bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of dose‐area product with GafChromic XR Type R film
Authors: Thomas George , Li Yushan , Chu Robert Y.L. , Cheung John Y. , Maqbool Feroz , Rabe Frank , Burns G. Scott 
Published: December 2008

Many of the newer X‐ray machines are equipped with electronic means to provide dose–area product (DAP) information. For machines without that ability, an alternative method is to record radiation on a film that can handle a large amount of cumulative exposure. The use of GafChromic XR Type R film was investigated for this purpose by placing it at the X‐ray tube assembly to record the radiation in interventional radiological procedures. Dose‐area product was determined with a reflective densitometer and then with a flatbed scanner. Precisions were demonstrated to be 5% and 2%, respectively. In a comparison with the machine‐recorded DAP, a regression analysis showed the validity of both techniques for values less than 1200 Gy‐cm2.PACS numbers: 87.52.Df, 87.66.Cd
Generation of wedge‐shaped dose distributions through dynamic multileaf collimator dose delivery
Authors: Zhu Jingeng 
Published: December 2008

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 the intensity‐modulated radiation therapy (IMRT) leaf sequence generation algorithm to create multileaf collimator (MLC) segments for dose delivery. Wedge‐shaped dose distributions are achieved through dynamic MLC dose delivery guided with the generated MLC segments. The method has been tested by generating wedge‐shaped doses for a set of conventional wedge angles (i.e., 15°, 30°, 45°, and 60°). Film dosimetry is used for dose distribution verification. For each dose delivery guided with MLC segments created for the indicated wedge angle, the desired wedge‐shaped dose distributions are observed. It is concluded that the dynamic MLC can be used to implement dynamic wedges in the clinic. This technique is different from the virtual wedge or the dynamic wedge developed for a particular type of LINAC. The same method can be applied to any machine equipped with a MLC. Other advantages are that it can generate a wedge field at an arbitrary orientation as the omni wedge does, and it creates wedged and shaped fields using a MLC only.PACS number(s): 87.53.Mr.
A 3D digitization system for conventional radiation therapy simulation
Authors: Lu Hsiao‐Ming 
Published: December 2008

While the majority of patients receiving external beam radiation therapy treatment are planned by CT simulation, a significant number of them are still planned using conventional simulators for various reasons. The information‐collection process in a conventional simulation is often fragmented and done with primitive tools. For example, in many institutions body contours are still acquired using solder wires and tracing paper, a time‐consuming and error‐prone procedure. We have developed a 3D digitization system to assist the information‐acquisition process at conventional simulations. The system consists of an infrared camera assembly, a wireless digitizer probe, and Windows‐based software. The system can provide 3D coordinates of any points in space accessible by the probe with submillimeter accuracy. It can be used to capture body contours, to record the coordinates of portal points, and to take various measurements for dose calculations as well as for patient setup. The software can display all the captured data together with the planned treatment fields, providing a comprehensive geometric verification of the treatment configuration. The system can also transfer all the information to dose‐planning programs in DICOM‐RT format, providing an integrated information flow from simulation to dose planning.PACS: 87.53.Vb, 87.53.Xd
Performance of magnetic field‐guided navigation system for interventional neurosurgical and cardiac procedures
Authors: Chu James C.H. , Hsi Wen Chien , Hubbard Lincoln , Zhang Yunkai , Bernard Damian , Reeder Pamela , Lopes Demetrius 
Published: December 2008

A hospital‐based magnetic guidance system (MGS) was installed to assist a physician in navigating catheters and guide wires during interventional cardiac and neurosurgical procedures. The objective of this study is to examine the performance of this magnetic field‐guided navigation system. Our results show that the system's radiological imaging components produce images with quality similar to that produced by other modern fluoroscopic devices. The system's magnetic navigation components also deflect the wire and catheter tips toward the intended direction. The physician, however, will have to oversteer the wire or catheter when defining the steering angle during the procedure. The MGS could be clinically useful in device navigation deflection and vessel access.PACS numbers: 07.55.Db, 07.85.‐m
A technique for reducing patient setup uncertainties by aligning and verifying daily positioning of a moving tumor using implanted fiducials
Authors: Nelson Christopher , Balter Peter , Morice Rodolfo C. , Choi Bum , Kudchadker Rajat J. , Bucci Kara , Chang Joe Y. , Dong Lei , Tucker Susan , Vedam Sastry , Briere Tina , Starkschall George 
Published: December 2008

