نتایج جستجو برای: radiotherapy beam scanning

تعداد نتایج: 319526  

2013
T.T. Böhlen J. Bauer M. Dosanjh A. Ferrari T. Haberer K. Parodi V. Patera A. Mairani

Ion beam therapy, as an emerging radiation therapy modality, requires continuous efforts to develop and improve tools for patient treatment planning (TP) and research applications. Dose and fluence computation algorithms using the Monte Carlo (MC) technique have served for decades as reference tools for accurate dose computations for radiotherapy. In this work, a novel MC-based treatment-planni...

Journal: :Physics in medicine and biology 2001
P J Keall V R Kini S S Vedam R Mohan

Intrafraction motion caused by breathing requires increased treatment margins for chest and abdominal radiotherapy and may lead to 'motion artefacts' in dose distributions during intensity modulated radiotherapy (IMRT). Technologies such as gated radiotherapy may significantly increase the treatment time, while breath-hold techniques may be poorly tolerated by pulmonarily compromised patients. ...

Journal: :Nano letters 2005
A Persaud S J Park J A Liddle T Schenkel J Bokor I W Rangelow

We report the integration of a scanning force microscope with ion beams. The scanning probe images surface structures non-invasively and aligns the ion beam to regions of interest. The ion beam is transported through a hole in the scanning probe tip. Piezoresistive force sensors allow placement of micromachined cantilevers close to the ion beam lens. Scanning probe imaging and alignment is demo...

2014
Koji Inaba Hiroyuki Okamoto Akihisa Wakita Satoshi Nakamura Kazuma Kobayashi Ken Harada Mayuka Kitaguchi Shuhei Sekii Kana Takahashi Kotaro Yoshio Naoya Murakami Madoka Morota Yoshinori Ito Minako Sumi Takashi Uno Jun Itami

During radiotherapy for gastric lymphoma, it is difficult to protect the liver and kidneys in cases where there is considerable overlap between these organs and the target volume. This study was conducted to compare the three radiotherapy planning techniques of four-fields 3D conformal radiotherapy (3DCRT), half-field radiotherapy (the half-beam method) and intensity-modulated radiotherapy (IMR...

2002
Hideyuki Harada Shigeyuki Murayama

This review summarizes the past and present status of proton beam therapy (PBT) for lung cancer. PBT has a unique characteristic called the Bragg peak that enables a reduction in the dose of normal tissue around the tumor, but is sensitive to the uncertainties of density changes. The heterogeneity in electron density for thoracic lesions, such as those in the lung and mediastinum, and tumor mov...

Fatemeh Moradi-Mocarram Mohammad Amin Mosleh-Shirazi, Reza Faghihi,

Introduction: The selection of suitable beam angles and weights in external-beam radiotherapy is at present generally based upon the experience of the planner. Therefore, automated selection of beam angles and weights in forward-planned radiotherapy will be beneficial. Material and Methods: In this work, an efficient method is presented within the MATLAB environment to investigate how to improv...

2018
Jihyung Yoon Yibo Xie Rui Zhang

The purpose of this study was to evaluate a methodology to reduce scatter and leakage radiations to patients' surface and shallow depths during conventional and advanced external beam radiotherapy. Superflab boluses of different thicknesses were placed on top of a stack of solid water phantoms, and the bolus effect on surface and shallow depth doses for both open and intensity-modulated radioth...

2005
W. PARKER H. PATROCINIO

External photon beam radiotherapy is usually carried out with more than one radiation beam in order to achieve a uniform dose distribution inside the target volume and an as low as possible a dose in healthy tissues surrounding the target. ICRU Report No. 50 recommends a target dose uniformity within +7% and –5% of the dose delivered to a well defined prescription point within the target. Moder...

C.H. Xie, D.Z. Jiang, H. Liu, J. Zhang, X.T. Huang, Y.F. Zhou, Z.R. Bao,

Background: Cone-beam computed tomography (CBCT) scanners for image-guided radiotherapy are in clinical use today, but there has been no consensus on uniform acceptance to verify the CBCT image quality yet. The present work proposed new methods to fully evaluate the performance of CBCT in its three-dimensional (3D) reconstruction space. Materials and Methods: Compared to the traditional methods...

2000
R. Sepulchre

Pencil Beam Scanning is a dynamic beam delivery system developed for proton therapy. The radiation field necessary to reach in a fast and robust way a prescribed 3D dose distribution is obtained by accurately controlling both the extraction of the beam from a 235 MeV accelerator and the motion of the beam spot thanks to scanning magnets. This paper focuses on the trajectory planning aspect of t...

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