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Sample records for dose lung ct

  1. Detection of lung nodules with low-dose spiral CT: comparison with conventional dose CT

    International Nuclear Information System (INIS)

    Zhu Tianzhao; Tang Guangjian; Jiang Xuexiang

    2004-01-01

    Objective: To investigate the effect of reducing scan dose on the lung nodules detection rate by scanning a lung nodule model at low dose and conventional dose. Methods: The lung and the thoracic cage were simulated by using a cyst filled with water surrounded by a roll bandage. Flour, butter, and paraffin wax were mixed together by a certain ratio to simulate lung nodules of 10 mm and 5 mm in diameter with the CT values ranging from -10 to 50 HU. Conventional-dose scan (240 mA, 140 kV) and low-dose scan of three different levels (43 mA, 140 kV; 50 mA, 120 kV; 75 mA, 80 kV) together with three different pitches (1.0, 1.5, and 2.0) were performed. The images of the simulated nodules were combined with the CT images of a normal adult's upper, middle, and inferior lung. Three radiologists read the images and the number of the nodules they detected including both the real ones and the false-positive ones was calculated to investigate weather there was any difference among different doses, pitch groups, and different locations. Results: The detection rate of the 10 mm and 5 mm nodules was 100% and 89.6% respectively by the low-dose scan. There was no difference between low-dose and conventional-dose CT (χ 2 =0.6907, P>0.70). The detection rate of 5 mm nodules declined when large pitch was used. Conclusion: The detection rates of 10 mm and 5 mm nodules had no difference between low-dose CT and conventional-dose CT. As the pitch augmented, the detection rate for the nodules declined

  2. Low dose CT in early lung cancer diagnosis: prevalence data

    International Nuclear Information System (INIS)

    Cardinale, Luciano; Cortese, Giancarlo; Ferraris, Fabrizio; Perotto, Fabio; Fava, Cesare; Borasio, Piero; Dogliotti, Luigi; Novello, Silvia; Scagliotti, Giorgio

    2005-01-01

    Purpose. Lung cancer has a high mortality rate and its prognosis largely depends on early detection. We report the prevalence data of the study on early detection of lung cancer with low-dose spiral CT underway at our hospital. Materials and methods. Since the beginning of 2001, 519 asymptomatic volunteers have undergone annual blood tests, sputum tests, urinalyses and low-dose spiral CT. The inclusion criteria were age (55 years old), a history of cigarette smoking and a negative history for previous neoplastic disease. The diagnostic workup varied depending on the size and CT features of the nodules detected. Results. At baseline, the CT scan detected nodules> 5 mm in 22% of subjects; the nodules were single in 42 and multiple in 71. In 53% of cases the findings were completely negative, while in 122 (23.4%) nodules with a diameter [it

  3. Low-dose CT: new tool for screening lung cancer?

    International Nuclear Information System (INIS)

    Diederich, S.; Wormanns, D.; Heindel, W.

    2001-01-01

    Lung cancer is the leading cause of death from malignant tumours as it is very common and has a poor prognosis at advanced tumour stages. Prognosis could be improved by treatment at early stages. As these stages are usually asymptomatic, a diagnostic test that would allow detection of early tumour stages in a population at risk could potentially reduce mortality from lung cancer. Previous approaches using chest radiography and sputum cytology in smokers have been disappointing. Fluorescent bronchoscopy and molecular markers are not yet applicable in clinical routine. Because of its high sensitivity for small pulmonary nodules, which are the most common manifestation of early lung cancer, CT appears suitable as a screening test. Low-dose examination parameters can and should be used for this purpose. From clinical practice it is well known that chest CT often demonstrates small pulmonary nodules, which do not represent lung cancer. Therefore, non-invasive diagnostic algorithms are required to avoid unnecessary biopsies in benign lesions. In preliminary studies of low-dose CT using algorithms based on size and density of detected nodules a large proportion of asymptomatic lung cancers and a large proportion of early, resectable tumour stages were found with a small proportion of invasive procedures for benign nodules. Before this technology can be recommended for broad application, however, further information is required regarding appropriate inclusion criteria (smoking habits, age groups) and screening intervals. Most importantly, further data are required to clarify whether lung cancer screening using low-dose CT can actually reduce mortality from lung cancer. (orig.)

  4. Lung cancer screening with low-dose CT

    International Nuclear Information System (INIS)

    Diederich, S.; Wormanns, D.; Heindel, W.

    2003-01-01

    Screening for lung cancer is hoped to reduce mortality from this common tumour, which is characterised by a dismal overall survival, relatively well defined risk groups (mainly heavy cigarette smokers and workers exposed to asbestos) and a lack of early symptoms. In the past studies using sputum cytology and chest radiography have failed to demonstrate any reduction in lung cancer mortality through screening. One of the reasons is probably the relatively poor sensitivity of both these tests in early tumours. Low radiation dose computed tomography (CT) has been shown to have a much higher sensitivity for small pulmonary nodules, which are believed to be the most common presentation of early lung cancer. As, however, small pulmonary nodules are common and most are not malignant, non-invasive diagnostic algorithms are required to correctly classify the detected lesions and avoid invasive procedures in benign nodules. Nodule density, size and the demonstration of growth at follow-up have been shown to be useful in this respect and may in the future be supplemented by contrast-enhanced CT and positron emission tomography. Based on these diagnostic algorithms preliminary studies of low-dose CT in heavy smokers have demonstrated a high proportion of asymptomatic, early, resectable cancers with good survival. As, however, several biases could explain these findings in the absence of the ultimate goal of cancer screening, i.e. mortality reduction, most researchers believe that randomised controlled trials including several 10000 subjects are required to demonstrate a possible mortality reduction. Only then general recommendations to screen individuals at risk of lung cancer with low-dose CT should be made. It can be hoped that international cooperation will succeed in providing results as early as possible

  5. Lung Dose Calculation With SPECT/CT for {sup 90}Yittrium Radioembolization of Liver Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Naichang, E-mail: yun@ccf.org [Department of Radiation Oncology, Cleveland Clinic, Cleveland, OH (United States); Srinivas, Shaym M.; DiFilippo, Frank P.; Shrikanthan, Sankaran [Department of Nuclear Medicine, Cleveland Clinic, Cleveland, OH (United States); Levitin, Abraham; McLennan, Gordon; Spain, James [Department of Interventional Radiology, Cleveland Clinic, Cleveland, OH (United States); Xia, Ping; Wilkinson, Allan [Department of Radiation Oncology, Cleveland Clinic, Cleveland, OH (United States)

    2013-03-01

    Purpose: To propose a new method to estimate lung mean dose (LMD) using technetium-99m labeled macroaggregated albumin ({sup 99m}Tc-MAA) single photon emission CT (SPECT)/CT for {sup 90}Yttrium radioembolization of liver tumors and to compare the LMD estimated using SPECT/CT with clinical estimates of LMD using planar gamma scintigraphy (PS). Methods and Materials: Images of 71 patients who had SPECT/CT and PS images of {sup 99m}Tc-MAA acquired before TheraSphere radioembolization of liver cancer were analyzed retrospectively. LMD was calculated from the PS-based lung shunt assuming a lung mass of 1 kg and 50 Gy per GBq of injected activity shunted to the lung. For the SPECT/CT-based estimate, the LMD was calculated with the activity concentration and lung volume derived from SPECT/CT. The effect of attenuation correction and the patient's breathing on the calculated LMD was studied with the SPECT/CT. With these effects correctly taken into account in a more rigorous fashion, we compared the LMD calculated with SPECT/CT with the LMD calculated with PS. Results: The mean dose to the central region of the lung leads to a more accurate estimate of LMD. Inclusion of the lung region around the diaphragm in the calculation leads to an overestimate of LMD due to the misregistration of the liver activity to the lung from the patient's breathing. LMD calculated based on PS is a poor predictor of the actual LMD. For the subpopulation with large lung shunt, the mean overestimation from the PS method for the lung shunt was 170%. Conclusions: A new method of calculating the LMD for TheraSphere and SIR-Spheres radioembolization of liver cancer based on {sup 99m}Tc-MAA SPECT/CT is presented. The new method provides a more accurate estimate of radiation risk to the lungs. For patients with a large lung shunt calculated from PS, a recalculation of LMD based on SPECT/CT is recommended.

  6. Lung Dose Calculation With SPECT/CT for 90Yittrium Radioembolization of Liver Cancer

    International Nuclear Information System (INIS)

    Yu, Naichang; Srinivas, Shaym M.; DiFilippo, Frank P.; Shrikanthan, Sankaran; Levitin, Abraham; McLennan, Gordon; Spain, James; Xia, Ping; Wilkinson, Allan

    2013-01-01

    Purpose: To propose a new method to estimate lung mean dose (LMD) using technetium-99m labeled macroaggregated albumin ( 99m Tc-MAA) single photon emission CT (SPECT)/CT for 90 Yttrium radioembolization of liver tumors and to compare the LMD estimated using SPECT/CT with clinical estimates of LMD using planar gamma scintigraphy (PS). Methods and Materials: Images of 71 patients who had SPECT/CT and PS images of 99m Tc-MAA acquired before TheraSphere radioembolization of liver cancer were analyzed retrospectively. LMD was calculated from the PS-based lung shunt assuming a lung mass of 1 kg and 50 Gy per GBq of injected activity shunted to the lung. For the SPECT/CT-based estimate, the LMD was calculated with the activity concentration and lung volume derived from SPECT/CT. The effect of attenuation correction and the patient's breathing on the calculated LMD was studied with the SPECT/CT. With these effects correctly taken into account in a more rigorous fashion, we compared the LMD calculated with SPECT/CT with the LMD calculated with PS. Results: The mean dose to the central region of the lung leads to a more accurate estimate of LMD. Inclusion of the lung region around the diaphragm in the calculation leads to an overestimate of LMD due to the misregistration of the liver activity to the lung from the patient's breathing. LMD calculated based on PS is a poor predictor of the actual LMD. For the subpopulation with large lung shunt, the mean overestimation from the PS method for the lung shunt was 170%. Conclusions: A new method of calculating the LMD for TheraSphere and SIR-Spheres radioembolization of liver cancer based on 99m Tc-MAA SPECT/CT is presented. The new method provides a more accurate estimate of radiation risk to the lungs. For patients with a large lung shunt calculated from PS, a recalculation of LMD based on SPECT/CT is recommended

  7. Lung dose calculation with SPECT/CT for ⁹⁰Yittrium radioembolization of liver cancer.

    Science.gov (United States)

    Yu, Naichang; Srinivas, Shaym M; Difilippo, Frank P; Shrikanthan, Sankaran; Levitin, Abraham; McLennan, Gordon; Spain, James; Xia, Ping; Wilkinson, Allan

    2013-03-01

    To propose a new method to estimate lung mean dose (LMD) using technetium-99m labeled macroaggregated albumin ((99m)Tc-MAA) single photon emission CT (SPECT)/CT for (90)Yttrium radioembolization of liver tumors and to compare the LMD estimated using SPECT/CT with clinical estimates of LMD using planar gamma scintigraphy (PS). Images of 71 patients who had SPECT/CT and PS images of (99m)Tc-MAA acquired before TheraSphere radioembolization of liver cancer were analyzed retrospectively. LMD was calculated from the PS-based lung shunt assuming a lung mass of 1 kg and 50 Gy per GBq of injected activity shunted to the lung. For the SPECT/CT-based estimate, the LMD was calculated with the activity concentration and lung volume derived from SPECT/CT. The effect of attenuation correction and the patient's breathing on the calculated LMD was studied with the SPECT/CT. With these effects correctly taken into account in a more rigorous fashion, we compared the LMD calculated with SPECT/CT with the LMD calculated with PS. The mean dose to the central region of the lung leads to a more accurate estimate of LMD. Inclusion of the lung region around the diaphragm in the calculation leads to an overestimate of LMD due to the misregistration of the liver activity to the lung from the patient's breathing. LMD calculated based on PS is a poor predictor of the actual LMD. For the subpopulation with large lung shunt, the mean overestimation from the PS method for the lung shunt was 170%. A new method of calculating the LMD for TheraSphere and SIR-Spheres radioembolization of liver cancer based on (99m)Tc-MAA SPECT/CT is presented. The new method provides a more accurate estimate of radiation risk to the lungs. For patients with a large lung shunt calculated from PS, a recalculation of LMD based on SPECT/CT is recommended. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Emphysema quantification and lung volumetry in chest X-ray equivalent ultralow dose CT - Intra-individual comparison with standard dose CT.

