Poster - Thur Eve - 04: Online review of beam output and profile constancy using statistical process control.

abstract：PURPOSE:To describe an efficient method for verifying the size and centering of the radiation field from the Cyberknife IRIS variable collimator with sub-millimeter accuracy using a general purpose commercially available diode array. METHODS:We present a technique using a conventional diode array (Sun Nuclear Profiler...

journal_title：Medical physics

authors： Gibbs G,White G,Bulz G

更新日期：2012-06-01 00:00:00

abstract：:We have made a comparative investigation of the estimated spectra obtained by the Laplace transform analysis of the transmitted exposure data measured in an absorption study of a 4-MV x-ray beam. Four transform pair models currently used with this method have been evaluated. It has been determined that the Archer-Wagn...

journal_title：Medical physics

authors： Ahuja SD,Steward PG,Roy TS,Slessinger ED

更新日期：1986-05-01 00:00:00

abstract：PURPOSE:This article presents a new reconstruction method for 3D imaging using a multiple 360 degrees circular orbit cone beam CT system, specifically a way to combine 3D volumes reconstructed with each orbit. The main goal is to improve the noise performance in the combined image while avoiding cone beam artifacts. M...

journal_title：Medical physics

authors： Baek J,Pelc NJ

更新日期：2010-10-01 00:00:00

abstract：:In the presence of intrafraction organ motion, target localization uncertainty can greatly hamper the advantage of highly conformal dose techniques such as intensity modulated radiation therapy (IMRT). To minimize the adverse dosimetric effect caused by tumor motion, a real-time knowledge of the tumor position is requ...

journal_title：Medical physics

authors： Wiersma RD,Mao W,Xing L

更新日期：2008-04-01 00:00:00

abstract：PURPOSE:IAEA TRS-398 notes that cylindrical ionization chambers are preferred for reference proton dosimetry. If a cylindrical ionization chamber is used in a phantom to measure the dose as a function of depth, the effective point of measurement (EPOM) must be taken into account. IAEA TRS-398 recommends a displacement ...

journal_title：Medical physics

authors： Sugama Y,Nishio T,Onishi H

更新日期：2015-07-01 00:00:00

abstract：PURPOSE:The aim of this study is to understand the characteristics of secondary electrons generated from the interaction of gold nanoparticles (GNPs) with x-rays as a function of nanoparticle size and beam energy and thereby further the understanding of GNP-enhanced radiotherapy. METHODS:The effective range, deflectio...

journal_title：Medical physics

authors： Leung MK,Chow JC,Chithrani BD,Lee MJ,Oms B,Jaffray DA

更新日期：2011-02-01 00:00:00

abstract：PURPOSE:To characterize the radiation dose and three-dimensional (3D) imaging performance of a recently developed mobile, isocentric C-arm equipped with a flat-panel detector (FPD) for intraoperative cone-beam computed tomography (CBCT) (Cios Spin 3D, Siemens Healthineers) and to identify potential improvements in 3D i...

journal_title：Medical physics

authors： Sheth NM,De Silva T,Uneri A,Ketcha M,Han R,Vijayan R,Osgood GM,Siewerdsen JH

更新日期：2020-03-01 00:00:00

abstract：:Electronic portal imaging devices (EPIDs) are mainly used for patient setup verification during treatment but other geometric properties like block shape and leaf positions are also determined. Electronic portal dosimetry allows dosimetric treatment verification. By combining geometric and dosimetric information, the ...

journal_title：Medical physics

authors： Nijsten SM,Minken AW,Lambin P,Bruinvis IA

更新日期：2004-02-01 00:00:00

abstract：PURPOSE:To estimate and correct for the volume averaging effect which results from the intra-chamber dose gradients when a Farmer ionization chamber (IC) is used for reference dosimetry in flattening-filter-free (FFF) MV photon beams. METHODS:An intra-chamber dose gradients correction factor (kicdg) to the charge read...

journal_title：Medical physics

authors： Ruggieri R,Naccarato S,Stavrev P,Stavreva N,Pasetto S,Salamone I,Alongi F

更新日期：2016-08-01 00:00:00

abstract：PURPOSE:For stereotactic radiosurgery (SRS), accurate evaluation of dose-volume metrics for small structures is necessary. The purpose of this study was to compare the DVH metric capabilities of five commercially available SRS DVH analysis tools (Eclipse, Elements, Raystation, MIM, and Velocity). METHODS:DICOM RTdose ...

journal_title：Medical physics

authors： Stanley DN,Covington E,Liu H,Alexandrian A,Cardan R,Bridges D,Thomas EM,Fiveash JB,Popple R

