bluuebunny/crossref_metadata_2025 huggingface dataset:
Herlitz Junctional Epidermolysis Bullosa with a Novel Mutation in LAMB3
Authors: Kittridge Ashley , Patel Riddhi , Novoa Roberto , Tamburro Joan
Published: December 2012

Herlitz junctional epidermolysis bullosa (H‐JEB) is a rare, heritable mechanobullous disease that affects infants at birth and causes early death. This disease is primarily caused by compound heterozygous or homozygous mutations in one of three genes affecting the function of one of the three chains of the laminin‐332 (formerly laminin‐5) protein. Here we report a case of H‐JEB with a novel heterozygous mutation in LAMB3,c.1597G>A (p.Ala533Thr). These findings attest to the molecular heterogeneity of JEB and emphasize the importance of genetic analysis to help make an accurate diagnosis, predict clinical prognosis, and identify phenotypic‐genotypic relationships that may aid in prenatal diagnosis and genetic counseling for the future.
Agminated Spitz Nevi: Case Report and Review of the Literature
Authors: Zeng M. H. , Kong Q. T. , Sang H. , Deng D. Q. , Xie Q. M.
Published: December 2012

Spitz nevi are benign melanocytic lesions with many histologic similarities to malignant melanoma. A case of agminated Spitz nevi on a 2‐year‐old boy's left cheek is reported and 41 other cases of agminated Spitz nevi are reviewed. In this case, two biopsies were performed on two different‐appearing lesions and the results of both biopsies showed Spitz nevi.
Childhood Vitiligo: Clinicoepidemiologic Profile of 268 Children from the Kumaun Region of Uttarakhand, India
Authors: Agarwal Saurabh , Gupta Shalini , Ojha Amit , Sinha Rajesh
Published: December 2012

Childhood vitiligo differs from adult vitiligo in many clinical parameters. The objective of the current study was to study the clinicoepidemiologic profile of childhood vitiligo and to compare various clinical characteristics of childhood‐ and later‐onset vitiligo. The clinical presentation of vitiligo was examined and analyzed in 762 individuals attending the Dermatology Clinic of Government Medical College, Haldwani, a referral center for the Kumaun region of Uttarakhand state, India, between January 2006 and December 2010. Of the 762 individuals with vitiligo, 268 (35.2%) were children: 152 (56.7%) female and 116 (43.3%) male. The mean age of onset of vitiligo was 6.9 years. A family history of vitiligo was found in 24.3% of children. The most common site of onset was the head and neck (36.9%), followed by the lower limbs and trunk. The most common type of vitiligo observed was acrofacial vitiligo (38.1%), followed by vulgaris, segmental, focal, and mucosal. Leukotrichia was observed in 32.5% of children and Koebner's phenomenon in 24.3%. On comparison of childhood‐ and later‐onset vitiligo, there were statistically significant differences (p < 0.05) in sex, family history, type of vitiligo (segmental and vulgaris), and site of onset. Atopic dermatitis was one of the important cutaneous diseases associated with childhood‐onset vitiligo. Thirty‐five percent of all patients with vitiligo were children (≤12 yrs). Childhood‐onset vitilgo differs from later‐onset vitiligo in many clinical parameters such as sex, family history, types of vitiligo, and sites of onset.
Maternal and Perinatal Risk Factors for Infantile Hemangioma: A Case–Control Study
Authors: Chen Xiao Dong , Ma Gang , Chen Hui , Ye Xiao Xiao , Jin Yun Bo , Lin Xiao Xi
Published: December 2012

Infantile hemangioma (IH) is the most common benign tumor occurring during childhood. We hypothesized that, in addition to already known risk factors, such as female sex, prematurity, and low birthweight (LBW), antenatal vaginal bleeding and progesterone therapy would be highly associated with IH. We randomly selected 650 individuals with IH and matched them with 650 children of the same age and nationality without IH. Trained investigators used a standardized questionnaire to collect data from both groups, including demographic, prenatal, and perinatal characteristics. Prematurity (p < .001, odds ratio [OR] = 2.22, 95% confidence interval [CI] = 1.44–3.41), LBW (p < .001, OR = 3.10, 95% CI = 1.87–5.16) and female sex (p < .001, OR = 2.06, 95% CI = 1.65–2.58) were significantly associated with IH. Maternal vaginal bleeding during the first trimester was shown to be an independent risk factor according to logistic regression analyses (p < .001, OR = 1.6, 95% CI = 1.36–1.91), which was most evident in those receiving progesterone therapy to prevent miscarriage (p < .001, OR = 2.11, 95% CI = 1.77–2.51). Subgroup analyses revealed that the effect was more pronounced in female than in male infants (OR = 2.82, 95% CI = 2.39–3.34). In addition to the known relationships, the present study identified a close relationship between maternal vaginal bleeding and progesterone therapy during early pregnancy and IH. Twins appeared to have a higher incidence of IH than singletons.
Systemic Antifungals to Treat Onychomycosis in Children: A Systematic Review
Authors: Gupta Aditya K , Paquet Maryse
Published: December 2012

