SU-E-T-127: Feasibility Study for Using a 2D Array Detector for All Beam Measurements in Monthly Quality Assurance Procedure for a Uniform Scanning Proton Therapy System

PURPOSE

To develop a more efficient monthly quality assurance (QA) process by utilizing one detector with multiple setups instead of multiple detectors with multiple setups.

METHOD

The Sun Nuclear IC Profiler was used to measure machine output, transverse profiles, and depth-dose profiles. The IC Profiler contains 251 ionization chambers aligned in the X, Y, and diagonal axes, and was designed to measure machine output and transverse profiles. In order to measure depth-doses, a Lucite compensator with an angled surface was fabricated. To test the capability of the detector, a proton beam of 10.5 cm range in water was used. The distal edge coincided with the overall water equivalent depth upstream of the detector on central axis. The measurement was repeated with an additional 1.0 mm of solid water placed in front of the detector. The measured profiles from both measurements were compared to quantify the IC Profiler response for a small range change.

RESULTS

The IC Profiler performs within vendor specification for measuring machine output and transverse profiles. When measuring depth-doses with an angled compensator, the IC profiler measures a change in profile along central axis of 17.0% for a 1.0mm range change. Based on overall reproducibility of the beam delivery system, the IC profiler is capable of detecting 0.3 mm range shift. Therefore, the sensivity of the IC profiler response is suffficient to detect sub millimeter changes in delivered range.

CONCLUSION

The Sun Nuclear IC Profiler is capable of measuring machine output, transverse profiles, and depth-dose profile constancy with a high degree of accuracy and precision. Using a single detector for all beam measurements increases the overall QA efficiency by reducing multiple detector overhead while not sacrificing the accuracy and precision of the measurements.

Risks for impaired cerebral autoregulation during cardiopulmonary bypass and postoperative stroke

BACKGROUND

Impaired cerebral autoregulation may predispose patients to cerebral hypoperfusion during cardiopulmonary bypass (CPB). The purpose of this study was to identify risk factors for impaired autoregulation during coronary artery bypass graft, valve surgery with CPB, or both and to evaluate whether near-infrared spectroscopy (NIRS) autoregulation monitoring could be used to identify this condition.

METHODS

Two hundred and thirty-four patients were monitored with transcranial Doppler and NIRS. A continuous, moving Pearson's correlation coefficient was calculated between mean arterial pressure (MAP) and cerebral blood flow (CBF) velocity, and between MAP and NIRS data, to generate the mean velocity index (Mx) and cerebral oximetry index (COx), respectively. Functional autoregulation is indicated by an Mx and COx that approach zero (no correlation between CBF and MAP); impaired autoregulation is indicated by an Mx and COx approaching 1. Impaired autoregulation was defined as an Mx ≥0.40 at all MAPs during CPB.

RESULTS

Twenty per cent of patients demonstrated impaired autoregulation during CPB. Based on multivariate logistic regression analysis, time-averaged COx during CPB, male gender, Pa(CO(2)), CBF velocity, and preoperative aspirin use were independently associated with impaired CBF autoregulation. Perioperative stroke occurred in six of 47 (12.8%) patients with impaired autoregulation compared with five of 187 (2.7%) patients with preserved autoregulation (P=0.011).

CONCLUSIONS

Impaired CBF autoregulation occurs in 20% of patients during CPB. Patients with impaired autoregulation are more likely than those with functional autoregulation to have perioperative stroke. Non-invasive monitoring autoregulation may provide an accurate means to predict impaired autoregulation. Clinical trials registration. www.clinicaltrials.gov (NCT00769691).