This study aimed to validate and implement a methodology in which fiducials implanted in the periphery of lung tumors can be used to reduce uncertainties in tumor location.Alignment software that matches marker positions on two‐dimensional (2D) kilovoltage portal images to positions on three‐dimensional (3D) computed tomography data sets was validated using static and moving phantoms. This software also was used to reduce uncertainties in tumor location in a patient with fiducials implanted in the periphery of a lung tumor.Alignment of fiducial locations in orthogonal projection images with corresponding fiducial locations in 3D data sets can position both static and moving phantoms with an accuracy of 1 mm. In a patient, alignment based on fiducial locations reduced systematic errors in the left–right direction by 3 mm and random errors by 2 mm, and random errors in the superior–inferior direction by 3 mm as measured by anterior–posterior cine images.Software that matches fiducial markers on 2D and 3D images is effective for aligning both static and moving fiducials before treatment and can be implemented to reduce patient setup uncertainties.PACS number: 81.40.Wx
Patient dosimetry for total body irradiation using single‐use MOSFET detectors
Authors: Briere Tina Marie , Tailor Ramesh , Tolani Naresh , Prado Karl , Lane Richard , Woo Shiao , Ha Chul , Gillin Michael T. , Beddar A. Sam 
Published: December 2008

We studied the usefulness of a new type of solid‐state detector, the OneDose single‐use MOSFET (metal oxide semiconductor field effect transistor) dosimeter, for entrance dose measurements for total body irradiation (TBI). The factory calibration factors supplied by the manufacturer are applicable to conventional radiotherapy beam arrangements and therefore may not be expected to be valid for TBI dosimetry because of the large field sizes and extended source‐to‐axis distances used. OneDose detectors were placed under a 1‐cm thick bolus at the head, neck, and umbilicus of 9 patients undergoing TBI procedures. Thermoluminescent dosimeters (TLDs) were placed beside the detectors. We found that the OneDose readings differed from the TLD readings by 4.6% at the head, 1.7% at the neck, and 3.9% at the umbilicus, with corresponding standard deviations of 3.9%, 2.2%, and 2.7%. For all patient measurements, 95% of the OneDose readings fell within 3. of the TLD readings. Anthropomorphic phantom measurements showed differences of at the neck and midway between the phantom's carina and umbilicus. Our results suggest that these detectors could be used for TBI quality assurance monitoring, although TLDs should remain the standard when critical dose measurements are performed. If OneDose detectors are to be used for TBI, the use of more than one at each location is strongly recommended. Because the detectors are designed for single use, they cannot be individually calibrated. However, to obtain institution‐specific correction factors for better applicability to TBI dosimetry, measurements of several detectors taken from a particular lot could also be obtained in phantom with the TBI geometry configurations used for patient treatment.PACS numbers: 87.53.Bn, 85.30.Tv, 87.55.‐x
Electron beam therapy at extended source‐to‐surface distance: a Monte Carlo investigation
Authors: O'Shea Tuathan P. , Foley Mark J. , Rajasekar David , Downes Patrick A. , van der Putten Wil , Moore Margaret , Shearer Andrew 
Published: December 2008

