Construction of Radiotherapy centre.pptx

Dr. Jayashree Deshmukh
JR-III, Dept. of Radiation Oncology.

CANCER BURDEN AND NEED FOR
RADIOTHERAPY
 Along with other chronic non communicable
diseases, cancer is gaining increasing
importance as a public health issue and affects
approximately 0.8 million new cases every year
in India.(R Sarin, 2005)
 Cancer incidence will continue to grow in the
country in the future as a result of:
1. Rising longevity,
2. Alterations in lifestyles, urbanization,
globalization,
3. Progressive control of communicable diseases
4. Absence of any mass screening programme in
the country

ESTIMATION OF CANCER LOAD IN INDIA
Year Estimated population
in millions
2016 1268
2021 1339
2026 1399
 The proportion of Indian population
in the age >40 years, which is more
prone to cancer, will increase from
28% in 2011 to 35.7% by 2026.
 In terms of absolute number, there
will be massive increase from 236
million to 326 millions.

Site Year
2016 2021 2026
M F M F M F
Head and Neck
(Oral cavity, BoT
Hypopharynx)
1,04,549 47,335 1,22,267 55,441 1,43,506 64,889
Breast - 1,78,337 - 2,05,538 - 2,35,490
Lung 73,770 25,496 87,400 30,051 1,03,360 35,436
Cervix - 1,12,048 - 1,29,493 - 1,48,813
CNS 22,384 13,734 25,106 15,285 28,029 16,938
All sites 3,81,440 7,02,151 4,48,276 8,11,688 9,34.268 9,35,715
PROJECTED NUMBER OF ANNUAL NEW
CANCER CASES IN INDIA

TMH STATISTICS
Year Co 60 LA TOMO
Jan-Dec, 2014 2958 2807 263
Jan-July, 2015 1903 1246 145
Total 4861 4053 408
 TMH STATISTICS –2014
 New cases registered -67,805
 New patient treated in RT Dept
-6028
 Patients treated with IMRT +
3DCRT: 3070
 Palliative treatment given to
>1500 pts.

RT CENTRE WORLDWIDE AND IN INDIA IN 2012
Worldwide
RT centres 7,642
Particle accelerator 10,744
Co-60 2,265
CT 7,312
Sim, 3,752
HDR-Ir 192 1,050
Rad onco 2,2541
Rad physicsts 9,450
RT Technologists 33,555
India
RT centre 302
Particle accelerator 177
Co-60 333
CT 49
Sim 80
HDR –Ir 192 59
Rad onco 347
Rad physicsts 190
RT Technologists 437

REQUIREMENTS AND GUIDELINES
TO START A RADIATION THERAPY FACILITY
 The requirements and guidelines to Procurement of any of the
Radiation Sources to be used in Radiation Therapy i.e. Source for
Telecobalt unit, Medical Accelerator, Sources for Gamma Knife unit,
Source(s) for Remote Afterloading Brachytherapy unit, Sources for
Manual Afterloading Brachytherapy, Simulator, Check source or any
other new modality involving ionizing radiation for therapeutic
purposes.

Employment
of qualified
staff.
Apply for
procurement of
teletherapy
source, Personnel
Monitors ,
Measuring and
Monitoring
Instruments
Construction
of building.
Approval of
building by
authority

Road
Transport
Approval
Installation
of
equipment.
Testing &
calibration
of
Teletherapy
unit.
Pre
commisi
oning
survey
Obtain
clearance for
use of unit

FORMULATION OF RADIOTHERAPY
PROGRAMME
• Describes all Resources (personnel, equipment and space ) required to
realize the clinical needs identified for the resultant programme to conform
to acceptable standards of practice. Depends on Patient load, clinical
training, and institute’s interest, and availability of funds.
• Cost–benefit analysis should be prepared.
• Staff requirements
• Equipments needed
• Need for external training of the radiation oncology and professional staff
• Finally, a master budget should be prepared. This budget should include the
costs of running and maintaining the equipment over the 10–15 year life
expectancy of the equipment

ESSSENTIAL EQUIPMENTS AND
STAFFING

PROGRAMME IMPLEMENTATION
 STAFF TRAINING
 EQUIPMENT SPECIFICATION
 PLANNING AND
CONSTRUCTION OF
FACILITIES
 DELIVERY OF EQUIPMENT
 PLANNING AND INITIATION
OF TREATMENT

