Abstract：
:In this work, leakage radiation from EA200 series electron applicators on Siemens Primus accelerators is quantified, and its penetration ability in water and/or the shielding material Xenolite-NL established. Initially, measurement of leakage from 10 x 10 - 25 x 25 cm2 applicators was performed as a function of height along applicator and of lateral distance from applicator body. Relative to central-axis ionization maximum in solid water, the maximum leakage in air observed with a cylindrical ion chamber with 1 cm solid water buildup cap at a lateral distance of 2 cm from the front and right sidewalls of applicators were 17% and 14%, respectively; these maxima were recorded for 18 MeV electron beams and applicator sizes of >or=20 x 20 cm2. In the patient plane, the applicator leakage gave rise to a broad peripheral dose off-axis distance peak that shifted closer to the field edge as the electron energy increases. The maximum peripheral dose from normally incident primary electron beams at a depth of 1 cm in a water phantom was observed to be equal to 5% of the central-axis dose maximum and as high as 9% for obliquely incident beams with angles of obliquity journal_name journal_title authors doi subject pub_date pages issue issn journal_volume pub_type
abstract：:In Winston-Lutz (WL) tests, the isocenter of a linear accelerator (linac) is determined as the intersection of radiation central axes (CAX) from multiple gantry, collimator, and couch angles. It is well known that the CAX can wobble due to mechanical imperfections of the linac. Previous studies suggested that the wobb...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v17i1.5792
更新日期：2016-01-08 00:00:00
abstract：PURPOSE:Elekta XVI 5.0 allows for four-dimensional cone beam computed tomography (4D CBCT) image acquisition during treatment delivery to monitor intrafraction motion. These images can have poorer image quality due to undersampling of kV projections and treatment beam MV scatter effects. We determine if a universal int...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12755
更新日期：2019-12-01 00:00:00
abstract：PURPOSE:Beam matching occurs on all linacs to some degree and when two are more are matched to each other, patients are able to be transferred between machines. Quality assurance of plans can also be performed "distributively" on any of the matched linacs. The degree to which machines are matched and how this translate...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12567
更新日期：2019-04-01 00:00:00
abstract：:Quality control (QC) of CT scanners is important to evaluate image quality and radiation dose. Different QC phantoms for testing image quality parameters on CT are commercially available, and Catphan phantoms are widely used for this purpose. More data from measured image quality parameters on CT are necessary to asse...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12186
更新日期：2017-11-01 00:00:00
abstract：:An inverse treatment planning (ITP) module on a commercial treatment planning system (TPS) (Helax AB, Uppsala, Sweden) is being used for an in-house clinical trial for treatment of nasopharyngeal cancer with contralateral parotid sparing. Intensity modulated radiation therapy (IMRT) fields are delivered by step and sh...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v3i2.2580
更新日期：2002-04-01 00:00:00
abstract：:The purpose of this study is to evaluate the accuracy of the electron Monte Carlo (eMC) dose calculation algorithm included in a commercial treatment planning system and compare its performance against an electron pencil beam algorithm. Several tests were performed to explore the system's behavior in simple geometries...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v16i3.4636
更新日期：2015-05-08 00:00:00
abstract：:The purpose of this study is to describe the comprehensive commissioning process and initial clinical experience of the Mevion S250 proton therapy system, a gantry-mounted, single-room proton therapy platform clinically implemented in the S. Lee Kling Proton Therapy Center at Barnes-Jewish Hospital in St. Louis, MO, U...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v17i2.5868
更新日期：2016-03-08 00:00:00
abstract：:The control loop in the Varian DMLC system (V4.8) requires approximately 65 msec to monitor and halt the irradiation of a segment, causing an "overshoot" effect: the segment ends on a fractional monitor unit larger than that planned. As a result, the actual MU delivered may differ from that planned. In general, for st...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v2i3.2607
