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Chest radiography remains the most often utilized radiological modality in the neonatal intensive care unit. Neonates are more radiosensitive and are at higher risk of cancer than adults. In addition, they have a longer life expectancy, which increases the risk of cancer. Therefore, it is essential to protect neonates from radiation hazards. The study aims to assess the effectiveness of using high HKVp technique on reducing radiation dose to neonates undergoing Antero-posterior (AP) chest x-rays. The experiment used a newborn anthropomorphic phantom to simulate a neonate. Chest x-ray images were acquired using different combinations of KVp and mAs. Dose area product (DAP) was recorded in the Digital Imaging and Communications in Medicine (DICOM) header. The effective dose was determined using Monte Carlo simulation. Subjective assessment of image quality was evaluated by three radiologists blindly. The Objective assessment of image quality uses the calculation of the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR). The reduction in the DAP and effective dose at 50 KVp was 26.7% and 19.2%, respectively and for 60 KVp it was 22.9 and 20.2, respectively. While, the reduction in the DAP and effective dose at 70 KVp was 40% and 26%, respectively. There were no significant differences in the means of the DAP, SNR, CNR, and effective dose among different combinations of KVp and mAs. The use of the high KVp technique can play an important role in reducing radiation dose without significant loss of image quality. • Use of the high KVp technique can reduce radiation dose without significant loss of image quality. • At 70 KVp, the DAP and effective dose reduced by 40% and 26%, respectively. • Use of high kVp showed no significant difference in SNR, CNR and radiation dose. • Effort should be made to reduce patients' dose without compromising diagnostic outcome. [ABSTRACT FROM AUTHOR]

Sparse spatial selection (SSS) allows insertions of new database objects and dynamically promotes some of the new objects as pivots. In this paper, we argue that SSS has fundamental problems that result in poor query performance for clustered or otherwise skewed distributions. Real datasets have often been observed to show such characteristics. We show that SSS has been optimized to work for a symmetrical, balanced distribution and for a specific radius value. Our main contribution is offering a new pivot promotion scheme that can perform robustly for clustered or skewed distributions. We show that our new indexing scheme performs significantly better than tree-based dynamic structures while having lower insertion costs. [ABSTRACT FROM AUTHOR]

This study compares the real-time dosimetric performance of a bpw34 photodiode (PD) and cold white light-emitting diodes (LEDs) based on diagnostic X-ray-induced signals. Signals were extracted when both the transducers were under identical exposure settings, including source-to-detector distance (SDD), tube voltage (kVp), and current-time product (mAs). The transducers were in a photovoltaic configuration, and black vinyl tape was applied on transducer active areas as a form of optical shielding. X-ray beam spectra and energies were simulated using Matlab-based Spektr functions. Transducer performance analysis was based on signal linearity to mAs and air kerma, and sensitivity dependence on absorbed dose, energy, and dose rate. Bpw34 PD and cold white LED output signals were 84.8% and 85.5% precise, respectively. PD signals were 94.7% linear to mAs, whereas LED signals were 91.9%. PD and LED signal linearity to dose coefficients were 0.9397 and 0.9128, respectively. Both transducers exhibited similar dose and energy dependence. However, cold white LEDs were 0.73% less dose rate dependent than the bpw34 PD. Cold white LEDs demonstrated potential in detecting diagnostic X-rays because their performance was similar to that of the bpw34 PD. Moreover, the cold white LED array's dosimetric response was independent of the heel effect. Although cold white LED signals were lower than bpw34 PD signals, they were quantifiable and electronically amplifiable. • LED-based diagnostic X-ray detection and dosimetry is innovative. • LEDs generated lower radiation-induced signals than the photodiode. • Both the photodiode and LEDs exhibited similar dose and energy dependence. • LEDs were slightly less dose rate dependent than the photodiode. • Both the photodiode and LED radiation-induced signals were ~ 85% precise. [ABSTRACT FROM AUTHOR]