Characteristics of quantitative perfusion parameters on dynamic contrast-enhanced MRI in mammographically occult breast cancer.
Abstract The purpose of this study was to compare the characteristics of quantitative per-fusion parameters obtained from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in patients with mammographically occult (MO) breast cancers and those with mammographically visible (MV) breast cancers. Quantitative parameters (AUC, Ktrans, kep, ve, vp, and wi) from 13 MO breast cancers and 16 MV breast cancers were mapped after the DCE-MRI data were acquired. Various prog-nostic factors, including axillary nodal status, estrogen receptor (ER), progesterone receptor (PR), Ki-67, p53, E-cadherin, and human epid...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Ryu JK, Rhee SJ, Song JY, Cho SH, Jahng GH Tags: J Appl Clin Med Phys Source Type: research

Is the dose distribution distorted in IMRT and RapidArc treatment when patient plans are swapped across beam-matched machines?
Abstract The purpose of this study is to evaluate the degree of dose distribution distortion in advanced treatments like IMRT and RapidArc when patient plans are swapped across dosimetrically equivalent so-called "beam-matched" machines. For this purpose the entire work is divided into two stages. At forefront stage all basic beam properties of 6 MV X-rays like PDD, profiles, output factors, TPR20/10 and MLC transmission of two beam-matched machines - Varian Clinac iX and Varian 600 C/D Unique - are compared and evaluated for differences. At second stage 40 IMRT and RapidArc patient plans from the pool o...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Chockkalingam K, Radha CA, Subramani V, Subramani V, Gunasekaran MK Tags: J Appl Clin Med Phys Source Type: research

Initial clinical experience with ArcCHECK for IMRT/VMAT QA.
Abstract Many devices designed for the purpose of performing patient-specific IMRT/VMAT QA are commercially available. In this work we report our experience and initial clinical results with the ArcCHECK. The ArcCHECK consists of a cylindrical array of diode detectors measuring entry and exit doses. The measured result is a cumulative dose displayed as a 2D matrix. The detector array requires both an absolute dose calibration, and a calibration of the detector response, relative to each other. In addition to the calibrations suggested by the manufacturer, various tests were performed in order to assess its stabili...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Aristophanous M, Suh Y, Chi PC, Whittlesey LJ, LaNeave S, Martel MK Tags: J Appl Clin Med Phys Source Type: research

Simultaneously integrated boost (SIB) spares OAR and reduces treatment time in locally advanced cervical cancer.
Abstract We performed a dosimetric comparison of sequential IMRT (sIMRT) and simul-taneously integrated boost (SIB) IMRT to boost PET-avid lymph nodes while concurrently treating pelvic targets to determine the potential of SIB IMRT to reduce overall treatment duration in locally advanced cervical cancer. Ten patients receiving definitive radiation therapy were identified retrospectively. RTOG consensus guidelines were followed to delineate the clinical target volume and organs at risk (OAR), which were then expanded per IMRT consortium guidelines to yield the planning target volume (PTV). Dosimetric parameters fo...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Feng CH, Hasan Y, Kopec M, Al-Hallaq HA Tags: J Appl Clin Med Phys Source Type: research

Revisiting fetal dose during radiation therapy: evaluating treatment techniques and a custom shield.
Abstract To create a comprehensive dataset of peripheral dose (PD) measurements from a new generation of linear accelerators with and without the presence of a newly designed fetal shield, PD measurements were performed to evaluate the effects of depth, field size, distance from the field edge, collimator angle, and beam modi-fiers for common treatment protocols and modalities. A custom fetal lead shield was designed and made for our department that allows external beam treatments from multiple angles while minimizing the need to adjust the shield during patient treatments. PD measurements were acquired for a comp...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Owrangi AM, Roberts DA, Covington EL, Hayman JA, Masi KM, Lee C, Moran JM, Prisciandaro JI Tags: J Appl Clin Med Phys Source Type: research

Translucent poly(vinyl alcohol) cryogel dosimeters for simultaneous dose buildup and monitoring during chest wall radiation therapy.
Abstract Chest wall radiation therapy treatment delivery was monitored using a 5 mm thick radiochromic poly(vinyl alcohol) cryogel that also provided buildup material. The cryogels were used to detect positioning errors and measure the impact of shifts for a chest wall treatment that was delivered to a RANDO phantom. The phantom was shifted by ± 2, ± 3, and ± 5 mm from the planned position in the anterior/posterior (A/P) direction; these shifts represent setup errors and the uncertainty associated with lung filling during breath-hold. The two-dimensional absolute dose distributions measured in...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Eyadeh MM, Weston MA, Juhasz J, Diamond KR Tags: J Appl Clin Med Phys Source Type: research