Synovial fluid dynamics with small disc perforation in temporomandibular joint

The articular disc plays an important role as a stress absorber in joint movement, resulting in stress reduction and redistribution in the temporomandibular joint (TMJ). The flow of synovial fluid in the TMJ may follow a regular pattern during movement of the jaw. We hypothesised that the regular pattern is disrupted when the TMJ disc is perforated. By computed tomography arthrography, we studied the upper TMJ compartment in patients with small disc perforation during jaw opening-closing at positions from 0 to 3 cm. Finite element fluid dynamic modelling was accomplished to analyse the pattern of fluid flow and pressure distribution during the movements. The results showed that the fluid flow in the upper compartment generally formed an anticlockwise circulation but with local vortexes with the jaw opening up to 2 cm. However, when the jaw opening-closing reached 3 cm, an abnormal flow field and the fluid pressure change associated with the perforation may increase the risk of perforation expansion or rupture and is unfavourable for self-repair of the perforated disc.

The impact of prior radiotherapy on fatal complications after self-expandable metallic stents (SEMS) for malignant dysphagia due to esophageal carcinoma

The esophageal stent has been demonstrated to serve as a safe and effective palliative treatment for advanced inoperable esophageal carcinoma. However, the safety of esophageal stents in patients with prior radiotherapy (RT) remains debated. This article aims to investigate the impact of prior RT on the incidence of fatal complications after self-expandable metallic stents for palliation of malignant dysphagia because of esophageal carcinoma. Between January 2007 and July 2010, 93 patients with malignant dysphagia because of esophageal carcinoma underwent placement of self-expandable metallic stents in our hospital. Patients were retrospectively separated into two groups: patients with RT before stent placement (RT group, n=57) and patients with no treatment before stent placement (no RT group, n=35).The median survival after stent placement was 77 days (7-842 days) in the RT group and 246 days (15-878 days) in the no RT group. Improvement in dysphagia score was similar in both groups. The fatal complications included fatal gastrointestinal hemorrhage and uncontrolled pneumonia. The incidence of fatal gastrointestinal hemorrhage and uncontrolled pneumonia were 28.1% and 5.7% (P=0.009), 28.1% and 5.7% (P=0.009), respectively. Logistic regression analysis showed a significant interaction between prior RT and fatal gastrointestinal hemorrhage (relative risk 7.82, 95% confidence interval 1.54-39.61; P=0.013). Mortality of massive hemorrhage was 5.7% (2/35), 0% (0/4), 12.5% (3/24), and 44.8% (13/29), respectively, in patients who received 0, 1Gy∼49Gy, 50Gy∼60Gy, and >60Gy (χ(2) =17.761; P=0.000). Logistic regression analysis disclosed prior RT did not significantly increase the risk of uncontrolled pneumonia (relative risk 1.47, 95% confidence interval 0.21-10.12; P=0.697).

Search for the standard model Higgs boson in the decay channel H→ZZ→4ℓ in pp collisions at √s=7 TeV

A search for a Higgs boson in the four-lepton decay channel H→ZZ, with each Z boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range of 110<m(H)<600 GeV. The analysis uses data corresponding to an integrated luminosity of 4.7 fb(-1) recorded by the CMS detector in pp collisions at √s=7 TeV from the LHC. Seventy-two events are observed with four-lepton invariant mass m(4ℓ)>100 GeV (with 13 below 160 GeV), while 67.1±6.0 (9.5±1.3) events are expected from background. The four-lepton mass distribution is consistent with the expectation of standard model background production of ZZ pairs. Upper limits at 95% confidence level exclude the standard model Higgs boson in the ranges of 134-158 GeV, 180-305 GeV, and 340-465 GeV. Small excesses of events are observed around masses of 119, 126, and 320 GeV, making the observed limits weaker than expected in the absence of a signal.

Search for signatures of extra dimensions in the diphoton mass spectrum at the large hadron collider

A search for signatures of extra spatial dimensions in the diphoton invariant-mass spectrum has been performed with the CMS detector at the LHC. No excess of events above the standard model expectation is observed using a data sample collected in proton-proton collisions at √s=7 TeV corresponding to an integrated luminosity of 2.2 fb(-1). In the context of the large-extra-dimensions model, lower limits are set on the effective Planck scale in the range of 2.3-3.8 TeV at the 95% confidence level. These limits are the most restrictive bounds on virtual-graviton exchange to date. The most restrictive lower limits to date are also set on the mass of the first graviton excitation in the Randall-Sundrum model in the range of 0.86-1.84 TeV, for values of the associated coupling parameter between 0.01 and 0.10.