Because of the low prevalence of onychomycosis in children, little is known about the efficacy and safety of systemic antifungals in this population. PubMed and Embase databases and the references of related publications were searched in March 2012 for clinical trials (CTs), retrospective analyses (RAs), and case reports (CRs) on the use of systemic antifungals for onychomycosis in children (<18 years). Twenty‐six studies (5 CTs, 3 RAs, and 18 CRs) were published between 1976 and 2011. Most of these studies reported the use of systemic terbinafine and itraconazole for the treatment of onychomycosis in children. Therapy with systemic antifungals alone in children ages 1 to 17 years resulted in a complete cure rate of 70.8% (n = 151), whereas combined systemic and topical antifungal therapy in one infant and 19 children age 8 and older resulted in a complete cure rate of 80.0% (n = 20). The efficacy and safety profiles of terbinafine, itraconazole, griseofulvin, and fluconazole in children were similar to those previously reported for adults. In conclusion, based on the little information available on onychomycosis in children, systemic antifungal therapies in children are safe and cure rates are similar to the rates achieved in adults.
Rapidly Fatal Multiorgan Langerhans Cell Histiocytosis in a Neonate
Authors: Gee Sarah N. , Huang Jennifer T. , Schmidt Birgitta A. , Gellis Stephen E.
Published: December 2012

Multiorgan Langerhans cell histiocytosis (LCH) presenting in the neonatal period is associated with a poor prognosis. We report a 5‐day‐old neonate who presented at birth with diffuse cutaneous nodules and respiratory failure who received a postmortem diagnosis of LCH. We emphasize the importance of recognizing the cutaneous findings of this rare disease.
DAS181 treatment of severe parainfluenza type 3 pneumonia in a lung transplant recipient
Authors: Drozd D.R. , Limaye A.P. , Moss R.B. , Sanders R.L. , Hansen C. , Edelman J.D. , Raghu G. , Boeckh M. , Rakita R.M.
Published: December 2012

Parainfluenza virus (PIV) may cause life‐threatening pneumonia in lung transplant patients and there are no proven effective therapies. We report the use of inhaled DAS181, a novel sialidase fusion protein, to treat severe PIV type 3 pneumonia in a lung transplant patient. Treatment was well tolerated and associated with improvement in oxygenation and symptoms, along with rapid clearance of PIV. DAS181 should be systematically evaluated for treatment of PIV infection in transplant recipients.
Fatal Escherichia coli skin and soft tissue infections in liver transplant recipients: report of three cases
Authors: Janny S. , Bert F. , Dondero F. , Nicolas Chanoine M.‐H. , Belghiti J. , Mantz J. , Paugam‐Burtz C.
Published: December 2012

Gram‐negative bacilli are unusual agents of skin and soft tissue infections. Most previous cases have been reported in cirrhotic or immunocompromised patients, including a single case in a liver transplant recipient. The present report describes 3 cases of fatal skin or soft tissue infections caused by Escherichia coli that occurred in the postoperative course of liver transplantation. The 3 patients were profoundly immunosuppressed as a result of pre‐transplant cirrhosis and the postoperative administration of a potent immunosuppressive therapy. Skin and soft tissue infections developed within the first week after liver transplantation, while graft liver function was satisfactory. The 3 patients presented with fever and skin lesions with or without bullae. Despite prompt appropriate antibiotic therapy and surgical debridement, the outcome was rapidly fatal (24 h on average). E. coli was isolated from subcutaneous tissues in 2 cases and from several blood cultures in the third one. The 3 isolates belonged to distinct phylogenetic groups, and did not harbor most of the virulence factors usually reported in extraintestinal pathogenic E. coli isolates. Our report suggests that E. coli can cause severe skin or soft tissue infection in the postoperative course of liver transplantation. The onset of infection is very early and the outcome is extremely poor, despite prompt adapted medical and surgical treatment. Host factors, rather than E. coli bacterial virulence potential, appear to be the major determinants of severity in these patients.
Expect the unexpected: pleuro‐pulmonary melioidosis in a renal transplant recipient
Authors: Jabbar Z. , Han T.M. , Gagan F.
Published: December 2012

Melioidosis is an infectious disease endemic in tropical northern Australia and Southeast Asia, and, if treated late or inappropriately, is usually fatal. We report a rare case of pleuro‐pulmonary melioidosis with septicemia in a renal transplant recipient to highlight the potential risk of acquiring this infection in at‐risk patients living in, or visiting, regions that are endemic for melioidosis, and to convey the importance of its early diagnosis and specific treatment.
A Cross‐Sectional Study of Hepatitis E Virus Infection in Healthy People Directly Exposed and Unexposed to Pigs in a Rural Community in Northern Thailand
Authors: Hinjoy S. , Nelson K. E. , Gibbons R. V. , Jarman R. G. , Mongkolsirichaikul D. , Smithsuwan P. , Fernandez S. , Labrique A. B. , Patchanee P.
Published: December 2012

A cross‐sectional study of the association between occupational pig exposure and hepatitis E virus (HEV) infection in adult pig farmers and the general population who were not directly exposed to pigs was conducted in Nan Province, Thailand, from November 2010 to April 2011. All participants were interviewed to provide information on their job history, eating habits and other potential confounders. The prevalence of anti‐HEV immunoglobulin G antibodies (IgG) among 513 subjects was 23.0%. Hand washing with water and soap was associated with a lower seroprevalence of HEV infection, whereas living in an area with frequent flooding (OR 1.64, 95% CI: 1.00–2.68) and consuming internal pig organs more than twice per week (OR 3.23, 95%CI: 1.15–9.01) were both associated with a higher seroprevalence of anti‐HEV IgG. There was no association between HEV seroprevalence and frequent, direct occupational pig contact.
Sci—Wed PM: Delivery—01: Clinically Viable Treatment Times with Dual‐slice Co‐60 Tomotherapy
Authors: Cadman P
Published: December 2012