    Science.gov (United States)

    Messerli, Michael; Ottilinger, Thorsten; Warschkow, René; Leschka, Sebastian; Alkadhi, Hatem; Wildermuth, Simon; Bauer, Ralf W

    2017-06-01

    To determine whether ultralow dose chest CT with tin filtration can be used for emphysema quantification and lung volumetry and to assess differences in emphysema measurements and lung volume between standard dose and ultralow dose CT scans using advanced modeled iterative reconstruction (ADMIRE). 84 consecutive patients from a prospective, IRB-approved single-center study were included and underwent clinically indicated standard dose chest CT (1.7±0.6mSv) and additional single-energy ultralow dose CT (0.14±0.01mSv) at 100kV and fixed tube current at 70mAs with tin filtration in the same session. Forty of the 84 patients (48%) had no emphysema, 44 (52%) had emphysema. One radiologist performed fully automated software-based pulmonary emphysema quantification and lung volumetry of standard and ultralow dose CT with different levels of ADMIRE. Friedman test and Wilcoxon rank sum test were used for multiple comparison of emphysema and lung volume. Lung volumes were compared using the concordance correlation coefficient. The median low-attenuation areas (LAA) using filtered back projection (FBP) in standard dose was 4.4% and decreased to 2.6%, 2.1% and 1.8% using ADMIRE 3, 4, and 5, respectively. The median values of LAA in ultralow dose CT were 5.7%, 4.1% and 2.4% for ADMIRE 3, 4, and 5, respectively. There was no statistically significant difference between LAA in standard dose CT using FBP and ultralow dose using ADMIRE 4 (p=0.358) as well as in standard dose CT using ADMIRE 3 and ultralow dose using ADMIRE 5 (p=0.966). In comparison with standard dose FBP the concordance correlation coefficients of lung volumetry were 1.000, 0.999, and 0.999 for ADMIRE 3, 4, and 5 in standard dose, and 0.972 for ADMIRE 3, 4 and 5 in ultralow dose CT. Ultralow dose CT at chest X-ray equivalent dose levels allows for lung volumetry as well as detection and quantification of emphysema. However, longitudinal emphysema analyses should be performed with the same scan protocol and

  9. Smoking habits in the randomised Danish Lung Cancer Screening Trial with low-dose CT

    DEFF Research Database (Denmark)

    Ashraf, Haseem; Saghir, Zaigham; Dirksen, Asger

    2014-01-01

    BACKGROUND: We present the final results of the effect of lung cancer screening with low-dose CT on the smoking habits of participants in a 5-year screening trial. METHODS: The Danish Lung Cancer Screening Trial (DLCST) was a 5-year screening trial that enrolled 4104 subjects; 2052 were randomised...... to annual low-dose CT (CT group) and 2052 received no intervention (control group). Participants were current and ex-smokers (≥4 weeks abstinence from smoking) with a tobacco consumption of ≥20 pack years. Smoking habits were determined annually. Missing values for smoking status at the final screening...... round were handled using two different models. RESULTS: There were no statistically significant differences in annual smoking status between the CT group and control group. Overall the ex-smoker rates (CT + control group) significantly increased from 24% (baseline) to 37% at year 5 of screening (p

  10. CT fluoroscopy-guided vs. multislice CT biopsy mode-guided lung biopsies: Accuracy, complications and radiation dose

    International Nuclear Information System (INIS)

    Prosch, Helmut; Stadler, Alfred; Schilling, Matthias; Bürklin, Sandra; Eisenhuber, Edith; Schober, Ewald; Mostbeck, Gerhard

    2012-01-01

    Background: The aim of this retrospective study was to compare the diagnostic accuracy, the frequency of complications, the duration of the interventions and the radiation doses of CT fluoroscopy (CTF) guided biopsies of lung lesions with those of multislice CT (MS-CT) biopsy mode-guided biopsies. Methods: Data and images from 124 consecutive patients undergoing CTF-guided lung biopsy (group A) and 132 MS-CT-biopsy mode-guided lung biopsy (group B) were reviewed. CTF-guided biopsies were performed on a Siemens Emotion 6 CT scanner with intermittent or continuous CT-fluoroscopy, MS-CT biopsy mode-guided biopsies were performed on a Siemens Emotion 16 CT scanner. All biopsies were performed with a coaxial needle technique. Results: The two groups (A vs. B) did not differ significantly regarding sensitivity (95.5% vs. 95.9%), specificity (96.7% vs. 95.5%), negative predictive value (87.9% vs. 84%) or positive predictive value (98.8% vs. 98.9%). Pneumothorax was observed in 30.0% and 32.5% of the patients, respectively. Chest tube placement was necessary in 4% (group A) and 13% (group B) of the patients. The duration of the intervention was significantly longer in group A (median 37 min vs. 32 min, p = 0.04). The mean CT dose index (CTDI) was 422 in group A and 36.3 in group B (p < 0.001). Conclusion: Compared to CTF-guided biopsies, chest biopsies using the MS-CT biopsy mode show dramatically lower CTDI levels. Although the diagnostic yield of the procedures do not differ significantly, biopsies using the MS-CT-biopsy mode have a three-fold higher rate of chest tube placement.

  11. CT imaging of congenital lung lesions: effect of iterative reconstruction on diagnostic performance and radiation dose

    International Nuclear Information System (INIS)

    Haggerty, Jay E.; Smith, Ethan A.; Dillman, Jonathan R.; Kunisaki, Shaun M.

    2015-01-01

    Different iterative reconstruction techniques are available for use in pediatric computed tomography (CT), but these techniques have not been systematically evaluated in infants. To determine the effect of iterative reconstruction on diagnostic performance, image quality and radiation dose in infants undergoing CT evaluation for congenital lung lesions. A retrospective review of contrast-enhanced chest CT in infants (<1 year) with congenital lung lesions was performed. CT examinations were reviewed to document the type of lung lesion, vascular anatomy, image noise measurements and image reconstruction method. CTDI vol was used to calculate size-specific dose estimates (SSDE). CT findings were correlated with intraoperative and histopathological findings. Analysis of variance and the Student's t-test were used to compare image noise measurements and radiation dose estimates between groups. Fifteen CT examinations used filtered back projection (FBP; mean age: 84 days), 15 used adaptive statistical iterative reconstruction (ASiR; mean age: 93 days), and 11 used model-based iterative reconstruction (MBIR; mean age: 98 days). Compared to operative findings, 13/15 (87%), 14/15 (93%) and 11/11 (100%) lesions were correctly characterized using FBP, ASiR and MBIR, respectively. Arterial anatomy was correctly identified in 12/15 (80%) using FBP, 13/15 (87%) using ASiR and 11/11 (100%) using MBIR. Image noise was less for MBIR vs. ASiR (P < 0.0001). Mean SSDE was different among groups (P = 0.003; FBP = 7.35 mGy, ASiR = 1.89 mGy, MBIR = 1.49 mGy). Congenital lung lesions can be adequately characterized in infants using iterative CT reconstruction techniques while maintaining image quality and lowering radiation dose. (orig.)

  12. CT imaging of congenital lung lesions: effect of iterative reconstruction on diagnostic performance and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Haggerty, Jay E.; Smith, Ethan A.; Dillman, Jonathan R. [University of Michigan Health System, Section of Pediatric Radiology, Department of Radiology, C.S. Mott Children' s Hospital, Ann Arbor, MI (United States); Kunisaki, Shaun M. [University of Michigan Health System, Section of Pediatric Surgery, Department of Surgery, C.S. Mott Children' s Hospital, Ann Arbor, MI (United States)

    2015-07-15

    Different iterative reconstruction techniques are available for use in pediatric computed tomography (CT), but these techniques have not been systematically evaluated in infants. To determine the effect of iterative reconstruction on diagnostic performance, image quality and radiation dose in infants undergoing CT evaluation for congenital lung lesions. A retrospective review of contrast-enhanced chest CT in infants (<1 year) with congenital lung lesions was performed. CT examinations were reviewed to document the type of lung lesion, vascular anatomy, image noise measurements and image reconstruction method. CTDI{sub vol} was used to calculate size-specific dose estimates (SSDE). CT findings were correlated with intraoperative and histopathological findings. Analysis of variance and the Student's t-test were used to compare image noise measurements and radiation dose estimates between groups. Fifteen CT examinations used filtered back projection (FBP; mean age: 84 days), 15 used adaptive statistical iterative reconstruction (ASiR; mean age: 93 days), and 11 used model-based iterative reconstruction (MBIR; mean age: 98 days). Compared to operative findings, 13/15 (87%), 14/15 (93%) and 11/11 (100%) lesions were correctly characterized using FBP, ASiR and MBIR, respectively. Arterial anatomy was correctly identified in 12/15 (80%) using FBP, 13/15 (87%) using ASiR and 11/11 (100%) using MBIR. Image noise was less for MBIR vs. ASiR (P < 0.0001). Mean SSDE was different among groups (P = 0.003; FBP = 7.35 mGy, ASiR = 1.89 mGy, MBIR = 1.49 mGy). Congenital lung lesions can be adequately characterized in infants using iterative CT reconstruction techniques while maintaining image quality and lowering radiation dose. (orig.)

  13. Accurate heterogeneous dose calculation for lung cancer patients without high‐resolution CT densities

    Science.gov (United States)

    Li, Jonathan G.; Liu, Chihray; Olivier, Kenneth R.; Dempsey, James F.

    2009-01-01

    The aim of this study was to investigate the relative accuracy of megavoltage photon‐beam dose calculations employing either five bulk densities or independent voxel densities determined by calibration of the CT Houndsfield number. Full‐resolution CT and bulk density treatment plans were generated for 70 lung or esophageal cancer tumors (66 cases) using a commercial treatment planning system with an adaptive convolution dose calculation algorithm (Pinnacle3, Philips Medicals Systems). Bulk densities were applied to segmented regions. Individual and population average densities were compared to the full‐resolution plan for each case. Monitor units were kept constant and no normalizations were employed. Dose volume histograms (DVH) and dose difference distributions were examined for all cases. The average densities of the segmented air, lung, fat, soft tissue, and bone for the entire set were found to be 0.14, 0.26, 0.89, 1.02, and 1.12 g/cm3, respectively. In all cases, the normal tissue DVH agreed to better than 2% in dose. In 62 of 70 DVHs of the planning target volume (PTV), agreement to better than 3% in dose was observed. Six cases demonstrated emphysema, one with bullous formations and one with a hiatus hernia having a large volume of gas. These required the additional assignment of density to the emphysemic lung and inflammatory changes to the lung, the regions of collapsed lung, the bullous formations, and the hernia gas. Bulk tissue density dose calculation provides an accurate method of heterogeneous dose calculation. However, patients with advanced emphysema may require high‐resolution CT studies for accurate treatment planning. PACS number: 87.53.Tf

  14. CT-based dose calculations and in vivo dosimetry for lung cancer treatment

    International Nuclear Information System (INIS)

    Essers, M.; Lanson, J.H.; Leunens, G.; Schnabel, T.; Mijnheer, B.J.

