Conformal Radiation Therapy with Cobalt-60 Tomotherapy
Authors
Dhanesar, Sandeep Kaur
Date
2008-04-28T19:03:27Z
Type
thesis
Language
eng
Keyword
Radiation Therapy , Conformal radiation therapy , Tomotherapy , Cobalt-60 tomotherapy , IMRT
Alternative Title
Abstract
Intensity-modulated radiation therapy (IMRT) is an advanced mode of high-
precision radiation therapy that utilizes computer-controlled x-ray accelerators to
deliver precise radiation doses to malignant tumors. The radiation dose is designed to
conform to the three-dimensional (3-D) shape of a tumor by modulating the intensity
of the radiation beam to focus a higher radiation dose to the tumor while minimizing
radiation exposure to surrounding normal tissue. One form of IMRT is known as
tomotherapy. Tomotherapy achieves dose conformity to a tumor by modulating the
intensity of a fan beam of radiation as the source revolves about a patient.
Current available tomotherapy machines use x-ray linear accelerators (linacs)
as a source of radiation. However, since linacs are technologically complex, the world-
wide use of linac-based tomotherapy is limited. This thesis involves an investigation
of Cobalt 60 (Co-60) based tomotherapy. The inherent simplicity of Co-60 has the
potential to extend the availability of this technique to clinics throughout the world.
The goal of this thesis is to generate two-dimensional (2-D) Co-60 tomotherapy con-
formal dose distributions with a computer program and experimentally validate them
on ¯lm using a ¯rst generation bench-top tomotherapy apparatus.
The bench-top apparatus consists of a rotation-translation stage that can
mimic a 2-D tomotherapy delivery by translating the phantom across a thin, "pencil-
like" photon beam from various beam orientations. In this thesis, several random and
clinical patterns are planned using an in-house inverse treatment planning system and
are delivered on ¯lm using the tomotherapy technique. The delivered dose plans are
compared with the simulated plans using the gamma dose comparison method. The
results show a reasonably good agreement between the plans and the measurements,
suggesting that Co-60 tomotherapy is indeed capable of providing state-of-the-art
conformal dose delivery.
Description
Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-04-25 02:20:56.102
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