In the present study, we attempt to estimate clinical treatment times that might be achieved with dual‐slice Co‐60 tomotherapy delivery through an investigation of the advantages gained by reduced thread effect and pitch. The helical thread effect (off‐axis ripple), was simulated using a 30 wide cylindrical phantom in our PinnacleTM treatment planning system for various slice widths and pitch values. A cylindrical Co‐60 source of 2 cm diameter was studied along with a typical linac source for both single‐ and dual‐slice delivery. Treatment times were estimated based on a clinical Hi‐ARTTM tomotherapy head and neck treatment but with consideration of reduced output from the Co‐60 source, dual slice collimator and variation in slice width. We determine that dual‐slice tomotherapy delivery provides not only a reduction in treatment time due to an increase in the number of slices but also a reduction in the thread effect and effective pitch which may lead to improved modulation in the S‐I direction with larger slice widths. The net effect is a clinically viable treatment time that may be comparable with linac‐based IMRT with a conventional MLC. This initial study provides the impetus to support further investigations of plan quality and treatment times using dual‐slice Co‐60 tomotherapy.
Sci—;Wed PM: Delivery—04: Real‐Time MR Tumour Tracking and Dose Adaptation
Authors: Yun J , Robinson D , MacKenzie M , Rathee S , Murray B , Fallone BG
Published: December 2012

Treating mobile tumours (e.g. lung tumours) with radiation is a difficult task. In current practice, radiotherapy plans are generated that irradiate extended regions surrounding the tumour in order to encompass the entire path of tumour motion. Doing so, however, can result in unacceptable medical complications or restricted radiation deliveries. Addressing these problems, researchers at our centre initiated the Advanced Real‐Time Adaptive Radiation Therapy () project with a novel design of a Linac‐MR device which can provide intra‐fractional real time MR imaging. Using this system, our objective is to develop and evaluate an algorithm that can track the tumour movement in real‐time and adapt the radiation delivery accordingly, depending on the shape, position, and surrounding anatomy of the tumour. An auto‐contouring algorithm was developed to identify the shape and location of tumours. A MR compatible motion phantom was built to simulate the motion of tumours and to perform dosimetric measurements. To conform the radiation beam in real‐time, a Multi‐Leaf Collimator (MLC) controller was developed. To compensate for the time delay between MR imaging and irradiating instances, a motion prediction algorithm was developed and optimized. The auto‐contouring algorithm showed successful results in the 4D MR images of thoracic region and phantom. The motion prediction algorithm was evaluated by various means, and in most cases the position of tumour was correctly predicted more than 95% of the total treatment time. Integrated with these algorithms, our MLC system fully demonstrated its real‐time tracking capability.
Sci—Wed PM: Delivery—07: Dosimetric Characterization of a New Pixel Ionization Chamber Array
Authors: Venkataraman S , Malkoske KE , Jensen M , Asuni G , Nakonechny KD , Berndt A , McCurdy BMC
Published: December 2012

A new ionization chamber array developed by IBA Dosimetry (Germany) is evaluated at our centre. The dosimetric characteristics of this device such as dose and dose rate dependence, stability, energy dependence, profiles and error detection ability were studied. COMPASS is an array with 1600 parallel plate ion chambers. Each chamber is 3.8 mm in diameter and 2mm in height spaced 6.5 mm apart. The array is mounted onto the wedge slot of the Varian Clinac 2100iX (Varian Medical Systems, Palo Alto, CA) linear accelerator. Linearity of the detector with dose and response to dose rate were done using Clinac 2100iX 6 MV beam. The detector showed excellent linearity response with dose and a variation of <0.2% with dose rates. Short term and long term reproducibility results showed a standard deviation of 0.05%. Energy dependence of COMPASS was evaluated by response of the device to beam energies ranging from to 18 MV X‐rays. , determined by COMPASS increases with energy as opposed to a decreased response with energy of a thimble ion chamber. Profiles measured with COMPASS were similar to Markus (plane parallel) ion chamber for field sizes . The chamber array showed increased dose response off‐axis for larger fields. The penumbra measured by COMPASS was 3.14± 0.03 mm vs. 1.25± 0.02 mm for film measurements for a range of field sizes. A leaf gap error of 1 mm was detected by the device using an IMRT test field. Research partially sponsored by IBA Dosimetry.
Sci—Wed PM: Delivery—08: Monte Carlo Based RapidArc QA Using LINAC Log Files
Authors: Teke T , Bergman A , Kwa W , Gill B , Duzenli C , Popescu IA
Published: December 2012

Purpose/Objective(s): To present our Monte Carlo based RapidArc quality assurance (QA) process to validate both the dose calculation and dynamic beam delivery accuracy using the planning MLC control files and the post‐delivery MLC diagnostic files. Materials/Methods: Ten clinically acceptable RapidArc treatment plans were generated with a clinical version of the planning system for various tumor sites. Monte Carlo dose calculations were performed in a water equivalent phantom for each plan using both DynaLog files and the planning control (DVA) files. Results were compared to measurements using a calibrated Farmer ionization chamber with an active volume of . Comparison of RapidArc and Monte Carlo 3D doses was performed using a 3 dimensional Gamma‐factor analysis with a 3%/3mm DTA criteria. A thorough analysis of the DynaLog files was performed to evaluate the treatment delivery accuracy. Results: Good agreement was observed between chamber measurements and MC dose calculations and between RapidArc and MC dose distributions with Gamma values below 1 in over 90% of the points considered for all plans. The analysis of the MLC DynaLog files indicated that the leaf position errors were lower than 1 mm in more than 94% of the time with none above 2.5 mm and that few beam hold‐offs occurred Conclusions The accuracy and flexibility of our Monte Carlo based RapidArc QA system was demonstrated. Good machine performance and accurate dose distributions delivery of RapidArc plans was observed.
Sci—Wed PM: Delivery—12: The Radiofrequency Noise from MLCs for a Linac‐MR System
Authors: Lamey M , Yun J , Burke B , Rathee S , Fallone BG
Published: December 2012

