bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tax Evasion in Europe: An Analysis Based on Spatial Dependence
Authors: García Gloria Alarcón , Azorín José Daniel Buendía , de la Vega María del Mar Sánchez 
Published: February 2017

ObjectiveThis article attempts to analyze tax evasion as a fundamental element of tax morale in the European countries from the perspective of spatial dependence. This research focuses on the contextual differences using country‐level and cross‐sectional European Value Survey data for the year 2008 to estimate the factors that affect the rejection of tax evasion.MethodThe application of a generalized linear model using spatial filtering allowed us to observe robust results on the role of contextual variables in explaining different patterns of the rejection of tax evasion in the European countries.ResultsThe results confirm the influence exerted by spatial dependence, economies of agglomeration, income inequality, economic imbalances, and perceived corruption on the variable “rejection of tax evasion.” A novel finding is the fact that income distribution is key in explaining the rejection of tax evasion.ConclusionThis study indicate that there is interaction of the rejection of tax evasion between neighboring countries, so that low/high levels of rejection of tax evasion at home are associated with low/high levels of rejection in a neighboring country. Therefore, policymakers should establish coordinated tax awareness measures in the supranational policies (e.g., European Union), since the rejection of tax evasion depends on internal factors of the country in which one lives and those of neighboring countries. Fiscal behavior (social norm) of individuals from neighboring countries affects the behavior of individuals in the country.
Liver transplantation with an uncommon full right hemiliver graft after hydatid cysts resection: Case report and review of the literature
Authors: Patrono Damiano , Tandoi Francesco , Rizza Giorgia , Catalano Giorgia , Mirabella Stefano , Celoria Piero , Corcione Silvia , De Rosa Francesco Giuseppe , Salizzoni Mauro , Romagnoli Renato 
Published: February 2017

AbstractBecause of widespread organ shortage, the transplant community has been exploiting more and more so‐called “extended criteria” donors. In this scenario, liver grafts harboring benign tumors or large cysts represent an infrequent but potentially valuable source of viable grafts. We depict a challenging case of liver transplantation performed using a graft harboring two large Echinococcus granulosus hydatid cysts in close proximity with the hilar plate and complicated by cystobiliary communication. Although liver transplantation using grafts with hydatid cyst has been rarely reported (three published cases), our case was peculiar as one of the cysts was located close to the hilum and was ruptured into the left hepatic duct. The graft was finally accepted taking into account the low risk profile of the recipient, the good quality and size of the remnant liver parenchyma, and only after complete resection of the cysts was achieved. Although the recipient had a complication due to biliary confluence necrosis, at 10‐months follow‐up he is in good health with normal hepatic function, and a graft that could have been otherwise discarded was successfully used. The decision process along with technical and management issues are discussed.
Effect of interfractional shoulder motion on low neck nodal targets for patients treated using volumetric‐modulated arc therapy (VMAT)
Authors: Casey Kevin E. , Wong Pei‐Fong , Tung Samuel S. 
Published: February 2017

VMAT is an important tool in the treatment of head and neck cancers, many of which also require treatment to the supraclavicular lymph nodes. However, full VMAT arcs treating this nodal region necessarily cause entrance beam to pass through patients' shoulders. Thus, interfractional variations in shoulder position may cause unwanted dose perturbations. To assess this possibility, six patients undergoing treatment at our institution for head and neck cancers with associated supraclavicular lymph node treatment were imaged with in‐room CT‐on‐rails during the course of their treatments. This allowed for the establishment of a true record of the actual shoulder position during selected treatment fractions. Then, a full VMAT plan and a plan with VMAT arcs superior to the shoulder and a static anteroposterior field inferiorly were copied onto the patients' weekly image sets. The average one‐dimensional shoulder motion was generally within 10 mm of the simulated position, with some notable exceptions. The standard deviation in week‐to‐week shoulder position relative to simulation was 4.3 mm and 4.2 mm in the SI and AP dimensions, respectively. The average nodal target mean dose across all fractions sampled was within 5% of planned for all patients and both plans. Similarly, the average D95 for the nodal target was within 5% of planned across all fractions sampled, with the single exception of the full VMAT plan for one patient. In most cases, the standard deviation in both target mean dose and D95 was smaller with the VMAT+static AP field plan than it was with the full VMAT plan.PACS number: 87.55.‐x
Amplitude gating for a coached breathing approach in respiratory gated 10 MV flattening filter‐free VMAT delivery
Authors: Viel Francis , Lee Richard , Gete Ermias , Duzenli Cheryl 
Published: February 2017