    1995-01-01

    Reliable CT-based dose calculations and dosimetric quality control are essential for the introduction of new conformal techniques for the treatment of lung cancer. The first aim of this study was therefore to check the accuracy of dose calculations based on CT-densities, using a simple inhomogeneity correction model, for lung cancer patients irradiated with an AP-PA treatment technique. Second, the use of diodes for absolute exit dose measurements and an Electronic Portal Imaging Device (EPID) for relative transmission dose verification was investigated for 22 and 12 patients, respectively. The measured dose values were compared with calculations performed using our 3-dimensional treatment planning system, using CT-densities or assuming the patient to be water-equivalent. Using water-equivalent calculations, the actual exit dose value under lung was, on average, underestimated by 30%, with an overall spread of 10% (1 SD). Using inhomogeneity corrections, the exit dose was, on average, overestimated by 4%, with an overall spread of 6% (1 SD). Only 2% of the average deviation was due to the inhomogeneity correction model. An uncertainty in exit dose calculation of 2.5% (1 SD) could be explained by organ motion, resulting from the ventilatory or cardiac cycle. The most important reason for the large overall spread was, however, the uncertainty involved in performing point measurements: about 4% (1 SD). This difference resulted from the systematic and random deviation in patient set-up and therefore in diode position with respect to patient anatomy. Transmission and exit dose values agreed with an average difference of 1.1%. Transmission dose profiles also showed good agreement with calculated exit dose profiles. Our study shows that, for this treatment technique, the dose in the thorax region is quite accurately predicted using CT-based dose calculations, even if a simple inhomogeneity correction model is used. Point detectors such as diodes are not suitable for exit

  15. Accuracy of lung nodule volumetry in low-dose CT with iterative reconstruction: an anthropomorphic thoracic phantom study.

    Science.gov (United States)

    Doo, K W; Kang, E-Y; Yong, H S; Woo, O H; Lee, K Y; Oh, Y-W

    2014-09-01

    The purpose of this study was to assess accuracy of lung nodule volumetry in low-dose CT with application of iterative reconstruction (IR) according to nodule size, nodule density and CT tube currents, using artificial lung nodules within an anthropomorphic thoracic phantom. Eight artificial nodules (four diameters: 5, 8, 10 and 12 mm; two CT densities: -630 HU that represents ground-glass nodule and +100 HU that represents solid nodule) were randomly placed inside a thoracic phantom. Scans were performed with tube current-time product to 10, 20, 30 and 50 mAs. Images were reconstructed with IR and filtered back projection (FBP). We compared volume estimates to a reference standard and calculated the absolute percentage error (APE). The APE of all nodules was significantly lower when IR was used than with FBP (7.5 ± 4.7% compared with 9.0 ±6.9%; p volumetry in low-dose CT by application of IR showed reliable accuracy in a phantom study. Lung nodule volumetry can be reliably applicable to all lung nodules including small, ground-glass nodules even in ultra-low-dose CT with application of IR. IR significantly improved the accuracy of lung nodule volumetry compared with FBP particularly for ground-glass (-630 HU) nodules. Volumetry in low-dose CT can be utilized in patient with lung nodule work-up, and IR has benefit for small, ground-glass lung nodules in low-dose CT.

  16. Automated lung module detection at low-dose CT: preliminary experience

    International Nuclear Information System (INIS)

    Goo, Jin-Mo; Lee, Jeong-Won; Lee, Hyun-Ju; Kim, Seung-Wan; Kim, Jong-Hyo; Im, Jung-Gi

    2003-01-01

    To determine the usefulness of a computer-aided diagnosis (CAD) system for the automated detection of lung nodules at low-dose CT. A CAD system developed for detecting lung nodules was used to process the data provided by 50 consecutive low-dose CT scans. The results of an initial report, a second look review by two chest radiologists, and those obtained by the CAD system were compared, and by reviewing all of these, a gold standard was established. By applying the gold standard, a total of 52 nodules were identified (26 with a diameter ≤ 5 mm; 26 with a diameter > 5 mm). Compared to an initial report, four additional nodules were detected by the CAD system. Three of these, identified only at CAD, formed part of the data used to derive the gold standard. For the detection of nodules > 5 mm in diameter, sensitivity was 77% for the initial report, for the second look review, and 88% for the second look review,and 65% for the CAD system. There were 8.0 ± 5.2 false-positive CAD results per CT study. These preliminary results indicate that a CAD system may improve the detection of pulmonary nodules at low-dose CT

  17. Lung and heart dose volume analyses with CT simulator in radiation treatment of breast cancer

    International Nuclear Information System (INIS)

    Das, Indra J.; Cheng, Elizabeth C.; Freedman, Gary; Fowble, Barbara

    1998-01-01

    Purpose: Radiation pneumonitis and cardiac effects are directly related to the irradiated lung and heart volumes in the treatment fields. The central lung distance (CLD) from a tangential breast radiograph is shown to be a significant indicator of ipsilateral irradiated lung volume. Retrospective analysis of the pattern of dose volume of lung and heart with actual volume data from a CT simulator in the treatment of breast cancer is presented with respect to CLD. Methods and Materials: The heart and lung volumes in the tangential treatment fields were analyzed in 108 consecutive cases (52 left and 56 right breast) referred for CT simulation. All patients in this study were immobilized and placed on an inclined breast board in actual treatment setup. Both arms were stretched over head to avoid collision with the scanner aperture. Radiopaque marks were placed on the medial and lateral borders of the tangential fields. All patients were scanned in spiral mode with slice width and thickness of 3 mm each, respectively. The lung and heart structures as well as irradiated areas were delineated on each slice and respective volumes were accurately measured. The treatment beam parameters were recorded and the digitally reconstructed radiographs (DRRs) were generated for the measurement of the CLD and analysis. Results: Using CT data the mean volume and standard deviation of left and right lungs were 1307.7 ± 297.7 cm 3 and 1529.6 ± 298.5 cm 3 , respectively. The magnitude of irradiated volume in left and right lung is nearly equal for the same CLD that produces different percent irradiated volumes (PIV). The left and right PIV lungs are 8.3 ± 4.7% and 6.6 ± 3.7%, respectively. The PIV data have shown to correlate with CLD with second- and third-degree polynomials; however, in this study a simple straight line regression is used to provide better confidence than the higher order polynomials. The regression lines for the left and right breasts are very different based on

  18. Computer-aided detection of early interstitial lung diseases using low-dose CT images

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Cheol; Kim, Soo Hyung [School of Electronics and Computer Engineering, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Tan, Jun; Wang Xingwei; Lederman, Dror; Leader, Joseph K; Zheng Bin, E-mail: zhengb@upmc.edu [Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15213 (United States)

    2011-02-21

    This study aims to develop a new computer-aided detection (CAD) scheme to detect early interstitial lung disease (ILD) using low-dose computed tomography (CT) examinations. The CAD scheme classifies each pixel depicted on the segmented lung areas into positive or negative groups for ILD using a mesh-grid-based region growth method and a multi-feature-based artificial neural network (ANN). A genetic algorithm was applied to select optimal image features and the ANN structure. In testing each CT examination, only pixels selected by the mesh-grid region growth method were analyzed and classified by the ANN to improve computational efficiency. All unselected pixels were classified as negative for ILD. After classifying all pixels into the positive and negative groups, CAD computed a detection score based on the ratio of the number of positive pixels to all pixels in the segmented lung areas, which indicates the likelihood of the test case being positive for ILD. When applying to an independent testing dataset of 15 positive and 15 negative cases, the CAD scheme yielded the area under receiver operating characteristic curve (AUC = 0.884 {+-} 0.064) and 80.0% sensitivity at 85.7% specificity. The results demonstrated the feasibility of applying the CAD scheme to automatically detect early ILD using low-dose CT examinations.

  19. CT patterns of fungal pulmonary infections of the lung: Comparison of standard-dose and simulated low-dose CT

    International Nuclear Information System (INIS)

    Christe, Andreas; Lin, Margaret C.; Yen, Andrew C.; Hallett, Rich L.; Roychoudhury, Kingshuk; Schmitzberger, Florian; Fleischmann, Dominik; Leung, Ann N.; Rubin, Geoffry D.; Vock, Peter; Roos, Justus E.

    2012-01-01

    Purpose: To assess the effect of radiation dose reduction on the appearance and visual quantification of specific CT patterns of fungal infection in immuno-compromised patients. Materials and methods: Raw data of thoracic CT scans (64 × 0.75 mm, 120 kVp, 300 reference mAs) from 41 consecutive patients with clinical suspicion of pulmonary fungal infection were collected. In 32 patients fungal infection could be proven (median age of 55.5 years, range 35–83). A total of 267 cuboids showing CT patterns of fungal infection and 27 cubes having no disease were reconstructed at the original and 6 simulated tube currents of 100, 40, 30, 20, 10, and 5 reference mAs. Eight specific fungal CT patterns were analyzed by three radiologists: 76 ground glass opacities, 42 ground glass nodules, 51 mixed, part solid, part ground glass nodules, 36 solid nodules, 5 lobulated nodules, 6 spiculated nodules, 14 cavitary nodules, and 37 foci of air-space disease. The standard of reference was a consensus subjective interpretation by experts whom were not readers in the study. Results: The mean sensitivity and standard deviation for detecting pathological cuboids/disease using standard dose CT was 0.91 ± 0.07. Decreasing dose did not affect sensitivity significantly until the lowest dose level of 5 mAs (0.87 ± 0.10, p = 0.012). Nodular pattern discrimination was impaired below the dose level of 30 reference mAs: specificity for fungal ‘mixed nodules’ decreased significantly at 20, 10 and 5 reference mAs (p < 0.05). At lower dose levels, classification drifted from ‘solid’ to ‘mixed nodule’, although no lesion was missed. Conclusion: Our simulation data suggest that tube current levels can be reduced from 300 to 30 reference mAs without impairing the diagnostic information of specific CT patterns of pulmonary fungal infections

  20. Variability in CT lung-nodule volumetry: Effects of dose reduction and reconstruction methods.

    Science.gov (United States)

    Young, Stefano; Kim, Hyun J Grace; Ko, Moe Moe; Ko, War War; Flores, Carlos; McNitt-Gray, Michael F

    2015-05-01

    Measuring the size of nodules on chest CT is important for lung cancer staging and measuring therapy response. 3D volumetry has been proposed as a more robust alternative to 1D and 2D sizing methods. There have also been substantial advances in methods to reduce radiation dose in CT. The purpose of this work was to investigate the effect of dose reduction and reconstruction methods on variability in 3D lung-nodule volumetry. Reduced-dose CT scans were simulated by applying a noise-addition tool to the raw (sinogram) data from clinically indicated patient scans acquired on a multidetector-row CT scanner (Definition Flash, Siemens Healthcare). Scans were simulated at 25%, 10%, and 3% of the dose of their clinical protocol (CTDIvol of 20.9 mGy), corresponding to CTDIvol values of 5.2, 2.1, and 0.6 mGy. Simulated reduced-dose data were reconstructed with both conventional filtered backprojection (B45 kernel) and iterative reconstruction methods (SAFIRE: I44 strength 3 and I50 strength 3). Three lab technologist readers contoured "measurable" nodules in 33 patients under each of the different acquisition/reconstruction conditions in a blinded study design. Of the 33 measurable nodules, 17 were used to estimate repeatability with their clinical reference protocol, as well as interdose and inter-reconstruction-method reproducibilities. The authors compared the resulting distributions of proportional differences across dose and reconstruction methods by analyzing their means, standard deviations (SDs), and t-test and F-test results. The clinical-dose repeatability experiment yielded a mean proportional difference of 1.1% and SD of 5.5%. The interdose reproducibility experiments gave mean differences ranging from -5.6% to -1.7% and SDs ranging from 6.3% to 9.9%. The inter-reconstruction-method reproducibility experiments gave mean differences of 2.0% (I44 strength 3) and -0.3% (I50 strength 3), and SDs were identical at 7.3%. For the subset of repeatability cases, inter

