Noise Index Research Articles

From the perspective of perceptual speech quality: The robustness of frequency bands to noise.

Speech quality is one of the main foci of speech-related research, where it is frequently studied with speech intelligibility, another essential measurement. Band-level perceptual speech intelligibility, however, has been studied frequently, whereas speech quality has not been thoroughly analyzed. In this paper, a Multiple Stimuli With Hidden Reference and Anchor (MUSHRA) inspired approach was proposed to study the individual robustness of frequency bands to noise with perceptual speech quality as the measure. Speech signals were filtered into thirty-two frequency bands with compromising real-world noise employed at different signal-to-noise ratios. Robustness to noise indices of individual frequency bands was calculated based on the human-rated perceptual quality scores assigned to the reconstructed noisy speech signals. Trends in the results suggest the mid-frequency region appeared less robust to noise in terms of perceptual speech quality. These findings suggest future research aiming at improving speech quality should pay more attention to the mid-frequency region of the speech signals accordingly.

“How much noise can a human being stand?”

This article places noise and sound at the center of an inquiry into the environmental impact of military occupations. Drawing from the example of the US occupation of Culebra, Puerto Rico (1902–75), I argue that conflicts over the impact of noise index epistemological uncertainties about the status of sound as a scientific object of study. Reading the records of the Electro-Acoustic and Psycho-Acoustic Laboratories at Harvard University in the 1940s against a Senate hearing conducted in the 1970s underscores the ways noise as a source of harm was both obvious to civilians in militarized zones and illegible as such to military and government officials. In part this was due to the science of sound itself, which had failed to account for the potential harm of military sound to humans and more than humans alike.

Associação entre limitação no trabalho por causa da voz, condições de trabalho e vulnerabilidade social de escolas metropolitanas no Brasil

ABSTRACT Purpose To verify the prevalence of limitations at work due to the voice of Brazilian basic education teachers in metropolitan schools and the association with working hours, self-reported noise and Social Vulnerability Index (SVI) in schools. Methods Cross-sectional observational study with a probabilistic sample of Brazilian teachers. A total of 4979 teachers from metropolitan schools participated and the following variables were analyzed: age, gender, level of education, workday for 40 hours/week or more, perception of intense noise with the need to raise the voice and SVI of the municipality. Descriptive analysis and multivariate Poisson regression model with robust variance were performed and a significance level of 5%. Results The Brazilian prevalence of limitation at work due to voice was 20.37%. It was found that there was a statistically significant difference between limitation at work due to voice and being female, elementary school level or combined levels, 40 or more working hours , perception of raising one’s voice in the presence of intense noise at work and medium and high/very high SVI. Conclusion Of every 100 teachers, approximately 20 reported limitations at work due to voice in Brazil, and considering the federative units, higher prevalences were observed in the North and Northeast regions. Being female, working 40 hours or more per week, teaching elementary school or at combined levels, perceiving raising one’s voice due to intense noise, and working in schools located in regions with medium, high/very high SVI increased the prevalence of perception of limitation at work due to vocal problems.

Validation of Optimal Imaging Conditions for Coronary Computed Tomography Angiography Using High-definition Mode and Deep Learning Image Reconstruction Algorithm

To verify the optimal imaging conditions for coronary computed tomography angiography (CCTA) examinations when using high-definition (HD) mode and deep learning image reconstruction (DLIR) in combination. A chest phantom and an in-house phantom using 3D printer were scanned with a 256-row detector CT scanner. The scan parameters were as follows - acquisition mode: ON (HD mode) and OFF (normal resolution [NR] mode), rotation time: 0.28 s/rotation, beam coverage width: 160 mm, and the radiation dose was adjusted based on CT-AEC. Image reconstruction was performed using ASiR-V (Hybrid-IR), TrueFidelity Image (DLIR), and HD-Standard (HD mode) and Standard (NR mode) reconstruction kernels. The task-based transfer function (TTF) and noise power spectrum (NPS) were measured for image evaluation, and the detectability index (d') was calculated. Visual evaluation was also performed on an in-house coronary phantom. The in-plane TTF was better for the HD mode than for the NR mode, while the z-axis TTF was lower for DLIR than for Hybrid-IR. The NPS values in the high-frequency region were higher for the HD mode compared to those for the NR mode, and the NPS was lower for DLIR than for Hybrid-IR. The combination of HD mode and DLIR showed the best value for in-plane d', whereas the combination of NR mode and DLIR showed the best value for z-axis d'. In the visual evaluation, the combination of NR mode and DLIR showed the best values from a noise index of 45 HU. The optimal combination of HD mode and DLIR depends on the image noise level, and the combination of NR mode and DLIR was the best imaging condition under noisy conditions.