The purpose of this study was to investigate amplitude gating combined with a coached breathing strategy for 10 MV flattening filter‐free (FFF) volumetric‐modulated arc therapy (VMAT) on the Varian TrueBeam linac. Ten patient plans for VMAT SABR liver were created using the Eclipse treatment planning system (TPS). The verification plans were then transferred to a CT‐scanned Quasar phantom and delivered on a TrueBeam linac using a 10 MV FFF beam and Varian's real‐time position management (RPM) system for respiratory gating based on breathing amplitude. Breathing traces were acquired from ten patients using two kinds of breathing patterns: free breathing and an interrupted ( pause) end of exhale coached breathing pattern. Ion chamber and Gafchromic film measurements were acquired for a gated delivery while the phantom moved under the described breathing patterns, as well as for a nongated stationary phantom delivery. The gate window was set to obtain a range of residual target motion from 2–5 mm. All gated deliveries on a moving phantom have been shown to be dosimetrically equivalent to the nongated deliveries on a static phantom, with differences in point dose measurements under 1% and average gamma agreement above 98.7%. Comparison with the treatment planning system also resulted in good agreement, with differences in point‐dose measurements under 2.5% and average gamma agreement of 97%. The use of a coached breathing pattern significantly increases the duty cycle, compared with free breathing, and allows for shorter treatment times. Patients' free‐breathing patterns contain considerable variability and, although dosimetric results for gated delivery may be acceptable, it is difficult to achieve efficient treatment delivery. A coached breathing pattern combined with a 5 mm amplitude gate, resulted in both high‐quality dose distributions and overall shortest gated beam delivery times.PACS number: 87.55.Qr
Evaluation of monitor unit calculation based on measurement and calculation with a simplified Monte Carlo method for passive beam delivery system in proton beam therapy
Authors: Hotta Kenji , Kohno Ryosuke , Nagafuchi Kohsuke , Yamaguchi Hidenori , Tansho Ryohei , Takada Yoshihisa , Akimoto Tetsuo 
Published: February 2017

Calibrating the dose per monitor unit (DMU) for individual patients is important to deliver the prescribed dose in radiation therapy. We have developed a DMU calculation method combining measurement data and calculation with a simplified Monte Carlo method for the double scattering system in proton beam therapy at the National Cancer Center Hospital East in Japan. The DMU calculation method determines the clinical DMU by the multiplication of three factors: a beam spreading device factor , a patient‐specific device factor , and a field‐size correction factor . We compared the calculated and the measured DMU for 75 dose fields in clinical cases. The calculated DMUs were in agreement with measurements in for all of 25 fields in prostate cancer cases, and in for 94% of 50 fields in head and neck (H&N) and lung cancer cases, including irregular shape fields and small fields. Although the in the DMU calculations is dominant as expected, we found that the patient‐specific device factor and field‐size correction also contribute significantly to the calculated DMU. This DMU calculation method will be able to substitute the conventional DMU measurement for the majority of clinical cases with a reasonable calculation time required for clinical use.PACS number: 87.55.kh
Comparative evaluation of modern dosimetry techniques near low‐ and high‐density heterogeneities
Authors: Alhakeem Eyad A. , AlShaikh Sami , Rosenfeld Anatoly B. , Zavgorodni Sergei F. 
Published: February 2017