Verification measurements of an eMC algorithm using a 2D ion chamber array.
Abstract The aim of this study was to assess the suitability of the Im'RT MatriXX 2D ion chamber array for performing verification measurements on the Varian Eclipse electron Monte Carlo (eMC) algorithm for a range of clinical energies (6, 12, and 20 MeV) on a Varian 2100iX linear accelerator. Firstly, the suitability of the MatriXX for measuring percentage depth doses (PDD) in water was assessed, including characterization of the inherent buildup found in the MatriXX. Secondly the suitability of the MatriXX for measuring dose distributions in homogeneous and heterogeneous phantoms was assessed using gamma analysis ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Wanklyn MD, Kidane G, Crees L Tags: J Appl Clin Med Phys Source Type: research

Implementation and evaluation of a protocol management system for automated review of CT protocols.
This article describes our experiences in the implementation and evaluation of this protocol monitoring system. In particular, we discuss various strategies for addressing each of the steps in our protocol-monitoring workflow, which are: maintaining an accurate set of master protocols, retrieving protocols from the scanners, comparing scanner protocols to master protocols, reviewing flagged differences between the scanner and master protocols, and updating the scanner and/or master protocols. In our initial evaluation focusing only on abdo-men and pelvis protocols, we detected 309 modified protocols in a 24-week trial peri...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Grimes J, Leng S, Zhang Y, Vrieze T, McCollough C Tags: J Appl Clin Med Phys Source Type: research

Dosimetric impact of cylinder size in high-dose rate vaginal cuff brachytherapy (VCBT) for primary endometrial cancer.
Abstract The purpose of this study was to evaluate the dosimetric impact of cylinder size in high-dose-rate (HDR) vaginal cuff brachytherapy (VCBT). Sample plans of HDR VCBT in a list of cylinders ranging from 2.5 to 4 cm in diameter at 0.5 cm incre-ment were created and analyzed. The doses were prescribed either at the 0.5cm depth with 5.5 Gy for 4 fractions or at the cylinder surface with 8.8 Gy for 4 frac-tions, in various treatment lengths. A 0.5 cm shell volume called PTV_Eval was contoured for each plan and served as the target volume for dosimetric evaluation. The cumulative and differential dose volume his...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Zhang H, Gopalakrishnan M, Lee P, Kang Z, Sathiaseelan V Tags: J Appl Clin Med Phys Source Type: research

On the use of a convolution-superposition algorithm for plan checking in lung stereotactic body radiation therapy.
Abstract Stereotactic body radiation therapy (SBRT) aims to deliver a highly conformal ablative dose to a small target. Dosimetric verification of SBRT for lung tumors presents a challenge due to heterogeneities, moving targets, and small fields. Recent software (M3D) designed for dosimetric verification of lung SBRT treatment plans using an advanced convolution-superposition algorithm was evaluated. Ten lung SBRT patients covering a range of tumor volumes were selected. 3D CRT plans were created using the XiO treatment planning system (TPS) with the superposition algorithm. Dose was recalculated in the Eclipse TP...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Hardcastle N, Oborn BM, Haworth A Tags: J Appl Clin Med Phys Source Type: research

Diode-based transmission detector for IMRT delivery monitoring: a validation study.
Abstract The purpose of this work was to evaluate the potential of a new transmission detector for real-time quality assurance of dynamic-MLC-based radiotherapy. The accuracy of detecting dose variation and static/dynamic MLC position deviations was measured, as well as the impact of the device on the radiation field (surface dose, transmission). Measured dose variations agreed with the known variations within 0.3%. The measurement of static and dynamic MLC position deviations matched the known deviations with high accuracy (0.7-1.2 mm). The absorption of the device was minimal (~ 1%). The increased surface dose w...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Li T, Wu QJ, Matzen T, Yin FF, O'Daniel JC Tags: J Appl Clin Med Phys Source Type: research