RADIOTHERAPY STAFFING
STAFF TRAINING
 Training should be completed
before installation of the
equipment.
 High standard in radiotherapy can
only be achieved and maintained
by full-time specialists.
 Training required for the staff
physician(s), physicist(s) and RTTs
also technicians and support
personnel.
RADIOTHERAPY STAFFING
 Clinical Oncologist
 Clinically qualified radiotherapy
medical physicists
 Radiation therapy technologists
 Dosimetrists and physics
assistants
 Radiation oncology nurses, social
workers and dieticians
 Radiation safety officer
 Maintenance personnel

EQUIPMENT SPECIFICATIONS
 Elements that are important for the life of
the equipment and for safety should be
addressed early in the planning stage and be
included in Contractual forms, such as
1. Compliance with quality and safety
standards;
2. Acceptance tests and conditions to correct
deficiencies revealed during acceptance;
3. Warranty conditions;
4. Enforceable assurances on availability of
maintenance support, manufacturer support,
manuals and spare parts;
5. Possible training of local engineers.
 Adequate provision for maintenance in
terms of both technical and financial support
must be made.

EQUIPMENT
 IMAGING
 TREATMENT PLANNING
 TREATMENT DELIVERY
 QUALITY ASSURANCE
 RADIATION SAFETY

PLANNING AND CONSTRUCTION FACILITIES
 Actual planning process needs to
be flexible and iterative.
 The planning may involve external
experts, but must always involve
the local hospital staff who will
actually be performing the
radiation therapy treatments as well
as representatives of the local
funding agency, such as the
hospital administration and the
equipment manufacturer.

1.Architectural and construction drawings
The layout of the facility should be planned
taking into consideration equipment
requirements, water and electrical utilities
needed, room shielding required
(including dosimetry ports) and climate
control.
Careful attention must be focused on the
flow of patients in the treatment facility.
The layout should be planned in accordance
with internationally accepted radiation
safety standards.
Advice on room construction and shielding,
including appropriate room drawings, can
be obtained from the manufacturers.
The responsibility for the drawings remains
with the institution, which may refer these
to a qualified medical physicist for advice.

2. Licensing
 Licensed by the national regulatory authority.
 Should contain all relevant elements to assure
regulatory authority that planned facility will be
safe.
3. Scheduling
 The delivery of equipment should be coordinated
with the construction schedule.
 The teletherapy machine and radioactive sources
may not be delivered until the facility is ready to
receive them safely. The staff must also have
completed their training and be prepared to
receive the equipment.
 Equipment that is needed to test and commission
the teletheray unit, radioactive sources and
afterloading device should arrive early enough to
be tested before use.

RADIOTHERAPY FACILITY DESIGN
 Basic considerations
(a) The medical and physical well-being of the patient
(b) Protection of the patient, staff, visitors and other members of the public
from radiation hazards
(c) Geographical and functional integration of the various activities related
to the treatment of the patient.
RT facility design
External Beam
radiotherapy
HDR-
Brachytherapy

 Periphery of the hospital complex.
 Proximity to adjacent facilities, ready access
for in-patients and out patients, Radiological
services.
 Below ground level, reduction in shielding
costs for floors and outside walls weighed
against the expense of excavation, watertight
sealing and of providing access.
 On or above ground level, outside walls
always require shielding; and additional
structural support for heavy equipment and
for the additional weight of shielding
barriers.
LOCATION OF RT
DEPARTMANT

BSS CLASSIFICATION OF AREAS
 A controlled area: is an area in
which specific protection measures
and safety provisions are needed
for controlling normal exposure
and for preventing potential
exposure.
 All irradiation rooms for
external beam radiotherapy.
 Remote afterloading
brachytherapy treatment
rooms.
 Brachytherapy patient
rooms.
 All radioactive source
storage and handling areas.
 A supervised area: is an area that
should be kept under review even
though specific protection
measures and safety provisions are
not normally needed.
 Preferable to define controlled
areas by physical boundaries such
as walls or other physical barriers
marked or identified with radiation
signs.

RADIOTHERAPY FACILITY DESIGN
EXTERNAL BEAM
RADIOTHERAPY BRACHYTHERAPY
 Examination rooms
 Simulator room
 Treatment planning room
 Mould room
 Treatment room
 Waiting areas
 Operating theatre
 Radiographic imaging system
 Treatment planning room
 Treatment room

EXTERNAL BEAM THERAPY
Room Description
Examination
Room
•Close proximity to treatment room
•Include standard and gynaecological examination table
•Head and neck examination chair,
•Other appropriate examination instruments and medical supplies
Simulation
Room
•Large enough to accommodate simulator with full range of motion of
table
•Patient positioning lasers securely mounted on wall at points
appropriate for projection of lines through isocentre
•Means for dimming room light
•Adequate space for cabinetry to store treatment devices and daily
used QA equipment
Treatment
Planning
Room
• Should be located in close proximity to simulation room
•Should house Treatment planning computers, printer, plotter and
other required equipment
•Space for viewing CT scan and plane X-ray films
Mould Room •To fabricate custom designed blocks and compensators
•Space for tools, a block cutter and counter-top workspace for pouring
and mounting the blocks is required.
•Adequate ventilation should be provided if shielding materials are
melted in this area.