The purpose of this study is to compare performance of several dosimetric methods in heterogeneous phantoms irradiated by 6 and 18 MV beams. Monte Carlo (MC) calculations were used, along with two versions of Acuros XB, anisotropic analytical algorithm (AAA), EBT2 film, and MOSkin dosimeters. Percent depth doses (PDD) were calculated and measured in three heterogeneous phantoms. The first two phantoms were a solid‐water slab that had an air‐gap of . The third phantom consisted of solid water slabs, two slabs of lung, and one solid water slab. Acuros XB, AAA, and MC calculations were within 1% in the regions with particle equilibrium. At media interfaces and buildup regions, differences between Acuros XB and MC were in the range of to . MOSkin and EBT2 measurements agreed to MC calculations within , except for the first centimeter of buildup where differences of 4.5% were observed. AAA did not predict the backscatter dose from the high‐density heterogeneity. For the third, multilayer lung phantom, 6 MV beam PDDs calculated by all TPS algorithms were within 2% of MC. 18 MV PDDs calculated by two versions of Acuros XB and AAA differed from MC by up to 2.8%, 3.2%, and 6.8%, respectively. MOSkin and EBT2 each differed from MC by up to 2.9% and 2.5% for the 6 MV, and by and for the 18 MV beams. All dosimetric techniques, except AAA, agreed within 3% in the regions with particle equilibrium. Differences between the dosimetric techniques were larger for the 18 MV than the 6 MV beam. MOSkin and EBT2 measurements were in a better agreement with MC than Acuros XB calculations at the interfaces, and they were in a better agreement to each other than to MC. The latter is due to their thinner detection layers compared to MC voxel sizes.PACS numbers: 87.55.K‐, 87.55.kd, 87.55.km, 87.53.Bn, 87.55.k
Estimating and reducing dose received by cardiac devices for patients undergoing radiotherapy
Authors: Bourgouin Alexandra , Varfalvy Nicolas , Archambault Louis 
Published: February 2017

The objectives of this project are to quantify the dose reduction effect provided by a lead shield for patients with cardiac implantable electronic devices (CIED) during a clinically realistic radiation treatment on phantom and to provide a simple model of dose estimation to predict dose received by CIED in a wide range of situations. The shield used in this project is composed of a lead sheet wrapped in thermoplastic. Dose measurements were made with a plastic scintillation detector (PSD). The phantom was treated with ten different plans. Three of these cases were treated with intensity‐modulated radiation therapy (IMRT) and the others received standard 3D conformal radiation therapy (3D CRT). Lateral dose measurement for photon fields was made to establish a dose prediction model. On average, the use of the lead shield reduced the dose to CIEDs by . Dose reduction was most important for breast cases, with a mean reduction of . In three cases, the total dose reduction was more than 25 cGy over the complete treatment. For the three IMRT cases, the mean dose reduction was . On average, the difference between the TPS prediction and the measurement was 71%, while it was only 14% for the dose prediction model. It was demonstrated that a lead shield can be efficiently used for reducing doses to CIED with a wide range of clinical plans. In patients treated with IMRT modality treatment, the shielding should be used only for those with more than two anterior fields over seven fields. In the case of 3D CRT patients, the shielding should be used for those with a dose on the CIED higher than 50 cGy and with a reduction of dose higher than 10 cGy. The dose prediction model developed in this study can be an easy way to have a better estimation of the out‐of‐field dose than the TPS.PACS number(s): 87.55.N, 87.55.km
Constancy checks of well‐type ionization chambers with external‐beam radiation units
Authors: Hackett Sara L. , Davis Benjamin , Nixon Andrew , Wyatt Ruth 
Published: February 2017