Introduction: This work reports on the feasibility of using an MLC for a linac‐MR system. The radiofrequency)RF(noise produced by a functioning MLC is a possible interference to an MR imaging system. The RF noise spectral density produced by two brushed motors used to drive MLC leaves and one brushless fan motor has been investigated as a function of applied magnetic field. Materials/methods: An electromagnet was used to subject two brushed motors from two MLC assemblies)a Varian 52‐leaf and a Millennium 120 leaf assembly(and one brushless fan motor to a variable magnetic field. The RF noise was measured while the motors moved. The RF noise was measured with a set of commercially available near field electromagnetic probes. In a separate investigation the 0.22 T MR of our linac‐MR system was used to image a phantom. Images were taken with the MLC not present and then again with the MLC present and thirteen leaves moving. Results/Discussion: When viewing the RF noise in the time domain we could see small spikes of measured noise when the two brushed MLC motors were running; no noise could be seen from the brushless fan motor. In the frequency domain, the Millennium MLC motor showed some noise above background. Images with a phantom showed no degradation from possible RF noise interference when 13 MLC leaves from a Varian 52‐leaf MLC assembly were brought close to the MR coil and were moved.
Poster — Wed Eve—06: Organ Equivalent and Effective Doses from Diagnostic Radiology Procedures
Authors: Osei EK , Govind K , Charters N , Barnett R
Published: December 2012

Diagnostic radiology imaging techniques including conventional radiography, fluoroscopy and computed tomography will continue to provide tremendous benefits to modern healthcare. The quantification of radiation risks associated with radiological examinations has been the subject of interest for some time now with the increased used of x‐rays in the radiology departments. Effective dose which is a risk‐weighted measure of radiation exposure to organs in the body associated with radiological examination(s) is considered a better indicator of radiological risk. We have therefore undertaken a survey to investigate patients' equivalent and effective doses from various radiological examinations. This will provide a meaningful indication of patient exposure, taking into account the details of the radiological technique used for particular examinations and help to establish some reference or guidance dose values for radiological examinations performed at this hospital. It would also allow us to monitor any changes over time that might arise from ageing equipment or changing protocols, as well as giving us a means to compare doses with other hospitals and regions. Organ and effective dose were estimated for 94 patients (60 adults and 34 children) who underwent computed tomography examination of the head, chest and abdomen‐pelvis areas and for 338 patients who had conventional radiography examinations. The OrgDose program was used to calculate for all patients doses to 13 organs with the International Commission on Radiological Protection specified tissue weighting factors, 10 organs listed as remainder organs and some additional organs such as lenses of eyes, heart, head, leg, and trunk regions.
Poster — Wed Eve—07: Software for the Estimation of Organ Equivalent and Effective Doses from Diagnostic Radiology Procedures
Authors: Osei EK , Barnett R
Published: December 2012

Diagnostic radiological imaging such as conventional radiography, fluoroscopy and computed tomography (CT) examinations will continue to provide tremendous benefits in modern healthcare. The benefit derived by the patient should far outweigh the risk associated with a properly conducted imaging examination. Nonetheless, it is very important to be able to quantify the risk associated with any radiological examination of patients, and effective dose has been considered a useful indicator of patient exposure. Quantification of the risks associated with radiological imaging is very important as such information will be helpful to physicians and their patients to compare risks from various imaging examinations and to make informed decisions whenever there is a need for any radiological imaging. The determination of equivalent and effective doses in diagnostic radiology is of interest as a basis for risk estimates from medical exposures. In this paper we describe a simple computer program OrgDose, which calculates the doses to 27 organs in the body and then calculates the organ equivalent and effective doses and the risk from various procedures in the radiology department including conventional radiography, fluoroscopy and computed tomography examinations. The program will be a useful tool for the medical and paramedical personnel who are involved with assessing organ and effective doses and risks from diagnostic radiology procedures.
Poster — Wed Eve—15: Development of Multiple Coincidence Compton Imager
Authors: Andreyev A , Sitek A , Celler A
Published: December 2012

We report on the development of a new type of nuclear medicine imaging device — a Multiple Coincidence Compton Imager (MCCI). MCCI is based on the principle of electronic collimation and is expected to provide comparable resolution and better sensitivity than currently available SPECT systems. Furthermore, MCCI is using the simultaneous acquisition of several photons from a cascade allowing improved localization of the origin of any single radioactive disintegration. We have developed data simulation software and a simplified image reconstruction algorithm, that can be used to make predictions about the sensitivity and the reconstructed image spatial resolution that will be achieved by the MCCI system. In particular, our simulations of a small animal systems, using Silicon and CZT detector combination confirmed that the Compton camera is able to provide 10 to 100 times higher sensitivity than a typical SPECT system and image resolution around 1 mm FWHM for small animal studies.
Poster — Wed Eve—31: Validation of the Delta4 Phantom for 3‐D Dosimetry of IMRT Plans
Authors: Zhang TJ , Norrlinger B , Islam M
Published: December 2012

