ConferenceCancer Research · February 15, 2020
AbstractObjectives: The machine learning (ML)-based automated treatment planning tool has been developed and evaluated for whole breast radiotherapy. This study implemented the tool in clinic and compared pl ...
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ConferenceMedical Physics · January 1, 2013
Purpose: Pre‐operative stereotactic body radiosurgery (SBRT) was delivered in a single fraction to treat patients with early stage breast cancer; however, few data are available regarding radiation‐induced changes by SBRT. In this work, diffusion weighted ...
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ConferenceMedical Physics · January 1, 2011
Purpose: Respiratory signal for 4DCT is typically extracted using an external respiratory positioning management device (RPM) which is often inconvenient and time consuming. The efficiency of 4DCT imaging could be substantially improved if anatomical body ...
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ConferenceMedical Physics · January 1, 2010
Purpose: To compare the dosimetric results and treatment efficiency of intensity modulated arc therapy using RapidArc™ to static‐gantry IMRT plans for conventional fractionation treatment of head‐and‐neck cancer. Materials and Methods: This study evaluated ...
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ConferenceMedical Physics · January 1, 2010
Purpose: Gantry‐angle dependence of dose measurement for intensity‐modulated arc therapy (IMAT) quality assurance (QA) using a two‐dimensional ion chamber array may be significant. A new device, the gantry angle sensor, has been provided to compensate for ...
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ConferenceMedical Physics · January 1, 2010
Purpose: The anisotropic analytical algorithm (AAA) has been shown to provide more accurate dose calculation due to 3D scatter and inhomogeneity corrections than the pencil beam convolution algorithm (PBC) for inhomogeneous anatomical regions such as lung ...
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ConferenceMedical Physics · January 1, 2010
Purpose: To assess imaging dose of partial and full‐angle CBCT scan protocols, and to evaluate their image quality. Method and Materials: The CTDI of the six new CBCT protocols for Varian OBI were obtained by ion chamber (IC) measurements and Monte Carlo ( ...
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ConferenceMedical Physics · January 1, 2010
The primary purpose of in‐room CBCT volumetric 3D verification images is to verify patient position and target localization in real‐time. However they are also used for clinical treatment evaluation or plan modification for adaptive radiation therapy. Dail ...
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ConferenceMedical Physics · January 1, 2009
Purpose: To present QA measurements over extended periods at our institute and recommend a QA program for image‐guided radiosurgery on Novalis Tx system. Method and Materials: Novalis Tx system is developed based on a Trilogy linear accelerator featuring B ...
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ConferenceMedical Physics · January 1, 2009
Purpose: The purpose of this study is to compare RapidArc plans and conventional IMRT plans for head‐and‐neck cancer treatment involving bilateral nodes. Methods and Materials: This study included 10 locally advanced head‐and‐neck cancer patients. The plan ...
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ConferenceMedical Physics · January 1, 2009
Purpose Volumetric modulated arc therapy (VMAT) is a rotational IMRT modality that combines dose rate modulation with gantry and MLC motion, thereby increasing the complexity of IMRT delivery. Effective implementation of this technology is still quite new ...
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ConferenceMedical Physics · January 1, 2009
Purpose: To investigate how a real‐time tracking technique, based on implanted transponders, could be effectively integrated into the current process for image‐guided radiation treatment of prostate cancer. Method and Materials: Current prostate IGRT proce ...
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ConferenceMedical Physics · January 1, 2009
Any deviation between treated and planned volumes for 3‐D conformal therapy, such as IMRT, may cause an adverse clinical outcome. It is therefore critical to minimize all potential deviations using an on‐board (or real‐time) imaging procedure immediately p ...
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ConferenceMedical Physics · January 1, 2009
Purpose: Volumetric modulated arc treatment (VMAT) reduces treatment time over static beam intensity modulated treatment (IMRT) by delivering IMRT using arcs. This clinical study evaluates the feasibility of using VMAT for spine stereotactic body radiother ...
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ConferenceMedical Physics · January 1, 2009
Purpose: The purpose of this report is to compare RapidArc plans and conventional IMRT plans for prostate cancer involving seminal vesicles. Methods and Materials: This study included 10 patients. The planning‐target volume (PTV) contained the prostate and ...
