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Helical tomotherapy

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https://www.readbyqxmd.com/read/28089479/estimation-of-radiation-induced-secondary-cancer-risks-for-early-stage-non-small-cell-lung-cancer-patients-after-stereotactic-body-radiation-therapy
#1
Chunhui Han, Timothy E Schultheiss, Jeffrey Y C Wong
PURPOSE: In this study, we evaluated radiation-induced secondary lung cancer risks for the lung and the breast from stereotactic body radiation therapy treatment of early-stage non-small cell lung cancer with different radiation therapy treatment modalities. METHODS AND MATERIALS: Ten patients (5 men and 5 women) with early-stage non-small cell lung cancer who received definitive stereotactic body radiation therapy treatments were retrospectively selected. For each patient, two 3-dimensional conformal radiation therapy (3D-CRT) plans using 6- and 10-MV photons, respectively; a helical tomotherapy (HT) plan; and 2 volumetric modulated arc therapy (VMAT) plans using 1 and 2 arcs, respectively, were generated...
October 19, 2016: Practical Radiation Oncology
https://www.readbyqxmd.com/read/28048605/su-f-t-331-the-effect-of-optimization-grid-size-on-helical-tomotherapy-for-nasopharyngeal-carcinama
#2
J Gu, Y Yin, J Zhu
PURPOSE: To investigate the effect of plan optimization grid size on helical tomotherapy for nasopharyngeal carcinoma (NPC) METHODS: Ten patients of NPC were enrolled. For each patient, three plans with different dose optimization grid size (fine, normal, coarse) were created by Helical Tomotherapy Planning Station (version: 5.0, GPU Acceleration and VoLo).The time consumed by 500 optimization iterations, the monitor units and the dose volume histogram factors were compared. Paired-Wilcoxon test was used in statistical analysis...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048587/tu-h-brc-07-therapeutic-benefit-in-spatially-fractionated-radiotherapy-grid-using-helical-tomotherapy
#3
G Narayanasamy, X Zhang, A Meigooni, X Liang, N Paudel, S Morrill, S Maraboyina, L Peacock, J Penagaricano
PURPOSE: The aim of this project is to study the therapeutic ratio (TR) for helical Tomotherapy (HT) based spatially fractionated radiotherapy (GRID). Estimation of TR was based on the linear-quadratic cell survival model by comparing the normal cell survival in a HT GRID to that of a uniform dose delivery in an open-field for the same tumor survival. METHODS: HT GRID plan was generated using a patient specific virtual GRID block pattern of non-divergent, cylinder shaped holes using MLCs...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048523/we-de-bra-09-fast-megavoltage-ct-imaging-with-rapid-scan-time-and-low-imaging-dose-in-helical-tomotherapy
#4
T Magome, A Haga, Y Takahashi, K Nakagawa, K Dusenbery, S Hui
PURPOSE: Megavoltage computed tomography (MVCT) imaging has been widely used for daily patient setup with helical tomotherapy (HT). One drawback of MVCT is its very long imaging time, owing to slow couch speed. The purpose of this study was to develop an MVCT imaging method allowing faster couch speeds, and to assess its accuracy for image guidance for HT. METHODS: Three cadavers (mimicking closest physiological and physical system of patients) were scanned four times with couch speeds of 1, 2, 3, and 4 mm/s...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048256/su-f-t-667-development-and-validation-of-dose-calculation-for-an-open-source-kv-treatment-planning-system-for-small-animal-radiotherapy
#5
S Prajapati, X Mo, B Bednarz, M Lawless, C Hammer, R Flynn, D Westerly, R Jeraj, T Mackie
PURPOSE: An open-source, convolution/superposition based kV-treatment planning system(TPS) was developed for small animal radiotherapy from previously existed in-house MV-TPS. It is flexible and applicable to both step and shoot and helical tomotherapy treatment delivery. For initial commissioning process, the dose calculation from kV-TPS was compared with measurements and Monte Carlo(MC) simulations. METHODS: High resolution, low energy kernels were simulated using EGSnrc user code EDKnrc, which was used as an input in kV-TPS together with MC-simulated x-ray beam spectrum...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047982/su-f-t-267-a-clarkson-based-independent-dose-verification-for-the-helical-tomotherapy