Modern radiotherapy techniques such as IMRT require time consuming dosimetric quality assurance (QA) for patient plans. ScandiDos (Uppsala, Sweden) has developed the Delta4 measurement system as a tool for efficient, three‐dimensional plan verification. The Delta4 system consists of two orthogonal detector planes, with a total of 1069 p‐type silicon diodes, embedded in an acrylic cylindrical phantom, 22 cm in diameter, 40 cm in length. The Delta4 software can reconstruct 3D dose distributions based upon the measured dose and the imported dose distributions from the planning system. The performance of the Delta4 system for the validation of IMRT plans, with emphasis on the dose measurement accuracy in areas away from the planes of the detectors, has been evaluated. Basic commissioning measurements of the Delta4 include dose linearity, dose rate dependence, angular sensitivity and reproducibility. For performance of IMRT plan validation, a region of interest (ROI) equivalent to a Farmer chamber was created in the plan at locations of high dose and low dose avoidance regions. The planned vs. measured dose for the chamber ROIs, as measured with the Delta4, were compared. To validate the plans, dose measurements were also performed using a cylindrical phantom with a Farmer chamber in the same locations. The Delta4's dose response was found to be linear (), and short term reproducibility is better that 0.15%. Results of the performance testing indicate that the Delta4 is suitable for clinical dosimetry. Comparisons of the Delta4 volumetric dose reconstruction with the dose measured using conventional tools show acceptable agreement.
Poster — Wed Eve—34: Design of a Primary Collimator for Cone Beam CT Imaging
Authors: Grant J , Dhanesar S , Joshi C , Darko J , Schreiner LJ , Kerr A
Published: December 2012

Intensity Modulated Radiation Therapy (IMRT) is becoming the standard of care for a number of cancer sites. Our research work has focused on developing Co‐60 based IMRT as an alternative for those areas in the world with limited infrastructure for supporting LINAC based systems. We have, to date, considered Co‐60 IMRT based on the tomotherapy approach because the full rotational delivery properties of tomotherapy helps to overcome the problems associated with the limited penetration of Co‐60 beams. However, with the recent introduction of arc based broad beam IMRT technology such as RapidArc (Varian Medical Systems, Palo Alto, CA), there is a potential for Co‐60 to be used in this approach. One potential advantage of broad beam versus fan beam Co‐60 IMRT delivery would be a reduction in the beam‐on time; a feature particularly important for a source that decays. Cone beam CT (CBCT) imaging is widely used for image guidance of broad‐beam IMRT and could likely play a role in a Co‐60 based broad beam IMRT system. The simplest and least complex design for such a system would consist of a single Co‐60 source for therapy and CBCT imaging. In this report we describe and analyze a new multileaf variable aperture primary collimator that permits a single Co‐60 source to be “switched” from therapy to a lower dose rate imaging mode. Monte carlo simulations of this design show that with a combination of altered aperture shape and an attenuator, an acceptable imaging dose rate without loss of spatial resolution is achieved.
Poster — Wed Eve—40: Comparison of CBCT CT Numbers to CT‐Simulator CT Numbers using Mutual Information and Joint Probability Distributions
Authors: Disher B , Kempe J , Gaede S , Battista JJ
Published: December 2012

The Varian On‐Board Imaging (OBI) system is an imaging tool used by the London Regional Cancer Program for image‐guided radiation therapy. The system consists of a kilovoltage source (120 kVp), emitting a conical X‐ray beam, and a flat panel amorphous silicon detector. Both source and detector are mounted on the linear accelerator gantry, rotating 360° about the patient creating 3‐dimensional volumetric computed tomography images. Unfortunately, cone‐beam computed tomography (CBCT) images are susceptible to many forms of artifacts resulting primarily from: increased amounts of scatter due to CBCT geometry, spectral X‐ray attenuation, and intra‐scanning organ motion. In order to assess the extent of CBCT image artifacts, we propose a new technique that compares CT Numbers in corresponding tissue regions obtained by the CBCT and Phillips Brilliance CT‐simulator systems. Our approach registers CT images from two imaging modalities using a mutual information (MI) algorithm. Once aligned, quantitative CT Number analysis is performed on the CT images using a 2‐dimensional histogram (or joint probability distribution) of pixel counts for geographically‐matched pairs of CT Numbers. Phantom studies have shown similarity between CBCT and CT‐simulation CT Numbers when the imaged medium is head‐like in diameter (20 cm) and homogeneous (Catphan 504 phantom). Greater discrepancies were observed (400 HU) when CT images of larger phantoms (30 cm diameter, Gammex RMI Tomo phantom) and increased heterogeneity were compared. Presently, quantitative CBCT CT Number inaccuracy precludes the use of CBCT images for whole body treatment planning, and adaptive dose computations.
Poster — Wed Eve—41: VMAT for Prostate Cancer: Superior Organ Sparing to IMRT and Delivery Efficiency to Helical Tomotherapy
Authors: Cheng J , Wu J‐K , Tsai C‐L , Chao H‐L , Tsai Y‐C
Published: December 2012