更新日期：2001-07-01 00:00:00
abstract：:Monte Carlo (MC)-based dose calculations are generally superior to analytical dose calculations (ADC) in modeling the dose distribution for proton pencil beam scanning (PBS) treatments. The purpose of this paper is to present a methodology for commissioning and validating an accurate MC code for PBS utilizing a parame...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12420
更新日期：2018-09-01 00:00:00
abstract：:The longitudinal coverage of a LINAC-mounted CBCT scan is limited to the corresponding dimensional limits of its flat panel detector, which is often shorter than the length of the treatment field. These limits become apparent when fields are designed to encompass wide regions, as when providing nodal coverage. Therefo...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v13i4.3796
更新日期：2012-07-05 00:00:00
abstract：OBJECTIVES:To compare the effectiveness of two different patient size metrics based on water equivalent diameter (Dw ), the mid-scan water equivalent diameter Dw_c , and the mean (average) water equivalent diameter in the imaged region, Dw_ave , for automatic detection of accidental changes in computed tomography (CT) ...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12240
更新日期：2018-01-01 00:00:00
abstract：:The purpose of this study was to compare two different styles of prostate IGRT: bony landmark (BL) setup vs. fiducial markers (FM) setup. Twenty-nine prostate patients were treated with daily BL setup and 30 patients with daily FM setup. Delivered dose distribution was reconstructed on cone-beam CT (CBCT) acquired onc...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v14i3.4203
更新日期：2013-05-06 00:00:00
abstract：:We investigate the role of adaptive radiation therapy in pediatric patients with diffuse pontine glioma and the impact of steroid-related weight gain on treatment parameters utilizing cone-beam CT. Fifteen patients with diffuse pontine glioma were treated with three-dimensional conformal radiation therapy and enrolled...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：
更新日期：2011-01-30 00:00:00
abstract：:PET/CT imaging could improve delineation of rectal carcinoma gross tumor volume (GTV) and reduce interobserver variability. The objective of this work was to compare various functional volume delineation algorithms. We enrolled 31 consecutive patients with locally advanced rectal carcinoma. The FDG PET/CT and the high...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v15i5.4696
更新日期：2014-09-08 00:00:00
abstract：:Measurement of cumulative dose ƒ(0,150) with a small ionization chamber within standard polymethyl methacrylate (PMMA) CT head and body phantoms, 150 mm in length, is a possible practical method for cone-beam computed tomography (CBCT) dosimetry. This differs from evaluating cumulative dose under scatter equilibrium c...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v16i6.5793
更新日期：2015-11-08 00:00:00
abstract：:This paper aims to evaluate the impact of spectral filtration on image quality in a microcomputed tomography (micro-CT) system. A mouse phantom comprising 11rods for modeling lung, muscle, adipose, and bones was scanned with 17 s and 2min, respectively. The current (μA) for each scan was adjusted to achieve identical ...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v17i1.5714
更新日期：2016-01-08 00:00:00
abstract：:This study investigates the dosimetry and radiobiological model variation when a second photon arc was added to prostate volumetric-modulated arc therapy (VMAT) using the single-arc technique. Dosimetry and radiobiological model comparison between the single-arc and double-arc prostate VMAT plans were performed on fiv...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v14i3.4053
更新日期：2013-05-06 00:00:00
abstract：:A new method of generating wedge-shaped dose distributions through dynamic multileaf collimator dose delivery rather than computer-controlled jaw motion is presented. The method starts with the calculation of a wedge-shaped beam profile for the desired wedge angle. The resultant wedge beam profile is then passed to th...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v6i3.2060
更新日期：2005-07-01 00:00:00
abstract：PURPOSE:To quantify the effects of combining layer-based repainting and respiratory gating as a strategy to mitigate the dosimetric degradation caused by the interplay effect between a moving target and dynamic spot-scanning proton delivery. METHODS:An analytic routine modeled three-dimensional dose distributions of p...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12702
更新日期：2019-09-01 00:00:00