  1. Lung and heart dose volume analyses with CT simulator in tangential field irradiation of breast cancer

    International Nuclear Information System (INIS)

    Das, Indra J.; Cheng, Elizabeth C.; Fowble, Barbara

    1997-01-01

    Objective: Radiation pneumonitis and cardiac effects are directly related to the irradiated lung and heart volumes in the treatment fields. The central lung distance (CLD) from a tangential breast radiograph is shown to be a significant indicator of ipsilateral irradiated lung volume based on empirically derived functions which accuracy depends on the actual measured volume in treatment position. A simple and accurate linear relationship with CLD and retrospective analysis of the pattern of dose volume of lung and heart is presented with actual volume data from a CT simulator in the treatment of breast cancer. Materials and Methods: The heart and lung volumes in the tangential treatment fields were analyzed in 45 consecutive (22 left and 23 right breast) patients referred for CT simulation of the cone down treatment. All patients in this study were immobilized and placed on an inclined breast board in actual treatment setup. Both arms were stretched over head uniformly to avoid collision with the scanner aperture. Radiopaque marks were placed on the medial and lateral borders of the tangential fields. All patients were scanned in spiral mode with slice width and thickness of 3 mm each, respectively. The lung and heart structures as well as irradiated areas were delineated on each slice and respective volumes were accurately measured. The treatment beam parameters were recorded and the digitally reconstructed radiographs (DRRs) were generated for the CLD and analysis. Results: Table 1 shows the volume statistics of patients in this study. There is a large variation in the lung and heart volumes among patients. Due to differences in the shape of right and left lungs the percent irradiated volume (PIV) are different. The PIV data have shown to correlate with CLD with 2nd and 3rd degree polynomials; however, in this study a simple straight line regression is used to provide better confidence than the higher order polynomial. The regression lines for the left and right

  2. Radiation dose reduction for CT lung cancer screening using ASIR and MBIR: a phantom study.

    Science.gov (United States)

    Mathieu, Kelsey B; Ai, Hua; Fox, Patricia S; Godoy, Myrna Cobos Barco; Munden, Reginald F; de Groot, Patricia M; Pan, Tinsu

    2014-03-06

    The purpose of this study was to reduce the radiation dosage associated with computed tomography (CT) lung cancer screening while maintaining overall diagnostic image quality and definition of ground-glass opacities (GGOs). A lung screening phantom and a multipurpose chest phantom were used to quantitatively assess the performance of two iterative image reconstruction algorithms (adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR)) used in conjunction with reduced tube currents relative to a standard clinical lung cancer screening protocol (51 effective mAs (3.9 mGy) and filtered back-projection (FBP) reconstruction). To further assess the algorithms' performances, qualitative image analysis was conducted (in the form of a reader study) using the multipurpose chest phantom, which was implanted with GGOs of two densities. Our quantitative image analysis indicated that tube current, and thus radiation dose, could be reduced by 40% or 80% from ASIR or MBIR, respectively, compared with conventional FBP, while maintaining similar image noise magnitude and contrast-to-noise ratio. The qualitative portion of our study, which assessed reader preference, yielded similar results, indicating that dose could be reduced by 60% (to 20 effective mAs (1.6 mGy)) with either ASIR or MBIR, while maintaining GGO definition. Additionally, the readers' preferences (as indicated by their ratings) regarding overall image quality were equal or better (for a given dose) when using ASIR or MBIR, compared with FBP. In conclusion, combining ASIR or MBIR with reduced tube current may allow for lower doses while maintaining overall diagnostic image quality, as well as GGO definition, during CT lung cancer screening.

  3. Reducing Radiation Doses in Female Breast and Lung during CT Examinations of Thorax: A new Technique in two Scanners

    Directory of Open Access Journals (Sweden)

    Mehnati P.

    2017-09-01

    Full Text Available Background: Chest CT is a commonly used examination for the diagnosis of lung diseases, but a breast within the scanned field is nearly never the organ of interest. Objective: The purpose of this study is to compare the female breast and lung doses using split and standard protocols in chest CT scanning. Materials and Methods: The sliced chest and breast female phantoms were used. CT exams were performed using a single-slice (SS- and a 16 multi-slice (MS- CT scanner at 100 kVp and 120 kVp. Two different protocols, including standard and split protocols, were selected for scanning. The breast and lung doses were measured using thermo-luminescence dosimeters which were inserted into different layers of the chest and breast phantoms. The differences in breast and lung radiation doses in two protocols were studied in two scanners, analyzed by SPSS software and compared by t-test. Results: Breast dose by split scanning technique reduced 11% and 31% in SS- and MS- CT. Also, the radiation dose of lung tissue in this method decreased 18% and 54% in SS- and MS- CT, respectively. Moreover, there was a significant difference (p< 0.0001 in the breast and lung radiation doses between standard and split scanning protocols. Conclusion: The application of a split scan technique instead of standard protocol has a considerable potential to reduce breast and lung doses in SS- and MS- CT scanners. If split scanning protocol is associated with an optimum kV and MSCT, the maximum dose decline will be provided.

  4. Simple pulmonary eosinophilia detected at low-dose CT for lung cancer screening

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Kyung Nyeo; Bae, Kyung Soo; Kim, Ho Cheol [Gyeongsang National University Hospital, Jinju (Korea, Republic of)] (and others)

    2006-05-15

    The aim of this study was to evaluate the frequency, radiologic findings and clinical significance of the simple pulmonary eosinophilia (SPE) that was diagnosed among the asymptomatic patients who underwent low-dose CT scans for the early detection of lung cancer. From June 2003 to May 2005, 1,239 asymptomatic patients (1,275 examinations) who visited the health promotion center in our hospital and who underwent low-dose CT were enrolled in this study. SPE was defined as the presence of > 500 eosinophils per microliter of peripheral blood and the presence of abnormal parenchymal lesions such as nodules, airspace consolidation or areas of ground-glass attenuation (GGA) on CT, and there was spontaneous resolution or migration of the lesions on the follow-up examination. We analyzed the CT findings of SPE and we investigated the relationship between the occurrence of SPE and the season, smoking and the presence of parasite infestation. 36 patients were finally diagnosed as having SPE; this was 24% of the 153 patients who were diagnosed with parasite infestation and 2.8% of the total low-dose CT scans. These 36 patients consisted of 31 men and 5 women with a mean age 45.7 years. There was no significant relationship between SPE and the presence of parasite infestation, smoking or gender. Among the patients with peripheral blood eosinophilia, the eosinophil count was significantly higher in the patients with SPE than that in the patients without pulmonary infiltration ({rho} < 0.05). SPE more frequently occurred in winter and spring than in summer and autumn ({rho} < 0.05). The CT findings were single or multiple nodules in 18 patients, nodules and focal GGA in 9 patients and GGA only in 9 patients. Most of the nodules were less than 10 mm (88%, 49/56) in diameter and they showed an ill-defined margin (82%, n = 46); 30% of the nodules (n = 17) showed a halo around them. Simple pulmonary eosinophilia can be suggested as the cause if single or multiple ill-defined nodules

  5. Simple pulmonary eosinophilia detected at low-dose CT for lung cancer screening

    International Nuclear Information System (INIS)

    Jeon, Kyung Nyeo; Bae, Kyung Soo; Kim, Ho Cheol

    2006-01-01

    The aim of this study was to evaluate the frequency, radiologic findings and clinical significance of the simple pulmonary eosinophilia (SPE) that was diagnosed among the asymptomatic patients who underwent low-dose CT scans for the early detection of lung cancer. From June 2003 to May 2005, 1,239 asymptomatic patients (1,275 examinations) who visited the health promotion center in our hospital and who underwent low-dose CT were enrolled in this study. SPE was defined as the presence of > 500 eosinophils per microliter of peripheral blood and the presence of abnormal parenchymal lesions such as nodules, airspace consolidation or areas of ground-glass attenuation (GGA) on CT, and there was spontaneous resolution or migration of the lesions on the follow-up examination. We analyzed the CT findings of SPE and we investigated the relationship between the occurrence of SPE and the season, smoking and the presence of parasite infestation. 36 patients were finally diagnosed as having SPE; this was 24% of the 153 patients who were diagnosed with parasite infestation and 2.8% of the total low-dose CT scans. These 36 patients consisted of 31 men and 5 women with a mean age 45.7 years. There was no significant relationship between SPE and the presence of parasite infestation, smoking or gender. Among the patients with peripheral blood eosinophilia, the eosinophil count was significantly higher in the patients with SPE than that in the patients without pulmonary infiltration (ρ < 0.05). SPE more frequently occurred in winter and spring than in summer and autumn (ρ < 0.05). The CT findings were single or multiple nodules in 18 patients, nodules and focal GGA in 9 patients and GGA only in 9 patients. Most of the nodules were less than 10 mm (88%, 49/56) in diameter and they showed an ill-defined margin (82%, n = 46); 30% of the nodules (n = 17) showed a halo around them. Simple pulmonary eosinophilia can be suggested as the cause if single or multiple ill-defined nodules or

  6. Radiation dose response of normal lung assessed by Cone Beam CT - a potential tool for biologically adaptive radiation therapy

    DEFF Research Database (Denmark)

    Bertelsen, Anders; Schytte, Tine; Bentzen, Søren M

    2011-01-01

    Density changes of healthy lung tissue during radiotherapy as observed by Cone Beam CT (CBCT) might be an early indicator of patient specific lung toxicity. This study investigates the time course of CBCT density changes and tests for a possible correlation with locally delivered dose....

  7. SU-F-T-687: Comparison of SPECT/CT-Based Methodologies for Estimating Lung Dose from Y-90 Radioembolization

    Energy Technology Data Exchange (ETDEWEB)

    Kost, S; Yu, N [Cleveland Clinic, Cleveland, OH (United States); Lin, S [Cleveland State University, Cleveland, OH (United States)

    2016-06-15

    Purpose: To compare mean lung dose (MLD) estimates from 99mTc macroaggregated albumin (MAA) SPECT/CT using two published methodologies for patients treated with {sup 90}Y radioembolization for liver cancer. Methods: MLD was estimated retrospectively using two methodologies for 40 patients from SPECT/CT images of 99mTc-MAA administered prior to radioembolization. In these two methods, lung shunt fractions (LSFs) were calculated as the ratio of scanned lung activity to the activity in the entire scan volume or to the sum of activity in the lung and liver respectively. Misregistration of liver activity into the lungs during SPECT acquisition was overcome by excluding lung counts within either 2 or 1.5 cm of the diaphragm apex respectively. Patient lung density was assumed to be 0.3 g/cm{sup 3} or derived from CT densitovolumetry respectively. Results from both approaches were compared to MLD determined by planar scintigraphy (PS). The effect of patient size on the difference between MLD from PS and SPECT/CT was also investigated. Results: Lung density from CT densitovolumetry is not different from the reference density (p = 0.68). The second method resulted in lung dose of an average 1.5 times larger lung dose compared to the first method; however the difference between the means of the two estimates was not significant (p = 0.07). Lung dose from both methods were statistically different from those estimated from 2D PS (p < 0.001). There was no correlation between patient size and the difference between MLD from PS and both SPECT/CT methods (r < 0.22, p > 0.17). Conclusion: There is no statistically significant difference between MLD estimated from the two techniques. Both methods are statistically different from conventional PS, with PS overestimating dose by a factor of three or larger. The difference between lung doses estimated from 2D planar or 3D SPECT/CT is not dependent on patient size.