EXTERNAL BEAM THERAPY
Room Description
Treatment
Room
•Should be large enough to accommodate the treatment machine,
allowing the full range of motion of the treatment table.
•Heavy electrically operated door with door interlock. Or an
extended corridor (called a maze) leading into the room
•Warning sign at the entrance
•Means for dimming Room lights.
•Patient positioning lasers securely mounted on wall at points
appropriate for projection of lines through isocentre
•Means for dimming room light
•Space for a console immediately outside the treatment area
overlooking the treatment room door.
Waiting
Room
•Separate waiting areas for patients attendants
•Treatment waiting area should be adjacent to treatment room,
with space for seating of about 12 people for each machine.
•Area for pts on stretchers large enough to accommodate 3
stretchers.
•Appropriate changing facilities close to entrance of treatment

SYSTEM CONVENTIONAL SIM CT SIM
- Fluoro / radiography
- 30 kW high frequency generator
- Radiography 125 kVp and 300 mAs
- Fluroscopy upto 15 mA
Imaging Systems
- Imaging intensifier with a diameter of
≥ 23 cm
-Lateral and long movements
- Max vertical source to input
screen distance of ≥ 175 cm
-35 cm x 43cm cassette film holder
- TV Circuit and monitor TV
Xray system
- High frequency xray
generator with power
rating of atleast ≥ 50kW
- 90- 140 kV or better
- 30- 400 mA or better
- Peak anode dissipation
rate of at least 800
kHU/min or better
Detectors:
Mulitple rows of ≥ 650
detectors for taking min
16 slices at a time

ADDITIONAL
REQUIRMENNTS
CONVENTIONAL SIM CT SIM
- Three Lasers positioning
system
- A front pointer
- Anticollision devices
Computer Hardware
For CT scanner
For moving laser system
Others
- UPS
- Pressure injector
- Dose computation and
display
- QA accessories and
phantom
- Immobilization system
- Water bath
- Electron styrofoam cutter
- Remote diagnostic
monitoring

GANTRY TELE – COBALT LINAC
Motorized with isocentric design
Rotation 0-3600 +/- 190 0
Source isocentre distance ≥ 80 cm ≥ 100cm
Isocentre height ≤ 130 cm ≤ 135 cm
Isocentre clearance ≥ 15cm ≥ 30 cm
Isocentre max sphere ≤ 3mm diameter ≤ 2mm
Hand held parameter inside treatment room

COLLIMATOR TELE - COBALT LINAC
Collimator jaw indication either mechanical /electrical
Rotation At least ± 100 0
ODI range SAD +/- 20 cm with mechanical backup.
-Secondary collimators to reduce penumbra
- Transparent shadow tray

COUCH TELE – COBALT LINAC
Table Top should have transparent window
exceeding max field size
Limits of angle of rotation of
top
+/- 180 0. +/- 90 0
Range of patient lateral
motion
+/- 20 cm
Vertical movements should be
motorized
with min height ≤ 80 cm
not < 40 cm below isocentre and
At least upto 3 cm above isocentre
Longitudinal range ≥ 70 cm
Sag of table top should be ≤ 5 mm
with patient of 80 kg weight

PARAMETRES TELE – COBALT LINAC
Max Field size at isocentre ≥ 30 x 30 cm ≥ 40 x40 cm
Min Field size ≤ 5 x 5 cm ≤ 4 x4 cm
Symmetry Better than +/- 3 % Better than +/- 3 %
Uniformity +/- 3 % over 80 % of field +/- 3 % over 80 % of field
Radiation field congruence ≤ 2 mm ≤ 2 mm
Source diameter ≤ 2.5 cm --
Achievable penumbra ≤ 1 cm ≤ 8 mm
Output ≥ 1.5 Gy/min 0.5 Gy – 3 Gy/min
Wedge angles 15,30,45,60 15,30,45,60
Wedge field size should be
at least 20 x 30 cm

ADDITIONAL
REQUIRMENTS
TELE – COBALT LINAC
- A counterweight or beamstopper
- Independent head rotation on arm (range: ±90°)
- A couch table with centre spine section
- An area monitor with an acoustic/ optical signal
of radiation
- Three lasers for patient centring(two cross and
one sagittal)
- Immobilization devices for arms, legs and head
- A backpointer
- Intercommunication with the patient (two
stations)