Electron‐beam therapy is used to treat superficial tumors at a standard 100 cm source‐to‐surface distance (SSD). However, certain clinical situations require the use of an extended SSD. In the present study, Monte Carlo methods were used to investigate clinical electron beams, at standard and non‐standard SSDs, from a Siemens Oncor Avant Garde (Siemens Healthcare, Erlangen, Germany) linear accelerator (LINAC). The LINAC treatment head was modeled in BEAMnrc for electron fields 5 cm in diameter and , , and ; for 6 MeV, 9 MeV, and 12 MeV; and for 100 cm, 110 cm, and 120 cm SSD. The DOSXYZnrc code was used to calculate extended SSD factors and dose contributions from various parts of the treatment head.The main effects of extended SSD on water phantom dose distributions were verified by Monte Carlo methods. Monte Carlo–calculated and measured extended SSD factors showed an average difference of . For the field 5 cm in diameter, the relative output at extended SSD declined more rapidly than it did for the larger fields. An investigation of output contributions showed this decline was mainly a result of a rapid loss of scatter dose reaching the point from the lower scrapers of the electron applicator. The field 5 cm in diameter showed a reduction in dose contributions; the larger fields generally showed an increased contribution from the scrapers with increase in SSD. Angular distributions of applicator‐scattered electrons have shown a large number of acute‐angle electron tracks contributing to the output for larger field sizes, explaining the shallow output reduction.PACS numbers: 87.53.Wz, 87.53.Vb, 87.53.Hv
An investigation of temporal resolution parameters in cine‐mode four‐dimensional computed tomography acquisition
Authors: Mutaf Yildirim D. , Brinkmann Debra H. 
Published: December 2008

The accuracy of four‐dimensional computed tomography (4DCT) imaging depends on temporal characteristics of the acquisition protocol—for example, the temporal spacing of the reconstructed images (also known as cine duration between images) and the gantry rotation speed. These parameters affect the temporal resolution of 4DCT images, and a single default acquisition protocol, as commonly used in most clinics, may be suboptimal for a subset of respiratory motion characteristics. It could lead to substantial inaccuracies in target delineation. The aim of the present study was to evaluate the interplay between parameters affecting temporal resolution and the accuracy of the resulting images.We acquired 4DCT images of cylindrical phantoms under repetitive motion induced by a translation platform. Acquisition settings varied with respect to temporal spacing, gantry rotation speed, and motion period of the phantoms. Reconstructed images were sorted into 10 phase bins and were compared to static phantom images acquired at corresponding positions of the respiration phase. Acquisitions with different temporal spacing did not play a significant role in the amount of motion observed in full‐cycle maximum intensity projection images. Target delineation accuracy at end‐of‐inhalation phase was observed to be constant up to a threshold in the value of the reconstruction interval, beyond which it varied arbitrarily. This threshold was found to be correlated with the number of phase bins and the motion period. No observable variations were noted with images from the end of exhalation when temporal spacing was varied. Target delineation accuracy was observed to be enhanced in acquisitions using faster gantry rotation speeds. An evaluation of the acquisition parameters needs to be performed depending on the period of the motion and limiting factors such as the availability of acquisition settings, X‐ray tube workload, image storage, and processing power.PACS numbers: 87.53.Xd, 87.57.‐s, 87.57.Gg, 87.59.Fm
Simulation of intrafraction motion and overall geometric accuracy of a frameless intracranial radiosurgery process
Authors: Feygelman Vladimir , Walker Luke , Chinnaiyan Prakash , Forster Kenneth 
Published: December 2008

We conducted a comprehensive evaluation of the clinical accuracy of an image‐guided frameless intracranial radiosurgery system. All links in the process chain were tested. Using healthy volunteers, we evaluated a novel method to prospectively quantify the range of target motion for optimal determination of the planning target volume (PTV) margin. The overall system isocentric accuracy was tested using a rigid anthropomorphic phantom containing a hidden target. Intrafraction motion was simulated in 5 healthy volunteers. Reinforced head‐and‐shoulders thermoplastic masks were used for immobilization. The subjects were placed in a treatment position for 15 minutes (the maximum expected time between repeated isocenter localizations) and the six‐degrees‐of‐freedom target displacements were recorded with high frequency by tracking infrared markers. The markers were placed on a customized piece of thermoplastic secured to the head independently of the immobilization mask. Additional data were collected with the subjects holding their breath, talking, and deliberately moving. As compared with fiducial matching, the automatic registration algorithm did not introduce clinically significant errors ( difference). The hidden target test confirmed overall system isocentric accuracy of ≤1 mm (total three‐dimensional displacement). The subjects exhibited various patterns and ranges of head motion during the mock treatment. The total displacement vector encompassing 95% of the positional points varied from 0.4 mm to 2.9 mm. Pre‐planning motion simulation with optical tracking was tested on volunteers and appears promising for determination of patient‐specific PTV margins. Further patient study is necessary and is planned. In the meantime, system accuracy is sufficient for confident clinical use with 3 mm PTV margins.PACS number: 87.53.Ly
Case study of radiation therapy treatment of a patient with a cardiac ventricular assist device∗
Authors: Lasher Donette E. , Wojcicka Jadwiga B. , Malcom Ronald , Shears Lawrence L 
Published: December 2008

