scholarly journals Fast filtered backprojection algorithm for low-dose computed tomography

2020 ◽  
Vol 4 (7) ◽  
pp. 45-50
Author(s):  
Zeng GL
Keyword(s):  
Computed Tomography ◽  
Low Dose ◽  
Iterative Algorithms ◽  
Short Paper ◽  
Filtered Backprojection ◽  
Low Dose Ct ◽  
Noisy Images ◽  
Artifacts Removal ◽  
Low Dose Computed Tomography

Low-dose computed tomography (CT) can produce noisy images that may contain streaking artifacts. Removal of streaking artifacts normally requires iterative algorithms that model the transmission noise physics. A fast filtered backprojection (FBP) algorithm is introduced in this short paper. This algorithm is very simple and effective in removing the streaking artifacts in low-dose CT.

scholarly journals Application of low dose computed tomography protocols in pediatric radiology

2020 ◽  
Vol 56 (1) ◽  
pp. 4-15
Author(s):  
Bruno Atalić ◽  
Damir Miletić ◽  
Goran Roić ◽  
Mirko Balić ◽  
Slaven Jurković ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Computerized Tomography ◽  
Pediatric Radiology ◽  
Low Dose ◽  
Low Dose Ct ◽  
Image Gently ◽  
Low Dose Computed Tomography

Djeca su zbog svoje male veličine, brojnih staničnih dioba još uvijek rastućih i razvijajućih tkiva i organa, kao i dužeg očekivanog životnog vijeka, otprilike tri puta osjetljivija na iste doze ionizirajućeg zračenja od odraslih. To je posebno izraženo kod pregleda kompjutoriziranom tomografijom (engl. computerized tomography, CT) koji, iako čine samo 17 % ionizirajućih radioloških pregleda, sudjeluju s čak 49 % u ukupnom ozračivanju pacijenata. Zbog toga se pod utjecajem kampanje Image Gently početkom 2010-ih godina razmišljalo o potpunom napuštanju CT pregleda u pedijatrijskoj radiologiji te njihovoj zamjeni ultrazvučnim odnosno pregledima učinjenim magnetskom rezonancijom kao metodama izbora. Pojava Flash CT tehnike koja istovremeno skraćuje vrijeme snimanja i smanjuje doze zračenja dovela je do odustajanja od toga. Tome u prilog išle su i činjenice da su s jedne strane CT pregledi praktički nezamjenjivi u slučajevima trauma, dok su s druge strane djeca, kao uostalom i pripadnici svih drugih dobnih skupina, neprestano izložena manjoj ili većoj količini pozadinskog ionizirajućeg zračenja (Zemlja, svemir, zrakoplovi). U tome smislu danas se sve više preporučuje uporaba low dose CT (LDCT) tehnika individualno prilagođenih svakom pacijentu zbog njihove manje količine ionizirajućeg zračenja. Na tome putu nastojali smo napraviti pregled najnovijih spoznaja o spomenutoj problematici na temelju znanstvenih radova objavljenih u protekle tri godine (2016. – 2018.). Oni pokazuju da CT pregledi ne samo da nisu napušteni u pedijatrijskoj radiologiji, već naprotiv, u slučajevima brojnih indikacija LDCT pregledi čine zlatni standard.

scholarly journals Three-dimensional oropharyngeal airway changes after facemask therapy using low-dose computed tomography: a clinical trial with a retrospectively collected control group

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Amr H. Husson ◽  
Ahmad S. Burhan ◽  
Mohammad Y. Hajeer ◽  
Fehmieh R. Nawaya
Keyword(s):  
Computed Tomography ◽  
Low Dose ◽  
Control Group ◽  
Class Iii ◽  
Bite Block ◽  
Maximum Displacement ◽  
Cross Sectional ◽  
Low Dose Ct ◽  
Oropharyngeal Airway ◽  
Low Dose Computed Tomography

Abstract Aims This study aimed to evaluate the short-term oropharyngeal airway volumetric changes in growing Class III maxillary-deficient patients treated by facemask without expansion compared with untreated Class III controls, using low-dose computed tomography. Methods Eighteen maxillary-deficient children (9 boys, nine girls) with a mean age of 7.81 ± 0.84 years were treated with maxillary bonded bite block and facemask (FM). Pre- (T1) and post-treatment (T2) low-dose CT images were acquired. Sixteen untreated Class III patients with a mean age of 7.03 ± 0.56 years had previously two low-dose CT scans within a one year of follow-up. Volumetric and minimal cross-sectional area measurements were obtained to assess the oropharyngeal airway changes. Quantitative mean, minimum, and maximum displacement of superimposed 3D models were estimated from a point-based analysis. Paired-samples t-tests were used for the intragroup comparisons, and an independent samples t-test and the Mann–Whitney U tests were carried out for the intergroup comparisons. Results A statistically significant increase in the total and retropalatal volumes oropharyngeal airway volume were observed in the control group (302.23 ± 345.58 and 145.73 ± 189.22 mm3, respectively). In the FM group, statistically significant increases in the total and retropalatal volumes were observed (738.86 ± 1109.37 mm3 and 388.63 ± 491.44 mm3, respectively). However, no statistically significant differences were found between the two groups, except for the maximum part analysis which was significantly greater in the FM group (p = 0.007). Conclusions FM therapy appeared to have no additional effects on the oropharyngeal airway other than those induced by growth.