Traffic noise pollution level at selected cities in Kelantan

In densely populated areas where the communities strive, noise pollution has become a critically alarming problem and must be addressed accordingly. The World Health Organization also recognizes it as a concerning public health issue in the urban areas. More often, the effects of noise towards the residents living in the vicinity areas can include the worsening of life quality and result in physiological effects, among others. We hypothesize that the increasing traffic results in higher noise pollution levels. The aim of this study was to quantify traffic noise pollution using noise pollution level (NPL) and traffic noise index (TNI) at selected cities in Kelantan, namely Tanah Merah and Pasir Mas. A sound level meter (TENMARS TM102) was used to record the noise level, and the traffic volumes were determined by using tally counts. The noises were measured during four different peak hours from 08:00 to 22:00. The recorded noise levels were compared with the Department of Environment (DOE) recommended limit of 60 dB(A) during daytime. The traffic noise pollution level was confirmed to be higher when the traffic volume counts increased. The results suggest proper mitigation measures such as enforcing zoning regulations and promoting public awareness campaigns were needed to reduce the noise pollution level.

An attempt to estimate the noises in Homeopathic Pathogenetic Trials by employing the Jaccard Similarity Index and Noise Index.

Background: The critical task of researchers conducting double-blinded, randomized, placebo-controlled homeopathic pathogenetic trials is to segregate the signals from the noises. The noises are signs and symptoms due to factors other than the trial drug; signals are signs and symptoms due to the trial drug. Unfortunately, the existing tools: the criteria for a causal association of symptoms with the tested medicine, qualitative pathogenetic index, quantitative pathogenetic index, and the pathogenic index, have limitations in analyzing the symptoms of the placebo group as a comparator resulting in inadequate segregation of the noises. Hence, proposing the Jaccard similarity index and Noise index for analyzing the symptoms of the placebo group as a comparator.
 Methods: This index is the ratio of the number of common elements among the placebo and intervention groups to the aggregated number of elements in these groups. The Noise index is the ratio of common elements among the placebo and intervention group to the total elements of the intervention group. The Homeopathic pathogenetic trials of Plumbum metallicum, Piper methysticum, and Hepatitis C nosode were selected for experimenting with the computation of the Jaccard similarity index and Noise index.
 Results: The Jaccard similarity index shows that 8% of Plumbum metallicum's elements, 10.7% of Piper methysticum's elements, and 19.3% of Hepatitis C nosode's elements were similar to the placebo group when elements of both the groups (intervention and placebo) aggregated. The noise index shows that 10.7 % of Plumbum metallicum's elements, 13.9% of Piper methysticum's elements, and 25.7% of Hepatitis C nosode's elements were similar to the placebo group.
 Conclusion: The Jaccard similarity index and Noise index might be considered an additional tool to analyze the symptoms of the placebo group as a comparator resulting in better noise segregation.

Association between occupational noise and obesity: a retrospective cohort study in China.