A patient with a cardiac ventricular assist device (VAD) with computer‐controlled driver presented to our department for radiation therapy. The treatment plan was 4500 cGy to the rectum over 25 fractions with 15MV photon beams. All beams avoided the pump and leads. The response to electromagnetic interference (EMI) was evaluated by observing a duplicate driver in the treatment configuration as the patient's fields were delivered to a solid water equivalent phantom. Pretreatment dose assessment included calculations with Pinnacle treatment planning system, AAPM TG36 data analysis, and MOSFET measurements on the surface of the driver during the phantom irradiation. During the first patient treatment, MOSFETs were placed on the pump and leads, approximately 1cm from the left lateral treatment portal. No additional shielding was applied to the VAD. EMI was absent and the VAD operated normally during the pretreatment test and throughout the treatment course. Radiation to the driver was too low to be detected by the MOSFETS. Cumulative dose estimates to the pump were 425cGy to 0. 1cc (DVH), 368cGy (TG36), and 158.5cGy (MOSFET). MOSFET readings to the leads were 70.5cGy. External beam radiation treatment was safely delivered to a VAD dependent patient. The VAD exhibited no adverse response to EMI and doses up to 425 cGy. Our results are based on one case and further study is encouraged.PACS number: 87.53.Dq
A Novel Mycovirus That Is Related to the Human PathogenHepatitis E Virusand Rubi-Like Viruses
Authors: Liu Huiquan , Fu Yanping , Jiang Daohong , Li Guoqing , Xie Jun , Peng Youliang , Yi Xianhong , Ghabrial Said A. 
Published: December 2008

ABSTRACTPreviously, we reported that three double-stranded RNA (dsRNA) segments, designated L-, M-, and S-dsRNAs, were detected inSclerotinia sclerotiorumstrain Ep-1PN. Of these, the M-dsRNA segment was derived from the genomic RNA of a potexvirus-like positive-strand RNA virus,Sclerotinia sclerotiorum debilitation-associated RNA virus. Here, we present the complete nucleotide sequence of the L-dsRNA, which is 6,043 nucleotides in length, excluding the poly(A) tail. Sequence analysis revealed the presence of a single open reading frame (nucleotide positions 42 to 5936) that encodes a protein with significant similarity to the replicases of the “alphavirus-like” supergroup of positive-strand RNA viruses. A sequence comparison of the L-dsRNA-encoded putative replicase protein containing conserved methyltransferase, helicase, and RNA-dependent RNA polymerase motifs showed that it has significant sequence similarity to the replicase ofHepatitis E virus, a virus infecting humans. Furthermore, we present convincing evidence that the virus-like L-dsRNA could replicate independently with only a slight impact on growth and virulence of its host. Our results suggest that the L-dsRNA from strain Ep-1PN is derived from the genomic RNA of a positive-strand RNA virus, which we namedSclerotinia sclerotiorum RNA virusL (SsRV-L). As far as we know, this is the first report of a positive-strand RNA mycovirus that is related to a human virus. Phylogenetic and sequence analyses of the conserved motifs of the RNA replicase of SsRV-L showed that it clustered with the rubi-like viruses and that it is related to the plant clostero-, beny- and tobamoviruses and to the insect omegatetraviruses. Considering the fact that these related alphavirus-like positive-strand RNA viruses infect a wide variety of organisms, these findings suggest that the ancestral positive-strand RNA viruses might be of ancient origin and/or they might have radiated horizontally among vertebrates, insects, plants, and fungi.
Thinking professionally
Authors: Gotterbarn Don 
Published: December 2008