 Primary Radiation
 Secondary barrier for Scattered Radiation
 Secondary barrier for leakage Radiation
 Door shielding
 Protection against neutrons.
TYPES OF SHIELDING

SOURCES OF RADIATION
Primary radiation
- Directly emitted
from treatment
machine
Scatter radiation - radiation produced
by scattering of primary radiation from
pt, collimators, beam shaping devices,
air, room wall, floor or ceiling.
Leakage
radiation:
Escapes
through
shielded head
of therapy unit

Primary barrier -
irradiated directly
by photons from
target or source.
Secondary barrier:
Scatter of primary
Leakage radiation
TYPES OF BARRIERS

Required Information:
 Equipment type
 Workload
 Limit value in area to be shielded
 Use factor and direction of
primary beam
 Occupancy of area to be shielded
 Distance to the area of interest
 Radiation limit
 Materials
SHIELDING CALCULATIONS
 Three steps to calculate thickness of
shielding material as per NCRP 151
report
 Establishing a dose value P in a
given occupied area
 Estimating dose D that would be
received if no shielding were to be
provided
 Obtaining the attenuation factor
that is necessary to reduce D to P;
for example, finding ratio D/P.

LIMIT VALUE(P)
 Usually 20 mSv per year for
occupationally exposed persons,
and 1 mSv for public.
 Occupational exposed persons i.e.
only for radiographers, physicists
and radiation oncologists.
D = WUT / d2
W = Workload, U = Use factor, T = Occupancy factor, d = Distance
EXPOSURE LEVEL (D)
 Barrier material such as concrete has a known tenth-value-
layer thickness (TVL) (in cm),
Thickness required = TVL × log10(D/P).
REQUIRED THICKNESS(T)

WORKLOAD
 Defined as the machine output in Gy per week at
a well defined point (usually machine isocentre
at 100 cm from the source) in the treatment
room.
 Two components:
 The clinical workload refers to the workload
produced at the point of interest in the
treatment room during the treatment of
patients.
 The physics workload results from the use
of the machine for calibration, quality
assurance, phantom measurements, servicing
and maintenance.
 The total workload is the sum of the clinical
and physics workload
W Total= W Clinical + W Physic

WORKLOAD
 Typical conservative clinical workload Wclin assumptions:
 50 patients per working day.
 3.3 Gy delivered dose at the isocentre per patient.
 5 working days per week.
 52 working weeks per year.
 A conservative estimate for Wphys is Wphys = 7100 Gy/year
    
clin
Gy pt day week
3.3 50 5 52
pt day w
Gy
42 900
eek year year
W
Wtot
 Wclin
Wphys
 5 104
Gy/year : 103
Gy/week

• Use factor U (for primary barriers)
• Fraction of the operating time during which the beam is directed towards a
particular barrier.
• Use factor U for all secondary barriers = 1
USE FACTOR
Primary Barrier Use factor
Floor 1
Walls 0.25
Ceiling 0.25
Each rotational direction 1
Gantry pointing down 1

OCCUPANCY FACTOR
 Fraction of operating time during which
area of interest adjacent to the treatment
room is occupied by the individual
 Occupancy factor T
 Offices, full occupancy areas:1
 Adjacent treatment room: 0.5
 Corridors, employee lounges: 0.2
 Waiting rooms:0.125

DISTANCE
 Distance (d) : Distance in meters from the
source to the area to be protected
 In linacs and isocentrically mounted Cobalt
units measured from the isocentre.
 Very important for shielding as dose falls off
with distance squared…...Inverse Square Law

SHIELDING FOR LEAKAGE RADIATION
 Leakage radiation - Percentage of
primary dose rate (% Dpri) in the
beam-on position
 Cobalt teletherapy – with the beam
in off position the leakage dose rate
should not exceed 2 mrad / hr on
average and 10 mrad / hr max at 1 m
from source. With the beam on
position, it should not exceed 0.1% of
useful beam.
 For megavoltage therapy
installation, the leakage barrier
usually far exceeds the barrier for
scattered radiation.
 Use factor U = 1 for leakage radiation
 Leakage dose at distance d leakage is:
DL = WT(% Dpri /100)d2 iso
d2
leakage
 Thickness required
= TVL × log10(DL /P)