Technical Note: A respiratory monitoring and processing system based on computer vision: prototype and proof of principle.
Abstract Monitoring and controlling respiratory motion is a challenge for the accuracy and safety of therapeutic irradiation of thoracic tumors. Various commercial systems based on the monitoring of internal or external surrogates have been developed but remain costly. In this article we describe and validate Madibreast, an in-house-made respiratory monitoring and processing device based on optical tracking of external markers. We designed an optical apparatus to ensure real-time submillimetric image resolution at 4 m. Using OpenCv libraries, we optically tracked high-contrast markers set on patients' breasts. Val...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Leduc N, Atallah V, Escarmant P, Vinh-Hung V Tags: J Appl Clin Med Phys Source Type: research

Investigation on using high-energy proton beam for total body irradiation (TBI).
Abstract This work investigated the possibility of using proton beam for total body irradia-tion (TBI). We hypothesized the broad-slow-rising entrance dose from a monoen-ergetic proton beam can deliver a uniform dose to patient with varied thickness. Comparing to photon-based TBI, it would not require any patient-specific com-pensator or beam spoiler. The hypothesis was first tested by simulating 250 MeV, 275 MeV, and 300 MeV protons irradiating a wedge-shaped water phantom in a paired opposing arrangement using Monte Carlo (MC) method. To allow ± 7.5% dose variation, the maximum water equivalent thickness ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Zhang M, Qin N, Jia X, Zou WJ, Khan A, Yue NJ Tags: J Appl Clin Med Phys Source Type: research

A noise power spectrum study of a new model-based iterative reconstruction system: Veo 3.0.
Abstract The purpose of this study was to evaluate performance of the third generation of model-based iterative reconstruction (MBIR) system, Veo 3.0, based on noise power spectrum (NPS) analysis with various clinical presets over a wide range of clinically applicable dose levels. A CatPhan 600 surrounded by an oval, fat-equivalent ring to mimic patient size/shape was scanned 10 times at each of six dose levels on a GE HD 750 scanner. NPS analysis was performed on images reconstructed with various Veo 3.0 preset combinations for comparisons of those images reconstructed using Veo 2.0, filtered back projection (FBP...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Li G, Liu X, Dodge CT, Jensen CT, Rong XJ Tags: J Appl Clin Med Phys Source Type: research

MRI quantification of pancreas motion as a function of patient setup for particle therapy -a preliminary study.
Abstract Particle therapy (PT) has shown positive therapeutic results in local control of locally advanced pancreatic lesions. PT effectiveness is highly influenced by target localization accuracy both in space, since the pancreas is located in proximity to radiosensitive vital organs, and in time as it is subject to substantial breathing-related motion. The purpose of this preliminary study was to quantify pancreas range of motion under typical PT treatment conditions. Three common immobilization devices (vacuum cushion, thermoplastic mask, and compressor belt) were evaluated on five male patients in prone and su...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Fontana G, Riboldi M, Gianoli C, Chirvase CI, Villa G, Paganelli C, Summers PE, Tagaste B, Pella A, Fossati P, Ciocca M, Baroni G, Valvo F, Orecchia R Tags: J Appl Clin Med Phys Source Type: research

Patient-specific 17-segment myocardial modeling on a bull's eye map.
Abstract The purpose of this study was to develop and validate cardiac computed tomog-raphy (CT) quantitative analysis software with a patient-specific, 17-segment myocardial model that uses electrocardiogram (ECG)-gated cardiac CT images to differentiate between normal controls and severe aortic stenosis (AS) patients. ECG-gated cardiac CT images from 35 normal controls and 144 AS patients were semiautomatically segmented to create a patient-specific, 17-segment myocardial model. Two experts then manually determined the anterior and posterior interven-tricular grooves to be boundaries between the 1st and 2nd segm...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Jung J, Kim YH, Kim N, Yang DH Tags: J Appl Clin Med Phys Source Type: research

MRI geometric distortion: Impact on tangential whole-breast IMRT.
Abstract The purpose of this study was to determine the impact of magnetic resonance imaging (MRI) geometric distortions when using MRI for target delineation and planning for whole-breast, intensity-modulated radiotherapy (IMRT). Residual system distortions and combined systematic and patient-induced distortions are considered. This retrospective study investigated 18 patients who underwent whole-breast external beam radiotherapy, where both CT and MRIs were acquired for treatment planning. Distortion phantoms were imaged on two MRI systems, dedicated to radiotherapy planning (a wide, closed-bore 3T and an open-b...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Walker A, Metcalfe P, Liney G, Batumalai V, Dundas K, Glide-Hurst C, Delaney GP, Boxer M, Yap ML, Dowling J, Rivest-Henault D, Pogson E, Holloway L Tags: J Appl Clin Med Phys Source Type: research