更新日期：2020-12-09 00:00:00

abstract：:Convolution/superposition software has been used to produce a library of photon pencil beam dose matrices. This library of pencil beams is designed to serve as a tool for both education and investigation in the field of radiotherapy optimization. The elegance of this pencil beam model stems from its cylindrical symmet...

journal_title：Medical physics

authors： Shepard DM,Olivera G,Angelos L,Sauer O,Reckwerdt P,Mackie TR

更新日期：1999-07-01 00:00:00

abstract：:For an effective radiotherapy the exact tumor location must be determined. The localization has to take into account patient's setup position as well as internal organ motion. Among the different localization methods, the use of a computer tomography (CT) scanner in the therapy room has been proposed recently. Achievi...

journal_title：Medical physics

authors： Vences L,Wulf J,Vordermark D,Sauer O,Berlinger K,Roth M

更新日期：2005-11-01 00:00:00

abstract：PURPOSE:The authors combine the registration of 2D beam's eye view (BEV) images and 3D planning computed tomography (CT) images, with relative, markerless tumor tracking to provide automatic absolute tracking of physician defined volumes such as the gross tumor volume (GTV). METHODS:During treatment of lung SBRT cases...

journal_title：Medical physics

authors： Bryant JH,Rottmann J,Lewis JH,Mishra P,Keall PJ,Berbeco RI

更新日期：2014-12-01 00:00:00

abstract：:The half-life of two I-125 encapsulated clinical seeds was measured with a Si(Li) semiconductor detector. Two measurements of each seed yielded an average half-life of 59.56 +/- 0.17 days. The results are discussed in terms of the influence of possible I-126 contamination and leakage of I-125 activity through encapsul...

journal_title：Medical physics

authors： Kubo H

更新日期：1983-11-01 00:00:00

abstract：:A novel multistage algorithm is proposed for the automatic segmentation of microcalcification clusters (MCCs) in digital mammography. First, a previously reported tree structured nonlinear filter is proposed for suppressing image noise, while preserving image details, to potentially reduce the false positive (FP) dete...

journal_title：Medical physics

authors： Qian W,Kallergi M,Clarke LP,Li HD,Venugopal P,Song D,Clark RA

更新日期：1995-08-01 00:00:00

abstract：:A realistic photon beam model based on Monte Carlo simulation of clinical linear accelerators was implemented in a convolution/superposition dose calculation algorithm. A primary and an extra-focal sources were used in this beam model to represent the direct photons from the target and the scattered photons from other...

journal_title：Medical physics

authors： Liu HH,Mackie TR,McCullough EC

更新日期：1997-12-01 00:00:00

abstract：PURPOSE:Monte Carlo (MC) dose calculation is generally superior to analytical dose calculation (ADC) used in commercial TPS to model the dose distribution especially for heterogeneous sites, such as lung and head/neck patients. The purpose of this study was to provide a validated, fast, and open-source MC code, MCsquar...

journal_title：Medical physics

authors： Huang S,Souris K,Li S,Kang M,Barragan Montero AM,Janssens G,Lin A,Garver E,Ainsley C,Taylor P,Xiao Y,Lin L

更新日期：2018-12-01 00:00:00

abstract：PURPOSE:In using flat panel detectors (FPD) for cone beam computed tomography (CBCT), pixel gain variations may lead to structured nonuniformities in projections and ring artifacts in CBCT images. Such gain variations can be caused by change in detector entrance exposure levels or beam hardening, and they are not accou...

journal_title：Medical physics

authors： Altunbas C,Lai CJ,Zhong Y,Shaw CC

更新日期：2014-09-01 00:00:00

abstract：PURPOSE:The present study was conducted to investigate salivary iodine kinetics and dosimetry during repeated courses of radioiodine ((131)I) therapy for differentiated thyroid cancer (DTC). Such data could provide a better understanding of the mechanisms of (131)I induced salivary toxicity and help to develop appropri...

journal_title：Medical physics

authors： Liu B,Huang R,Kuang A,Zhao Z,Zeng Y,Wang J,Tian R

更新日期：2011-10-01 00:00:00

abstract：:It is known that motion of an object imaged by magnetic resonance imaging leads to errors and artifacts in the image. This effect is especially important when a pulse sequence with long echo time (TE) and long TR is used to provide T2-weighted images. We have modified the usual spin warp imaging pulse sequence in a wa...