 Radiation is scattered in all
direction.
 Depends upon intensity of incident
beam, area of the beam on the
scatterer and the scattering angle.
 The ratio of scattered dose to
incident dose is referred as α.
 For megavoltage beams, α is
assumed to be 0.1% for 900
scatter.
 DS = aWTFd2iso
d2
sca d2
sec
Ds - dose from scattered
radiation at point of interest;
 a - scattering factor;
F - field size factor;
diso - distance in metres from
source to isocentre;
dsca - distance in metres from
source to scatterer; and
dsec - distance in metres from
scatterer to the barrier.
 Thickness required
= TVL × log10(DL /P)
SHIELDING FOR LEAKAGE RADIATION

SHIELDING
 If at any point, primary beam is directed
that would be the greatest thickness.
 If there is no primary beam at that point,
use larger of leakage or scattering
thickness if one is larger than other by at
least one TVL.
 otherwise use the larger value and add
0.333TVL.

SHIELDING MATERIALS
 For new buildings to house radiation treatment facilities, concrete will
usually be the material of choice since it is the least expensive. However, if
space is at a premium it may be necessary to use a higher density building
material.
Shielding
material
Characteristics
Lead • High physical density - small space requirements
• High atomic number - good shielding for low energy X-rays
• Relatively expensive
• Not self supporting
Iron/ Steel • Relatively high physical density – space requirements acceptable
• Self supporting structure - easy to mount
• Relatively expensive
Concrete • Cheapest material, easier to bring to site and use for construction
• Self supporting - Easy to use
• Relatively thick barriers required for megavoltage radiation.
• Density varies according to local aggregate- Needs checking
• More difficult to monitor and control.
Other • Hematite concrete: thickness is reduced proportional to their densities
• Walls, bricks, wood, any structure used for building
• High density concrete (density up to 4g/cm3 as compared with around 2.3 for normal
concrete)
• Composite materials, eg, metal bits embedded in concrete (eg. ledite

SHIELDING MATERIALS
Typical shielding thickness of ordinary concrete to
protect members of the public in adjacent areas
Radiation
Quality
Primary
Barrier (cm)
Secondary Barrier
(cm)
Co-60 130 65
10-25 MV 240 120
Thicknesses of primary barriers for different
energies
Beam TVL (cm) Typical wall
thickness (m)
Co-60 23 1.38
4 MV 27 1.64
6 MV 34 2.03
10 MV 38 2.32
20 MV 47 2.74

BEAM STOPPERS
 Beam stoppers minimize required
thickness of primary barriers and are
used in installations in which space
constraints prevent the use of adequate
primary barrier thickness.
 Treatment machines equipped with
beam stoppers are cumbersome with
regard to patient setup on machine.
 With the use of beam stoppers, primary
barrier wall thickness becomes close to
(but cannot be less than) that required
for secondary barriers

MAZE
 A restricted access passageway leading to
room termed maze.
 Reduce radiation dose near entrance.
 Ideally - As long as and with as small a
cross-section as possible.
 A maze ensures that photon radiation can
only exit room after multiple scattering
has attenuated it.
 Reduces need for heavy shielding door.
 Another advantage of a maze is a route for
ventilation ducts and electrical conduits
without compromising shielding.

DOORS AND INTERLOCKS
 To restrict access during exposures.
 If shielded barrier is required to
reduce dose rates, a motorized door
may be necessary.
 Must have a manual means of
opening the door in the event of a
power or mechanical failure.
 All doors, gates, photoelectric
beams and motion detectors must
be interlocked to the treatment unit
to prevent an exposure if a door is
open.
 The interlock must also ensure that
when the door is opened the
irradiation will be terminated.
√
√
√
√

DUCTS AND CONDUITS
 Cables necessary to control treatment unit, heating and
ventilation ducts, ducts for physics equipment and other
service ducts should only penetrate through secondary
barriers.
 No duct with a diameter > 30 mm should penetrate
primary shielding.
 No duct should run orthogonally through a radiation
barrier. It could either run at an angle through barrier or
have one or more bends in it.
 Lead or steel plates are suitable materials to compensate
for displaced shielding.
 To shield the scattered radiation that passes along
the duct, it is better to place the additional shielding
outside the treatment room,
 Treatment machine cables are usually run below the
floor level under the
 primary or secondary barriers, before bending up to
reach the treatment control area.

PROTECTION AGAINST NEUTRONS
 High-energy x-ray beams (e.g., >10 MV) are contaminated with
neutrons.
 Photoneutrons are produced when photons interact with collimators,
target, flattening filter and other material along path of electron and
photon beam.
 For LAs between 10-25 MV, average energy of direct neutrons
exiting shielded head is never >1 MeV, and average energy of
neutrons scattered by the room is about 0.24 MeV.
 Fast neutrons are attenuated efficiently by materials with high
hydrogen content.
 Neutrons will be sufficiently attenuated by primary barrier designed
to attenuate photons.

