نتایج جستجو برای: lung tissue dosimetry

تعداد نتایج: 1182379  

Journal: :Radiation Physics and Chemistry 2021

Tissue-equivalent phantoms are suitable tools for radiation dosimetry investigations. The goal of this study was to determine the scattered dose in a simple phantom model mouse with xenographic tumour using experimental measurements and Monte-Carlo calculations. We manufactured cubic polymethyl methacrylate (PMMA) an extrusion on its side both normal tissue xenograft tumour-bearing mouse. posit...

2006
Chao Sheng Brian W. Pogue

Photodynamic therapy (PDT) is used to cause specific tissue destruction, using photochemical reactions that result from light excitation of photosensitizer, which has localized in the target tissue. The process of photosensitizer photobleaching was investigated to redefine the approach to dosimetry, when applied to treatment of Barrett’s esophagus.

A R Mehdizadeh H Mostaghimi, M Karimi, S. F Shams,

The aim of this report is to present a new two-piece thyroid-neck phantom produced by the concurrent use of epoxy resin and poly(methyl methacrylate) (PMMA: plexiglass) soft tissue equivalent materials. Accordingly, mass attenuation coefficients of the epoxy resin and the plexiglass compounds were obtained from simulation (NIST XCOM 3.1) and measurements (practical dosimetry) and compared to th...

ژورنال: سنجش و ایمنی پرتو 2020

Unlike proton therapy, conventional radiation therapy directs X-rays not only at the tumor but also unavoidably at nearby healthy tissue. Protons deliver radiation to tumor tissue while the healthy structures will be spared during proton therapy. When protons travel through matter, secondary particles like neutrons and photons are produced. It is believed that the secondary dose can lead to sec...

A Shabestani Monfared, F Niksirat Gh Ataei, K Ebrahimnejad Gorji S Cham

Accuracy of the radiotherapy requires some routine quality control and dosimetry calculations, which would be done by radiotherapy physicists. Due to the increasing use of computers and simulation software in medical science, as well as trends indicating its continued growth, this study aims to develop a new smart-phone application to perform common radiotherapy-related calculations. Computatio...

2003
Chao Sheng Brian W. Pogue Hamid Dehghani Julia A. O’Hara P. Jack Hoopes

In order to better understand light dosimetry issues for photodynamic therapy (PDT), we have used various tumor and normal tissue geometries to develop a diffusion model of light transport in tissues. We hypothesize that tumor tissues with curved surfaces will have significantly different internal fluence distributions, as compared to tissues with flat surfaces. Using a mouse subcutaneous tumor...

2015
Eileen D. Kuempel Lisa M. Sweeney John B. Morris Annie M. Jarabek

The purpose of this article is to provide an overview and practical guide to occupational health professionals concerning the derivation and use of dose estimates in risk assessment for development of occupational exposure limits (OELs) for inhaled substances. Dosimetry is the study and practice of measuring or estimating the internal dose of a substance in individuals or a population. Dosimetr...

Journal: :Journal of biomedical optics 2013
Kimberley S Samkoe Amber Bryant Jason R Gunn Stephen P Pereira Tayyaba Hasan Brian W Pogue

The use of in vivo contrast-enhanced magnetic resonance (MR) imaging as a surrogate for photosensitizer (verteporfin) dosimetry in photodynamic therapy of pancreas cancer is demonstrated by correlating MR contrast uptake to ex vivo fluorescence images on excised tissue. An orthotopic pancreatic xenograft mouse model was used for the study. A strong correlation (r = 0.57) was found for bulk inte...

2005
Jian‐Yue Jin Eric E. Klein Feng‐Ming Kong Zuofeng Li

The purpose of the present study was to compare a new internal mammary irradiation technique with traditional techniques for locally advanced breast cancers in terms of sparing ipsilateral lung and heart and reducing the "cold" and "hot spots"in breast tissue. The new technique uses wide tangential fields for the first eight fractions of treatment. A medial internal mammary field (IMF) of elect...

Journal: :Journal of Synchrotron Radiation 2021

Spatially fractionated ultra-high-dose-rate beams used during microbeam radiation therapy (MRT) have been shown to increase the differential response between normal and tumour tissue. Quality assurance of MRT requires a dosimeter that possesses tissue equivalence, high tolerance spatial resolution. This is currently an unsolved challenge. work explored use 500 nm thick organic semiconductor for...

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