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This study focused on predicting the electronic portal imaging device (EPID) image of intensity modulated radiation treatment (IMRT) fields in the absence of attenuation material in the beam with Monte Carlo methods. As IMRT treatments consist of a series of segments of various sizes that are not always delivered on the central axis, large spectral(More)
For EPID dosimetry, the calibration should ensure that all pixels have a similar response to a given irradiation. A calibration method (MC), using an analytical fit of a Monte Carlo simulated flood field EPID image to correct for the flood field image pixel intensity shape, was proposed. It was compared with the standard flood field calibration (FF), with(More)
Liver irradiation leads to a decreased uptake of a hepatobiliary directed MRI contrast agent (Gd-EOB-DTPA) as shown in studies performed 1-6 months after proton therapy, stereotactic ablative body radiation therapy and brachytherapy. Therefore, Gd-EOB-DTPA enhanced MRI could potentially be used for in vivo verification of the delivered dose distribution.(More)
INTRODUCTION The physical properties of proton beam radiation may offer advantages for treating patients with non-small-cell lung cancer (NSCLC). However, its utility for the treatment of medically inoperable stage I NSCLC patients with stereotactic body radiation therapy (SBRT) is unknown. METHODS Outcomes for patients with medically inoperable stage I(More)
We present and validate a computed tomography (CT) metal artifact reduction method that is effective for a wide spectrum of clinical implant materials. Projections through low-Z implants such as titanium were corrected using a novel physics correction algorithm that reduces beam hardening errors. In the case of high-Z implants (dental fillings, gold,(More)
PURPOSE To investigate the feasibility of using MRI to verify proton beam distal range for liver tumor treatment in a retrospective study. METHODS AND MATERIALS Because the follow-up hepatocyte-specific functional MR imaging can detect the radiobiological change of liver tissue after radiation, we firstly registered the contrast-enhanced MR images to the(More)
Experimental and Monte Carlo simulations were conducted for an Elekta Ltd Precise Treatment System linac fitted with a low Z insert of sufficient thickness to remove all primary electrons. A variety of amorphous silicon based panels employing different scintillators were modelled to determine their response to a variety of x-ray spectra and produce an(More)
Interplay between organ (breathing) motion and leaf motion has been shown in the literature to have a small dosimetric impact for clinical conditions (over a 30 fraction treatment). However, previous studies did not consider the case of treatment beams made up of many few-monitor-unit (MU) segments, where the segment delivery time (1-2 s) is of the order of(More)
Treatment delivery with active beam scanning in proton radiation therapy introduces the problem of interplay effects when pencil beam motion occurs on a similar time scale as intra-fractional tumor motion. In situations where fractionation may not provide enough repetition to blur the effects of interplay, repeated delivery or 'repainting' of each field(More)