Constancy checks of a well‐type ionization chamber should be performed regularly as part of a quality assurance regime. The goal of this work was to test the feasibility of using a linear accelerator and an orthovoltage unit to check the constancy of a well‐type chamber's response to an external radiation source. The reproducibility, linearity with dose, variation with dose‐rate, and variation between energy‐matched units of the well‐type chamber response when exposed to 6 MV beams was examined. The robustness to errors in establishing the measurement conditions, including setting the source‐to‐surface distance and gantry angle, rotation of the chamber around the central axis of the beam, and the effect of changing the length of the chamber cable exposed to the field, were tested. The reproducibility and linearity with dose of the chamber response, and robustness to errors in establishing the measurement conditions for 100 kVp and 250 kVp beams from an orthovoltage unit, were also examined. The combined uncertainty, including contributions from errors in establishing the reference conditions, for well‐type chamber measurements using a 6 MV beam from a linear accelerator is 1.0%. The combined uncertainties for measurements using 100 and 250 kVp beams were 1.8% and 1.5%, respectively. When focus‐source distance errors were reduced to , the combined uncertainties for the 100 and 250 kVp beams were 1.2% and 1.1%, respectively, when the dose to the chamber was confined to the linear region of the dose‐response curve. The response of a well‐type chamber should remain constant to within 1.2% when exposed to a constant dose from an external beam unit, if reference conditions can be reproducibly established. However, the uncertainty for establishing reference conditions for output measurements for an orthovoltage unit can be reduced, which would justify a reduction of the tolerance for constancy measurements.PACS numbers: 87.55.Qr, 87.56.Fc
Beam‐specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors
Authors: Lin Liyong , Kang Minglei , Huang Sheng , Mayer Rulon , Thomas Andrew , Solberg Timothy D. , McDonough James E. , Simone Charles B. 
Published: February 2017

The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties, and patient setup variations. Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4D CT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4D CT phases, using uncertainty in stopping power and uncertainty in patient setup in each direction, were used to create PBS plans for the evaluation of 10 patients. Plans were normalized to provide identical coverage between DS and PBS. The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and V45 were reduced from 10.4% and 7.5% in DS to 8.1% and 5.4% for PBS, respectively. Furthermore, the maximum spinal cord, esophagus, and heart doses were decreased from 37.1 Gy, 71.7 Gy, and 69.2 Gy with DS to 31.3 Gy, 67.9 Gy, and 64.6 Gy with PBS. The conformity index (CI), homogeneity index (HI), and global maximal dose were improved from 3.2, 0.08, 77.4 Gy with DS to 2.8, 0.04, and 72.1 Gy with PBS. All differences are statistically significant, with p‐values , with the exception of the heart V45 (). PBS with BSPTV achieves better organ sparing and improves target coverage using a repainting method for the treatment of thoracic tumors. Incorporating motion‐related uncertainties is essential.PACS number: 87.55.D
A neural network‐based 2D/3D image registration quality evaluator for pediatric patient setup in external beam radiotherapy
Authors: Wu Jian , Su Zhong , Li Zuofeng 
Published: February 2017

Our purpose was to develop a neural network‐based registration quality evaluator (RQE) that can improve the 2D/3D image registration robustness for pediatric patient setup in external beam radiotherapy. Orthogonal daily setup X‐ray images of six pediatric patients with brain tumors receiving proton therapy treatments were retrospectively registered with their treatment planning computed tomography (CT) images. A neural network‐based pattern classifier was used to determine whether a registration solution was successful based on geometric features of the similarity measure values near the point‐of‐solution. Supervised training and test datasets were generated by rigidly registering a pair of orthogonal daily setup X‐ray images to the treatment planning CT. The best solution for each registration task was selected from 50 optimizing attempts that differed only by the randomly generated initial transformation parameters. The distance from each individual solution to the best solution in the normalized parametrical space was compared to a user‐defined error tolerance to determine whether that solution was acceptable. A supervised training was then used to train the RQE. Performance of the RQE was evaluated using test dataset consisting of registration results that were not used in training. The RQE was integrated with our in‐house 2D/3D registration system and its performance was evaluated using the same patient dataset. With an optimized sampling step size (i.e., 5 mm) in the feature space, the RQE has the sensitivity and the specificity in the ranges of 0.865–0.964 and 0.797–0.990, respectively, when used to detect registration error with mean voxel displacement (MVD) greater than 1 mm. The trial‐to‐acceptance ratio of the integrated 2D/3D registration system, for all patients, is equal to 1.48. The final acceptance ratio is 92.4%. The proposed RQE can potentially be used in a 2D/3D rigid image registration system to improve the overall robustness by rejecting unsuccessful registration solutions. The RQE is not patient‐specific, so a single RQE can be constructed and used for a particular application (e.g., the registration for images acquired on the same anatomical site). Implementation of the RQE in a 2D/3D registration system is clinically feasible.PACS numbers: 87.57.nj, 87.85.dq, 87.55.Qr
Confidence limits for patient‐specific IMRT dose QA: a multi‐institutional study in Korea
Authors: Kim Jung‐in , Chung Jin‐Beom , Song Ju‐Young , Kim Sung Kyu , Choi Yunseok , Choi Chang Heon , Choi Won Hoon , Cho Byungchul , Kim Jin Sung , Kim Sung Jin , Ye Sung‐Joon 
Published: February 2017