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ConferenceMedical Physics · January 1, 2009
Purpose: It has been shown that cone‐beam computed tomography (CBCT) can be used in dose calculation for treatment planning. This study investigates the HU and dosimetric properties of six CBCT techniques in comparison with conventional CT to determine whi ...
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ConferenceMedical Physics · January 1, 2008
Purpose: In head‐and‐neck IMRT treatment, doses to targets and critical organs are affected by many factors including patient positioning, weight loss and tumor shrinkage. To ensure therapeutic effectiveness, re‐planning with a new CT is often conducted. H ...
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ConferenceMedical Physics · January 1, 2008
Purpose: Using an on‐board cone‐beam CT (CBCT) based statistical margin model to determine whether a prostate center‐of‐mass (COM) based translation correction procedure can significantly reduce the CTV‐to‐PTV margin required for prostate patients who were ...
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ConferenceMedical Physics · January 1, 2008
Purpose: To investigate a method to convert the pixel values of DTS images to HU values with reference HU values from CT images. Method and Materials: This study included CT and DTS images of two phantoms (Catphan and a chest phantom) and three patients (p ...
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ConferenceMedical Physics · January 1, 2008
Purposes: A research platform was developed for target verification using digital tomosynthesis (DTS). To verify its accuracy, a phantom study was conducted and several clinical cases were investigated. Method and Materials: customer‐developed reconstructi ...
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ConferenceMedical Physics · January 1, 2008
Purpose: This work investigates the feasibility of verifying respiratory gated treatments using a new 3D dosimetry system consisting of a radiochromic plastic (PRESAGE™) with optical‐CT readout. Method and Materials: Three identical PRESAGE™ dosimeters (5c ...
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ConferenceMedical Physics · January 1, 2008
Purpose: To investigate the feasibility of a novel online IMRT re‐optimization process. This online process can be an integral part to the current prostate IGRT paradigm to augment the existing patient alignment techniques for cases with complex daily orga ...
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ConferenceMedical Physics · January 1, 2008
Purpose: It is critical that image‐guided radiation therapy (IGRT) and adaptive radiation therapy (ART) are performed with clearly defined goals without abusing the technologies. This study illustrates the current integrated system that provides efficient ...
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ConferenceMedical Physics · January 1, 2008
Purpose: To assess the absorbed doses in and around lung tumor by performing radiochromic film measurements. Method and Materials: A phantom was made to have a water equivalent central core, a low‐density middle layer and a water equivalent outer layer to ...
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ConferenceMedical Physics · January 1, 2007
Purpose: To describe challenges in limiting kidney dose when delivering TBI to SSc patients enrolled on a multicenter Phase II/III SCOT (Scleroderma Cyclophosphamide or Transplantation) protocol. Material and Methods: The SCOT protocol uses a preparative r ...
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ConferenceMedical Physics · January 1, 2007
Purpose: To demonstrate clinical feasibility of generating digital tomosynthesis (DTS) in a single breath‐hold (BH) period compared to multiple BH periods for CBCT acquisition and to examine on‐board BH‐DTS as an efficient alternative to BH‐CBCT for target ...
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ConferenceMedical Physics · January 1, 2007
Purpose: To compare treatment isocenter placement based on OBI 2D kV imaging and OBI 3D‐CBCT imaging for patients undergoing SBRT, and compare the CBCT based isocenter shifts among liver, lung and spine lesions. Material and Methods: 119 SBRT fractions wer ...
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ConferenceMedical Physics · January 1, 2007
Purpose: To investigate the clinical feasibility of performing concurrent kilovoltage (kV) x‐ray imaging while the patient at the treatment position was irradiated by megavoltage (MV) beams. Method and Materials: Anatomical visibility and contrast details ...
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ConferenceMedical Physics · January 1, 2007
Purpose: To evaluate the dosimetric improvement of IMRT treatment plans generated with patient‐specific margins compared to uniform margins for prostate cancer patients. Methods and Materials: For 13 prostate cancer patients who underwent IMRT treatment, d ...
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ConferenceIfmbe Proceedings · January 1, 2007
Purpose: To develop a comprehensive quality assurance (QA) program for the On-Board Imager (OBI) used for patient positioning verification and to present the results of QA tests over extended periods from multiple institutions. Radiographic and cone-beam c ...
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ConferenceMedical Physics · January 1, 2007
Purpose: To evaluate radiation dose in kV cone‐beam computed tomography (CBCT) and to benchmark Monte Carlo (MC) simulations in the PMMA CT phantoms Method and Materials: Using an On‐Board Imager (Varian Medical Systems), we measured absorbed doses to the ...