Oral DNA vaccination of rainbow trout, Oncorhynchus mykiss (Walbaum), against infectious haematopoietic necrosis virus using PLGA [Poly(D,L-Lactic-Co-Glycolic Acid)] nanoparticles

A DNA vaccine against infectious haematopoietic necrosis virus (IHNV) is effective at protecting rainbow trout, Oncorhynchus mykiss, against disease, but intramuscular injection is required and makes the vaccine impractical for use in the freshwater rainbow trout farming industry. Poly (D,L-lactic-co-glycolic acid) (PLGA) is a U.S. Food and Drug Administration (FDA) approved polymer that can be used to deliver DNA vaccines. We evaluated the in vivo absorption of PLGA nanoparticles containing coumarin-6 when added to a fish food pellet. We demonstrated that rainbow trout will eat PLGA nanoparticle coated feed and that these nanoparticles can be detected in the epithelial cells of the lower intestine within 96 h after feeding. We also detected low levels of gene expression and anti-IHNV neutralizing antibodies when fish were fed or intubated with PLGA nanoparticles containing IHNV G gene plasmid. A virus challenge evaluation suggested a slight increase in survival at 6 weeks post-vaccination in fish that received a high dose of the oral vaccine, but there was no difference when additional fish were challenged at 10 weeks post-vaccination. The results of this study suggest that it is possible to induce an immune response using an orally delivered DNA vaccine, but the current system needs improvement.

Development of primary central nervous system lymphoma in an HIV-infected patient after multiple opportunistic infections

A 35-year-old Chinese man presented to medical attention with fever, cough and shortness of breath and HIV infection. His CD4+ lymphocyte count was 28 cells/μL and his HIV viral load was 386,891 copies/mL. Diagnosis of tuberculosis, Pneumocystis jiroveci pneumonia, mycobacterium avium complex, fungal infection and cytomegalovirus retinitis were confirmed according to the symptoms, laboratory results and radiology. After therapy for all these opportunistic infections, his symptoms were relieved. In addition, highly active antiretroviral therapy (HAART) was also initiated two weeks after his admission. The patient had a headache two months after admission and the magnetic resonance image of the brain showed left frontal lobe hypodensity. The patient then accepted brain biopsy and the pathological result proved to be primary central nervous system lymphoma). The patient refused further therapy and lost in our follow-up.

Noggin is required for early development of murine upper incisors

BMP signaling plays crucial roles in the development of many organs, including the tooth. Equally important is BMP signaling homeostasis, as demonstrated by multiple organ defects in mice lacking the extracellular BMP antagonist Noggin. Here, we show that Noggin is initially expressed in the maxillary mesenchyme adjunct to the upper incisor at the initiation stage, and then in the developing teeth, including incisors and molars, from the bud stage. Noggin mutants develop normal molars and mandibular incisors, but form a single, medially located upper incisor that is arrested at the late bud stage. Histological and molecular marker analyses demonstrated that two distinct upper incisor placodes initiate independently at E11.5, but begin to fuse at E12.5, coupling with elevated cell proliferation rates in the developing tooth germs. We further found that Chordin and Gremlin, two other BMP antagonists, are co-expressed with Noggin in the developing lower incisor and molar teeth. These observations indicate the importance of BMP signaling homeostasis, and suggest a functional redundancy between BMP antagonists during tooth development.

Review of key findings from the Singapore Malay Eye Study (SiMES-1)

INTRODUCTION

This study highlights the key epidemiological findings from the Singapore Malay Eye Study (SiMES-1).

METHODS

SiMES-1 was a cross-sectional, population-based epidemiological study on eye diseases. It was performed on 3,280 randomly selected Malay adults living in the south-western part of Singapore. All study participants underwent various validated questionnaires and detailed eye examinations. A review of all papers published from SiMES-1 was performed.

