Traditionally, smear microscopy has been used to estimate bacillary burden in order to assess infectiousness in tuberculosis (TB) patients. Since Xpert MTB assays might replace smear microscopy as ...the first-line diagnostic test for pulmonary tuberculosis, an alternative measure of bacillary load that correlates with smear positivity is needed. This study assessed the correlation between C
(with and without normalization), smear status, culture time-to-positivity (TTP), and clinical factors in patients with Xpert ultra positive sputum during a four-year period. A cut-off C
value for smear positivity was also estimated. 204 samples were included. Strong correlation between both Xpert Ultra C
values (raw and normalized) and smear status was obtained (r = 0.78 and - 0.79, respectively). The association between Raw-C
and TTP was weaker than normalized-C
(N-C
) and TTP (r = 0.50 and r = - 0.70, respectively). A Raw-C
cut-off value of 21.4 was identified with 85.7% (95% CI 65.4-95) sensitivity and 92.9% (95% CI 84.3-96.9) specificity. A N-C
cut-off value of 5.2 yielded a sensitivity of 94.3% (95% CI 86.2-97.8) and specificity of 85.7% (95% CI 65.4-95). Our study demonstrates that Xpert Ultra C
value correlates well with other measures of bacillary load such as smear status or TTP. The correlation with TTP is stronger when the C
value is normalized using the internal control. The proposed N-C
cut-off value of 5.2 shows a better sensitivity than the Raw-CT when predicting smear positive status.
A mixed-signal ASIC for timing and energy measurements with radiation detectors is described. The chip embeds 64 channels, each of which features a charge-sensitive amplifier followed by a ...dual-shaper coupled to low-offset discriminators. A versatile back-end, incorporating low-power Time to Digital Converters and Wilkinson Analog to Digital Converters with derandomizing buffers allows to encode both the time of arrival and the charge of the input signal. The ASIC is designed for a maximum detector capacitance of 100 pF and an event rate in excess of 60 kHz per channel. A peak detector samples the input signal with an excellent linearity in the range 5÷55 fC. Charge digitization with Time-over-Threshold is also supported to extend the dynamic range. Fabricated in a 110 nm CMOS process, the chip dissipates 10 mW/channel. The ASIC was primarily developed to readout the cylindrical GEM detector of the BESIII experiment. For its characteristics it can serve however a broad class of radiation sensors, including silicon microstrip detectors.
The CGEM-IT readout chain Amoroso, A.; Baldini Ferroli, R.; Balossino, I. ...
Journal of instrumentation,
08/2021, Letnik:
16, Številka:
8
Journal Article
Recenzirano
Odprti dostop
An innovative Cylindrical Gas Electron Multiplier (CGEM) detector is under construction for the upgrade of the inner tracker of the BESIII experiment. A novel system has been worked out for the ...readout of the CGEM detector, including a new ASIC, dubbed TIGER -Torino Integrated GEM Electronics for Readout, designed for the amplification and digitization of the CGEM output signals. The data output by TIGER are collected and processed by a first FPGA-based module, GEM Read Out Card, in charge of configuration and control of the front-end ASICs. A second FPGA-based module, named GEM Data Concentrator, builds the trigger selected event packets containing the data and stores them via the main BESIII data acquisition system. The design of the electronics chain, including the power and signal distribution, will be presented together with its performance.
TOFPET ASIC for PET applications Rolo, MD; Bugalho, R; Goncalves, F ...
Journal of instrumentation,
02/2013, Letnik:
7, Številka:
2
Journal Article
Recenzirano
Odprti dostop
A 64-channel ASIC for Time-of-Flight Positron Emission Tomography (TOF PET) imaging has been designed and simulated. The circuit is optimized for the readout of signals produced by the scintillation ...of a L(Y)SO crystal optically coupled to a silicon photomultiplier (SiPM). Developed in the framework of the EndoTOFPET-US collaboration 1, the ASIC is integrated in the external PET plate and performs timing, digitization and data transmission for 511 keV and lower-energy events due to Compton scattering. Multi-event buffering capability allows event rates up to 100 kHz per channel. The channel cell includes a low input impedance low-noise current conveyor and two trans-impedance amplifier branches separately optimized for energy and time resolution. Two voltage mode discriminators generate respectively a fast trigger for accurate timing and a signal for time-over-threshold calculation, used for charge measurement. The digitization of these signals is done by two low-power TDCs, providing coarse and fine time stamps that are saved into a local register and later managed by a global controller, which builds-up the 40-bit event data and runs the interface with the data acquisition back-end. Running at 160 MHz the chip yields a 50 ps time binning and dissipates approximately 7 mW per channel (simulated for 40 kHz event rate p/channel) for high capacitance photodetectors (9 mm super(2) active area Silicon Photomultiplier with 320 pF terminal capacitance). The minimum SNR of 23.5 dB expected with this capacitance should allow triggering on the first photoelectron to achieve the envisaged timing performance for a TOF-PET system.