To determine the relationship between occupational noise, and obesity and body mass index (BMI) changes. Baseline data were collected from participants (n = 1264) who were followed for 6years in a retrospective study. The noise exposure level (LAeq,8h) was determined by equivalent continuous weighted sound pressure levels using the fixed-point surveillance method for noise monitoring. The cumulative noise exposure (CNE) level was determined using the equal energy formula, which is based on exposure history and level. The incidence of obesity at low (RR = 2.364, 95% CI 1.123-4.739]), medium (RR = 3.921, 95% CI 1.946-7.347]), high (RR = 5.242, 95% CI 2.642-9.208]), and severe noise levels (RR = 9.322, 95% CI 5.341-14.428]) was higher risk than the LAeq,8h control level. The risk of obesity among participants exposed to low (RR = 2.957, 95% CI 1.441-6.068]) and high cumulative noise levels (RR = 7.226, 95% CI 3.623-14.415]) was greater than the CNE control level. For every 1dB(A) increase in LAeq,8h, the BMI increased by 0.063kg/m2 (95% CI 0.055-0.071], SE = 0.004). For every 1dB(A) increase in the CNE, the BMI increased by 0.102kg/m2 (95% CI 0.090-0.113], SE = 0.006). Occupational noise is related to the incidence of obesity. The occupational noise level and occupational noise cumulative level were shown to be positively correlated with an increase in BMI.

Effect of Noise, Blood Glucose, and Body Mass Index on Lactate Levels in Textile Industry Workers

Occupational fatigue remains a prevalent concern in occupational health. This study investigated the association between noise intensity, blood glucose levels, body mass index (BMI), and lactate levels as an indicator of occupational fatigue among textile industry workers in Surakarta, Indonesia. An analytical observational study with a cross-sectional design was conducted, with 82 participants recruited from a local textile industry. Multivariate analysis using multiple binary logistic regression revealed that noise intensity, blood glucose levels, and BMI were significant risk factors for occupational fatigue, as indicated by elevated lactate levels. These findings highlight the importance of noise reduction measures, a healthy lifestyle, and regular monitoring of blood glucose levels and BMI to mitigate occupational fatigue among textile industry workers

Analysis of noise levels in The Sultan Thaha Jambi Airport Area based on geographical information systems

This research focuses on the noise level at Sultan Thaha Jambi Airport due to aircraft activity which took place from 06.05 to 22.40 WIB. This research started from observation, collecting noise level data and measuring data. The method used is the Weighted Equivalent Continuous Perceived Noise Level (WECPNL) method to measure noise points at each measurement point. Measurement points were taken at 6 points for 24 hours/14 days. This research also uses a Geographic Information System (GIS) to map the distribution of noise levels. The research results showed that the highest noise values ​​occurred in the air side area and occurred during holidays. WECPNL results from April 27 to May 10 showed that the average noise index reached 58 to 59 (dB), close to the noise quality standard of 55 (dB). In the Liverpool airport and residential area, the purple color has an index <67 (dBA), which indicates low noise levels, while red indicates high noise level due to airport activities. WECPNL results from May 1 to May 5 had a noise index of 70.5 (dBA). 2D and 3D contour maps show that the darker the color, the lower the noise level, while the fainter the color, the higher the noise level. The benefits of this research are: For people living in the Jambi Sultan Thaha Airport area, it is hoped that they will be able to find out what effects can be caused by airport noise and know the regional zones that fall into noise level categories I, II, III.

A mini review of the Chinese literature on noise maps

According to the recently published 'Noise pollution prevention and control action plan' by the Chinese government, all the prefecture-level cities should achieve acoustic environmental quality monitoring for the functional areas. The noise map is essential for noise monitoring, evaluation and regulation. This paper reviews the Chinese literature on noise maps in the past three decades, particularly concerning noise indexes. Most studies adopted A-weighted equivalent sound pressure level (LAeq), whereas a few investigated noise pollution index (NPI), noise impact index (NII), and index of noise evaluation model (ANEM) by considering the influence of different functional areas, the distribution of people, and both, respectively. However, studies are mostly based on sound energy parameters and rarely have considered the differences in subjective discomfort for the dynamic evolvement of changing populations among different areas and periods. The appropriate noise evaluation index for noise maps, which can reasonably reflect the influence of noise on people in various functional areas, merits further research. Recommendations for future work in this area are presented.