A comparative study of identical VMAT plans with and without jaw tracking technique.
Abstract The unwanted radiation transmission through the multileaf collimators could be reduced by the jaw tracking technique which is commercially available on Varian TrueBeam accelerators. On the basis of identical plans, this study aims to investigate the dosimetric impact of jaw tracking on the volumetric-modulated arc therapy (VMAT) plans. Using Eclipse treatment planning system (TPS), 40 jaw-tracking VMAT plans with various tumor volumes and shapes were optimized. Fixed jaw plans were created by editing the jaw coordinates of the jaw-tracking plans while other parameters were identical. The deliverability of...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Wu H, Jiang F, Yue H, Hu Q, Zhang J, Liu Z, Gong J, Li S, Geng J, Zhang Y Tags: J Appl Clin Med Phys Source Type: research

Clinical experience with planning, quality assurance, and delivery of burst-mode modulated arc therapy.
We present our clinical experience with the planning techniques and plan quality assurance measurements of mARC delivery. Clinical mARC plans for five representative cases (prostate, low-dose-rate brain, brain with partial-arc vertex fields, pancreas, and liver SBRT) were generated using a Monte Carlo-based treatment planning system. A conventional-dose-rate flat 6 MV and a high-dose-rate non-flat 7 MV beam are available for planning and delivery. mARC plans for intact-prostate cases can typically be created using one 360° arc, and treatment times per fraction seldom exceed 6 min using the flat beam; using the nonflat ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Kainz K, Prah D, Ahunbay E, Li XA Tags: J Appl Clin Med Phys Source Type: research

Dosimetric comparison between cone/Iris-based and InCise MLC-based CyberKnife plans for single and multiple brain metastases.
Abstract We performed an evaluation of the CyberKnife InCise MLC by comparing plan qualities for single and multiple brain lesions generated using the first version of InCise MLC, fixed cone, and Iris collimators. We also investigated differences in delivery efficiency among the three collimators. Twenty-four patients with single or multiple brain mets treated previously in our clinic on a CyberKnife M6 using cone/Iris collimators were selected for this study. Treatment plans were generated for all lesions using the InCise MLC. Number of monitor units, delivery time, target coverage, conformity index, and dose fal...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Jang SY, Lalonde R, Ozhasoglu C, Burton S, Heron D, Huq MS Tags: J Appl Clin Med Phys Source Type: research

Evaluation of the uncertainty in an EBT3 film dosimetry system utilizing net optical density.
rcía-Garduño OA Abstract Radiochromic film has become an important tool to verify dose distributions for intensity-modulated radiotherapy (IMRT) and quality assurance (QA) procedures. A new radiochromic film model, EBT3, has recently become available, whose composition and thickness of the sensitive layer are the same as those of previous EBT2 films. However, a matte polyester layer was added to EBT3 to prevent the formation of Newton's rings. Furthermore, the symmetrical design of EBT3 allows the user to eliminate side-orientation dependence. This film and the flatbed scanner, Epson Perfection V750,...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: León Marroquin EY, Herrera González JA, Camacho López MA, Villarreal Barajas JE, García-Garduño OA Tags: J Appl Clin Med Phys Source Type: research

A dosimetric comparison of copper and Cerrobend electron inserts.
Abstract The purpose of this work was to evaluate differences in dose resulting from the use of copper aperture inserts compared to lead-alloy (Cerrobend) aperture inserts for electron beam therapy. Specifically, this study examines if copper aperture inserts can be used clinically with the same commissioning data measured using lead-alloy aperture inserts. The copper inserts were acquired from .decimal, LLC and matching lead-alloy, Cerrobend inserts were constructed in-house for 32 com-binations of nine square insert field sizes (2 × 2 to 20 × 20 cm2) and five applicator sizes (6 × 6 to 25 &time...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Rusk BD, Carver RL, Gibbons JP, Hogstrom KR Tags: J Appl Clin Med Phys Source Type: research

Surface dose variations in 6 and 10 MV flattened and flattening filter-free (FFF) photon beams.
Abstract As the use of linear accelerators operating in flattening filter-free (FFF) modes becomes more widespread, it is important to have an understanding of the surface doses delivered to patients with these beams. Flattening filter removal alters the beam quality and relative contributions of low-energy X-rays and contamination electrons in the beam. Having dosimetric data to describe the surface dose and buildup regions under a range of conditions for FFF beams is important if clinical decisions are to be made. An Elekta Synergy linac with standard MLCi head has been commissioned to run at 6 MV and 10 MV runn...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Cashmore J Tags: J Appl Clin Med Phys Source Type: research