#6
H Nagata, H Hongo, D Kawai, R Takahashi, H Hashimoto, H Tachibana
PURPOSE: There have been few reports for independent dose verification for Tomotherapy. We evaluated the accuracy and the effectiveness of an independent dose verification system for the Tomotherapy. METHODS: Simple MU Analysis (SMU, Triangle Product, Ishikawa, Japan) was used as the independent verification system and the system implemented a Clarkson-based dose calculation algorithm using CT image dataset. For dose calculation in the SMU, the Tomotherapy machine-specific dosimetric parameters (TMR, Scp, OAR and MLC transmission factor) were registered as the machine beam data...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047842/su-f-t-420-dosimetry-comparison-of-advanced-external-beam-radiation-treatment-modalities-to-brachytherapy-treatments-in-patients-with-cervical-cancer
#7
U Mwidu, S Devic, M Shehadeh, M AlKafi, R Mahmood, B Moftah
PURPOSE: A retrospective comparison of dose distributions achievable by High dose rate brachytherapy (HDRBT), Helical TomoTherapy (TOMO), CyberKnife (CK) and RapidArc (RA) in locally advanced inoperable cervical cancer patients is presented. METHODS: Five patients with advanced stage cervical carcinoma were selected for this study after a full course of external beam radiotherapy (EBRT), chemotherapy and HDR Brachytherapy. To highlight any significant similarities/differences in dose distributions, high-risk clinical target volume (HRCTV) coverage, organs at risk (OAR) sparing, and machine specific delivery limitations, we used D90 (dose received by 90% of the volume) as the parameter for HRCTV coverage as recommended by the GEC-ESTRO Working Group...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047821/su-f-t-523-radiobiological-comparison-of-helical-tomotherapy-and-vmat-in-the-treatment-of-head-and-neck-tumors
#8
R Woods, P Mavroidis, M Lehman-Davis, M Kostich, T Cook, B Chera, S Das, J Lian
PURPOSE: This study aims at comparing the efficacy of Helical Tomotherapy (TOMO) and Volumetric Modulated Arc Therapy (VMAT) in producing highly conformal dose distributions in challenging head & neck cancer patients. Furthermore, to interpret the dosimetric findings into expected tissue response rates in order to estimate their clinical impact. METHODS: Seven patients were studied and for each patient two treatment plans (one TOMO and one VMAT) were created. Structures used for optimization were: high risk PTV, standard risk PTV, brainstem, spinal cord, parotid gland, larynx, mandible and surrounding tissue...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047751/su-f-t-456-tomotherapy-mlc-synchronization-and-leaf-open-time-measurements-using-arccheck
#9
B Yang, R Wong, W Lam, H Geng, K Cheung, S Yu
PURPOSE: To develop a practical method for routine QA of the MLC of a Tomotherapy unit using ArcCheck. METHODS: Two standard test plans were used in this study. One was a helical test, in which the central leaves No. 32 and 33 opened simultaneously for 277.8ms at projections centered at 0°, 120° and 240° gantry angles. The other test plan was a static test with the gantry angle set at 0°, 45°, 90° and 135° respectively and leaves No. 32 and 33 opened sequentially for total 20s which was further divided into eleven or ten segments at each beam angle...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047728/su-f-t-485-independent-remote-audits-for-tg51-noncompliant-photon-beams-performed-by-the-iroc-houston-qa-center
#10
P Alvarez, A Molineu, J Lowenstein, P Taylor, S Kry, D Followill