Environmental controls of air-conditioned noise with the aid of the Psychoacoustics Perception Scale (PPS)

It is known that an air-conditioning system is an essential component of modern buildings for maintaining good indoor environmental quality. However, the adverse effect due to air-conditioned noise can offset its benefits. Although several noise indices such as Noise Criteria (NC), Noise Rating (NR), Room Criteria (RC), and A-weighted equivalent continuous sound pressure level (LAeq) have been developed to assess the acceptability of indoor noise environments, the noise feature of the environments and its psychological impacts on the occupants are not comprehensively evaluated. Psychoacoustics Perception Scale (PPS) is a psychometric tool to assess the psychological impacts about general judgment (Evaluation, E), sensitivity to the magnitude (Potency, P), and sensation of the temporal and spectral compositions (Activity, A) of noise on occupants. This study aimed to evaluate the air-conditioning building environments by using the traditional noise indices, psychoacoustic metrics, and the PPS. The significant correlations were found between the objective and subjective data. The results of the study provided the useful knowledge on future designs of the environmental controls of air-conditioned noise.

Impacts of the covid lockdown on the soundscape of an urban area: noise, psychoacoustic metrics and ecoacoustic indices

Urban noise is both a serious environmental pollutant affecting ecological systems, and a major public health issue impacting millions of people worldwide. Noise levels are increasing and, without action, will lead to significant disruption of ecosystem services and a multitude of health effects such as cardiovascular diseases, hypertension, hearing impairment, preterm births, decreased cognitive performance, sleep disturbance, annoyance, anxiety and depression. The covid pandemic presented a unique opportunity to study the soundscape of cities with reduced human activity, especially the decreased use of motor vehicles, a primary source of urban noise. In this paper, we compare noise metrics, psychoacoustic indices and ecoacoustic indices derived from urban transect walks undertaken during (2020) and after (2022) the covid lockdowns in Southampton, UK. In this way, we assess not only noise levels, but also changes to the quality of the urban soundscape. Our aim is to understand the "art of the possible" in improving the soundscapes of active cities, and to help better inform urban planners and health practitioners in tackling a serious yet often hidden environmental crisis.

Analysis on the Effect of Phase Noise on the Performance of Satellite Communication and Measurement System

An oscillator is a key component of a satellite communication measurement and control system, performing symmetry precisely as a time frequency reference. At the same time, the phase noise index has a close coupling relationship with the overall performance of the entire system, while persistently breaking the symmetry property of the oscillator during work. It is very important to study and reasonably allocate the phase noise index. According to the theoretical formula of phase noise, this paper analyzes the power law spectral model in the frequency domain and the noise jitter characteristics in the time domain. Using the carrier tracking loop in the measurement system, the frequency domain transfer model of phase noise is established, and typical analysis results are given. A discrete fractional integration algorithm is proposed, which can generate the phase noise time domain sequence under the given power law spectral model coefficients. The proposed algorithm is more realistic compared with the previous numerical calculation method, and has sufficient accuracy compared with the results of the instrument. After frequency domain conversion, the RMS deviation between the simulated noise sequence in the frequency domain and the measured single sideband power spectral density is less than 2.5 dB, indicating that the phase noise sequence can reflect the frequency domain characteristics more completely. A communication measurement simulation system is built, and a discrete sequence simulation analysis method combining frequency domain and time domain is provided, and the coupling relationship of key indicators such as phase noise, thermal noise, communication data rate, modulation method and bit error rate is synthesized. The results show that the BER of the QPSK/BPSK communication system will not be significantly reduced if the phase jitter RMS caused by the phase noise is less than 5 degrees, so 5 degrees can be used as a reference for the decomposition of the carrier SSB phase noise index. The simulation results have been successfully applied to a satellite inter-satellite link system, which has universal practical application value.