RadShield: semiautomated shielding design using a floor plan driven graphical user interface.
Abstract The purpose of this study was to introduce and describe the development of RadShield, a Java-based graphical user interface (GUI), which provides a base design that uniquely performs thorough, spatially distributed calculations at many points and reports the maximum air-kerma rate and barrier thickness for each barrier pursuant to NCRP Report 147 methodology. Semiautomated shielding design calculations are validated by two approaches: a geometry-based approach and a manual approach. A series of geometry-based equations were derived giv-ing the maximum air-kerma rate magnitude and location through a first ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: DeLorenzo MC, Wu DH, Yang K, Rutel IB Tags: J Appl Clin Med Phys Source Type: research

Comprehensive dosimetric planning comparison for early-stage, non-small cell lung cancer with SABR: fixed-beam IMRT versus VMAT versus TomoTherapy.
This study aims to provide an extensive dosimetric compari-son among these various IMRT techniques for treating early-stage NSCLC with SABR. Ten early-stage NSCLC patients were retrospectively optimized using three fixed-beam techniques via nine to eleven beams (high and low modulation step-and-shoot (SS), and sliding window (SW)), two VMAT techniques via two partial arcs (SmartArc (SA) and RapidArc (RA)), and three HT techniques via three different fan beam widths (1 cm, 2.5 cm, and 5 cm) for 80 plans total. Fixed-beam and VMAT plans were generated using flattening filter-free beams. SS and SA, HT treatment plans, and SW ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Xhaferllari I, El-Sherif O, Gaede S Tags: J Appl Clin Med Phys Source Type: research

Method and phantom to study combined effects of in-plane (x,y) and z-axis resolution for 3D CT imaging.
This study investigates ways to consider both the in-plane resolution and the z-axis resolution in a single phantom wherein analytic or visualized analysis can yield information on these combined effects. A new phantom called the "Wave Phantom" is developed that can be used to sample the 3D resolution properties of a CT image, including in-plane (x,y) and z-axis information. The key development in this Wave Phantom is the incorporation of a z-axis aspect of a more traditional step (bar) resolution gauge phantom. The phantom can be examined visually wherein a cutoff level may be seen; and/or the analytic analysis ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Goodenough D, Levy J, Kristinsson S, Fredriksson J, Olafsdottir H, Healy A Tags: J Appl Clin Med Phys Source Type: research

Technical Note: Out-of-field dose measurement at near surface with plastic scintillator detector.
This study shows that a PSD can measure a dose as low as 0.51 ± 0.17 cGy for photon beam and 0.58 ± 0.20 cGy for electron beam with a difference of 0.2 and 0.1 cGy compared to a parallel-plate ion chamber. This study demonstrates the potential of using PSD as an out-of-field dosimeter since measure-ments with PSD avoid averaging over a too-large depth, at 1 mm diameter, and can make precise measurement at very low dose. Also, electronic equilibrium is easier to reach with PSD due to its small sensitive volume and its water equivalence. PMID: 27685131 [PubMed - as supplied by publisher] (Source: Journal o...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Bourgouin A, Varfalvy N, Archambault L Tags: J Appl Clin Med Phys Source Type: research

An EPID-based system for gantry-resolved MLC quality assurance for VMAT.
Abstract Multileaf collimator (MLC) positions should be precisely and independently mea-sured as a function of gantry angle as part of a comprehensive quality assurance (QA) program for volumetric-modulated arc therapy (VMAT). It is also ideal that such a QA program has the ability to relate MLC positional accuracy to patient-specific dosimetry in order to determine the clinical significance of any detected MLC errors. In this work we propose a method to verify individual MLC trajectories during VMAT deliveries for use as a routine linear accelerator QA tool. We also extend this method to reconstruct the 3D patien...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Zwan BJ, Barnes MP, Fuangord T, Stanton CJ, O'Connor DJ, Keall PJ, Greer PB Tags: J Appl Clin Med Phys Source Type: research