Volumetric modulated arc therapy (VMAT) has been developed for the better dose conformity and shorter treatment time. This study is aimed to compare the dosimetric and treatment parameters between step‐and‐shoot intensity modulated radiation therapy (IMRT), helical tomotherapy (HT), and volumetric modulated arc therapy (VMAT). Eight patients with localized prostate cancer with the dosimetric plans of 5‐field IMRT, HT, and VMAT for their 78‐Gy definitive treatment formed the basis of the study. Treatment target was prostate and proximal seminal vesicles. The goals were minimum clinical target volume (CTV) dose ≥ 78Gy, and 95% of planning target volume (PTV) ≥ 78Gy in 39 fractions. Target comparison showed PTV V95% of 99.95±0.05% for VMAT, 99.84±0.21% for IMRT, and 99.39±0.49% for HT; maximum dose to PTV was 82.44±0.29Gy, 82.45±0.54Gy, 82.80±0.72Gy, respectively. The rectum V65Gy was 11.18±1.52% for VMAT, 13.77±1.68% for IMRT, and 8.44±1.13% for HT, respectively. The bladder V65Gy was 13.25±8.22% for VMAT, 16.51±11.05 % for IMRT, and 10.63±4.47% for HT, respectively. Total monitor units were 304.3±42.3 for VMAT, 335.8±19.0 for IMRT, and 3073.4±532.6 for HT, respectively. Treatment time was 2.47±0.10 minutes for VMAT, 3.71±0.29 minutes for IMRT, and 3.64±0.60 minutes for HT, respectively. The VMAT plans in all 8 patients met the quality assurance criteria of 3% and 3mm. In conclusion, VMAT is a practical technique with comparable target coverage, better organ sparing than IMRT, and superior treatment efficiency to HT in prostate cancer patients.
Poster — Wed Eve—45: Imaging and Radiation Delivery in Helical Tomotherapy: Phantom Study of a Moving Target
Authors: Gallagher C , Yartsev S , Gaede S , Van Dyk J
Published: December 2012

Radiation is an effective method of treating lung cancer, however, the tumour moves while the patient breathes. To ensure radiation always covers the tumour, a volume larger than the target must be treated. For conventional treatments, gating can be employed, but helical tomotherapy treatments cannot be gated. We hypothesized that, through judicious choice of planning computed tomography (CT) imaging methods, radiation can be accurately planned and delivered to a moving tumour using tomotherapy. A breathing phantom was used which allowed one‐dimensional motion of a lung‐equivalent cylinder containing a target. By varying the imaging parameters, we obtained numerous different planning studies with target motion in both the superior‐inferior and lateral directions. These studies included a static study, fast‐CT studies, a maximum intensity projection (MIP), an average intensity projection (AveIP) and an untagged average study. Planning studies were acquired with the cylinder moving sinusoidally with a period of 4 s and amplitude of 1 cm. Treatment plans were created for each CT study and delivered using tomotherapy. Dose was measured using self‐developing film. Dose‐area histograms were used to compare the dose delivery to the central coronal plane of the target for all planning studies. A similar experiment was also performed using an irregular breathing pattern. Results indicated that planning using the AveIP study results in the most accurate treatment of a moving target. The amount of dose delivered to the normal tissue did not change significantly, due to the small increase in irradiated area compared to the entire area of the film.
Massively parallelizable list‐mode reconstruction using a Monte Carlo‐based elliptical Gaussian model
Authors: Sportelli G. , Ortuño J. E. , Vaquero J. J. , Desco M. , Santos A.
Published: December 2012

Purpose:

A fully three‐dimensional (3D) massively parallelizable list‐mode ordered‐subsets expectation‐maximization (LM‐OSEM) reconstruction algorithm has been developed for high‐resolution PET cameras. System response probabilities are calculated online from a set of parameters derived from Monte Carlo simulations. The shape of a system response for a given line of response (LOR) has been shown to be asymmetrical around the LOR. This work has been focused on the development of efficient region‐search techniques to sample the system response probabilities, which are suitable for asymmetric kernel models, including elliptical Gaussian models that allow for high accuracy and high parallelization efficiency. The novel region‐search scheme using variable kernel models is applied in the proposed PET reconstruction algorithm.

Methods:

A novel region‐search technique has been used to sample the probability density function in correspondence with a small dynamic subset of the field of view that constitutes the region of response (ROR). The ROR is identified around the LOR by searching for any voxel within a dynamically calculated contour. The contour condition is currently defined as a fixed threshold over the posterior probability, and arbitrary kernel models can be applied using a numerical approach. The processing of the LORs is distributed in batches among the available computing devices, then, individual LORs are processed within different processing units. In this way, both multicore and multiple many‐core processing units can be efficiently exploited. Tests have been conducted with probability models that take into account the noncolinearity, positron range, and crystal penetration effects, that produced tubes of response with varying elliptical sections whose axes were a function of the crystal's thickness and angle of incidence of the given LOR. The algorithm treats the probability model as a 3D scalar field defined within a reference system aligned with the ideal LOR.

Results:

This new technique provides superior image quality in terms of signal‐to‐noise ratio as compared with the histogram‐mode method based on precomputed system matrices available for a commercial small animal scanner. Reconstruction times can be kept low with the use of multicore, many‐core architectures, including multiple graphic processing units.