This study aims to investigate tolerance levels for patient‐specific IMRT dose QA (DQA) using the confidence limits (CL) determined by a multi‐institutional study. Eleven institutions participated in the multi‐institutional study in Korea. A total of 155 DQA measurements, consisting of point‐dose differences (high‐ and low‐dose regions) and gamma passing rates (composite and per‐field) for IMRT patients with brain, head and neck (H&N), abdomen, and prostate cancers were examined. The Shapiro‐Wilk test was used to evaluate the normality of data grouped by the treatment sites and the DQA methods. The confidence limit coefficients in cases of the normal distribution, and the two‐sided Student's t‐distribution were applied to determine the confidence limits for the grouped data. The Spearman's test was applied to assess the sensitivity of DQA results within the limited groups. The differences in CLs between the two confidence coefficients based on the normal and t‐distributions were negligible for the point‐dose data and the gamma passing rates with criteria. However, with criteria, the difference in CLs were 1.6% and 2.2% for composite and per‐field measurements, respectively. This resulted from the large standard deviation and the more sensitive criteria of . There was no noticeable correlation among the different QA methods. Our multi‐institutional study suggested that the CL was not a suitable metric for defining the tolerance level when the statistics of the sample group did not follow the normality and had a large standard deviation.PACS number: 87.55.Qr
Dosimetric effects of positioning shifts using 6D‐frameless stereotactic Brainlab system in hypofractionated intracranial radiotherapy
Authors: Jin Hosang , Keeling Vance P. , Ali Imad , Ahmad Salahuddin 
Published: February 2017

Dosimetric consequences of positional shifts were studied using frameless Brainlab ExacTrac X‐ray system for hypofractionated (3 or 5 fractions) intracranial stereotactic radiotherapy (SRT). SRT treatments of 17 patients with metastatic intracranial tumors using the stereotactic system were retrospectively investigated. The treatments were simulated in a treatment planning system by modifying planning parameters with a matrix conversion technique based on positional shifts for initial infrared (IR)‐based setup (XC: X‐ray correction) and post‐correction (XV: X‐ray verification). The simulation was implemented with (a) 3D translational shifts only and (b) 6D translational and rotational shifts for dosimetric effects of angular correction. Mean translations and rotations (± 1 SD) of 77 fractions based on the initial IR setup (XC) were (lateral), (longitudinal), and (vertical); (pitch), (roll), and (yaw), respectively. These were , , , , , and , respectively, for the postcorrection (XV). Substantial degradation of the treatment plans was observed in of PTV (; simulated treatment versus treatment planning), of PTV (), and of CTV (, with the maximum error of 10.0%) from XC, while dosimetrically negligible changes were detected for both CTV and PTV from XV simulation. 3D angular correction significantly improved CTV dose coverage when the total angular shifts were greater than 2°. With the 6D stereoscopic X‐ray verification imaging and frameless immobilization, submillimeter and subdegree accuracy is achieved with negligible dosimetric deviations. 3D angular correction is required when the angular deviation is substantial. A CTV‐to‐PTV safety margin of 2 mm is large enough to prevent deterioration of CTV coverage.PACS number: 87.55.dk