  8. Comparison of measured and estimated maximum skin doses during CT fluoroscopy lung biopsies

    Energy Technology Data Exchange (ETDEWEB)

    Zanca, F., E-mail: Federica.Zanca@med.kuleuven.be [Department of Radiology, Leuven University Center of Medical Physics in Radiology, UZ Leuven, Herestraat 49, 3000 Leuven, Belgium and Imaging and Pathology Department, UZ Leuven, Herestraat 49, Box 7003 3000 Leuven (Belgium); Jacobs, A. [Department of Radiology, Leuven University Center of Medical Physics in Radiology, UZ Leuven, Herestraat 49, 3000 Leuven (Belgium); Crijns, W. [Department of Radiotherapy, UZ Leuven, Herestraat 49, 3000 Leuven (Belgium); De Wever, W. [Imaging and Pathology Department, UZ Leuven, Herestraat 49, Box 7003 3000 Leuven, Belgium and Department of Radiology, UZ Leuven, Herestraat 49, 3000 Leuven (Belgium)

    2014-07-15

    Purpose: To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. Methods: Data from 50 patients with lung lesions who underwent a CT fluoroscopy-guided biopsy were collected. The CT protocol consisted of a low-kilovoltage (80 kV) protocol used in combination with an algorithm for dose reduction to the radiology staff during the interventional procedure, HandCare (HC). MSD was assessed during each intervention using EBT2 gafchromic films positioned on patient skin. Lesion size, position, total fluoroscopy time, and patient-effective diameter were registered for each patient. Dose rates were also estimated at the surface of a normal-size anthropomorphic thorax phantom using a 10 cm pencil ionization chamber placed at every 30°, for a full rotation, with and without HC. Measured MSD was compared with MSD values estimated from the phantom measurements and with the cumulative CTDIvol of the procedure. Results: The median measured MSD was 141 mGy (range 38–410 mGy) while the median cumulative CTDIvol was 72 mGy (range 24–262 mGy). The ratio between the MSD estimated from phantom measurements and the measured MSD was 0.87 (range 0.12–4.1) on average. In 72% of cases the estimated MSD underestimated the measured MSD, while in 28% of the cases it overestimated it. The same trend was observed for the ratio of cumulative CTDIvol and measured MSD. No trend was observed as a function of patient size. Conclusions: On average, estimated MSD from dose rate measurements on phantom as well as from CTDIvol of patient examinations underestimates the measured value of MSD. This can be attributed to deviations of the patient's body habitus from the standard phantom size and to patient positioning in the gantry during the procedure.

  9. Comparison of measured and estimated maximum skin doses during CT fluoroscopy lung biopsies

    International Nuclear Information System (INIS)

    Zanca, F.; Jacobs, A.; Crijns, W.; De Wever, W.

    2014-01-01

    Purpose: To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. Methods: Data from 50 patients with lung lesions who underwent a CT fluoroscopy-guided biopsy were collected. The CT protocol consisted of a low-kilovoltage (80 kV) protocol used in combination with an algorithm for dose reduction to the radiology staff during the interventional procedure, HandCare (HC). MSD was assessed during each intervention using EBT2 gafchromic films positioned on patient skin. Lesion size, position, total fluoroscopy time, and patient-effective diameter were registered for each patient. Dose rates were also estimated at the surface of a normal-size anthropomorphic thorax phantom using a 10 cm pencil ionization chamber placed at every 30°, for a full rotation, with and without HC. Measured MSD was compared with MSD values estimated from the phantom measurements and with the cumulative CTDIvol of the procedure. Results: The median measured MSD was 141 mGy (range 38–410 mGy) while the median cumulative CTDIvol was 72 mGy (range 24–262 mGy). The ratio between the MSD estimated from phantom measurements and the measured MSD was 0.87 (range 0.12–4.1) on average. In 72% of cases the estimated MSD underestimated the measured MSD, while in 28% of the cases it overestimated it. The same trend was observed for the ratio of cumulative CTDIvol and measured MSD. No trend was observed as a function of patient size. Conclusions: On average, estimated MSD from dose rate measurements on phantom as well as from CTDIvol of patient examinations underestimates the measured value of MSD. This can be attributed to deviations of the patient's body habitus from the standard phantom size and to patient positioning in the gantry during the procedure

  10. A national survey of lung cancer specialists' views on low-dose CT screening for lung cancer in Korea.

    Directory of Open Access Journals (Sweden)

    Dong Wook Shin

    Full Text Available Lung cancer specialists play an important role in designing and implementing lung cancer screening. We aimed to describe their 1 attitudes toward low-dose lung computed tomography (LDCT screening, 2 current practices and experiences of LDCT screening and 3 attitudes and opinions towards national lung cancer screening program (NLCSP. We conducted a national web-based survey of pulmonologists, thoracic surgeons, medical oncologists, and radiological oncologists who are members of Korean Association for Lung Cancer (N = 183. Almost all respondents agreed that LDCT screening increases early detection (100%, improves survival (95.1%, and gives a good smoking cessation counseling opportunity (88.6%. Most were concerned about its high false positive results (79.8% and the subsequent negative effects. Less than half were concerned about radiation hazard (37.2%. Overall, most (89.1% believed that the benefits outweigh the risks and harms. Most (79.2% stated that they proactively recommend LDCT screening to those who are eligible for the current guidelines, but the screening propensity varied considerably. The majority (77.6% agreed with the idea of NLCSP and its beneficial effect, but had concerns about the quality control of CT devices (74.9%, quality assurance of radiologic interpretation (63.3%, poor access to LDCT (56.3%, and difficulties in selecting eligible population using self-report history (66.7%. Most (79.2% thought that program need to be funded by a specialized fund rather than by the National Health Insurance. The opinions on the level of copayment for screening varied. Our findings would be an important source for health policy decision when considering for NLCSP in Korea.

  11. TU-H-207A-08: Estimating Radiation Dose From Low-Dose Lung Cancer Screening CT Exams Using Tube Current Modulation

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, A; Bostani, M [University of California, Los Angeles, Los Angeles, CA (United States); McMillan, K [Mayo Clinic, Rochester, MN (United States); Zankl, M [Helmholtz Zentrum Munchen, Neuherberg (Germany); Cagnon, C [UCLA Medical Center, Los Angeles, CA (United States); McNitt-Gray, M [UCLA School of Medicine, Los Angeles, CA (United States)

    2016-06-15

    Purpose: The purpose of this work is to estimate effective and lung doses from a low-dose lung cancer screening CT protocol using Tube Current Modulation (TCM) across patient models of different sizes. Methods: Monte Carlo simulation methods were used to estimate effective and lung doses from a low-dose lung cancer screening protocol for a 64-slice CT (Sensation 64, Siemens Healthcare) that used TCM. Scanning parameters were from the AAPM protocols. Ten GSF voxelized patient models were used and had all radiosensitive organs identified to facilitate estimating both organ and effective doses. Predicted TCM schemes for each patient model were generated using a validated method wherein tissue attenuation characteristics and scanner limitations were used to determine the TCM output as a function of table position and source angle. The water equivalent diameter (WED) was determined by estimating the attenuation at the center of the scan volume for each patient model. Monte Carlo simulations were performed using the unique TCM scheme for each patient model. Lung doses were tallied and effective doses were estimated using ICRP 103 tissue weighting factors. Effective and lung dose values were normalized by scanspecific 32 cm CTDIvol values based upon the average tube current across the entire simulated scan. Absolute and normalized doses were reported as a function of WED for each patient. Results: For all ten patients modeled, the effective dose using TCM protocols was below 1.5 mSv. Smaller sized patient models experienced lower absolute doses compared to larger sized patients. Normalized effective and lung doses showed some dependence on patient size (R2 = 0.77 and 0.78, respectively). Conclusion: Effective doses for a low-dose lung screening protocol using TCM were below 1.5 mSv for all patient models used in this study. Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical

  12. TU-H-207A-08: Estimating Radiation Dose From Low-Dose Lung Cancer Screening CT Exams Using Tube Current Modulation

    International Nuclear Information System (INIS)

    Hardy, A; Bostani, M; McMillan, K; Zankl, M; Cagnon, C; McNitt-Gray, M

    2016-01-01

    Purpose: The purpose of this work is to estimate effective and lung doses from a low-dose lung cancer screening CT protocol using Tube Current Modulation (TCM) across patient models of different sizes. Methods: Monte Carlo simulation methods were used to estimate effective and lung doses from a low-dose lung cancer screening protocol for a 64-slice CT (Sensation 64, Siemens Healthcare) that used TCM. Scanning parameters were from the AAPM protocols. Ten GSF voxelized patient models were used and had all radiosensitive organs identified to facilitate estimating both organ and effective doses. Predicted TCM schemes for each patient model were generated using a validated method wherein tissue attenuation characteristics and scanner limitations were used to determine the TCM output as a function of table position and source angle. The water equivalent diameter (WED) was determined by estimating the attenuation at the center of the scan volume for each patient model. Monte Carlo simulations were performed using the unique TCM scheme for each patient model. Lung doses were tallied and effective doses were estimated using ICRP 103 tissue weighting factors. Effective and lung dose values were normalized by scanspecific 32 cm CTDIvol values based upon the average tube current across the entire simulated scan. Absolute and normalized doses were reported as a function of WED for each patient. Results: For all ten patients modeled, the effective dose using TCM protocols was below 1.5 mSv. Smaller sized patient models experienced lower absolute doses compared to larger sized patients. Normalized effective and lung doses showed some dependence on patient size (R2 = 0.77 and 0.78, respectively). Conclusion: Effective doses for a low-dose lung screening protocol using TCM were below 1.5 mSv for all patient models used in this study. Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical

  13. Screenings of lung cancer with low dose spiral CT: results of a three year pilot study and design of the randomised controlled trial Italung-CT

    International Nuclear Information System (INIS)

    Picozzi, Giulia; Paci, Enrico; Lopes Pegna, Andrea

    2005-01-01

    Purpose: To report the results of a three-year observational pilot study of lung cancer screening with low dose computed tomography (CT) and to present the study design of a randomised clinical trial named as Italung CT. Materials and methods: Sixty (47 males and 13 females, mean age 64±4.5 years) heavy smokers (at least 20 packs-year) underwent three low-dose spiral CT screening tests one year apart on a single slice or multislice CT scanner. Indeterminate nodules were managed according to the recommendations of the Early Lung Cancer Action Project. Results: Indeterminate nodules were observed in 33 (55%) of the subjects (60% at the baseline screening test, 24% at the first annual test and 16% at the second annual test). The size of the largest indeterminate nodule was [it

  14. Cystic Fibrosis: Are Volumetric Ultra-Low-Dose Expiratory CT Scans Sufficient for Monitoring Related Lung Disease?

    DEFF Research Database (Denmark)

    Loeve, Martine; Lequin, Maarten H; Bruijne, Marleen de

    2009-01-01

    Purpose: To assess whether chest computed tomography (CT) scores from ultra-low-dose end-expiratory scans alone could suffice for assessment of all cystic fibrosis (CF)-related structural lung abnormalities. Materials and Methods: In this institutional review board–approved study, 20 patients...... with CF aged 6–20 years (eight males, 12 females) underwent low-dose end-inspiratory CT and ultra-low-dose end-expiratory CT. Informed consent was obtained. Scans were randomized and scored by using the Brody-II CT scoring system to assess bronchiectasis, airway wall thickening, mucus plugging......-Altman plots. Results: Median age was 12.6 years (range, 6.3–20.3 years), median forced expiratory volume in 1 second was 100% (range, 46%–127%) of the predicted value, and median forced vital capacity was 99% (range, 61%–123%) of the predicted value. Very good agreement was observed between end...