We present a readout and digitization ASIC featuring low-noise and low-power for time-of flight (TOF) applications using SiPMs. The circuit is designed in standard CMOS 110 nm technology, has 64 ...independent channels and is optimized for time-of-flight measurement in Positron Emission Tomography (TOF-PET). The input amplifier is a low impedance current conveyor based on a regulated common-gate topology. Each channel has quad-buffered analogue interpolation TDCs (time binning 20 ps) and charge integration ADCs with linear response at full scale (1500 pC). The signal amplitude can also be derived from the measurement of time-over-threshold (ToT). Simulation results show that for a single photo-electron signal with charge 200 (550) fC generated by a SiPM with 320 pF capacitance the circuit has 24 (30) dB SNR, 75(39) ps r.m.s. resolution, and 4(8) mW power consumption. The event rate is 600 kHz per channel, with up to 2 MHz dark counts rejection.
Tuberculosis is a global public health problem. Extra-pulmonary tuberculosis accounts for an increasing proportion of cases worldwide, although information about epidemiological, clinical, or ...microbiological factors is lacking.
We conducted a retrospective observational study of tuberculosis cases diagnosed between 2016 and 2021, classified into Pulmonary and Extra-pulmonary tuberculosis. Univariable and multivariable logistic regression models were used to investigate risk factors of Extra-pulmonary tuberculosis.
20.9% of overall cases were classified as Extra-pulmonary tuberculosis, with a rising trend from 22.6% in 2016 to 27.9% in 2021. Lymphatic tuberculosis accounted for 50.6% of cases, followed by pleural tuberculosis (24.1%). 55.4% of cases belonged toforeign-born patients. Microbiological culture tested positive in 92.8% of Extra-pulmonary cases. Logistic regression analysis showed that women were more predisposed to develop Extra-pulmonary tuberculosis (aOR 2.46, 95% CI 1.45–4.20) as well as elderly patients (aged ≥ 65 years) (aOR 2.47, 95% CI 1.19–5.13) and persons with previous history of tuberculosis (4.99, 95% CI 1.40–17.82).
Extra-pulmonary Tuberculosis have increased within our study period. A profound decline occurred in 2021 tuberculosis cases, probably due to COVID-19. Women, elderly population, and persons with previous history of tuberculosis are at higher risk of developing Extra-pulmonary tuberculosis in our setting.
Positron emission tomography is one of the most mature techniques for monitoring the particles range in hadron therapy, aiming to reduce treatment uncertainties and therefore the extent of safety ...margins in the treatment plan. In-beam PET monitoring has been already performed using inter-spill and post-irradiation data, i.e. while the particle beam is off or paused. The full beam acquisition procedure is commonly discarded because the particle spills abruptly increase the random coincidence rates and therefore the image noise. This is because random coincidences cannot be separated by annihilation photons originating from radioactive decays and cannot be corrected with standard random coincidence techniques due to the time correlation of the beam-induced background with the ion beam microstructure. The aim of this paper is to provide a new method to recover in-spill data to improve the images obtained with full-beam PET acquisitions. This is done by estimating the temporal microstructure of the beam and thus selecting input PET events that are less likely to be random ones. The PET detector we used was the one developed within the INSIDE project and tested at the CNAO synchrotron-based facility. The data were taken on a PMMA phantom irradiated with 72 MeV proton pencil beams. The obtained results confirm the possibility of improving the acquired PET data without any external signal coming from the synchrotron or ad hoc detectors.
Display omitted
•Range monitoring is necessary to fully exploit hadrontherapy advantages.•The Monte Carlo (MC) simulation tool for the INSIDE in-beam PET scanner is described.•The Monte Carlo tool ...provides images directly comparable with the experimental ones.•The comparison with in vivo experimental data validates the tool reliability.•The simulation information is already reliable after the first half of the treatment.
Hadrontherapy is a method for treating cancer with very targeted dose distributions and enhanced radiobiological effects. To fully exploit these advantages, in vivo range monitoring systems are required. These devices measure, preferably during the treatment, the secondary radiation generated by the beam-tissue interactions. However, since correlation of the secondary radiation distribution with the dose is not straightforward, Monte Carlo (MC) simulations are very important for treatment quality assessment.
The INSIDE project constructed an in-beam PET scanner to detect signals generated by the positron-emitting isotopes resulting from projectile-target fragmentation. In addition, a FLUKA-based simulation tool was developed to predict the corresponding reference PET images using a detailed scanner model.
The INSIDE in-beam PET was used to monitor two consecutive proton treatment sessions on a patient at the Italian Center for Oncological Hadrontherapy (CNAO). The reconstructed PET images were updated every 10 s providing a near real-time quality assessment. By half-way through the treatment, the statistics of the measured PET images were already significant enough to be compared with the simulations with average differences in the activity range less than 2.5 mm along the beam direction. Without taking into account any preferential direction, differences within 1 mm were found.
In this paper, the INSIDE MC simulation tool is described and the results of the first in vivo agreement evaluation are reported. These results have justified a clinical trial, in which the MC simulation tool will be used on a daily basis to study the compliance tolerances between the measured and simulated PET images.
Abstract
A Cylindrical Gas Electron Multiplier (CGEM) is under construction for the upgrade of the BESIII inner tracker. A preliminary simulation of the CGEM signal before the frond-end electronics ...has been worked out by making some sampling models from the beforehand Garfield++ simulation. The electronics response functions are implemented making the simulation of CGEM more complete. By comparing the cosmic-ray data acquired by two layers of CGEM and the simulation, the micro-sector effect is simulated and some key parameters in the sampling models are fine tuned in this order: gain, charge sharing, charge fluctuation and electron diffusion. A general agreement is achieved between the cosmic-ray data and the simulation with these improvements.
PDF
