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|
Identifier |
000373934 |
Title |
Προσομοίωση ακτινοθεραπευτικών τεχνικών έκτοπης οστεοποίησης και καρκίνου του μαστού με μεθοδολογία Monte Carlo:υπολογισμοί δόσεων ακτινοευαίσθητων οργάνων |
Alternative Title |
Simulation of radiotherapeutic techniques for heterotric ossification and breast cancer using Monte Carlo methods:calculation of radiosensitive organ doses. |
Author
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Μπέρρης, Θεοχάρης Β
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Thesis advisor
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Μαζωνάκης, Μιχαήλ
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Abstract |
The treatment of cancer with radiotherapeutic techniques constitutes a
widespread practice. Nevertheless, radiotherapeutic applications are not limited to the
treatment of cancer. There are also benign diseases for which radiotherapy has
comparable or even greater effectiveness than other potential treatments. An example
of such a disease is heterotopic ossification. Many clinics worldwide utilize radiation
therapy to treat heterotopic ossification.
Due to the risk for second cancer induction following radiation exposure of the
patient, the physician should be able to quantitatively weigh up the expected benefit
against the detriment of the treatment in question. The need to perform such
estimations becomes greater for young patients who are expected to live long after
irradiation takes place. Except for radiation treatment of benign diseases, the risk for
second cancer induction due to irradiation is important in the case of cancers with
good prognosis, such as breast cancer.
The first step towards the quantification of second cancer risk is the
determination of radiation doses, absorbed by the various radiosensitive organs of the
patient. However it is difficult to directly measure organ doses provided that it is not
possible to insert dosimeters in the patient’s body. A way to get over this obstacle is
to simulate radiotherapeutic techniques using human-like phantoms. Recently,
advances in computer technology have made possible to simulate radiation therapy
techniques using suitable computer codes. Today, computational methods are
widespread in the field of Medical Physics because of their usefulness, low cost and
precision of the calculations they can perform.
In the current study, in order to exploit the power of computational techniques,
therapies of heterotopic ossification and breast cancer were simulated using Monte
Carlo methods. A large part of the total effort was dedicated to the construction of a
simulated model of the photon beam produced by a Phillips SL 75/5 linear
accelerator. The simulated beam model was verified by comparing calculated
dosimetric quantities to measurements performed on the real linear accelerator. The
way the model was constructed allowed the calculation of certain actinometrical
characteristics of the photon beam, such as particle flow and spectral distribution, and
their correlation to dosimetric quantities, such as percentage depth dose and dose
profiles in a water phantom. An investigation of the effect of the electron beam
parameters on the photon beam characteristics was also realized. The investigation
confirmed the reliability of the simulation.
Finally, the photon beam model was combined with a mathematical phantom
in order to simulate radiation therapy of heterotopic ossification and breast cancer.
Radiation doses to radiosensitive organs of the mathematical phantom were calculated
for all treatments in question. The effect of radiation field size on organ doses was
investigated. The effect of suitably placed lead blocks on organ doses was also studied
for the fields where they are typically used.
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Language |
Greek |
Subject |
Breast cancer |
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Dose |
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Heterotopic ossification |
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Monte carlo |
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Radiation protection |
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Radiation therapy |
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Radiology |
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imulation |
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Έκτοπη οστεοποίηση |
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Ακτινοθεραπεία |
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Ακτινοπροστασία |
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Δόση |
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Καρκίνος Μαστού |
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Προσομοίωση |
Issue date |
2010-07-20 |
Collection
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School/Department--School of Medicine--Department of Medicine--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/5/9/4/metadata-dlib-1336462135-462068-23528.tkl
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Views |
427 |