  15. Evaluation of chronic infectious interstitial pulmonary disease in children by low-dose CT-guided transthoracic lung biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Heyer, Christoph M.; Lemburg, Stefan P.; Kagel, Thomas; Nicolas, Volkmar [Ruhr-University of Bochum, Institute of Diagnostic Radiology, Interventional Radiology and Nuclear Medicine, BG Clinics Bergmannsheil, Bochum (Germany); Mueller, Klaus-Michael [Ruhr-University of Bochum, Institute of Pathology, BG Clinics Bergmannsheil, Bochum (Germany); Nuesslein, Thomas G.; Rieger, Christian H.L. [Ruhr-University of Bochum, Pediatric Hospital, Bochum (Germany)

    2005-07-01

    Children with chronic infectious interstitial lung disease often have to undergo open lung biopsy to establish a final diagnosis. Open lung biopsy is an invasive procedure with major potential complications. Transthoracic lung biopsy (TLB) guided by computed tomography (CT) is a less-invasive well-established procedure in adults. Detailing the role of low-dose CT-guided TLB in the enhanced diagnosis of chronic lung diseases related to infection in children. A group of 11 children (age 8 months to 16 years) underwent CT-guided TLB with a 20-gauge biopsy device. All investigations were done under general anaesthesia on a multidetector CT scanner (SOMATOM Volume Zoom, Siemens, Erlangen, Germany) using a low-dose protocol (single slices, 120 kV, 20 mAs). Specimens were processed by histopathological, bacteriological, and virological techniques. All biopsies were performed without major complications; one child developed a small pneumothorax that resolved spontaneously. A diagnosis could be obtained in 10 of the 11 patients. Biopsy specimens revealed chronic interstitial alveolitis in ten patients. In five patients Chlamydia pneumoniae PCR was positive, in three Mycoplasma pneumoniae PCR was positive, and in two Cytomegalovirus PCR was positive. The average effective dose was 0.83 mSv. Low-dose CT-guided TLB can be a helpful tool in investigating chronic infectious inflammatory processes in children with minimal radiation exposure. It should be considered prior to any open surgical procedure performed for biopsy alone. In our patient group no significant complication occurred. A disadvantage of the method is that it does not allow smaller airways and vessels to be assessed. (orig.)

  16. Longitudinal follow-up study of smoking-induced emphysema progression in low-dose CT screening of lung cancer

    Science.gov (United States)

    Suzuki, H.; Matsuhiro, M.; Kawata, Y.; Niki, N.; Nakano, Y.; Ohmatsu, H.; Kusumoto, M.; Tsuchida, T.; Eguchi, K.; Kaneko, Masahiro; Moriyama, N.

    2014-03-01

    Chronic obstructive pulmonary disease is a major public health problem that is predicted to be third leading cause of death in 2030. Although spirometry is traditionally used to quantify emphysema progression, it is difficult to detect the loss of pulmonary function by emphysema in early stage, and to assess the susceptibility to smoking. This study presents quantification method of smoking-induced emphysema progression based on annual changes of low attenuation volume (LAV) by each lung lobe acquired from low-dose CT images in lung cancer screening. The method consists of three steps. First, lung lobes are segmented using extracted interlobar fissures by enhancement filter based on fourdimensional curvature. Second, LAV of each lung lobe is segmented. Finally, smoking-induced emphysema progression is assessed by statistical analysis of the annual changes represented by linear regression of LAV percentage in each lung lobe. This method was applied to 140 participants in lung cancer CT screening for six years. The results showed that LAV progressions of nonsmokers, past smokers, and current smokers are different in terms of pack-year and smoking cessation duration. This study demonstrates effectiveness in diagnosis and prognosis of early emphysema in lung cancer CT screening.

  17. Reduced-dose chest CT with 3D automatic exposure control vs. standard chest CT: Quantitative assessment of emphysematous changes in smokers’ lung parenchyma

    International Nuclear Information System (INIS)

    Koyama, Hisanobu; Ohno, Yoshiharu; Yamazaki, Youichi; Matsumoto, Keiko; Onishi, Yumiko; Takenaka, Daisuke; Yoshikawa, Takeshi; Nishio, Mizuho; Matsumoto, Sumiaki; Murase, Kenya; Nishimura, Yoshihiro

    2012-01-01

    Objectives: To determine the capability of reduced-dose chest CT with three-dimensional (3D) automatic exposure control (AEC) on quantitative assessment of emphysematous change in smoker’ lung parenchyma, compared to standard chest CT. Methods: Twenty consecutive smoker patients (mean age 62.8 years) underwent CT examinations using a standard protocol (150 mAs) and a protocol with 3D-AEC. In this study, the targeted standard deviations number was set to 160. For quantitative assessment of emphysematous change in lung parenchyma in each subject using the standard protocol, a percentage of voxels less than −950 HU in the lung (%LAA −950 ) was calculated. The 3D-AEC protocol's %LAA was computed from of voxel percentages under selected threshold CT value. The differences of radiation doses between these two protocols were evaluated, and %LAAs −950 was compared with the 3D-AEC protocol %LAAs. Results: Mean dose length products were 780.2 ± 145.5 mGy cm (standard protocol), and 192.0 ± 95.9 (3D-AEC protocol). There was significant difference between them (paired Student's t test, p −950 and 3D-AEC protocol %LAAs. In adopting the feasible threshold CT values of the 3D-AEC protocol, the 3D-AEC protocol %LAAs were significantly correlated with %LAAs −950 (r = 0.98, p < 0.001) and limits of agreement from Bland–Altman analysis was 0.52 ± 4.3%. Conclusions: Changing threshold CT values demonstrated that reduced-dose chest CT with 3D-AEC can substitute for the standard protocol in assessments of emphysematous change in smoker’ lung parenchyma.

  18. Lung cancer screening with low-dose helical CT in Korea: experiences at the Samsung Medical Center.

    Science.gov (United States)

    Chong, Semin; Lee, Kyung Soo; Chung, Myung Jin; Kim, Tae Sung; Kim, Hojoong; Kwon, O Jung; Choi, Yoon-Ho; Rhee, Chong H

    2005-06-01

    To determine overall detection rates of lung cancer by low-dose CT (LDCT) screening and to compare histopathologic and imaging differences of detected cancers between high- and low-risk groups, this study included 6,406 asymptomatic Korean adults with >or=45 yr of age who underwent LDCT for lung cancer screening. All were classified into high- (>or=20 pack-year smoking; 3,353) and low-risk (3,053; <20 pack-yr smoking and non-smokers) groups. We compared CT findings of detected cancers and detection rates between high- and low-risk. At initial CT, 35% (2,255 of 6,406) had at least one or more non-calcified nodule. Lung cancer detection rates were 0.36% (23 of 6,406). Twenty-one non-small cell lung cancers appeared as solid (n=14) or ground-glass opacity (GGO) (n=7) nodules. Cancer likelihood was higher in GGO nodules than in solid nodules (p<0.01). Fifteen of 23 cancers occurred in high-risk group and 8 in low-risk group (p=0.215). Therefore, LDCT screening help detect early stage of lung cancer in asymptomatic Korean population with detection rate of 0.36% on a population basis and may be useful for discovering early lung cancer in low-risk group as well as in high-risk group.

  19. SU-E-I-34: Evaluating Use of AEC to Lower Dose for Lung Cancer Screening CT Protocols

    International Nuclear Information System (INIS)

    Arbique, G; Anderson, J; Guild, J; Duan, X; Malguria, N; Omar, H; Brewington, C; Zhang, D

    2015-01-01

    Purpose: The National Lung Screening Trial mandated manual low dose CT technique factors, where up to a doubling of radiation output could be used over a regular to large patient size range. Recent guidance from the AAPM and ACR for lung cancer CT screening recommends radiation output adjustment for patient size either through AEC or a manual technique chart. This study evaluated the use of AEC for output control and dose reduction. Methods: The study was performed on a multidetector helical CT scanner (Aquillion ONE, Toshiba Medical) equipped with iterative reconstruction (ADIR-3D), AEC was adjusted with a standard deviation (SD) image quality noise index. The protocol SD parameter was incrementally increased to reduce patient population dose while image quality was evaluated by radiologist readers scoring the clinical utility of images on a Likert scale. Results: Plots of effective dose vs. body size (water cylinder diameter reported by the scanner) demonstrate monotonic increase in patient dose with increasing patient size. At the initial SD setting of 19 the average CTDIvol for a standard size patient was ∼ 2.0 mGy (1.2 mSv effective dose). This was reduced to ∼1.0 mGy (0.5 mSv) at an SD of 25 with no noticeable reduction in clinical utility of images as demonstrated by Likert scoring. Plots of effective patient diameter and BMI vs body size indicate that these metrics could also be used for manual technique charts. Conclusion: AEC offered consistent and reliable control of radiation output in this study. Dose for a standard size patient was reduced to one-third of the 3 mGy CTDIvol limit required for ACR accreditation of lung cancer CT screening. Gary Arbique: Research Grant, Toshiba America Medical Systems; Cecelia Brewington: Research Grant, Toshiba America Medical Systems; Di Zhang: Employee, Toshiba America Medical Systems

  20. Dosimetric comparison of stereotactic body radiotherapy using 4D CT and multiphase CT images for treatment planning of lung cancer: Evaluation of the impact on daily dose coverage

    International Nuclear Information System (INIS)

    Wang Lu; Hayes, Shelly; Paskalev, Kamen; Jin Lihui; Buyyounouski, Mark K.; Ma, Charlie C.-M.; Feigenberg, Steve

    2009-01-01

    Purpose: To investigate the dosimetric impact of using 4D CT and multiphase (helical) CT images for treatment planning target definition and the daily target coverage in hypofractionated stereotactic body radiotherapy (SBRT) of lung cancer. Materials and methods: For 10 consecutive patients treated with SBRT, a set of 4D CT images and three sets of multiphase helical CT scans, taken during free-breathing, end-inspiration and end-expiration breath-hold, were obtained. Three separate planning target volumes (PTVs) were created from these image sets. A PTV 4D was created from the maximum intensity projection (MIP) reconstructed 4D images by adding a 3 mm margin to the internal target volume (ITV). A PTV 3CT was created by generating ITV from gross target volumes (GTVs) contoured from the three multiphase images. Finally, a third conventional PTV (denoted PTV conv ) was created by adding 5 mm in the axial direction and 10 mm in the longitudinal direction to the GTV (in this work, GTV = CTV = clinical target volume) generated from free-breathing helical CT scans. Treatment planning was performed based on PTV 4D (denoted as Plan-1), and the plan was adopted for PTV 3CT and PTV conv to form Plan-2 and Plan-3, respectively, by superimposing 'Plan-1' onto the helical free-breathing CT data set using modified beam apertures that conformed to either PTV 3CT or PTV conv . We first studied the impact of PTV design on treatment planning by evaluating the dosimetry of the three PTVs under the three plans, respectively. Then we examined the effect of the PTV designs on the daily target coverage by utilizing pre-treatment localization CT (CT-on-rails) images for daily GTV contouring and dose recalculation. The changes in the dose parameters of D 95 and D 99 (the dose received by 95% and 99% of the target volume, respectively), and the V p (the volume receiving the prescription dose) of the daily GTVs were compared under the three plans before and after setup error correction

  1. Radiation dose response of normal lung assessed by Cone Beam CT - A potential tool for biologically adaptive radiation therapy

    International Nuclear Information System (INIS)

    Bertelsen, Anders; Schytte, Tine; Bentzen, Soren M.; Hansen, Olfred; Nielsen, Morten; Brink, Carsten

    2011-01-01

    Background: Density changes of healthy lung tissue during radiotherapy as observed by Cone Beam CT (CBCT) might be an early indicator of patient specific lung toxicity. This study investigates the time course of CBCT density changes and tests for a possible correlation with locally delivered dose. Methods: A total of 665 CBCTs in 65 lung cancer patients treated with IMRT/VMAT to 60 or 66 Gy in 2 Gy fractions were analyzed. For each patient, CBCT lung density changes during the treatment course were related to the locally delivered dose. Results: A dose response is observed for the patient population at the end of the treatment course. However, the observed dose response is highly variable among patients. Density changes at 10th and 20th fraction are clearly correlated to those observed at the end of the treatment course. Conclusions: CBCT density changes in healthy lung tissue during radiotherapy correlate with the locally delivered dose and can be detected relatively early during the treatment. If these density changes are correlated to subsequent clinical toxicity this assay could form the basis for biological adaptive radiotherapy.

