level in dose measurements;
Traceability: to establish and facilitate links between end users of dosimeters, the SSDL
members;
Consistency: to promote international recommendations on methods applied for calibration
and performance of dosimetry in order to achieve consistency of measurements in all
countries;
IAEA/WHO SSDL Network

COMPUTER OPERATED X-RAY /GAMMA CALIBRATOR SYSTEM AND WBC AT SSDL

Quality Assurance in Radiotherapy and Dosimetry

Quality Assurance in Radiotherapy and Dosimetry

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