Correlation of quantitative dynamic contrast-enhanced MRI with microvascular density in necrotic, partial necrotic, and viable liver tumors in a rabbit model.
Abstract The purpose of this study was to examine the correlation of quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) with microvessel density (MVD) in necrotic, partial necrotic, and viable tumors using a rabbit VX2 liver tumor model. Nine rabbits were used for this study. The complete necrotic area (CNA), partial necrotic area (PNA), and viable tumor area (VTA) of liver tumors were experimentally induced by radiofrequency ablation (RFA). DCE-MRI data were processed based on the extended Kety model to estimate Ktrans, ve and vp parameters. The boundaries among CNA, PNA, and VTA were d...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Moon J, Kim JH, Choi D, Yang J, Lee MW, Choi YL, Rhim H Tags: J Appl Clin Med Phys Source Type: research

Dosimetric validation for an automatic brain metastases planning software using single-isocenter dynamic conformal arcsDosimetric validation for an automatic brain metastases planning software using single-isocenter dynamic conformal arcs.
This study is to validate the calculated absolute dose and dose distribution of ABMP. Three types of measurements were performed to validate the planning software: 1, dual micro ion chambers were used with an acrylic phantom to measure the absolute dose; 2, a 3D cylindrical phantom with dual diode array was used to evaluate 2D dose distribution and point dose for smaller targets; and 3, a 3D pseudo-in vivo patient-specific phantom filled with polymer gels was used to evaluate the accuracy of 3D dose distribution and radia-tion delivery. Micro chamber measurement of two targets (volumes of 1.2 cc and 0.9 cc, respectively) s...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Liu H, Li J, Pappas E, Andrews D, Evans J, Werner-Wasik M, Yu Y, Dicker A, Shi W Tags: J Appl Clin Med Phys Source Type: research

Characterization of a 2.5 MV inline portal imaging beam.
Abstract A new megavoltage (MV) energy was recently introduced on Varian TrueBeam linear accelerators for imaging applications. This work describes the experimental characterization of a 2.5 MV inline portal imaging beam for commissioning, routine clinical use, and quality assurance purposes. The beam quality of the 2.5 MV beam was determined by measuring a percent depth dose, PDD, in water phantom for 10 × 10 cm2 field at source-to-surface distance 100 cm with a CC13 ion chamber, plane parallel Markus chamber, and GafChromic EBT3 film. Absolute dosimetric output calibration of the beam was performed using a...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Grafe JL, Owen J, Villarreal-Barajas JE, Khan RF Tags: J Appl Clin Med Phys Source Type: research

Spot scanning proton therapy minimizes neutron dose in the setting of radiation therapy administered during pregnancy.
Abstract This is a real case study to minimize the neutron dose equivalent (H) to a fetus using spot scanning proton beams with favorable beam energies and angles. Minimum neutron dose exposure to the fetus was achieved with iterative planning under the guidance of neutron H measurement. Two highly conformal treatment plans, each with three spot scanning beams, were planned to treat a 25-year-old pregnant female with aggressive recurrent chordoma of the base of skull who elected not to proceed with termination. Each plan was scheduled for delivery every other day for robust target coverage. Neutron H to the fetus ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Wang X, Poenisch F, Sahoo N, Zhu RX, Lii M, Gillin MT, Li J, Grosshans D Tags: J Appl Clin Med Phys Source Type: research

Comparison of automatic image registration uncertainty for three IGRT systems using a male pelvis phantom.
Abstract A series of phantom images using the CIRS Virtual Human Male Pelvis was acquired across available dose ranges for three image-guided radiotherapy (IGRT) imaging systems: Elekta XVI CBCT, Varian TrueBeam CBCT, and TomoTherapy MV CT. Each image was registered to a fan-beam CT within the XVI software 100 times with random initial offsets. The residual registration error was analyzed to assess the role of imaging hardware and reconstruction in the uncertainty of the IGRT process. Residual translation errors were similar for all systems and < 0.5 mm. Over the clinical dose range for prostate IGRT images...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Barber J, Sykes JR, Holloway L, Thwaites DI Tags: J Appl Clin Med Phys Source Type: research

Difference in dose-volumetric data between the analytical anisotropic algorithm, the dose-to-medium, and the dose-to-water reporting modes of the Acuros XB for lung stereotactic body radiation therapy.
Abstract The purpose of this study was to evaluate the difference in dose-volumetric data between the analytical anisotropic algorithms (AAA) and the two dose reporting modes of the Acuros XB, namely, the dose to water (AXB_Dw) and dose to medium (AXB_Dm) in lung stereotactic body radiotherapy (SBRT). Thirty-eight plans were generated using the AXB_Dm in Eclipse Treatment Planning System (TPS) and then recalculated with the AXB_Dw and AAA, using identical beam setup. A dose of 50 Gy in 4 fractions was prescribed to the isocenter and the planning target volume (PTV) D95%. The isocenter was always inside the PTV. Th...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Mampuya WA, Nakamura M, Hirose Y, Kitsuda K, Ishigaki T, Mizowaki T, Hiraoka M Tags: J Appl Clin Med Phys Source Type: research