Statistical Analysis of Traffic Noise Status at Selected Junctions in Port Harcourt Metropolis

Traffic noise is one of the dominant forms of environmental pollution in most urban cities that adversely affect human health globally. The traffic noise emanating from motor vehicles has become a common health problem in many metropolitan cities in developing countries of the world. This study evaluated traffic noise at selected major junctions (Rumuola, Garisson, Boro Pack, and Lagos Bus stop) in Port Harcourt Metropolis. Traffic noise levels at four congested junctions and a control junction in the Metropolis were monitored using a digital sound level meter. Noise indices, L10, L50, L90 equivalent noise levels (Leq), noise climate (NC), noise pollution index (NPI); traffic noise index (TNI); noise pollution level (Lnp); day-evening-night equivalent metric (LDEN) and percentage highly annoyed (%HA) were statistically determined. Traffic noise at Rumuola junction showed traffic noise ranging from 51.9 to 107.9dBA with a mean deviation of 91.3±8.4dBA; traffic noise at Garrison junction ranged from 52.8 to 107.6dBA with a mean deviation of 88.5±9.7dBA; Boro Park junction showed traffic noise ranging from 48.9 to 106.4dBA with a mean deviation of 83.7±10.1dBA; Lagos Bus Stop junction ranged from 45.4 to 94.9dBA with a mean deviation of 81.5±10.8dBA; while the Control junction (Ibadan Street junction)showed a traffic noise ranging from 48.4 to 61.3dBA with a mean deviation of 51.6±5.3dBA. Noise levels at the studied junctions were significantly high and exceeded permissible limit compared to the control junction (p-value = 0.00485; 95%CI). L10 (94.8dBA), L50 (86.8dBA), L90 (76.1dBA) and Leq (92.4dBA) were highest at Rumuola junction and lowest at Control junction (with 57.3dBA, 52.8dBA, 48.4dBA and 54.1dBA, respectively). Computed NPI values (1.25-1.34) indicated high traffic noise levels at the four junctions and low (0.77) at the control junction; Lnp values (105.0-116.6dBA) indicated high traffic noise pollution at the four junctions and low (63.0dBA) at the control junction; TNI values (120.9-138.5) indicated high traffic noise impacts at the four junctions and low (54.0) at the control junction. Computed LDEN and %HA indicated high level of traffic noise annoyance to the four junctions. The study revealed high traffic noise pollution at the four junctions that may significantly affect public health and therefore requires further investigation by concerned authorities to assess the health effects of traffic noise on the surrounding residents and traders at the studied junction.

PENGARUH PARAMETER CT UNTUK OPTIMISASI DOSIS RADIASI DAN KUALITAS CITRA CT SCAN PADA PEMERIKSAAN KEPALA DAN ABDOMEN DI RS SENTRA MEDIKA CIBINONG

Radiation dose optimization in head and abdomen examinations is an effort to ensure safety and minimize the risks of exposure to CT Scan radiation. Therefore, various efforts are necessary to reduce radiation doses. This study aims to obtain an optimal radiation dose while maintaining image quality. The optimization efforts were carried out by the radiology team at RS Sentra Medika Cibinong using the CT Scan GE OPTIMA 660. The method involved scanning head and abdomen phantoms using optimization factors (Noise Index, Slice Thickness, Pitch, and Rotation Time) and then analyzing the images for noise uniformity, MTF (Modulation Transfer Function), and NPS (Noise Power Spectrum) while recording radiation dose in terms of CTDIvol and DLP. Based on the research data using GE standard Head protocol and respective optimizations, the radiation dose values obtained were CTDIVol = 68 mGy; DLP = 2042 mGy.cm and CTDIVol = 48 mGy; DLP = 1662 mGy.cm. Furthermore, the image quality produced by the GE standard Head protocol and respective optimizations resulted in MTF values of 0.55 (1/mm) and 0.91 (1/mm), noise uniformity of 0.6 HU and 1.6 HU, and NPS deviation of 8.7%. Regarding the Abdomen protocol, using GE standard and respective optimizations, the radiation dose values obtained were CTDIVol = 32 mGy; DLP = 1025 mGy.cm and CTDIVol = 22 mGy; DLP = 955 mGy.cm. Additionally, the image quality produced by the GE standard Abdomen protocol and respective optimizations resulted in MTF values of 0.58 (1/mm) and 0.6 (1/mm), noise uniformity of 0.6 HU and 1.6 HU, and NPS deviation of 7.6%. Thus, the protocols using optimization factors were proven to reduce radiation dose by approximately 41.6-45.4% while maintaining image quality compared to the GE standard protocol, which focuses more on improving image quality rather than optimizing the radiation dose received by patients. Keywords: CT Scan, Optimization Factors, Image Quality, CTDIvol, DLP.