  2. Percutaneous CT-guided high-dose brachytherapy (CT-HDRBT) ablation of primary and metastatic lung tumors in nonsurgical candidates; Perkutane CT-gesteuerte Hochdosis-Brachytherapie (CT-HDRBT) von primaeren und metastatischen Lungentumoren in nicht chirurgischen Kandidaten

    Energy Technology Data Exchange (ETDEWEB)

    Collettini, F.; Schnapauff, D.; Poellinger, A.; Denecke, T.; Banzer, J.; Golenia, M.J.; Gebauer, B. [Charite - Universitatesmedizin Berlin (Germany). Inst. fuer Radiologie; Wust, P. [Charite - Universitatesmedizin Berlin (Germany). Klinik fuer Strahlentherapie

    2012-04-15

    To evaluate the safety and efficacy of CT-guided high-dose brachytherapy (CT-HDRBT) ablation of primary and metastatic lung tumors. Between November 2007 and May 2010, all consecutive patients with primary or metastatic lung tumors, unsuitable for surgery, were treated with CT-HDRBT. Imaging follow-up after treatment was performed with contrast-enhanced CT at 6 weeks, 3 months and every 6 months after the procedure. The endpoints of the study were local tumor control and time to progression. The Kaplan-Meier method was used to estimate survival functions and local tumor progression rates. 34 procedures were carried out on 33 lesions in 22 patients. The mean diameter of the tumors was 33.3 mm (SD = 20.4). The first contrast-enhanced CT showed that complete ablation was achieved in all lesions. The mean minimal tumor enclosing dose was 18.9 Gy (SD = 2). Three patients developed a pneumothorax after the procedure. The mean follow-up time was 13.7 (3 - 29) months. 2 of 32 lesions (6.25 %) developed a local tumor progression. 8 patients (36.3 %) developed a distant tumor progression. After 17.7 months, 13 patients were alive and 9 patients had died. CT-HDRBT ablation is a safe and attractive treatment option for patients with lung malignancies and allows targeted destruction of tumor tissue with simultaneous preservation of important lung structures. Furthermore, CT-HDRBT is independent of the size of the lesion and its location within the lung parenchyma. (orig.)

  3. TH-AB-207A-12: CT Lung Cancer Screening and the Effects of Further Dose Reduction On CAD Performance

    International Nuclear Information System (INIS)

    Young, S; Lo, P; Hoffman, J; Kim, H; Hsu, W; Flores, C; Lee, G; Brown, M; McNitt-Gray, M

    2016-01-01

    Purpose: CT lung screening is already performed at low doses. In this study, we investigated the effects of further dose reduction on a lung-nodule CAD detection algorithm. Methods: The original raw CT data and images from 348 patients were obtained from our local database of National Lung Screening Trial (NLST) cases. 61 patients (17.5%) had at least one nodule reported on the NLST reader forms. All scans were acquired with fixed mAs (25 for standard-sized patients, 40 for large patients) on a 64-slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1-mm slice thickness, B50 kernel. Based on a previously-published technique, we added noise to the raw data to simulate reduced-dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, a CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to “truth”, defined as the approximate nodule centroids from the NLST forms. Sensitivities and false-positive rates (FPR) were calculated for each dose level, with a sub-analysis by nodule LungRADS category. Results: For larger category 4 nodules, median sensitivities were 100% at all three dose levels, and mean sensitivity decreased with dose. For the more challenging category 2 and 3 nodules, the dose dependence was less obvious. Overall, mean subject-level sensitivity varied from 38.5% at 100% dose to 40.4% at 50% dose, a difference of only 1.9%. However, median FPR quadrupled from 1 per case at 100% dose to 4 per case at 25% dose. Conclusions: Dose reduction affected nodule detectability differently depending on the LungRADS category, and FPR was very sensitive at sub-screening levels. Care should be taken to adapt CAD for the very challenging noise characteristics of screening. Funding support: NIH U01 CA181156; Disclosures (McNitt-Gray): Institutional research agreement, Siemens

  4. TH-AB-207A-12: CT Lung Cancer Screening and the Effects of Further Dose Reduction On CAD Performance

    Energy Technology Data Exchange (ETDEWEB)

    Young, S; Lo, P; Hoffman, J; Kim, H; Hsu, W; Flores, C; Lee, G; Brown, M; McNitt-Gray, M [UCLA School of Medicine, Los Angeles, CA (United States)

    2016-06-15

    Purpose: CT lung screening is already performed at low doses. In this study, we investigated the effects of further dose reduction on a lung-nodule CAD detection algorithm. Methods: The original raw CT data and images from 348 patients were obtained from our local database of National Lung Screening Trial (NLST) cases. 61 patients (17.5%) had at least one nodule reported on the NLST reader forms. All scans were acquired with fixed mAs (25 for standard-sized patients, 40 for large patients) on a 64-slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1-mm slice thickness, B50 kernel. Based on a previously-published technique, we added noise to the raw data to simulate reduced-dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, a CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to “truth”, defined as the approximate nodule centroids from the NLST forms. Sensitivities and false-positive rates (FPR) were calculated for each dose level, with a sub-analysis by nodule LungRADS category. Results: For larger category 4 nodules, median sensitivities were 100% at all three dose levels, and mean sensitivity decreased with dose. For the more challenging category 2 and 3 nodules, the dose dependence was less obvious. Overall, mean subject-level sensitivity varied from 38.5% at 100% dose to 40.4% at 50% dose, a difference of only 1.9%. However, median FPR quadrupled from 1 per case at 100% dose to 4 per case at 25% dose. Conclusions: Dose reduction affected nodule detectability differently depending on the LungRADS category, and FPR was very sensitive at sub-screening levels. Care should be taken to adapt CAD for the very challenging noise characteristics of screening. Funding support: NIH U01 CA181156; Disclosures (McNitt-Gray): Institutional research agreement, Siemens

  5. Incidental renal tumours on low-dose CT lung cancer screening exams.

    Science.gov (United States)

    Pinsky, Paul F; Dunn, Barbara; Gierada, David; Nath, P Hrudaya; Munden, Reginald; Berland, Lincoln; Kramer, Barnett S

    2017-06-01

    Introduction Renal cancer incidence has increased markedly in the United States in recent decades, largely due to incidentally detected tumours from computed tomography imaging. Here, we analyze the potential for low-dose computed tomography lung cancer screening to detect renal cancer. Methods The National Lung Screening Trial randomized subjects to three annual screens with either low-dose computed tomography or chest X-ray. Eligibility criteria included 30 + pack-years, current smoking or quit within 15 years, and age 55-74. Subjects were followed for seven years. Low-dose computed tomography screening forms collected information on lung cancer and non-lung cancer abnormalities, including abnormalities below the diaphragm. A reader study was performed on a sample of National Lung Screening Trial low-dose computed tomography images assessing presence of abnormalities below the diaphragms and abnormalities suspicious for renal cancer. Results There were 26,722 and 26,732 subjects enrolled in the low-dose computed tomography and chest X-ray arms, respectively, and there were 104 and 85 renal cancer cases diagnosed, respectively (relative risk = 1.22, 95% CI: 0.9-1.5). From 75,126 low-dose computed tomography screens, there were 46 renal cancer diagnoses within one year. Abnormalities below the diaphragm rates were 39.1% in screens with renal cancer versus 4.1% in screens without (P cancer cases versus 13% of non-cases had abnormalities below the diaphragms; 55% of cases and 0.8% of non-cases had a finding suspicious for renal cancer (P cancers. The benefits to harms tradeoff of incidental detection of renal tumours on low-dose computed tomography is unknown.

  6. More than lung cancer: Automated analysis of low-dose screening CT scans

    NARCIS (Netherlands)

    Mets, O.M.

    2012-01-01

    Smoking is a major health care problem and is projected to cause over 8 million deaths per year worldwide in the coming decades. To reduce lung cancer mortality in heavy smokers, several randomized screening trials were initiated in the past years using screening with low-dose Computed Tomography

  7. Helical CT for lung-cancer screening. 3. Fundamental study for ultra-low-dose CT by application of small tube current and filter

    International Nuclear Information System (INIS)

    Itoh, Shigeki; Koyama, Shuji; Tusaka, Masatoshi; Maekoshi, Hisashi; Satake, Hiroko; Ishigaki, Takeo.

    1996-01-01

    In order to develop ultra-low-dose helical CT for lung cancer screening, the effect of reduction of the tube current to 20 mA and application of a 10 mm thick aluminium filter upon radiation dose and image quality was evaluated with a phantom. Exposure dose at the center of a gantry and absorbed dose at the center of an acrylic phantom at 20 mA with the filter were 15% and 29% of the dose at 50 mA without the filter, respectively. For reduction of absorbed dose, reduction of the tube current was more useful than application of the filter. Image noise at 20 mA with the filter was double that at 50 mA without the filter. Neither reduction of the tube current nor application of the filter changed full width at half maximum on section sensitivity of the Z-axis. Although reduction of the tube current did not affect the difference in CT values between an acrylic sphere and styroform, application of the filter caused a reduction of 4.5% in the difference in CT values. Neither reduction of the tube current nor application of the filter affected the contrast resolution of the high-contrast phantom; however, that of the low-contrast phantom deteriorated. Although improvement of the filter and evaluation of clinical images are necessary, reduction of the tube current to 20 mA and application of the aluminium filter appear to be a promising method for ultra-low-dose helical CT of the lung. (author)

  8. 4D cone beam CT-based dose assessment for SBRT lung cancer treatment

    International Nuclear Information System (INIS)

    Cai, Weixing; Dhou, Salam; Cifter, Fulya; Myronakis, Marios; Hurwitz, Martina H; Williams, Christopher L; Berbeco, Ross I; Seco, Joao; Lewis, John H

    2016-01-01

    The purpose of this research is to develop a 4DCBCT-based dose assessment method for calculating actual delivered dose for patients with significant respiratory motion or anatomical changes during the course of SBRT. To address the limitation of 4DCT-based dose assessment, we propose to calculate the delivered dose using time-varying (‘fluoroscopic’) 3D patient images generated from a 4DCBCT-based motion model. The method includes four steps: (1) before each treatment, 4DCBCT data is acquired with the patient in treatment position, based on which a patient-specific motion model is created using a principal components analysis algorithm. (2) During treatment, 2D time-varying kV projection images are continuously acquired, from which time-varying ‘fluoroscopic’ 3D images of the patient are reconstructed using the motion model. (3) Lateral truncation artifacts are corrected using planning 4DCT images. (4) The 3D dose distribution is computed for each timepoint in the set of 3D fluoroscopic images, from which the total effective 3D delivered dose is calculated by accumulating deformed dose distributions. This approach is validated using six modified XCAT phantoms with lung tumors and different respiratory motions derived from patient data. The estimated doses are compared to that calculated using ground-truth XCAT phantoms. For each XCAT phantom, the calculated delivered tumor dose values generally follow the same trend as that of the ground truth and at most timepoints the difference is less than 5%. For the overall delivered dose, the normalized error of calculated 3D dose distribution is generally less than 3% and the tumor D95 error is less than 1.5%. XCAT phantom studies indicate the potential of the proposed method to accurately estimate 3D tumor dose distributions for SBRT lung treatment based on 4DCBCT imaging and motion modeling. Further research is necessary to investigate its performance for clinical patient data. (paper)

  9. Loss of lung function after chemo-radiotherapy for NSCLC measured by perfusion SPECT/CT: Correlation with radiation dose and clinical morbidity

    DEFF Research Database (Denmark)

    Farr, Katherina P; Møller, Ditte S; Khalil, Azza A

    2015-01-01

    BACKGROUND: The purpose of the study was to assess dose and time dependence of radiotherapy (RT)-induced changes in regional lung function measured with single photon emission computed tomography (SPECT) of the lung and relate these changes to the symptomatic endpoint of radiation pneumonitis (RP......) in patients treated for non-small cell lung cancer (NSCLC). MATERIAL AND METHODS: NSCLC patients scheduled to receive curative RT of minimum 60 Gy were included prospectively in the study. Lung perfusion SPECT/CT was performed before and three months after RT. Reconstructed SPECT/CT data were registered...

