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Journal of Applied Clinical Medical Physics

Neelam Tyagi, Michelle Cloutier, Kristen Zakian, Joseph O Deasy, Margie Hunt, Andreas Rimner
PURPOSE: To compare single-shot echo-planar (SS-EPI)-based and turbo spin-echo (SS-TSE)-based diffusion-weighted imaging (DWI) in Non-Small Cell Lung Cancer (NSCLC) patients and to characterize the distributions of apparent diffusion coefficient (ADC) values generated by the two techniques. METHODS: Ten NSCLC patients were enrolled in a prospective IRB-approved study to compare and optimize DWI using EPI and TSE-based techniques for radiotherapy planning. The imaging protocol included axial T2w, EPI-based DWI and TSE-based DWI on a 3 T Philips scanner...
November 12, 2018: Journal of Applied Clinical Medical Physics
Kuo Men, Pamela Boimel, James Janopaul-Naylor, Chingyun Cheng, Haoyu Zhong, Mi Huang, Huaizhi Geng, Yong Fan, John P Plastaras, Edgar Ben-Josef, Ying Xiao
PURPOSE: Convolutional neural networks (CNN) have greatly improved medical image segmentation. A robust model requires training data can represent the entire dataset. One of the differing characteristics comes from variability in patient positioning (prone or supine) for radiotherapy. In this study, we investigated the effect of position orientation on segmentation using CNN. METHODS: Data of 100 patients (50 in supine and 50 in prone) with rectal cancer were collected for this study...
November 12, 2018: Journal of Applied Clinical Medical Physics
Sophie C Huijskens, Irma W E M van Dijk, Jorrit Visser, Brian V Balgobind, Coen R N Rasch, Tanja Alderliesten, Arjan Bel
BACKGROUND: While four-dimensional computed tomography (4DCT) is extensively used in adults, reluctance remains to use 4DCT in children. Day-to-day (interfractional) variability and irregular respiration (intrafractional variability) have shown to be limiting factors of 4DCT effectiveness in adults. In order to evaluate 4DCT applicability in children, the purpose of this study is to quantify inter- and intrafractional variability of respiratory motion in children and adults. The pooled analysis enables a solid comparison to reveal if 4DCT application for planning purposes in children could be valid...
November 9, 2018: Journal of Applied Clinical Medical Physics
Klaus Bratengeier, Kostyantyn Holubyev, Sonja Wegener
PURPOSE: To quantify the contribution of penumbra in the improvement of healthy tissue sparing at reduced source-to-axis distance (SAD) for simple spherical target and different prescription isodoses (PI). METHOD: A TPS-independent method was used to estimate three-dimensional (3D) dose distribution for stereotactic treatment of spherical targets of 0.5 cm radius based on single beam two-dimensional (2D) film dosimetry measurements. 1 cm target constitutes the worst case for the conformation with standard Multi-Leaf Collimator (MLC) with 0...
November 9, 2018: Journal of Applied Clinical Medical Physics
Justine M Cunningham, Enzo A Barberi, John Miller, Joshua P Kim, Carri K Glide-Hurst
MR-only treatment planning and MR-IGRT leverage MRI's powerful soft tissue contrast for high-precision radiation therapy. However, anthropomorphic MR-compatible phantoms are currently limited. This work describes the development and evaluation of a custom-designed, modular, pelvic end-to-end (PETE) MR-compatible phantom to benchmark MR-only and MR-IGRT workflows. For construction considerations, subject data were assessed for phantom/skeletal geometry and internal organ kinematics to simulate average male pelvis anatomy...
November 8, 2018: Journal of Applied Clinical Medical Physics
Julianne M Pollard-Larkin, Kelly C Paradis, Jean M Moran, Mary K Martel, Yi Rong
No abstract text is available yet for this article.
November 8, 2018: Journal of Applied Clinical Medical Physics
Sara Gholampourkashi, Joanna E Cygler, Jason Belec, Miro Vujicic, Emily Heath
PURPOSE: To explain the deviation observed between measured and Monaco calculated dose profiles for a small field (i.e., alternating open-closed MLC pattern). A Monte Carlo (MC) model of an Elekta Infinity linac with Agility MLC was created and validated against measurements. In addition, an analytic model which predicts the fluence at the isocenter plane was used to study the impact of multiple beam parameters on the accuracy of dose calculations for small fields. METHODS: A detailed MC model of a 6 MV Elekta Infinity linac with Agility MLC was created in EGSnrc/BEAMnrc and validated against measurements...