 Neutrons are not attenuated by scattering in same way as photons so
maze design has to be considered.
 Neutrons Induced activity both in walls of room and materials of
head of accelerator.
 Neutron energy is considerably degraded after multiple scattering
and consequently, proportion of fast neutron (>0.1 MeV) reaching
inside of maze is usually small.
 Reflections from walls cause a reduction in neutron Fluence.
 A longer maze (>5 m) is desirable in reducing neutron fluence at
door.
 Hydrogenous material (polyethylene)can be added to door to
thermalize neutrons and reduce neutron dose further.
PROTECTION AGAINST NEUTRONS

WARNING LIGHTS AND SIGNS
 Red warning light should be provided
above the door.
 Interlinked to control panel.
 Light glows when source is in “ON”
position.
 One or more emergency off switches
should be conveniently placed inside the
treatment room to allow interruption of
radiation from inside the room.
 A Radiation area sign (along with a
visible red light) needs to be provided
above door to the treatment room, and
preferably also on control room door, to
indicate a beam on condition.

EMERGENCY OFF BUTTONS:
WHERE SHOULD THEY GO?

CONVENTIONAL SIMULATOR CT SIM
GANTRY - Motorized
- 0 –360° rotation
- Focus to isocentre distance:
80–120 cm
- Isocenter ht ≤ 130 cm
-Isocentre max. sphere diam. of
3.0 mm.
Collimators
- Motarised diaphragm
- Field definifng wires
- Rotation +/- 1000
- ODI – SAD +/- 20 cm
- Field size
- Field congruence
- Transparent shadow tray
-Apertures of at least 80 cm
- Scan field of view of at least
50 cm
- Extended field of view of min
70 cm
- Laser positioning of lights
with a positioning accuracy of
+/- 1 mm or better

CONVENTIONAL SIM CT SIM
COUCH - Xray transparent
- Rotation limit +/- 900
- Lat motion +/- 20 cm
- Longitudinal range ≥ 70
cm
- Couch sag ≤ 5 mm with 80
kg weight
- Carbon fiber with min dimensions of
23.5 x 40 cm
- Horizontal moving range of ≥ 170cm
- Max speed of horizontal
movement at least 100 mm/ sec.
- Accuracy better than +/- 0.25 mm
- Vertical movements ranges
1) 55 – 95 cm outside gantry
2) Within the gantry range of 20 cm
3) Min height outside the gantry 52
cm +/- 1 cm
- Able to take max weight of ≥ 180 kg

PARAMETERS CONVENTIONAL
SIM
CT SIM
- Slice thickness should be at least sub
millimeter.
-90 – 140 kV
- 30- 400 mA in increments of 10 mA or
better.
- Scan time of ≤ 0.5 sec for full 360 0
rotation
- Accuracy of slice prescription & dose
measurement +/- 0.5 mm or better.
Support for respiratory management
system

SELECTION OF MACHINE
1. Patient Load
2. Clinical need
3. Cost
4. Energy
5. TPS
6. MLC
7. 3D CRT, IMRT, IGRT

LINAC V/S Co 60
LA Co60 Comments
Dose rate 600 MU/min Reducing dose
starts at 200R/min
In cobalt dose will reduce
because of decay
Energy
diameter
<2 mm 20 mm Higher penumbra in
cobalt
Source
change
None Every 7 years Current cost for 12000Ci is
Rs. 35, 00,000
Dmax 1.5 cm for 6 MV 0.5 cm Skin sparing effect
PDD at 10cm 67% 55% Diificult to treat deep
seated tumors with cobalt
Collimator
transmission
≤ 0.5% >3%
Min FS 0.5x0.5 cm 5x5 cm

LINAC V/S Co 60
LA Co60 Comments
Radiation
leakage
Nil <0.2%
Penumbra <5 mm >1 cm
Precision More Less
Motorized
wedges
Possible Not possible
Variable dose
rate
80-600 Mu/min Not variable DR decreases with decay
for cobalt
MLC/
Stereotactic
attachments
Possible Not possible Increases accuracy in dose
delivery

LA Co60 Comments
Parts replacement Parts
costlier
No The costly replacement is
compensated as source cost is
not required for LINACS
Portal vision
attachment
Yes No Allows to view actual tumor
while treatment
Civil requirements
for installation of
teletherapy unit
Marginally
costly
Source disposal Nil Major
problem.
Source cost is
increasing
every year
BAARC doesnot permit
disposal of imported source.
Imported source has to be
transferred back to
manufacturer.
Cost of the
machine
2.5-3 crores Rs. 1.9 crores is cost of source
Spare parts cost for
10 years operation
Rs.
20,00,000
Rs. 10,00,000
LINAC V/S Co 60