Many of us are from a generation when video games were wholesome and character building and the games did not reward, murder, torture, or theft. Those early games like Pong morphed into Wii's Family Table Tennis and Major League Eating which can be played even while seated in a retirement home.
The widespread use of video-games in education, training, entertainment and the use of video game technology in the design and control of medical, commercial, and military systems has a significant impact on the present and the future directions of society. As in other rapid advances in technology, the speed of the development and immersion of this technology in our lives has left numerous significant questions.
CS research
Authors: Lister Raymond 
Published: December 2008

If our human bodies are a reflection of what we eat, then the collective body of an academic community is a reflection of what its members cite. To better understand the Computing Education Research Community, I recently counted the conferences, journals and books cited in the 43 papers comprising the first three International Computing Education Research Workshops (i.e. ICERs 2007-2007).
These 43 ICER papers contained 1130 citations, which is a remarkable average of 26 citations per publication. Almost one third (32%) of the citations were to conferences, while 38% of citations were to journals, and 21% to books and book chapters.
Contributing student pedagogy
Authors: Hamer John , Cutts Quintin , Jackova Jana , Luxton-Reilly Andrew , McCartney Robert , Purchase Helen , Riedesel Charles , Saeli Mara , Sanders Kate , Sheard Judithe 
Published: December 2008

A Contributing Student Pedagogy (CSP) is a pedagogy that encourages students to contribute to the learning of others and to value the contributions of others. CSP in formal education is anticipatory of learning processes found in industry and research, in which the roles and responsibilities of 'teacher' and 'student' are fluid. Preparing students for this shift is one motivation for use of CSP. Further, CSP approaches are linked to constructivist and community theories of learning, and provide opportunities to engage students more deeply in subject material.
In this paper we advance the concept of CSP and relate it to the particular needs of computer science. We present a number of characteristics of this approach, and use case studies from the available literature to illustrate these characteristics in practice. We discuss enabling technologies, provide guidance to instructors who would like to incorporate this approach in their teaching, and suggest some future directions for the study and evaluation of this technique. We conclude with an extensive bibliography of related research and case studies which exhibit elements of CSP.
Ischaemic stroke patients with heterozygous factor V Leiden present with multiple brain infarctions and widespread atherothrombotic disease
Authors: Helenius Johanna , Jakovljeviâ Dimitrije , Soinne Lauri , Syrjälä Martti , Kaste Markku , Lassila Riitta , Tatlisumak Turgut , Haapaniemi Elena 
Published: December 2008

SummaryFactor V Leiden (FVL) mutation is a risk factor for venous and, to a degree, arterial thrombosis. It is unknown whether and how FVL affects the manifestations of ischaemic stroke (IS). We assessed the clinical, laboratory, radiological, and prognostic characteristics in an observational study with adult IS patients having FVL. We tested 860 patients with first-ever IS for FVL and found 48 FVL positive patients. Detailed clinical, laboratory, and radiological evaluation were compared with that of 144 (1:3) gender and age matched IS patients without FVL. All patients underwent a prognostic evaluation at an average of five years follow-up. Despite the relatively young age (mean 48.5 years, range 44–54 years) of the FVL positive IS patients, peripheral arterial occlusive disease (PAOD), coronary artery disease (CAD), and previous transient cerebrovascular event occurred more frequently compared with controls. Family history of cardiovascular disease (CVD) and multiple silent brain infarctions were revealed in half of the FVL positive patients, whereas these were seldom encountered among controls. Stroke severity, long-term recovery, and recurrence rates seemed similar irrespective of FVL status. Our findings indicate that the clinical profile of IS patients with FVL associated with wider manifestation of atherothrombosis, positive family history of arterial thrombosis, and presence of multiple silent infarctions on brain images.