نتایج جستجو برای: intensity modulation

تعداد نتایج: 326343  

2004
Yin Zhang Michael Merritt

Intensity-modulated radiation therapy (IMRT) is a state-of-the-art technique for administering radiation to cancer patients. The goal of a treatment is to deliver a prescribed amount of radiation to the tumor, while limiting the amount absorbed by the surrounding healthy and critical organs. Planning an IMRT treatment requires determining fluence maps, each consisting of hundreds or more beamle...

2016
Lama Ghattas Serge Bories Dominique Picard Philippe Pouliguen Patrick Potier

Antenna arrays for direction finding (DF) are usually designed and tested in controlled environments such as anechoic chambers. However, antenna pattern may change significantly when antennas are placed in their operational environment. In such perturbing close context, the antennas calibration validity becomes a major issue which can lead to DF performance degradation and costly recalibration ...

2012

Innovation/Impact: We propose a novel delivery method for intensity modulated radiation therapy (IMRT) that significantly reduces treatment delivery times by delivering dose during both inhale and exhale windows. We developed an inverse treatment planning method for developing inhale and exhale IMRT fluence maps that produce a final dose (the summed inhale and exhale doses) that meets clinical ...

2014
Christopher W. Jarrett Charles F. Caskey John C. Gore

A novel form of acoustic modulation of light from an incoherent source has been detected in water as well as in turbid media. We demonstrate that patterns of modulated light intensity appear to propagate as the optical shadow of the density variations caused by ultrasound within an illuminated ultrasonic focal zone. This pattern differs from previous reports of acousto-optical interactions that...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 1999
M Quarantelli B Alfano M Larobina E Tedeschi A Brunetti E M Covelli A Ciarmiello C Mainolfi M Salvatore

UNLABELLED An original method for simultaneous display of functional and anatomic images, based on frequency encoding (FE), merges color PET with T1-weighted MR brain images, and grayscale PET with multispectral color MR images. A comparison with two other methods reported in the literature for image fusion (averaging and intensity modulation techniques) was performed. METHODS For FE, the Fou...

2015
Ankita Choubey Deepak Sharma

Wireless communication technology is emerging very fast with reliable communication lead to emergence of very numerous technologies. There are various modulation schemes suitable in optical wireless communication like OOK, PPM, DPIM, DHPIM, and OFDM. As modulation techniques is categorized into bandwidth & power efficient but for error performance there are few assumptions where there is no ban...

2010
Jean M. Moran

As the complexity of radiation therapy has increased, the need for quantitative dosimetric evaluation of treatment delivery has also increased. A growing number of investigations have expanded the use of EPIDs from anatomic applications to dosimetric verification. This work focuses on the applications of EPIDs for pre-treatment dosimetric verification of IMRT and intensity modulated arc therapy...

2002
K. Van Den Abeele

An acousto-optical reconstruction method for acoustic signals using multidirectional light diffraction by finite amplitude ultrasonic pulses is presented. When crossing the ultrasonic field, the far field diffracted laser light intensity of an incident convergent lightbeam becomes modulated in time. It is found that for special conditions, concerning direction of observation, ultrasonic frequen...

1999
Martin A. Mason Kevin K. Lehmann

In the laser-induced fluorescence spectrum of HCP, a sharp decrease in fluorescence intensity was observed at 41 680 cm-‘. This diminuation in emission intensity is due to a rotatio_nally mediated coupling of the excited vibronic level with the dissociative continuum of the X state; this has allowed us to place an upper limit on Do for the ground electronic state. A lower limit for De can be pl...

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