PURPOSE: IROC_H conducts external audits for output check verification of photon and electron beams. Many of these beams can meet the geometric requirements of the TG 51 calibration protocol. For those photon beams that are non TG 51 compliant like Elekta GammaKnife, Accuray CyberKnife and TomoTherapy, IROC_H has specific audit tools to monitor the reference calibration. METHODS: IROC_H used its TLD and OSLD remote monitoring systems to verify the output of machines with TG 51 non compliant beams...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047412/su-g-brb-13-precision-qa-measurement-of-gantry-angle-and-speed-in-tomotherapy-using-arccheck
#11
B Yang, R Wong, Y Ho, H Geng, W Lam, K Cheung, S Yu
PURPOSE: To develop a methodology using an ArcCheck for accurate QA measurements of the gantry angle and speed of a Tomotherapy unit. METHODS: Two test plans recommended by TG148 were chosen for this study. One was the helical star shot test which had a total of 40 gantry rotations while the couch moved continuously and the multi-leaves opened for projections centered at 0°, 120° and 240°. The plan set a gantry start angle of -2.5° to ensure the projections were centered at the expected angles...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047244/tu-fg-201-08-investigation-of-systematic-low-rpc-calibration-result-for-tomotherapy
#12
Q Chen
PURPOSE: Independent IROC (formally RPC) TLD-based output checks have found a ∼-3% systematic calibration difference for our (and general) Tomotherapy treatment machines. The purpose of this study is to identify source of this bias. METHODS: The entire Tomotherapy calibration process is analyzed. Unlike conventional linacs, Tomotherapy unit absolute dose calibrations are based on calibration plans (tomoPhant plans on a tomocheese phantom) created at the time of commissioning...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047155/su-c-brb-01-automated-dose-deformation-for-re-irradiation
#13
S Lim, K Kainz, X Li
PURPOSE: An objective of retreatment planning is to minimize dose to previously irradiated tissues. Conventional retreatment planning is based largely on best-guess superposition of the previous treatment's isodose lines. In this study, we report a rigorous, automated retreatment planning process to minimize dose to previously irradiated organs at risk (OAR). METHODS: Data for representative patients previously treated using helical tomotherapy and later retreated in the vicinity of the original disease site were retrospectively analyzed in an automated fashion using a prototype treatment planning system equipped with a retreatment planning module (Accuray, Inc...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047098/su-f-t-457-a-filmless-method-for-measurement-of-couch-translation-per-gantry-rotation-and-couch-speed-for-tomotherapy-using-arccheck
#14
B Yang, R Wong, H Geng, W Lam, K Cheung, S Yu
PURPOSE: To develop a filmless methodology based on an ArcCheck for QA measurement of the couch translation per gantry rotation and couch speed of a Tomotherapy unit. METHODS: Two test plans recommended by TG148 were chosen for this study. A helical plan with 1 cm field size opened the leaves for 180 degrees at the 2nd, 7th and 12th of total 13 rotations and was used to verify if the couch travelled the expected distance per gantry rotation. The other test plan was a static plan with the gantry at 0°, 1cm field width and constant couch movement speed of 0...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047037/su-f-t-435-helical-tomotherapy-for-craniospinal-irradiation-what-we-have-learned-from-a-multi-institutional-study
#15
D Du, C Han, J Chen, A Perez-Andujar, B Lee, T Kaprealian, D Low, X Qi
PURPOSE: To report cranio-spinal irradiation (CSI) planning experience, compare dosimetric quality and delivery efficiency with Tomotherapy from different institutions, and to investigate effect of planning parameters on plan quality and treatment time. METHODS: Clinical helical tomotherapy IMRT plans for thirty-nine CSI cases from three academic institutions were retrospectively evaluated. The planning parameters: field width (FW), pitch, modulation factor (MF), and achieved dosimetric endpoints were cross-compared...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046723/su-f-t-27-a-comparative-case-study-among-four-modalities-for-the-superficial-treatment-of-squamous-cell-carcinoma
