نتایج جستجو برای: Asymmetric Wedged Field Output Factor

تعداد نتایج: 1812658  

Farnaz Rahimli hamideh mazraeh Mahbube Fadaei Mansour Zabihzadeh Mojtaba Hoseini- Ghahfarokhi Seyed Mohammad Hoseini Sholeh Arvandi

Introduction: Physical wedge as a useful tool has been utilized in radiotherapy to modify photon beam shape and intensity such that it distributes dose uniformly in tumor site and reduces hot points. Since during Linac commissioning dosimetric parameters like output factors and lateral dose profiles are measured only for symmetric open and wedged fields, so calculation the par...

Introduction: Physical wedge by modify photon beam shape and intensity has been utilized in radiotherapy to obtain uniformly dose distribution in tumor site with reduced hot spots. Calculation of dosimetric parameters for both symmetric and asymmetric wedged fields is proved necessary during linear accelerator (Linac) commissioning. The present study aimed to achieve o...

2003
B. D. Wichman

Enhanced dynamic wedges can be very useful in increasing radiation therapy treatment efficiency. A drawback to their use is finding a factor analogous to a conventional wedge factor to calculate the dose to a point in a dynamically wedged field. A formalism has previously been published [J. Gibbons, Med. Phys. 25, 1411-1418 (1998)] to determine this factor at the central point of a dynamically ...

Journal: :iranian journal of medical physics 0
alireza mohammadkarim department of medical radiation engineering, science and research branch, islamic azad university, tehran, iran ph.d student, department of medical physics, faculty of medical sciences, tarbiat modares university, tehran, iran hasan ali nedaie department of radiotherapy, oncology and medical physics, tehran university of medical sciences, tehran, iran mahmoud allahverdi department of medical physics, tehran university of medical sciences, tehran, iran mahbod esfehani department of radiation oncology, cancer institute of iran, tehran university of medical sciences, tehran, iran alireza shirazi department of medical physics, tehran university of medical sciences, tehran, iran ghazale geraily department of medical physics, tehran university of medical sciences, tehran, iran

introduction evaluation of the delivered dose of externally wedged photon beams by external diode dosimeters during the treatment process requires the estimation of exit surface dose correction factors in various wedge angles and field sizes. materials and methods a system of absorbed dose evaluation, using p-type diode dosimeters placed on the exit surface of a phantom, was characterized for e...

Introduction Evaluation of the delivered dose of externally wedged photon beams by external diode dosimeters during the treatment process requires the estimation of exit surface dose correction factors in various wedge angles and field sizes. Materials and Methods A system of absorbed dose evaluation, using p-type diode dosimeters placed on the exit surface of a phantom, was characterized for e...

2003
K. L. Prado S. M. Kirsner R. J. Kudchadker R. E. Steadham R. G. Lane

Several recent reports have described methods for calculating enhanced dynamic wedge factors (EDWFs). Many of these reports use the monitor-unit (MU) fraction method to predict EDWFs as a function of field size. Although simple in approach, MU fraction methods do not produce accurate EDWFs in large or asymmetric fields. A recently described technique, based on the MU fraction method works well ...

Journal: :Physics in medicine and biology 1997
P Keall S Zavgorodni L Schmidt D Haskard

Dose profiles produced by wedge filters in the non-wedged direction can exhibit a 7% or greater dose reduction at the outer ends of the field compared with open field profiles. However, many planning systems use open field profiles to model wedged dose distributions. In the present work, wedges have been modified to reproduce open field profile shapes. This modification involved removing varyin...

2013
M Jahangir Alam Syed Md Akram Hussain Kamila Afroj Shyam Kishore Shrivastava

A three dimensional treatment planning system has been installed in the Oncology Center, Bangladesh. This system is based on the Anisotropic Analytical Algorithm (AAA). The aim of this study is to verify the validity of photon dose distribution which is calculated by this treatment planning system by comparing it with measured photon beam data in real water phantom. To do this verification, a q...

Journal: :International Journal of Cancer Therapy and Oncology 2015

Journal: :پژوهش های اقتصادی ایران 0

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