The Design of a Low-Noise, High-Speed Readout-Integrated Circuit for Infrared Focal Plane Arrays

This paper describes the design of a low-noise, high-speed readout-integrated circuit for use in InGaAs infrared focal plane arrays, and analyzes the working principle and noise index of the pixel circuit in detail. The design fully considers the dynamic range, noise, and power consumption of the pixel circuit in which a capacitance transimpedance amplifier structure is adopted as the input stage circuit, and chip fabrication via an XFAB 0.18 µm CMOS process is successfully realized. The ROIC adopts monolithic integration and implements various functions, such as windowing, subsampling, and different integration and readout modes. The ROIC reached an array scale of 32 × 32, a frame rate of 100 Hz, and a readout rate of 20 Mbps with an analog power consumption of less than 52 mW. The measurement results show that the input reference noise can be reduced to 143 e- via the CDS, and the fully customized scheme has certain advantages in the research of high-performance ROICs.

Association of road traffic noise exposure and school childrens’ cognition: A structural equation model approach

This study explores the complex relationship between traffic noise and school children's cognition, acknowledging existing empirical inconsistencies and aiming to contribute to a richer understanding of this pivotal issue. Schools adjacent to noisy roads were selected, and outdoor noise levels were measured employing a Kimo dB300 sound level meter, focusing on noise level indices LAeq, L10, and L90. Subsequent calculations were performed to determine the noise pollution level (Lnp), noise climate (NC), and traffic noise index (TNI), revealing a severe noise exposure when compared to standard guidelines. A perception questionnaire for various noise and acoustic factors influencing cognition was developed, and 1524 student responses were collected. Data analysis incorporated Principal Component Analysis (PCA) and Exploratory Factor Analysis (EFA) for dimension reduction, revealing three latent factors labelled 'annoyance,' 'behaviour,' and 'cognition'. Further, Structural Equation Modeling (SEM) was utilized to explore multivariate relationships between variables and latent factors. Resultant path coefficients were obtained as 0.12, 0.98, and 0.10 for the impact of 'behaviour' and 'annoyance' on 'cognition' and the correlation between 'annoyance' and 'behaviour', respectively. Findings underscore a potent positive impact of annoyance, stemming from acute ambient noise exposure, on the deterioration of children's cognition. While suggesting that ambient noise may be correlated with adverse health impacts due to its influence on cognition, this study emphasizes the pressing necessity for noise mitigation in roadside schools and stringent enforcement of noise pollution guidelines in academic zones.

Optimising image quality in intravenous cerebral cone beam computed tomography.

The efficacy of intravenous cerebral Cone Beam Computed Tomography (IV CBCT) is well established; however, image quality has only ever been authenticated by subjective evaluation. The aim of this study was to quantify the factors pertinent to achieving consistent and optimal image quality when performing IV CBCT. Between 1 March 2021 and 30 October 2022, 79 patients received IV CBCT. These candidates were divided into three main acquisition field size categories (22/32, 42 and 48 cm) according to the clinical indication. The images were analysed using both a quantitative assessment and a subjective evaluation. Here, a comparison of Hounsfield units (HUs), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and noise index was conducted for each study and compared relative to the acquisition field size. The subjective analysis was performed in a non-blinded fashion where the diagnostic value (DV) of the exam was determined according to a graded scale. A phantom analysis for each of the acquisition field sizes was conducted and modulation transfer function (MTF) graphed. Significantly higher HU, SNR, CNR and lower noise indices were achieved with the 42-cm protocol than the 22/32 and 48-cm protocols. Here a greater DV was also reported. The MTF demonstrates marginally improved spatial resolution for the 22-cm protocol, but this is near equivocal for the 32-, 42 and 48-cm protocols. The use of larger acquisition field sizes provides improved image quality when performing IV CBCT as an alternative to intra-arterial (IA) CBCT.