RESULTS

A total of 24.6% of the study population had myopia, while 35.3% had hyperopia and 39.4% had astigmatism. 20.4% of the population had under-corrected refractive error. 1,338 (45.7%) participants were diagnosed to have cataracts in at least one eye. 8.6% of the study population had undergone cataract surgery in either eye, while 4.7% had bilateral cataract surgery. 150 (4.6%) participants were diagnosed to have glaucoma, of which primary open angle glaucoma was the most common type (3.2% of the study population), followed by secondary glaucoma (0.8%) and primary angle closure glaucoma (0.2%). Pterygium was diagnosed in 508 out of 3,266 study participants, giving a prevalence rate of 15.6%. The presence of diabetic retinopathy was observed in 421 (12.9%) out of 3,265 study participants. 183 (5.6%) study participants had some degree of age-related macular degeneration (AMD), of which 23 (0.7%) were classified as having late AMD.

CONCLUSION

This paper provides a summary of the prevalence of common eye diseases among the Singaporean adult Malay population and provides data useful for public health education and disease prevention.

Telocytes in trachea and lungs

We show the existence of a novel type of interstitial cell-telocytes (TC) in mouse trachea and lungs. We used cell cultures, vital stainings, as well as scanning electron microscopy (SEM), transmission electron microscopy (TEM) and immunohistochemistry (IHC). Phase contrast microscopy on cultured cells showed cells with unequivocally characteristic morphology of typical TC (cells with telopodes-Tp). SEM revealed typical TC with two to three Tp-very long and branched cell prolongations. Tp consist of an alternation of thin segments (podomers) and thick segments (podoms). The latter accommodate mitochondria (as shown by Janus Green and MitoTracker), rough endoplasmic reticulum and caveolae. TEM showed characteristic podomers and podoms as well as close relationships with nerve endings and blood capillaries. IHC revealed positive expression of TC for c-kit, vimentin and CD34. In conclusion, this study shows the presence in trachea and lungs of a peculiar type of cells, which fulfils the criteria for TC.

Search for a vectorlike quark with charge 2/3 in t+Z events from pp collisions at √s=7 TeV

A search for pair-produced heavy vectorlike charge-2/3 quarks, T, in pp collisions at a center-of-mass energy of 7 TeV, is performed with the CMS detector at the LHC. Events consistent with the flavor-changing-neutral-current decay of a T quark to a top quark and a Z boson are selected by requiring two leptons from the Z-boson decay, as well as an additional isolated charged lepton. In a data sample corresponding to an integrated luminosity of 1.14  fb(-1), the number of observed events is found to be consistent with the standard model background prediction. Assuming a branching fraction of 100% for the decay T→tZ, a T quark with a mass less than 475  GeV/c(2) is excluded at the 95% confidence level.

Search for supersymmetry at the LHC in events with jets and missing transverse energy

A search for events with jets and missing transverse energy is performed in a data sample of pp collisions collected at √s=7 TeV by the CMS experiment at the LHC. The analyzed data sample corresponds to an integrated luminosity of 1.14 fb(-1). In this search, a kinematic variable α(T) is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. No excess of events over the standard model expectation is found. Exclusion limits in the parameter space of the constrained minimal supersymmetric extension of the standard model are set. In this model, squark masses below 1.1 TeV are excluded at 95% C.L. Gluino masses below 1.1 TeV are also ruled out at 95% C.L. for values of the universal scalar mass parameter below 500 GeV.

Search for new physics with a monojet and missing transverse energy in pp collisions at √s = 7 TeV

A study of events with missing transverse energy and an energetic jet is performed using pp collision data at a center-of-mass energy of 7 TeV. The data were collected by the CMS detector at the LHC, and correspond to an integrated luminosity of 36 pb(-1). An excess of these events over standard model contributions is a signature of new physics such as large extra dimensions and unparticles. The number of observed events is in good agreement with the prediction of the standard model, and significant extension of the current limits on parameters of new physics benchmark models is achieved.