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‫أجهزة العالج اإلشعاعي‬
Clinical Radiation Generator
‫إعـداد‬
‫ أنور صالح عطاهللا‬.‫م‬
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Clinical Radiation Generator
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‫المعالجة اإلشعاعية‬
Radiotherapy
‫استخدام اإلشعاع المؤين في معالجة السرطان‬
Using the ionizing Radiation to treat cancer
)‫معالجة خارجية (عن بعد‬
)‫معالجة داخلية (عن قرب‬
External Beam
Therapy (EBT)
Brachytherapy
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Radiotherapy
• One of the main treatment
Siemens Oncology
modalities for cancer (often in
combination with chemotherapy and
surgery)
• It is generally assumed that 50 to 60% of
cancer patients will benefit from
radiotherapy
• Minor role in other diseases
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External Beam Radiotherapy
Beam 2
Beam 3
Beam 1
tumor
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patient
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External Beam Therapy (EBT)
Non-invasive
 Target localization important and beam
placement may be tricky
 Usually multiple beams to place target
in the focus of all beams

Single beam
Three coplanar beam
Multiple noncoplanar beams
patient
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External Beam Radiotherapy
• More than 90% of all radiotherapy patients
are treated using EBT
• Most of these are treated using X-rays
ranging from 20keV to 20MeV in peak-energy
• Other EBT treatment options include telecurie
units (60-Co and 137-Cs), electrons from
linear accelerators and accelerators for heavy
charged particles such as protons
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Cancer incidence (WHO)
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Major indications for
radiotherapy
•
•
•
•
•
•
•
Head and neck cancers
Gynaecological cancers (eg. Cervix)
Prostate cancer
Other pelvic malignancies (rectum, bladder)
Adjuvant breast treatment
Brain cancers
Palliation
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Approaches
• Palliative radiotherapy to reduce pain and
address acute symptoms - eg bone
metastasis, spinal cord compression, ...
• Radical radiotherapy as primary modality
for cure - eg head and neck
• Adjuvant treatment in conjunction with
surgery - eg breast cancer
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Patient
Aim
Critical
organs
• To kill ALL viable
cancer cells
• To deliver as much
dose as possible to the
target while
minimising the dose to
surrounding healthy
tissues
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Beam
directions target
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Prognostic Factors
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•
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Cancer type and stage
Patient performance
Radiation dose
...
survival
Bad prognosis
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Good prognosis
time
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Prognostic Factors
•
•
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Cancer type and stage
Patient performance
Radiation dose
...
Accurate dose delivery
matters!
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Dose should be accurate
• To target:
• 5% too low - may result in clinically detectable
reduction in tumour control (eg. Head and neck
cancer: 15%)
• To normal tissues:
• 5% too high - significant increase in normal
tissue complication probability = morbidity =
unacceptable side effects
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External beam radiotherapy (EBT)
treatment approaches
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•
•
•
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Superficial X-rays
Orthovoltage X-rays
Telecurie units
Megavoltage X-rays
Electrons
Heavy charged particles
Others
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External beam radiotherapy (EBT)
treatment approaches
•
•
•
•
•
•
Superficial X-rays
Orthovoltage X-rays
Telecurie units
Megavoltage X-rays
Electrons
Heavy charged
particles
• Others
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40 to 120kVp
150 to 400kVp
137-Cs and 60-Co
Linear accelerators
Linear accelerators
Protons from
cyclotron, C, Ar, ...
Neutrons, pions
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Superficial radiotherapy
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•
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50 to 120kVp - similar to diagnostic X-ray qualities
Low penetration
Limited to skin lesions treated with single beam
Typically small field sizes
Applicators required to collimate beam on patient’s
skin
• Short distance between X-ray focus and skin
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Superficial radiotherapy
Philips RT 100
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Superficial radiotherapy issues
• Due to short FSD high output and large
influence of inverse square law
• Calibration difficult (strong dose gradient,
electron contamination)
• Dose determined by a timer - on/off effects
must be considered
• Photon beams may be contaminated with
electrons from the applicator
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Orthovoltage radiotherapy
• 150 - 400kVp
• Penetration sufficient for palliative
treatment of bone lesions relatively close to
the surface (ribs, spinal cord)
• Largely replaced by other treatment
modalities
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60-‫أول جهاز معالجة بالكوبالت‬
1951
ELDORADO “A”
Installed at Victoria Hospital,
London, Ontario, Canada.
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1962 The world’s first isocentric unit
THERATRON 80
Setting the world
standard
for 80 SAD units.
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Kilovoltage Equipment (150 - 400
kVp)

Depth dose
dramatically
affected by
the FSD
FSD 6cm,
HVL 6.8mm Cu
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FSD 30cm,
HVL 4.4mm Cu
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Orthovoltage patient set-up

Like for superficial
irradiation units the
beam is set-up with
cones directly on
the patient’s skin
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Megavoltage radiotherapy
• 60-Cobalt (energy 1.25MeV)
• Linear accelerators (4 to
25MVp)
• Skin sparing in photon beams
• Typical focus to skin distance
80 to 100cm
• Isocentrically mounted
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‫مع أطيب األمنيات‬
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