Computed tomography dose index determination in dose modulation prospectively involving the third-generation iterative reconstruction and noise index.

Optimizing CT protocols is challenging in the presence of automatic dose modulation because the CT dose index (CTDIvol) at different patient sizes is unknown to the operator. The task is more difficult when both the image quality index and iterative reconstruction prospectively affect the dose determination. It is of interest in practice to be informed of the CTDIvol during the protocol initialization and evaluation. It was our objective to obtain a predictive relationship between CTDIvol, the image quality index, and iterative reconstruction strength at various patient sizes. Dose modulation data were collected on a GE Revolution 256-slice scanner utilizing a Mercury phantom and selections of the noise index (NI) from 8 to 17, the third generation iterative reconstruction (ASIR-V) from 0% to 80%, and phantom diameters from 16 to 36cm. The fixed parameters were 120kVp, a pitch of .984, and a collimation of 40mm with a primary slice width of 2.5mm. The CTDIvol per diameter was based on the average tube current over three adjacent slices (same or similar diameter) multiplied by a conversion factor between the average mA of the series and the reported CTDIvol. The relationship between CTDIvol, NI, and ASIR-V for each diameter was fitted with a 2nd order polynomial of ASIR-V multiplied by a power law of NI. The ASIR-V fit parameters versus diameter followed a Lorentz function while the NI exponent versus diameter followed an exponential growth function. The CTDIvol predictions were accurate within 15% compared to phantom results on a separate GE Revolution. For clinical relevance, the phantom diameter was converted to an abdomen or chest equivalent diameter and was well matched to patient data. The fitted relationship for CTDIvol. for given values of NI and ASIR-V blending for a range of phantom sizes was a good match to phantom and patient data. The results can be of direct help for selecting adequate parameters in CT protocol development.

Optimization of the Acquisition Time and Injected Dose of 18 F-Fluorodeoxyglucose Based on Patient Specifications for High-Sensitive Positron Emission Tomography/Computed Tomography Scanner.

Background This study was aimed to optimize the fluorodeoxyglucose (FDG)-administered dose and scan time based on patient specifications using a highly sensitive five-ring bismuth germanium oxide (BGO)-based positron emission tomography/computed tomography (PET/CT) scanner (Discovery IQ). Methods We retrospectively analyzed 101 whole-body 18 F-FDG PET/CT images. Patient data were reconstructed using ordered subset expectation maximization with resolution recovery algorithms (OSEM + SharpIR). Signal-to-noise ratio (SNR) was calculated for each patient, standardized to SNR norm , and plotted against three body index parameters (weight, body mass index, and lean body mass). Two professional physicians blindly examined image quality at different patient time per bed positions to determine the minimum acceptable quality. To select images of acceptable quality, the noise index parameter was also measured. A new dose-time product (DTP) was established for each patient, and a predicted injected dose was assumed. Results We found an almost linear association between patient weight and normalized SNR, and patient weight had the highest R 2 in the fitting. The redesigned DTP can reduce results by approximately 74 and 38% compared with ordinary DTP for 80- and 160-s scan durations. The new dose regimen formula was found to be DTP = c/t × m 1.24 , where m is the patient weight, t is the scan time per bed position, and c is 1.8 and 4.3 for acceptable and higher confidence states, respectively, in Discovery IQ PET/CT. Conclusion Patient weight is the best clinical parameter for the implementation of 18 F-FDG PET/CT image quality assessment. A new dose-time regimen based on body weight was proposed for use in highly sensitive five-ring BGO PET-CT scanners to significantly reduce the injection dose and scan times while maintaining sufficient image quality for diagnosis.