November 8, 2018: Journal of Applied Clinical Medical Physics
Zhengzheng Xu, Gregory Warrell, Soyoung Lee, Valdir Colussi, Yiran Zheng, Rodney Ellis, Mitchell Machtay, Tarun Podder
PURPOSE: Dosimetric accuracy is critical when switching a patient treated with stereotactic body radiation therapy (SBRT) or stereotactic fractionated radiotherapy (SRT) among beam-matched linacs. In this study, the dose delivery accuracy of volumetric modulated arc therapy (VMAT) plans for SBRT/SRT patients were evaluated on three beam-matched linacs. METHOD: Beam data measurements such as percentage depth dose (PDD10 ), beam profiles, output factors, and multi-leaf collimator (MLC) leaf transmission factor for 6 MV photon beam were performed on three beam-matched linacs...
November 7, 2018: Journal of Applied Clinical Medical Physics
Yuehong Kong, Tengfei Yan, Yanze Sun, Jianjun Qian, Gang Zhou, Shang Cai, Ye Tian
PURPOSE: The aim of the study was to compare the dose differences between two kinds of materials (silica gel and hydrogel) used to prepare boluses based on three-dimensional (3D) printing technologies and commercial bolus in head phantoms simulating nose, ear, and parotid gland radiotherapy. METHODS AND MATERIALS: We used 3D printing technology to make silica gel and hydrogel boluses. To evaluate the clinical feasibility, intensity modulated radiation therapy (IMRT) plans were created for head phantoms that were bolus-free or had a commercial bolus, a silica gel bolus, or a hydrogel bolus...
November 7, 2018: Journal of Applied Clinical Medical Physics
Hideyuki Mizuno, Akifumi Fukumura, Nobuyuki Kanematsu, Shunsuke Yonai, Toshiyuki Shirai, Ken Yusa, Toshihiro Yanou, Masaki Suga, Manabu Mizota, Shinichi Minohara, Tatsuaki Kanai, Tadashi Kamada
PURPOSE: The QA team of the Japan carbon-ion radiation oncology study group (J-CROS) was organized in 2015 to enhance confidence in the accuracy of clinical dosimetry and ensure that the facility QA procedures are adequate. The team conducted onsite dosimetry audits in all the carbon-ion radiation therapy centers in Japan. MATERIALS AND METHODS: A special phantom was fabricated for the onsite dosimetry audit. Target volumes such as the GTV, CTV, and PTV were contoured to the obtained CT images, and two plans with different isocenter depths were created...
November 1, 2018: Journal of Applied Clinical Medical Physics
Hideyuki Mizuno, Osami Saito, Minoru Tajiri, Taku Kimura, Daigo Kuroiwa, Toshiyuki Shirai, Taku Inaniwa, Mai Fukahori, Kentaro Miki, Shigekazu Fukuda
This study reports the commissioning methodology and results of a respiratory gating system [AZ - 733 V/733 VI (Anzai Medical Co., Japan)] using a pressure sensor in carbon-ion scanning radiotherapy. Commissioning includes choosing a location and method for pressure sensor installation, delay time measurement of the system, and the final flow test. Additionally, we proposed a methodology for the determination of a threshold level of generating an on/off gate for the beam to the respiratory waveform, which is important for clinical application...
November 1, 2018: Journal of Applied Clinical Medical Physics
Andrew M McDonald, Tyler Colvin, D Hunter Boggs, Sharon A Spencer, Richard A Popple, Ravinder Clayton, Douglas Minnich, Michael C Dobelbower
PURPOSE: To assess the long-term stability of the anchored radiofrequency transponders and compare displacement rates with other commercially available lung fiducial markers. We also sought to describe late toxicity attributable to fiducial implantation or migration. MATERIALS AND METHODS: The transponder cohort was comprised of 17 patients at our institution who enrolled in a multisite prospective clinical trial and underwent bronchoscopic implantation of three anchored transponders into small (2-2...
November 1, 2018: Journal of Applied Clinical Medical Physics
Robert Chuter, Marcel van Herk, Hafid Akhiat, Peter Voet, Ranald MacKay, Ananya Choudhury, Alan McWilliam
PURPOSE: For the 1.5 T Elekta MR-Linac it is essential that the optimisation of a treatment plan accounts for the electron return effect on the planned dose distribution. The ability of two algorithms for the first stage fluence optimisation, pencil beam (PB) and Monte Carlo (MC), to produce acceptable plan quality was investigated. Optimisation time for each algorithm was also compared. METHODS: Ten head and neck patients, ten lung patients and five prostate patients were selected from the clinical archive...