LA Co60
Source sticking No Yes
Electric shock Yes Slight
Faulty tray resulting in falling blocks Yes Yes
Accidental irradiation if staff left in Bunker Yes Yes
Accidental irradiation during source replacement No Yes
Malfunction of machine Yes Yes
LINAC V/S Co 60

ELECTRON ENERGY
 Choice of photon energies doesn’t impact
on choice of electron energies.
 Maximum use between 6 and 12 MeV.
 Little benefit from energies above 15 MeV.
 Cautious use of high energy electrons in
areas of low tissue density.
 For any curative treatment, advice of a
physicist must be sought especially for
energies above 12 MeV.
 Advantage of a mixed modality machine,
pts dont have to move between machines.

LIST OF ITEMS IN A TREATMENT ROOM

QA OF RADIATION PROGRAMME
 Clinical aspect
 Physical aspect
 Radiation planning and
delivery
 Maintenance program
 Quality audits
 Investigation of radiation
accident

CLINICAL ASPECTS PHYSICAL ASPECTS
 Treatment policies
 Clinical case conferences
for review of
proposed/recent patient
treatments
 Clinical follow-up and
statistical review
 Once the equipment has been shown to
meet its specifications and has been
accepted from the manufacturer it will
then be commissioned for clinical use.
The results of the commissioning tests
serve as a reference for subsequent
checks
 The acceptance tests must demonstrate
that the equipment meets or exceeds the
bid specifications
 Acceptance test protocols specify which
tests will be performed, which equipment
is used to perform these tests and what
the results of these tests should be.
 At the completion of acceptance tests,
commissioning measurements begin
QA OF RADIATION PROGRAMME

SAFETY ASSOCIATED WITH INSTALLATION,
ACCEPTANCE TESTS, COMMISSIONING AND
OPERATION
 Important steps between issuing a purchase order for
radiation-emitting equipment and its eventual clinical use
 Installation and preliminary radiation survey.
 Rigorous radiation survey and acceptance testing.
 Commissioning.
 Development of quality assurance and quality control
procedures.
 Introduction of maintenance and servicing procedures.
 Start of clinical operation.

OPERATION
 The first act during installation - a preliminary
radiation survey of area immediately adjacent to
treatment room.
 To verify that radiation levels under the most
adverse conditions do not exceed levels estimated in
the planning process and approved by the licensing
body.

 To verify that:
 Equipment conforms to technical specifications given by
manufacturer.
 Equipment complies with the IEC safety requirements.
 The following generally applies:
 It is assumed that equipment belongs to manufacturer
until acceptance process has been completed.
 Usually carried out by a manufacturer’s representative in
presence of personnel representing user (medical
physicist) who will decide upon acceptance.
OPERATION

OPERATION
 After acceptance and before
starting clinical operation,
commissioning is performed.
 During commissioning medical
physicists:
 Calibrate the radiation
beam output.
 Measure all data required
for clinical use of machine,
including all data to be used
in treatment planning
computers (TPSs).
 Measure all data required
for specialized treatment
techniques to be used on
equipment.
 Quality control protocols:
Equipment parameters should
be tested:
Periodically under normal
operating conditions.
After radiation source has
been installed or replaced.
After repairs or maintenance
work are carried out on a
treatment machine that have
potential to alter radiation
output.

 Operated in accordance with technical documents,
ensuring satisfactory operation at all times in
respect of both tasks to be accomplished and
radiation safety.
 The manufacturer’s operating manual, and any
additional procedures, should be approved in
accordance with quality assurance system by a
national or international body that is responsible for
type approval of radiation emitting devices.
OPERATION

INVESTIGATION OF ACCIDENTAL
MEDICAL EXPOSURES
• Any therapeutic treatment delivered to either wrong patient or wrong
tissue, or using the wrong radioisotope, or with a dose or dose fractionation
differing substantially from the values prescribed by the radiation
oncologist or that may lead to undue acute secondary effects.
• Any equipment failure, accident, error, mishap, miscalculation or other
unusual occurrence with the potential for causing a patient dose
significantly different from that intended.
• In most cases the radiation physicist will be the most appropriate person
to undertake such an investigation, which should include:
• A calculation or estimation of the doses received and their distribution
within the patient;
• Corrective measures required to prevent recurrence of such an
accident;
• A method to implement any corrective measures.