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ConferenceIfmbe Proceedings · January 1, 2007
Purpose: This study investigates feasibility of CBCT-based treatment planning. Methods and materials: Hounsfield unit (HU) values and profiles of phantoms and patients in CBCT images were compared to those in CT images. CBCT-based treatment plans for the p ...
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ConferenceMedical Physics · January 1, 2007
Objective: The true dose distribution is subject to change due to organ shifts and also deformations. The goal of this work is to estimate the effect of the elastic organ deformations on the dose distribution for the average prostate IMRT treatment. Method ...
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ConferenceMedical Physics · January 1, 2006
Purpose: To evaluate the dosimetric consequence of 3D positioning verification for prostate IMRT treatment using CBCT. Method and Materials: Patients in this study were repositioned using 2D orthogonal radiographic images, taken prior to treatment to match ...
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ConferenceMedical Physics · January 1, 2006
Purpose: A medical physicist's time and resources are always balanced between many clinical obligations. It would be advantageous for physicists to forgo measurements of IMRT plans in lieu of independent computer calculations. In this work, we investigate ...
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ConferenceMedical Physics · January 1, 2006
Purpose: To develop and assess a technique using cone‐beam CT (CBCT) to localize treatment targets for stereotactic body radiation therapy (SBRT). Material and Methods: Patients selected for SBRT had 3‐D or 4‐D CT simulation with immobilization. GTV, CTV, ...
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ConferenceMedical Physics · January 1, 2006
Purpose: A novel imaging based model is proposed to describe the stochastic nature of the shape and location of a volume of interest (VOI). Based on the VOIs in sequential patient images, the model can predict the probability that a specific point will bel ...
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ConferenceMedical Physics · January 1, 2006
Purpose: Partial breast irradiation with multiple external beams requires accurate alignment of the target volume and treatment isocenter. On‐board plannar kV/MV imaging can verify set‐up based on boney landmarks. On‐board cone beam CT (CBCT) may provide a ...
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ConferenceMedical Physics · January 1, 2006
Purpose: The internal target volume (ITV) could be determined using 4D CT simulation images and be verified in the treatment room using on‐board cone‐beam CT (CBCT) since the CBCT projection images are acquired over approximately 10 breathing cycles. This ...
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ConferenceMedical Physics · January 1, 2006
Purpose: We have applied OBI guidance together with a respiratory gating system to effectively control patient positioning for amplitude gating treatment with breath hold. The deep inspiration breath‐hold treatment has been proven effective in reducing the ...
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ConferenceMedical Physics · January 1, 2006
Daily target localization is a critical step to secure accurate delivery for 3‐D conformal radiation therapy and intensity‐modulated radiation therapy. One emerging technology using in‐room kilovoltage (kV) imaging has shown to be very promising for target ...
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ConferenceMedical Physics · January 1, 2006
Purpose: To implement a clinical tool for off‐line review of Cone‐Beam Computed Tomography (CBCT) based 3D target verification and localization. Methods and Materials: An in‐house 3D target localization and verification tool is being developed to allow phy ...
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ConferenceMedical Physics · January 1, 2006
Purpose: To develop a comprehensive quality assurance (QA) program for the On‐Board Imager (OBI) used for patient positioning verification and to present the results of QA tests over extended periods from multiple institutions. Radiographic and cone‐beam c ...
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ConferenceMedical Physics · January 1, 2006
Purpose: To investigate the feasibility of cone‐beam computed tomography (CBCT)‐based treatment planning. Methods: HU of material disks in Catphan, HU profiles for homogeneous and inhomogeneous phantoms, and HU values in different tissue areas of brain, th ...
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ConferenceMedical Physics · January 1, 2005
Purpose: It has been noted that dosimetric difference due to tissue inhomogeneity is significant for a lung patient. If there is no tissue inhomogeneity correction (IC) made, the treatment plan could mislead treatment. Commercial radiation treatment planni ...
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ConferenceMedical Physics · January 1, 2005
Purpose: The newly installed OBI system consists of a kilo‐voltage (KV) X‐ray source and a flat‐ panel detector mounted orthogonally to the megavoltage portal imager (MV) in Varian 21EX machine. These devices are linked to the OBI workstation which provide ...
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