October 29, 2018: Journal of Applied Clinical Medical Physics
Nevin McVicar, Steven Thomas, Mitchell Liu, Hannah Carolan, Alanah Bergman
The objective of this note is to introduce a clinical tool that generates ideal base plan dose distributions to enable re-irradiation volumetric modulated arc therapy (VMAT) optimization based on cumulative biological effective dose objectives for specific organs at risk (OARs). The tool is demonstrated with a lung cancer case that required re-irradiation at our clinic. First, previous treatment dose is deformed onto the retreatment computed tomography (CT) using commercial software. Then, the in-house Matlab tool alters the deformed previous dose using radiobiological concepts on a voxel-by-voxel manner to generate an ideal base plan dose distribution...
October 29, 2018: Journal of Applied Clinical Medical Physics
Karen Buch, Hirofumi Kuno, Muhammad M Qureshi, Baojun Li, Osamu Sakai
OBJECTIVES: To evaluate the influence of MRI scanning parameters on texture analysis features. METHODS: Publicly available data from the Reference Image Database to Evaluate Therapy Response (RIDER) project sponsored by The Cancer Imaging Archive included MRIs on a phantom comprised of 18 25-mm doped, gel-filled tubes, and 1 20-mm tube containing 0.25 mM Gd-DTPA (EuroSpinII Test Object5, Diagnostic Sonar, Ltd, West Lothian, Scotland). MRIs performed on a 1.5 T GE HD, 1...
October 27, 2018: Journal of Applied Clinical Medical Physics
Christian Gustafsson, Emilia Persson, Adalsteinn Gunnlaugsson, Lars E Olsson
Prostate cancer radiotherapy workflows, solely based on magnetic resonance imaging (MRI), are now in clinical use. In these workflows, intraprostatic gold fiducial markers (GFM) show similar signal behavior as calcifications and bleeding in T2-weighted MRI-images. Accurate GFM identification in MRI-only radiotherapy workflows is therefore a major challenge. C-arm X-ray images (CkV-images), acquired at GFM implantation, could provide GFM position information and be used to confirm correct identification in T2-weighted MRI-images...
October 24, 2018: Journal of Applied Clinical Medical Physics
Eunah Chung, Dongyeol Kwon, Taeyang Park, Hyeri Kang, Yoonsun Chung
PURPOSE: The delivery quality assurance (DQA) of intensity-modulated radiotherapy (IMRT) plans is a prerequisite for ensuring patient treatments. This work investigated the clinical usefulness of a new DQA system, Dosimetry Check™(DC), on TomoTherapy® -based helical IMRT plans. METHODS: The DQA was performed for 15 different TomoTherapy® -based clinical treatment plans. In Tomotherapy® machines, the couch position was set to a height of 400 mm and the treatment plans were delivered using QA-Treatment mode...
October 24, 2018: Journal of Applied Clinical Medical Physics
Ehsan Samei, Michael D Mills
No abstract text is available yet for this article.
October 19, 2018: Journal of Applied Clinical Medical Physics
Gilles Moliner, Lise Sorro, Rodolfe Verstraet, Paul Alexandre Daviau, Mélanie Casas, Bérengère Piron, Karine Dubois, Charles Debrigode, Corinne Barrau, Françoise Bons, Joël Greffier
PURPOSE: To assess the efficiency of combined use of ArcCheck® detector (AC) and portal dosimetry (PDIP) for delivery quality assurance of head and neck and prostate volumetric-modulated arc therapy. MATERIALS AND METHODS: Measurement processes were studied with the Gamma index method according to three analysis protocols. The detection sensitivity to technical errors of each individual or combined measurement processes was studied by inserting collimator, dose and MLC opening error into five head and neck and five prostate initial treatment plans...
October 19, 2018: Journal of Applied Clinical Medical Physics
Choirul Anam, Toshioh Fujibuchi, Wahyu Setia Budi, Freddy Haryanto, Geoff Dougherty
PURPOSE: The purpose of this study was to introduce a new algorithm for automated measurement of the modulation transfer function (MTF) using an edge of a readily available phantom and to evaluate the effect of reconstruction filter and field of view (FOV) on the spatial resolution in the CT images. METHODS: Our automated MTF measurement consisted of several steps. The center of the image was established and an appropriate region of interest (ROI) designated. The edge spread function (ESF) was determined, and a suitably interpolated ESF curve was differentiated to obtain the line spread function (LSF)...
October 19, 2018: Journal of Applied Clinical Medical Physics
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