QUALITY AUDITS
 A quality audit is an independent examination and evaluation
of the quality assurance activities and results of a particular
cancer centre.
 Ideally, quality audits review the entire quality assurance
process.
 Internal: Conducted by personnel of operating institution
 External: Conducted by personnel outside operating institution
 With regard to an external quality audit, the best results are
achieved with site visits by outside, qualified, experts;
however, this is an expensive process

RADIATION PROTECTION AND
SAFETY OF SOURCES
PUBLIC EXPOSURE SAFETY IN THE TRANSPORT
OF RADIOACTIVE MATERIALS
 The licensee is responsible for
controlling public exposures.
 Is controlled by proper design
of shielding and, in large part,
by ensuring that radiation
sources are shielded and
secured.
 Presence of members of the
public in and near the
radiotherapy department
should be taken into account
when designing the shielding
of storage and treatment
facilities.
 Suppliers transport external
beam sources and remote
control brachytherapy sources
under their own responsibility
until the source change has been
completed and the transfer of
ownership has been
accomplished with the
acceptance tests.

EMERGENCY PLANS
LOST SOURCES STUCK SOURCES
 It is critical that an up to date
inventory exist so that it can be
determined immediately which
source(s) is (are) missing, what
their type and activity are, when
and where they were last known to
be, and who last took possession of
them.
 The area where the sources were
last known to be should be sealed
until a survey has been performed.
This search needs to be performed
with the most sensitive radiation
detection (usually of the GM type)
survey meter available.
 There should be emergency
procedures posted at the treatment
unit for this event.
 In general, the first steps are to use
the source driving mechanism to
return the source to the shielded
position (external beam or HDR
unit).
 If this is not immediately
successful and there is a patient
present, the patient must be
removed from the radiation field
and the area must be secured from
further entry until the RSO is
notified and takes control of the
situation.

CONTAMINATION ACCIDENTAL EXPOSURE OF
PATIENTS
 Occurs if radioactive material
has spread outside its container
or encapsulation.
 It is very important that the
area be sealed until.
 All those persons who were in
the area to be surveyed and
decontaminated if necessary.
 If there are windows or
ventilation shafts, these should
be closed and the RPO should
take control of the situation.
 Emergency procedures should
be posted at the control
console.
 The BSS requirements on
investigation of accidental
medical exposures have already
been referred to above,
including the reporting and
corrective measures to be
taken. Formal procedures need
to be developed to report and
deal with the situation upon
detection of an exposure
different than that intended.
EMERGENCY PLANS

Need for monitoring
Provision of apparently adequate barriers & protective
devices does not guarantee the safety of workers
concerned
 Barrier may not be adequate
 cracks or errors in construction
 workers may ignore or fail to take full advantage of
protection provided
Dose monitoring
Personal
Workplace monitoring

Personal monitoring
 Measurement of the total dose received by
individual radiation workers over a specified
period of time.
 Aims
Monitor and Control individual dose regularly.
Report and investigate overexposures and
recommend necessary remedial measures
urgently.
Maintain lifetime cumulative dose record of the
users of the service.

Personal monitoring devices
 TLD
 Film badge
 Direct reading pocket dosimeters
 Optically stimulated devices (OSD).
 Specialized personal monitoring devices-neutron
radiation

Workplace monitoring
 Monitoring of exposure
levels should be conducted
through the use of area
monitors in teletherapy
and HDR treatment rooms.
 Monitoring of the source
storage and handling area
is to be conducted with a
survey meter immediately
following the removal from
and return to storage of
brachytherapy sources.
Ionisation
chamber type
Geiger mueller
type

Correction for TBI
Total body irradiation is performed with the patient at
extended distances from the isocenter (typically 2 to 5
M ) which significantly raises the number of MU ( 9 to
36 times ) needed to deliver the prescribed dose at the
patient.
TBI contributes no scatter from the Isocenter while
producing a higher direct radiation incident on the
primary barrier behind the patient

Corrections
 Work load factor : higher dose is delivered per week
as compared to conventional treatment
 Use factor distributions for direct, leakage radiation
(left, right, up, down) use factor
without TBI : (1/4, 1/4, 1/4, 1/4)
With TBI : (4/7, 1/7, 1/7, 1/7)

Construction of Radiotherapy centre.pptx

Recommended

Recommended

More Related Content

Similar to Construction of Radiotherapy centre.pptx

Similar to Construction of Radiotherapy centre.pptx (20)

More from TaushifulHoque

More from TaushifulHoque (17)

Recently uploaded

Recently uploaded (20)

Construction of Radiotherapy centre.pptx

Editor's Notes