Thin-film CdTe detector for microdosimetric study of radiation dose enhancement at gold-tissue interface.
Abstract Presence of interfaces between high and low atomic number (Z) materials, often encountered in diagnostic imaging and radiation therapy, leads to radiation dose perturbation. It is characterized by a very narrow region of sharp dose enhancement at the interface. A rapid falloff of dose enhancement over a very short distance from the interface makes the experimental dosimetry nontrivial. We use an in-house-built inexpensive thin-film Cadmium Telluride (CdTe) photodetector to study this effect at the gold-tissue interface and verify our experimental results with Monte Carlo (MC) modeling. Three-micron thick ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Paudel NR, Shvydka D, Parsai EI Tags: J Appl Clin Med Phys Source Type: research

Accuracy of one algorithm used to modify a planned DVH with data from actual dose delivery.
This study aims to evaluate the accuracy of DVH based QA in quantifying delivery errors. Eighteen previously treated VMAT plans (prostate, H&N, and brain) were randomly chosen for this study. Conventional IMRT delivery QA was done with the ArcCHECK diode detector for error-free plans and plans with the following modifications: 1) induced monitor unit differences up to ± 3.0%, 2) control point deletion (3, 5, and 8 control points were deleted for each arc), and 3) gantry angle shift (2° uniform shift clockwise and counterclockwise). 2D and 3D distance-to-agreement (DTA) analyses were performed for all pla...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Ma T, Podgorsak MB, Kumaraswamy LK Tags: J Appl Clin Med Phys Source Type: research

Implementation of a double Gaussian source model for the BEAMnrc Monte Carlo code and its influence on small fields dose distributions.
Abstract The shape of the radiation source of a linac has a direct impact on the delivered dose distributions, especially in the case of small radiation fields. Traditionally, a single Gaussian source model is used to describe the electron beam hitting the target, although different studies have shown that the shape of the electron source can be better described by a mixed distribution consisting of two Gaussian components. Therefore, this study presents the implementation of a double Gaussian source model into the BEAMnrc Monte Carlo code. The impact of the double Gaussian source model for a 6 MV beam is assessed...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Doerner E, Caprile P Tags: J Appl Clin Med Phys Source Type: research

Simple quality assurance method of dynamic tumor tracking with the gimbaled linac system using a light field.
Abstract We proposed a simple visual method for evaluating the dynamic tumor tracking (DTT) accuracy of a gimbal mechanism using a light field. A single photon beam was set with a field size of 30 × 30 mm2 at a gantry angle of 90°. The center of a cube phantom was set up at the isocenter of a motion table, and 4D modeling was performed based on the tumor and infrared (IR) marker motion. After 4D modeling, the cube phantom was replaced with a sheet of paper, which was placed perpen-dicularly, and a light field was projected on the sheet of paper. The light field was recorded using a web camera in a treatm...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Miura H, Ozawa S, Hayata M, Tsuda S, Yamada K, Nagata Y Tags: J Appl Clin Med Phys Source Type: research

A methodology for on-board CBCT imaging dose using optically stimulated luminescence detectors.
This study pre-sents a complete procedure for the CBCT dosimetry using the InLight optically-stimulated-luminescence (OSL) nanoDots. We report five dose parameters: the mean slice dose (DMSD); the cone beam dose index (CBDIW); the mean volume dose (DMVD); point-dose profile, D(FOV); and the off-field Dose. In addition, CBCT skin doses for seven pelvic tumor patients are reported. CBCT-dose mea-surement was performed on a custom-made cylindrical acrylic body phantom (50cm length, 32cm diameter). We machined 25 circular disks (2 cm thick) with grooves and holes to hold OSL-nanoDots. OSLs that showed similar sensitivities wer...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Mail N, Yusuf M, Alothmany N, Kinsara AA, Abdulkhaliq F, Ghamdi SM, Saoudi A Tags: J Appl Clin Med Phys Source Type: research