journal_title：Medical physics

authors： Joseph PM,Shetty A,Bonaroti EA

更新日期：1987-07-01 00:00:00

abstract：PURPOSE:The study aims to investigate whether Nakagami parameters--estimated from the statistical distribution of the backscattered ultrasound radio-frequency (RF) signals--could provide a means for quantitative characterization of parotid-gland injury resulting from head-and-neck radiotherapy. METHODS:A preliminary c...

journal_title：Medical physics

authors： Yang X,Tridandapani S,Beitler JJ,Yu DS,Wu N,Wang Y,Bruner DW,Curran WJ,Liu T

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:A dosimetry evaluation model for treatment planning of esophageal radiation therapy is developed using a deep learning model. The model predicts dose volume histogram (DVH) from distance to target histogram (DTH) based on stacked de-noise auto-encoder (SDAE) and one-dimensional convolutional network (1D-CN). M...

journal_title：Medical physics

authors： Jiang D,Yan H,Chang N,Li T,Mao R,Du C,Guo B,Liu J

更新日期：2020-10-01 00:00:00

abstract：PURPOSE:To evaluate dependence of measured dose on size and location of region of interest (ROI) in Gafchromic EBT3 film dosimetry. METHODS:Gafchromic EBT3 films were irradiated perpendicularly using the 6MV beam from a linear accelerator at 10 cm depth (100 cm SSD) of a 30 × 30 × 20 cm3 solid water phantom for a rang...

journal_title：Medical physics

authors： Gholizadeh Sendani N,Karimian A,Ferreira C,Alaei P

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:Computer-aided diagnosis (CAD) systems assist in solving subjective diagnosis problems that typically rely on personal experience. A CAD system has been developed to differentiate malignant thyroid nodules from benign thyroid nodules in ultrasound images based on deep learning methods. The diagnostic performanc...

journal_title：Medical physics

authors： Sun C,Zhang Y,Chang Q,Liu T,Zhang S,Wang X,Guo Q,Yao J,Sun W,Niu L

更新日期：2020-09-01 00:00:00

abstract：:Noise characterization through estimation of the noise power spectrum (NPS) is a central component of the evaluation of digital x-ray systems. We begin with a brief review of the fundamentals of NPS theory and measurement, derive explicit expressions for calculation of the one- and two-dimensional (1D and 2D) NPS, and...

journal_title：Medical physics

authors： Williams MB,Mangiafico PA,Simoni PU

更新日期：1999-07-01 00:00:00

abstract：:For Monte Carlo linac simulations and patient dose calculations, it is important to accurately determine the phase space parameters of the initial electron beam incident on the target. These parameters, such as mean energy and radial intensity distribution, have traditionally been determined by matching the calculated...

journal_title：Medical physics

authors： Aljarrah K,Sharp GC,Neicu T,Jiang SB

更新日期：2006-04-01 00:00:00

abstract：PURPOSE:A commonly used beam quality index (Q) for high-energy photon beams is the tissue phantom ratio (TPR20,10) for a square field of 10 x 10 cm2 and SDD of 100 cm. On some specialized radiotherapy treatment equipment such a reference collimator setting is not achievable. Likewise a flat beam profile, not explicitly...

journal_title：Medical physics

authors： Sauer OA

更新日期：2009-09-01 00:00:00

abstract：:Angioplasty balloons inflated with a solution of the beta-emitter Re-188 have been used for intravascular brachytherapy to prevent restenosis. Coronary stents are in extensive clinical use for the treatment of de novo atherosclerotic stenoses. In this study, the effect of an interposed stent on the dose distribution h...

journal_title：Medical physics

authors： Wuu CS,Schiff P,Maryanski MJ,Liu T,Borzillary S,Weinberger J

更新日期：2003-02-01 00:00:00

abstract：PURPOSE:This work describes the performance characterization of a cone-beam CT-guided radiosurgery device, the Gamma Knife® Icon™. METHODS:The performance tests have been categorized into: (a) image quality and mechanical integrity; (b) image coregistration fidelity; (c) adaptive treatment delivery quality; (d) high d...

journal_title：Medical physics

authors： Sarfehnia A,Ruschin M,Chugh B,Yeboah C,Becker N,Cho YB,Lee Y

更新日期：2018-06-29 00:00:00

abstract：:Monte Carlo calculations have been made to determine the energy delivered to a phantom by neutrons escaping from the head of a Varian Clinac 35 medical accelerator at an SSD of 1 m. The energy was sorted into two regions: inside and outside a volume defined by a circular beam of area 100 and 600 cm2. For the two beam ...

journal_title：Medical physics

authors： Ing H,Shore RA

更新日期：1982-01-01 00:00:00