#16
M Ashenafi, N Koch, J Peng, L Terwillinger, J Wilder, D McDonald, C Mart, J Jenrette, K Vanek
PURPOSE: We performed a comparative planning study among High Dose Rate (HDR) brachytherapy, superficial electrons, Volume Modulated Arc Therapy (VMAT), and Helical IMRT (Tomotherapy) for squamous cell carcinoma of the abdominal wall with consideration for the underlining bowel. METHODS: A 69-year old female presented with squamous cell carcinoma protruding 8mm beyond the anterior skin surface of the midabdomen was considered for treatment. The patient had a ventral hernia which resulted in the reduction of the abdominal wall thickness and the adjacent small bowel being the dose limiting structure...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046636/tu-ab-brc-10-modeling-of-radiotherapy-linac-source-terms-using-archer-monte-carlo-code-performance-comparison-of-gpu-and-mic-computing-accelerators
#17
T Liu, H Lin, L Su, C Shi, X Tang, B Bednarz, X Xu
PURPOSE: (1) To perform phase space (PS) based source modeling for Tomotherapy and Varian TrueBeam 6 MV Linacs, (2) to examine the accuracy and performance of the ARCHER Monte Carlo code on a heterogeneous computing platform with Many Integrated Core coprocessors (MIC, aka Xeon Phi) and GPUs, and (3) to explore the software micro-optimization methods. METHODS: The patient-specific source of Tomotherapy and Varian TrueBeam Linacs was modeled using the PS approach...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28044341/filmless-methods-for-quality-assurance-of-tomotherapy-using-arccheck
#18
B Yang, W K R Wong, H Geng, W W Lam, Y W Ho, W M Kwok, K Y Cheung, S K Yu
PURPOSE: Tomotherapy delivers an intensity-modulated radiation therapy (IMRT) treatment by the synchronization of gantry rotation, multileaf collimator (MLC), and couch movement. This dynamic nature makes the quality assurance (QA) important and challenging. The purpose of this study is to develop some methodologies using an ArcCHECK for accurate QA measurements of the gantry angle and speed, MLC synchronization and leaf open time, couch translation per gantry rotation, couch speed and uniformity, and constancy of longitudinal beam profile for a Tomotherapy unit...
November 21, 2016: Medical Physics
https://www.readbyqxmd.com/read/27989415/feasibility-of-voxel-based-dose-painting-for-recurrent-glioblastoma-guided-by-adc-values-of-diffusion-weighted-mr-imaging
#19
M Orlandi, A Botti, R Sghedoni, E Cagni, P Ciammella, C Iotti, M Iori
PURPOSE: Glioblastoma Multiforme (GBM) is the most common malignant brain tumor and frequently recurs in the same location after radiotherapy. Intensive treatment targeting localized lesion is required to improve GBM outcome, but dose escalation using conventional methods is limited by healthy tissue tolerance. Helical Tomotherapy (HT) Dose Painting (DP) treatments were simulated to safely deliver high doses in the recurrent regions. MATERIALS AND METHODS: Apparent Diffusion Coefficient (ADC) data from five recurrent GBM were retrospectively considered for planning...
December 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27974508/adequate-target-volume-in-total-body-irradiation-by-intensity-modulated-radiation-therapy-using-helical-tomotherapy-a-simulation-study
#20
Ryosuke Takenaka, Akihiro Haga, Hideomi Yamashita, Keiichi Nakagawa
Recently, intensity-modulated radiation therapy (IMRT) has been used for total-body irradiation (TBI). Since the planning target volume (PTV) for TBI includes the surrounding air, a dose prescription to the PTV provides high fluence to the body surface. Thus with just a small set-up error, the body might be exposed to a high-fluence beam. This study aims to assess which target volume should be prescribed the dose, such as a clinical target volume (CTV) with a margin, or a CTV that excludes the surface area of the skin...
December 14, 2016: Journal of Radiation Research
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