Aceeptance testing and commisioning data measurement for photon beam

Performed By
Md. Din Muhammad
B.Sc.(Hons.) MPBME
Gono Bishwabidyalay, Savar, Dhaka

1. Introduction
1.1 General introduction
During accepting testing and commissioning medical
physicists are faced with many challenges, like a
variety of scientific testing methods, setting for
highest precision, data accuracy, etc.
Accepting testing procedure agreed on between the
manufacturer’s representative and the facility physicist
 Commissioning is a process to prepare machine for
any clinical use and investigated, measured, and
recorded. Commissioning of a treatment unit should
only start after a thorough acceptance process has
established its mechanical and radiation consistency.

1.2 Objectives of the study
The objectives of this study are-
 To prepare necessary documents for acceptance testing
and commissioning.
 To perform acceptance testing and safety checks
 Output Calibration of the machine for each photon
energy.
 To measure all relative data required to configure AAA
algorithm.
 To commission the machine for all designated clinical
uses
 To establish treatment procedures and train personnel

1.3 Aims & Scopes
The main aims of acceptance tests and
commissioning are:
 To assure all specifications are fulfilled.
 To calculate how much area is free of radiation.
 To protect the staffs from irradiation.
 To know how much accurate beam is produced
 To prepare the machine for clinical treatment
 To ensure the better quality of treatment

2.Materials and Methods
2.1 Materials:
There are some equipments that
used in my project work . These
are:
Linear Accelerator(Varian 2300
C/D)
Mini Water Phantom (WP34)
Cylindrical Ionization Chamber
Monitoring Device
Geiger Muller (GM) Counters
Electrometer(IBA-DOSE-1)
Plane-parallel Chamber
Film (X-Omat V)

2.2.1 Safety Checks
 Warning lights
 Door Interlock.
 Patient monitoring equipment
 Emergency Buttons
 Interlocks
2.2 Acceptance Tests
Acceptance tests procedures are divided into three groups:
Safety Checks
Mechanical checks
Dosimetry measurements

2.2.2Radiation Survey:
This test is followed by IEC 61217 protocol
 Materials:
 Geiger Muller (GM) Counters
2.2.3 Collimator Axis of
Rotation
This test is followed by IEC 61217 protocol
Materials:
 Front pointer
 Graph paper
 Microspore tape
 Pinpricks, etc.
Method of Test:
The graph paper sets under the front pointer tip
rotate the collimator from 90° to 270° while observing
the pointer run-out .Verify that the worst case run-out
≤1.0 mm.
Fig-Collimator Axis
of Rotation

2.2.4 Gantry Axis of Rotation
This test is followed by IEC 61217 and
IAEA TECDOC_1540 protocol
 Materials:
 Front pointer
Microspore tape
 Pinpricks, etc.
Method of Test:
Rotate the gantry through 360° angle and visually checking
the front pointer run-out after the rotation of every 90°.
Fig-Gantry Axis of
Rotation

2.2.5 Couch Axis of Rotation
This test is followed by IEC 61217 and
IAEA TECDOC_1540 protocol
 Materials:
 Front pointer
 Graph paper
 Microspore tape
 Pinpricks, etc.
Method of Test:
 Slowly rotate the Couch from 90° to 270° while observing the
front pointer run-out every 45°
 Verify the worse case run-out is ≤1.0 mm radius for
counterweight systems and ≤2.0 mm for Beam-stopper systems.
Fig-Couch Axis of
Rotation

2.2.6 Light Field and X-Ray Field
Methods:
Set up a piece of film on the Couch with the light field
visible on one half of the film sheet. Mark the edges of
the light field and expose the film.
Shift the film to expose the other half of the film
using the same condition for X-ray field.
After developing the film compare 50% intensity
regions of X-ray edges to the marks representing the
light field edges. The difference between the light field
marks and the x-ray field edges should coincide within
±2.0 mm.
Fig: Light Field and
X-Ray Field
2.2.7 Gantry Rotation Spoke Shot
Method of Test:
Rotate gantry successfully 90 t0 185 for exposed film
Bisect 1.0cm exposure
Measure the longest line of the trapezoid

2.2.9 ODI Calibration
Method of Test:
 Turn on the Field Light and project the crosshairs and
ODI rangefinder display on a piece of white paper.
Verify the ODI meets specification for the 100 cm
position.
 Drive the Couch 20 cm above and then 30 cm below
the 100 cm reference position. Verify the ODI display
meets specification.

2.2.10 Photon Energy Depth of Ionization
Method of Test:
 Beam on and scan the central axis depth of ionization for both.
 Analyze the scans and verify each energy meets the specifications.
2.2.11 Photon Field Flatness and Symmetry
Method of Test:
 Scan through the X-ray field central
 axis at a depth if 10 cm in the radial plane for each energy at field sizes
of 40×40 cm and 10×10 cm. Radial scans should always be performed
prior to transverse scans in cause any steering adjustments are
required.
 Setup the Welhofer scanning system for CROSSPLANE scanning and
repeat the scans in the transverse plane. For Buddle-ship tanks rotate
the couch to 90° or 270°.

4. Discussion:
 The study helps to understand the important of
Acceptance tests and commissioning for linear
accelerator.
 The study gives an ideas to improve the work
accurately.
 The study helps the staffs to update their
knowledge in this procedures
 The study helps to measure the errors.

5. Conclusion:
All measurements are done properly and carefully.
All data readings are include carefully.
During Absolute and Reference Dosimetry all
equipments are setup accurately according to the
protocol TRS-398.
I could not include some data like beam profiles
for both photon energy at all depth ,wedge ,PDD
etc.
 All data are measured before treating the patients.

Aceeptance testing and commisioning data measurement for photon beam

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