abstract：:The purpose of this study was to assess treatment margins in free-breathing irradiation of pancreatic cancer after bone alignment, and evaluate their impact on conformal radiotherapy. Fifteen patients with adenocarcinoma of the head of the pancreas underwent implantation of single fiducial marker. Intrafraction uncert...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v14i4.4152
更新日期：2013-07-08 00:00:00
abstract：BACKGROUND:We analyzed the clinical and imaging characteristics of patients with breast ductal carcinoma in situ with microinvasion (DCISM) and breast ductal carcinoma in situ (DCIS). METHODS:We analyzed the records of 40 patients diagnosed with DCISM and 61 patients with DCIS who were hospitalized at Shengjing Hospit...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.13122
更新日期：2020-12-17 00:00:00
abstract：:We have investigated the combined effect of tissue heterogeneity and its variation associated with geometric error in stereotactic body radiotherapy (SBRT) for lung cancer. The treatment plans for eight lung cancer patients were calculated using effective path length (EPL) correction and Monte Carlo (MC) algorithms, w...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v16i5.5397
更新日期：2015-09-08 00:00:00
abstract：PURPOSE:We introduce an automated, quantitative image analysis package for gamma camera and single photon emission computed tomography quality control. Our focus was to produce consistent methods that are feasible in clinical settings and use standard phantoms. METHODS:Four gamma cameras were used to acquire planar im...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.13057
更新日期：2020-11-03 00:00:00
abstract：:The purpose of this study was to develop and evaluate filmless quality assurance (QA) tools for helical tomotherapy by using the signals from the on-board megavoltage computed tomography (MVCT) detector and applying a dedicated step-wedge phantom. The step-wedge phantom is a 15 cm long step-like aluminum block positio...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v13i1.3585
更新日期：2012-01-05 00:00:00
abstract：:Optimal choice of beam energy in radiation therapy is easy in many well-documented cases, but less obvious in some others. Low-energy beams may provide better conformity around the target than their high-energy counterparts due to reduced lateral scatter, but they also contribute to overdosage of peripheral normal tis...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v10i4.3012
更新日期：2009-09-03 00:00:00
abstract：:The purpose of this investigation is to measure, characterize and report stray photon leakage and scatter radiation measurements from the Mobetron, an intraoperative electron linear accelerator designed for use in an operating room environment. The study is needed due to recent changes to the shielding design of the M...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v11i4.3151
更新日期：2010-09-07 00:00:00
abstract：:A custom-made computer program, SWIMRT, to construct "multileaf collimator (MLC) machine" file for intensity-modulated radiotherapy (IMRT) fluence maps was developed using MATLAB and the sliding window algorithm. The user can either import a fluence map with a graphical file format created by an external treatment-pla...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v7i2.2231
更新日期：2006-05-25 00:00:00
abstract：:This study evaluated the extent of improvement in dose predication accuracy achieved by the Fast Monte Carlo algorithm (MC) compared to the Ray Tracing algorithm (RAT) in stereotactic body radiotherapy (SBRT) of non-small cell lung cancer (NSCLC), and how their differences were influenced by the tumor site and size. T...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v14i5.4280
更新日期：2013-09-06 00:00:00
abstract：OBJECTIVE:To evaluate the accuracy of a deep learning-based auto-segmentation mode to that of manual contouring by one medical resident, where both entities tried to mimic the delineation "habits" of the same clinical senior physician. METHODS:This study included 125 cervical cancer patients whose clinical target volu...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.13097
更新日期：2020-12-01 00:00:00
abstract：:Monte Carlo simulations are widely used for calculation of the dosimetric parameters of brachytherapy sources. MCNP4C2, MCNP5, MCNPX, EGS4, EGSnrc, PTRAN, and GEANT4 are among the most commonly used codes in this field. Each of these codes utilizes a cross-sectional library for the purpose of simulating different elem...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v17i2.5797
更新日期：2016-03-08 00:00:00