Conclusions

: A highly parallelizable LM reconstruction method has been proposed based on Monte Carlo simulations and new parallelization techniques aimed at improving the reconstruction speed and the image signal‐to‐noise of a given OSEM algorithm. The method has been validated using simulated and real phantoms. A special advantage of the new method is the possibility of defining dynamically the cut‐off threshold over the calculated probabilities thus allowing for a direct control on the trade‐off between speed and quality during the reconstruction.
Distribution of Pilus Islands in Streptococcus agalactiae That Cause Human Infections: Insights into Evolution and Implication for Vaccine Development
Authors: Martins E. R. , Andreu A. , Melo-Cristino J. , Ramirez M.
Published: December 2012

At least one pilus island, PI-1 (70%), PI-2a (79%), or PI-2b (21%), was found among 898
Streptococcus agalactiae
(group B streptococcus [GBS]) isolates recovered from humans, supporting the use of pilus proteins in vaccines. The stability and dominance of PI-1 and PI-2a in multiple serotypes and founder multilocus sequence types disseminated worldwide suggest it could be the PI combination present in ancestral GBS human pathogens.
Adhesion Protein ApfA of Actinobacillus pleuropneumoniae Is Required for Pathogenesis and Is a Potential Target for Vaccine Development
Authors: Zhou Yang , Li Lu , Chen Zhaohui , Yuan Hong , Chen Huanchun , Zhou Rui
Published: December 2012

Actinobacillus pleuropneumoniae
is the etiologic agent of porcine pleuropneumonia, which causes serious economic losses in the pig farming industry worldwide. Due to a lack of knowledge of its virulence factors and a lack of effective vaccines able to confer cross-serotype protection, it is difficult to place this disease under control. By analyzing its genome sequences, we found that type IV fimbrial subunit protein ApfA is highly conserved among different serotypes of
A. pleuropneumoniae
. Our study shows that ApfA is an adhesin since its expression was greatly upregulated (135-fold) upon contact with host cells, while its deletion mutant attenuated its capability of adhesion. The inactivation of
apfA
dramatically reduced the ability of
A. pleuropneumoniae
to colonize mouse lung, suggesting that
apfA
is a virulence factor. Purified recombinant ApfA elicited an elevated humoral immune response and conferred robust protection against challenges with
A. pleuropneumoniae
serovar 1 strain 4074 and serovar 7 strain WF83 in mice. Importantly, the anti-ApfA serum conferred significant protection against both serovar 1 and serovar 7 in mice. These studies indicate that ApfA promotes virulence through attachment to host cells, and its immunogenicity renders it a promising novel subunit vaccine candidate against infection with
A. pleuropneumoniae
.
Comparing Pulsed-Field Gel Electrophoresis with Multilocus Sequence Typing,
spa
Typing, Staphylococcal Cassette Chromosome
mec
(SCC
mec
) Typing, and PCR for Panton-Valentine Leukocidin,
arcA
, and
opp3
in Methicillin-Resistant Staphylococcus aureus Isolates at a U.S. Medical Center
Authors: David Michael Z. , Taylor Alexis , Lynfield Ruth , Boxrud Dave J. , Short Ginette , Zychowski Diana , Boyle-Vavra Susan , Daum Robert S.
Published: December 2012

Methicillin-resistant
Staphylococcus aureus
(MRSA) has become a common cause of skin infections and invasive infections in community dwellers in the United States since the late 1990s. Isolates characterized as USA300 by pulsed-field gel electrophoresis (PFGE) are the predominant strain type in these infections. USA100 and USA500 strains commonly cause health care-associated infections. We compared PFGE with a number of other methods of genotyping in a sample of 149 clinical MRSA isolates from the University of Chicago Medical Center. The 5 USA500 isolates yielded 3
spa
types and 2 multilocus sequence types (MLSTs). Among the 24 USA100 isolates, 21 (88%) were of
spa
type t002, 19 (79%) were of ST5, 2 carried
arcA
and
opp3
, and 1 was Panton-Valentine leukocidin positive (PVL
+
). Among the 102 USA300 isolates, 96 (94%) were of ST8 and 94 (92%) were of
spa
type t008. The combination of traits that provided the best sensitivity (98%), specificity (97%), positive predictive value (PPV) (99%), and negative predictive value (NPV) (95%) for identifying USA300 isolates were the presence of the
arcA
gene and the presence of the PVL genes (area under the curve, 0.980; 95% confidence interval [CI], 0.955 to 1.0). PFGE did not delineate a homogeneous group of MRSA genetic backgrounds, as documented for other typing methods, particularly for USA500 and USA100 pulsotypes. Documenting the presence of
arcA
and PVL genes by PCR was an efficient and accurate means of identifying USA300 in a collection of MRSA isolates in which USA300 is common. None of the tested genotyping methods provided an accurate means of identifying the next most common PFGE-based backgrounds, USA100 and USA500.
Longitudinal Analyses of Gut Mucosal Microbiotas in Ulcerative Colitis in Relation to Patient Age and Disease Severity and Duration
Authors: Fite Alemu , Macfarlane Sandra , Furrie Elizabeth , Bahrami Bahram , Cummings John H. , Steinke Douglas T. , Macfarlane George T.
Published: December 2012

Bacteria belonging to the normal colonic microbiota are associated with the etiology of ulcerative colitis (UC). Although several mucosal species have been implicated in the disease process, the organisms and mechanisms involved are unknown. The aim of this investigation was to characterize mucosal biofilm communities over time and to determine the relationship of these bacteria to patient age and disease severity and duration. Multiple rectal biopsy specimens were taken from 33 patients with active UC over a period of 1 year. Real-time PCR was used to quantify mucosal bacteria in UC patients compared to 18 noninflammatory bowel disease controls, and the relationship between indicators of disease severity and bacterial colonization was evaluated by linear regression analysis. Significant differences were detected in bacterial populations on the UC mucosa and in the control group, which varied over the study period. High clinical activity indices (CAI) and sigmoidoscopy scores (SS) were associated with enterobacteria, desulfovibrios, type E
Clostridium perfringens
, and
Enterococcus faecalis
, whereas the reverse was true for
Clostridium butyricum
,
Ruminococcus albus
, and
Eubacterium rectale
. Lactobacillus and bifidobacterium numbers were linked with low CAI. Only
E. rectale
and
Clostridium clostridioforme
had a high age dependence. These findings demonstrated that longitudinal variations in mucosal bacterial populations occur in UC and that bacterial community structure is related to disease severity.
Evaluation of the Chromogenic Agar chromID C. difficile
Authors: Eckert Catherine , Burghoffer Béatrice , Lalande Valérie , Barbut Frederic
Published: December 2012