Canadian Partnership for Quality Radiotherapy (CPQR) and the Canadian Organization of Medical Physicists (COMP) - Driving safety and quality assurance practice in Canada through the development of technical quality control guidelines.
PMID: 27685144 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Bissonnette JP, Milosevic M, Carlone M, Malkoske KE Tags: J Appl Clin Med Phys Source Type: research

Erratum: Evaluation of the tool "Reg Refine" for user-guided deformable image registration.
Erratum: Evaluation of the tool "Reg Refine" for user-guided deformable image registration. J Appl Clin Med Phys. 2016;17(5):6526 Authors: Johnson P, Padgett KR, Chen KL, Dogan N PMID: 27685145 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Johnson P, Padgett KR, Chen KL, Dogan N Tags: J Appl Clin Med Phys Source Type: research

Embracing Progress: Thoughts on Open Access Publishing, the JACMP, and its $500 Article Publication Fee.
PMID: 27685146 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Mills MD Tags: J Appl Clin Med Phys Source Type: research

Alexander P. Turner, PhD (1940-2016).
PMID: 27685147 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Mills MD Tags: J Appl Clin Med Phys Source Type: research

Embracing Progress: Thoughts on Open Access Publishing, the JACMP, and its $500 Article Publication Fee
- (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - September 16, 2016 Category: Physics Source Type: research

Erratum: Evaluation of the tool “Reg Refine” for user-guided deformable image registration
- (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - September 8, 2016 Category: Physics Source Type: research

Canadian Partnership for Quality Radiotherapy (CPQR) and the Canadian Organization of Medical Physicists (COMP) — Driving safety and quality assurance practice in Canada through the development of technical quality control guidelines
-   (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - September 8, 2016 Category: Physics Source Type: research

Technical Note: Out-of-field dose measurement at near surface with plastic scintillator detector
This study shows that a PSD can measure a dose as low as 0.51 ± 0.17 cGy for photon beam and 0.58 ± 0.20 cGy for electron beam with a difference of 0.2 and 0.1 cGy compared to a parallel-plate ion chamber. This study demonstrates the potential of using PSD as an out-of-field dosimeter since measure­ments with PS D avoid averaging over a too-large depth, at 1 mm diameter, and can make precise measurement at very low dose. Also, electronic equilibrium is easier to reach with PSD due to its small sensitive volume and its water equivalence. (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - September 8, 2016 Category: Physics Source Type: research

Technical Note: A respiratory monitoring and processing system based on computer vision: prototype and proof of principle
Monitoring and controlling respiratory motion is a challenge for the accuracy and safety of therapeutic irradiation of thoracic tumors. Various commercial systems based on the monitoring of internal or external surrogates have been developed but remain costly. In this article we describe and validate Madibreast, an in-house-made respiratory monitoring and processing device based on optical tracking of external markers. We designed an optical apparatus to ensure real-time submillimetric image resolution at 4 m. Using OpenCv libraries, we optically tracked high-contrast markers set on patients ’ breasts. Validation of ...
Source: Journal of Applied Clinical Medical Physics - September 8, 2016 Category: Physics Source Type: research

Implementation and evaluation of a protocol management system for automated review of CT protocols
This article describes our experiences in the implementation and evaluation of this protocol monitoring system. In particular, we discuss various strategies for addressing each of the steps in our protocol-monitoring workflow, which are: maintaining an accurate set of mas ter protocols, retrieving protocols from the scanners, comparing scanner protocols to master protocols, reviewing flagged differences between the scanner and master protocols, and updating the scanner and/or master protocols. In our initial evaluation focusing only on abdo­men and pelvis protocols, we detected 309 modified protocols in a 24-week trial...
Source: Journal of Applied Clinical Medical Physics - September 8, 2016 Category: Physics Source Type: research

RadShield: semiautomated shielding design using a floor plan driven graphical user interface
The purpose of this study was to introduce and describe the development of RadShield, a Java-based graphical user interface (GUI), which provides a base design that uniquely performs thorough, spatially distributed calculations at many points and reports the maximum air-kerma rate and barrier thickness for each barrier pursuant to NCRP Report 147 methodology. Semiautomated shielding design calculations are validated by two approaches: a geometry-based approach and a manual approach. A series of geometry-based equations were derived giv ­ing the maximum air-kerma rate magnitude and location through a first derivative ro...
Source: Journal of Applied Clinical Medical Physics - September 8, 2016 Category: Physics Source Type: research