Liver density in routine and low-dose computed tomography: the effect of image noise on measurement accuracy

2020 ◽  
Vol 24 (1) ◽  
pp. 39-47
Author(s):  
A. P. Gonchar ◽  
V. A. Gombolevskij ◽  
A. B. Elizarov ◽  
N. S. Kulberg ◽  
V. G. Klyashtorny ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Measurement Accuracy ◽  
Low Dose ◽  
Image Noise ◽  
Low Dose Computed Tomography

LUNGRADS AND UPDATE OF LUNG NODULES SCREENING BY LOW DOSE COMPUTED TOMOGRAPHY

2015 ◽  
pp. 12-19
Author(s):  
Thi Ngoc Ha Hoang ◽  
Trong Khoan Le
Keyword(s):  
Lung Cancer ◽  
Low Dose ◽  
False Negative ◽  
Lung Nodule ◽  
Lung Cancer Mortality ◽  
Smoking History ◽  
Low Dose Ct ◽  
History Of ◽  
Chest X Ray ◽  
Low Dose Computed Tomography

Background: A pulmonary nodule is defined as a rounded or irregular opacity, well or poorly defined, measuring up to 3 cm in diameter. Early detection the malignancy of nodules has a significant role in decreasing the mortality, increasing the survival time and consider as early diagnosis lung cancer. The main risk factors are those of current or former smokers, aged 55 to 74 years with a smoking history of at least 1 pack-day. Low dose CT: screening individuals with high risk of lung cancer by low dose CT scans could reduce lung cancer mortality by 20 percent compared to chest X-ray. Radiation dose has to maximum reduced but respect the rule of ALARA (As Low as Resonably Archivable). LungRADS 2014: Classification of American College of Radiology, LungRADS, is a newly application but showed many advantages in comparison with others classification such as increasing positive predict value (PPV), no result of false negative and cost effectiveness. Key words: LungRADS, screening lung nodule, low dose CT, lung cancer

LOW-DOSE COMPUTED TOMOGRAPHY IN MOSCOW FOR LUNG CANCER SCREENING (LDCT-MLCS): BASELINE RESULTS

2019 ◽  
Vol 65 (2) ◽  
pp. 224-233
Author(s):  
Sergey Morozov ◽  
Viktor Gombolevskiy ◽  
Anton Vladzimirskiy ◽  
Albina Laypan ◽  
Pavel Kononets ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Lung Cancer ◽  
Cancer Screening ◽  
Low Dose ◽  
Early Stage ◽  
Lung Cancer Screening ◽  
Stage I ◽  
Malignant Neoplasms ◽  
Number Needed To Screen ◽  
Low Dose Computed Tomography

Study aim. To justify selective lung cancer screening via low-dose computed tomography and evaluate its effectiveness. Materials and methods. In 2017 we have concluded the baseline stage of “Lowdose computed tomography in Moscow for lung cancer screening (LDCT-MLCS)” trial. The trial included 10 outpatient clinics with 64-detector CT units (Toshiba Aquilion 64 and Toshiba CLX). Special low-dose protocols have been developed for each unit with maximum effective dose of 1 mSv (in accordance with the requirements of paragraph 2.2.1, Sanitary Regulations 2.6.1.1192-03). The study involved 5,310 patients (53% men, 47% women) aged 18-92 years (mean age 62 years). Diagnosis verification was carried out in the specialized medical organizations via consultations, additional instrumental, laboratory as well as pathohistological studies. The results were then entered into the “National Cancer Registry”. Results. 5310 patients (53% men, 47% women) aged 18 to 92 years (an average of 62 years) participated in the LDCT-MLCS. The final cohort was comprised of 4762 (89.6%) patients. We have detected 291 (6.1%) Lung-RADS 3 lesions, 228 (4.8%) Lung- RADS 4A lesions and 196 (4.1%) Lung-RADS 4B/4X lesions. All 4B and 4X lesions were routed in accordance with the project's methodology and legislative documents. Malignant neoplasms were verified in 84 cases (1.76% of the cohort). Stage I-II lung cancer was actively detected in 40.3% of these individuals. For the first time in the Russian Federation we have calculated the number needed to screen (NNS) to identify one lung cancer (NNS=57) and to detect one Stage I lung cancer (NNS=207). Conclusions. Based on the global experience and our own practices, we argue that selective LDCT is the most systematic solution to the problem of early-stage lung cancer screening.

Sign in / Sign up

Export Citation Format

Share Document