Three selective media (chromID C. difficile agar, taurocholate cycloserine cefoxitin agar [TCCA; homemade], and CLO medium) were compared from 406 stool samples of patients suspected of having
Clostridium difficile
infection. The sensitivities of chromID C. difficile agar at 24 h and 48 h, CLO medium, and TCCA were 74.1%, 87%, 85.2%, and 70.4%, respectively.
Development of a Clinically Comprehensive Database and a Simple Procedure for Identification of Molds from Solid Media by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry
Authors: Lau Anna F. , Drake Steven K. , Calhoun Leslie B. , Henderson Christina M. , Zelazny Adrian M.
Published: December 2012

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a powerful tool for the rapid and highly accurate identification of clinical pathogens but has not been utilized extensively in clinical mycology due to challenges in developing an effective protein extraction method and the limited databases available. Here, we developed an alternate extraction procedure and constructed a highly stringent database comprising 294 individual isolates representing 76 genera and 152 species. To our knowledge, this is the most comprehensive clinically relevant mold database developed to date. When challenged with 421 blinded clinical isolates from our institution, by use of the BioTyper software, accurate species-level (score of ≥2.0) and genus-level (score of ≥1.7) identifications were obtained for 370 (88.9%) and 18 (4.3%) isolates, respectively. No isolates were misidentified. Of the 33 isolates (7.8%) for which there was no identification (score of <1.7), 25 were basidiomycetes not associated with clinical disease and 8 were
Penicillium
species that were not represented in the database. Our library clearly outperformed the manufacturer's database that was obtained with the instrument, which identified only 3 (0.7%) and 26 (6.2%) isolates at species and genus levels, respectively. Identification was not affected by different culture conditions. Implementation into our routine workflow has revolutionized our mycology laboratory efficiency, with improved accuracy and decreased time for mold identification, eliminating reliance on traditional phenotypic features.
Molecular Characterization of High-Level Mupirocin Resistance in Staphylococcus pseudintermedius
Authors: Matanović Krešimir , Pérez-Roth Eduardo , Pintarić Selma , Šeol Martinec Branka
Published: December 2012

The genetic analysis of high-level mupirocin resistance (Hi-Mup
r
) in a
Staphylococcus pseudintermedius
isolate from a dog is presented. The Hi-Mup
r
ileS2
gene flanked by a novel rearrangement of directly repeated insertion sequence IS
257
elements was located, together with the aminoglycoside resistance
aacA-aphD
determinant, on a conjugative plasmid related to the pSK41/pGO1 family plasmids.
Performance of Clostridium difficile Toxin Enzyme Immunoassay and Nucleic Acid Amplification Tests Stratified by Patient Disease Severity
Authors: Humphries Romney M. , Uslan Daniel Z. , Rubin Zachary
Published: December 2012

Many clinical laboratories in the United States are transitioning from toxin enzyme immunoassays (EIA) to nucleic acid amplification tests (NAATs) as the primary diagnostic test for
Clostridium difficile
infection (CDI). While it is known that the analytical sensitivity of the toxin EIA is poor, there are limited clinical data on the performance of these assays for patients with mild or severe CDI. Two hundred ninety-six hospital inpatients with diarrhea and clinical suspicion for CDI were tested prospectively by toxin EIA, by
C. difficile
NAAT, and with a reference standard toxigenic culture. Following completion of laboratory testing, retrospective chart reviews were performed to stratify patients into mild and severe disease groups based on clinical criteria using a standard point-based system. One hundred forty-three patients with CDI confirmed by toxigenic culture were evaluated in this study. Among the patients with mild CDI, 49% tested positive by toxin EIA and 98% tested positive by NAAT. Among patients with severe CDI, 58% tested positive by toxin EIA and 98% tested positive by NAAT. Increased CDI disease severity was not associated with an increased sensitivity of EIA (
P
= 0.31). These data demonstrate that toxin EIA performs poorly both for patients with severe CDI and for those with mild CDI and support the routine use of NAAT for the diagnosis of CDI. The presence of stool toxin measured by EIA does not correlate with disease severity.
Education of Phlebotomy Teams Improves Blood Volume in Blood Culture Bottles
Authors: van Ingen Jakko , Hilt Nataliya , Bosboom Ron
Published: December 2012

The volume of blood sampled for blood culture determines its sensitivity. We measured low mean blood volumes in submitted aerobic (8.38 ± 3.88 ml) and anaerobic (7.16 ± 3.83 ml) blood culture bottles. Educational seminars were held for phlebotomy teams, and renewed measurements thereafter revealed significantly higher blood volumes in submitted aerobic (9.77 ± 4.42 ml) and anaerobic (8.30 ± 3.64 ml) bottles. Education of phlebotomy teams improves the blood volume in blood culture bottles and should be part of quality control procedures.