  10. Clinical application of low-dose CT combined with computer-aided detection in lung cancer screening

    International Nuclear Information System (INIS)

    Xu Zushan; Hou Hongjun; Xu Yan; Ma Daqing

    2010-01-01

    Objective: To investigate the clinical value of chest low-dose CT (LDCT) combined with computer-aided detection (CAD) system for lung cancer screening in high risk population. Methods: Two hundred and nineteen healthy candidates underwent 64-slice LDCT scan. All images were reviewed in consensus by two radiologists with 15 years of thoracic CT diagnosis experience. Then the image data were analyzed with CAD alone. Finally images were reviewed by two radiologists with 5 years of CT diagnosis experience with and without CT Viewer software. The sensitivity, false positive rate of CAD for pulmonary nodule detection were calculated. SPSS 11.5 software and Chi-square test were used for the statistics. Results: Of 219 candidates ,104(47.5% ) were detected with lung nodules. There were 366 true nodules confirmed by the senior radiologists. The CAD system detected 271 (74.0%) true nodules and 424 false-positive nodules. The false-positive rate was 1.94/per case. The two junior radiologists indentifid 292 (79.8%), 286(78.1%) nodules without CAD and 336 (91.8%), 333 (91.0%) nodules with CAD respectively. There were significant differences for radiologists in indentifying nodules with or without CAD system (P<0.01). Conclusions: CAD is more sensitive than radiologists for indentifying the nodules in the central area or in the hilar region of the lung. While radiologists are more sensitive for the peripheral and sub-pleural nodules,or ground glass opacity nodules, or nodules smaller than 4 mm. CAD can not be used alone. The detection rate can be improved with the combination of radiologist and CAD in LDCT screen. (authors)

  11. Early detection of lung cancer using ultra-low-dose computed tomography in coronary CT angiography scans among patients with suspected coronary heart disease.

    Science.gov (United States)

    Zanon, Matheus; Pacini, Gabriel Sartori; de Souza, Vinicius Valério Silveiro; Marchiori, Edson; Meirelles, Gustavo Souza Portes; Szarf, Gilberto; Torres, Felipe Soares; Hochhegger, Bruno

    2017-12-01

    To assess whether an additional chest ultra-low-dose CT scan to the coronary CT angiography protocol can be used for lung cancer screening among patients with suspected coronary artery disease. 175 patients underwent coronary CT angiography for assessment of coronary artery disease, additionally undergoing ultra-low-dose CT screening to early diagnosis of lung cancer in the same scanner (80kVp and 15mAs). Patients presenting pulmonary nodules were followed-up for two years, repeating low-dose CTs in intervals of 3, 6, or 12 months based on nodule size and growth rate in accordance with National Comprehensive Cancer Network guidelines. Ultra-low-dose CT identified 71 patients with solitary pulmonary nodules (41%), with a mean diameter of 5.50±4.00mm. Twenty-eight were >6mm, and in 79% (n=22) of these cases they were false positive findings, further confirmed by follow-up (n=20), resection (n=1), or biopsy (n=1). Lung cancer was detected in six patients due to CT screening (diagnostic yield: 3%). Among these, four cases could not be detected in the cardiac field of view. Most patients were in early stages of the disease. Two patients diagnosed at advanced stages died due to cancer complications. The addition of the ultra-low-dose CT scan represented a radiation dose increment of 1.22±0.53% (effective dose, 0.11±0.03mSv). Lung cancer might be detected using additional ultra-low-dose protocols in coronary CT angiography scans among patients with suspected coronary artery disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. The use of the multislice CT for the determination of respiratory lung tumor movement in stereotactic single-dose irradiation

    International Nuclear Information System (INIS)

    Hof, H.; Herfarth, K.K.; Muenter, M.; Debus, J.; Essig, M.; Wannenmacher, M.

    2003-01-01

    Background: In three-dimensional (3-D) precision high-dose radiation therapy of lung tumors, the exact definition of the planning target volume (PTV) is indispensable. Therefore, the feasibility of a 3-D determination of respiratory lung tumor movements by the use of a multislice CT scanner was investigated. Patients and Methods: The respiratory motion of 21 lung tumors in 20 consecutively treated patients was examined. An abdominal pressure device for the reduction of respiratory movement was used in 14 patients. Two regions of the tumor were each scanned repeatedly at the same table position, showing four simultaneously acquired slices for each cycle. Stereotactic coordinates were determined for one anatomic reference point in each tumor region (Figure 1). The 3-D differences of these coordinates between the sequentially obtained cycles were assessed (Figure 2), and a correlation with the tumor localization was performed. Results: In the craniocaudal (Z-)direction the mean tumor movement was 5.1 mm (standard deviation [SD] 2.4 mm, maximum 10 mm), in the ventrodorsal (Y-)direction 3.1 mm (SD 1.5 mm, maximum 6.7 mm), and in the lateral (X-)direction 2.6 mm (SD 1.4 mm, maximum 5.8 mm; Figures 3 to 5). Inter- and intraindividual differences were present in each direction. With an abdominal pressure device no clinically significant difference between tumors in different locations was seen. Conclusion: The 3-D assessment of lung tumor movements due to breathing is possible by the use of multislice CT. The determination, indispensable to the PTV definition, should be performed individually for several regions, because of the inter- and intraindividual deviations detected. (orig.)

  13. Uncertainties in planned dose due to the limited voxel size of the planning CT when treating lung tumors with proton therapy

    International Nuclear Information System (INIS)

    Espana, Samuel; Paganetti, Harald

    2011-01-01

    Dose calculation for lung tumors can be challenging due to the low density and the fine structure of the geometry. The latter is not fully considered in the CT image resolution used in treatment planning causing the prediction of a more homogeneous tissue distribution. In proton therapy, this could result in predicting an unrealistically sharp distal dose falloff, i.e. an underestimation of the distal dose falloff degradation. The goal of this work was the quantification of such effects. Two computational phantoms resembling a two-dimensional heterogeneous random lung geometry and a swine lung were considered applying a variety of voxel sizes for dose calculation. Monte Carlo simulations were used to compare the dose distributions predicted with the voxel size typically used for the treatment planning procedure with those expected to be delivered using the finest resolution. The results show, for example, distal falloff position differences of up to 4 mm between planned and expected dose at the 90% level for the heterogeneous random lung (assuming treatment plan on a 2 x 2 x 2.5 mm 3 grid). For the swine lung, differences of up to 38 mm were seen when airways are present in the beam path when the treatment plan was done on a 0.8 x 0.8 x 2.4 mm 3 grid. The two-dimensional heterogeneous random lung phantom apparently does not describe the impact of the geometry adequately because of the lack of heterogeneities in the axial direction. The differences observed in the swine lung between planned and expected dose are presumably due to the poor axial resolution of the CT images used in clinical routine. In conclusion, when assigning margins for treatment planning for lung cancer, proton range uncertainties due to the heterogeneous lung geometry and CT image resolution need to be considered.

  14. TU-G-204-09: The Effects of Reduced- Dose Lung Cancer Screening CT On Lung Nodule Detection Using a CAD Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Young, S; Lo, P; Kim, G; Hsu, W; Hoffman, J; Brown, M; McNitt-Gray, M [UCLA School of Medicine, Los Angeles, CA (United States)

    2015-06-15

    Purpose: While Lung Cancer Screening CT is being performed at low doses, the purpose of this study was to investigate the effects of further reducing dose on the performance of a CAD nodule-detection algorithm. Methods: We selected 50 cases from our local database of National Lung Screening Trial (NLST) patients for which we had both the image series and the raw CT data from the original scans. All scans were acquired with fixed mAs (25 for standard-sized patients, 40 for large patients) on a 64-slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1-mm slice thickness, B50 kernel. 10 of the cases had at least one nodule reported on the NLST reader forms. Based on a previously-published technique, we added noise to the raw data to simulate reduced-dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, the CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to “truth”, defined as the approximate nodule centroids from the NLST reports. Subject-level mean sensitivities and false-positive rates were calculated for each dose level. Results: The mean sensitivities of the CAD algorithm were 35% at the original dose, 20% at 50% dose, and 42.5% at 25% dose. The false-positive rates, in decreasing-dose order, were 3.7, 2.9, and 10 per case. In certain cases, particularly in larger patients, there were severe photon-starvation artifacts, especially in the apical region due to the high-attenuating shoulders. Conclusion: The detection task was challenging for the CAD algorithm at all dose levels, including the original NLST dose. However, the false-positive rate at 25% dose approximately tripled, suggesting a loss of CAD robustness somewhere between 0.5 and 1.0 mGy. NCI grant U01 CA181156 (Quantitative Imaging Network); Tobacco Related Disease Research Project grant 22RT-0131.

  15. TU-G-204-09: The Effects of Reduced- Dose Lung Cancer Screening CT On Lung Nodule Detection Using a CAD Algorithm

    International Nuclear Information System (INIS)

    Young, S; Lo, P; Kim, G; Hsu, W; Hoffman, J; Brown, M; McNitt-Gray, M

    2015-01-01

    Purpose: While Lung Cancer Screening CT is being performed at low doses, the purpose of this study was to investigate the effects of further reducing dose on the performance of a CAD nodule-detection algorithm. Methods: We selected 50 cases from our local database of National Lung Screening Trial (NLST) patients for which we had both the image series and the raw CT data from the original scans. All scans were acquired with fixed mAs (25 for standard-sized patients, 40 for large patients) on a 64-slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1-mm slice thickness, B50 kernel. 10 of the cases had at least one nodule reported on the NLST reader forms. Based on a previously-published technique, we added noise to the raw data to simulate reduced-dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, the CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to “truth”, defined as the approximate nodule centroids from the NLST reports. Subject-level mean sensitivities and false-positive rates were calculated for each dose level. Results: The mean sensitivities of the CAD algorithm were 35% at the original dose, 20% at 50% dose, and 42.5% at 25% dose. The false-positive rates, in decreasing-dose order, were 3.7, 2.9, and 10 per case. In certain cases, particularly in larger patients, there were severe photon-starvation artifacts, especially in the apical region due to the high-attenuating shoulders. Conclusion: The detection task was challenging for the CAD algorithm at all dose levels, including the original NLST dose. However, the false-positive rate at 25% dose approximately tripled, suggesting a loss of CAD robustness somewhere between 0.5 and 1.0 mGy. NCI grant U01 CA181156 (Quantitative Imaging Network); Tobacco Related Disease Research Project grant 22RT-0131

  16. Evaluation of low-dose CT implementation for lung cancer screening in a general practice hospital

    Science.gov (United States)

    Karostik, D. V.; Kamyshanskaya, I. G.; Cheremisin, V. M.; Drozdov, A. A.; Vodovatov, A. V.

    2018-02-01

    The aim of the current study was to evaluate the possibility of the implementation of LDCT for the screening for lung cancer and tuberculosis in a typical general hospital practice. Diagnostic and economic effectiveness, patient doses and the corresponding radiation risks for LDCT were compared with the existing digital chest screening radiography. The results of the study indicate that the implementation of LDCT allowed verifying false-positive cases or providing additional excessive diagnostic information, but did not significantly improve the sensitivity of screening. Per capita costs for LDCT were higher compared to digital radiography up to a factor of 12; corresponding radiation risk - by a factor of 4. Hence, it was considered unjustified to implement LDCT in a general practice hospital.

  17. Low-dose CT screening in an Asian population with diverse risk for lung cancer: A retrospective cohort study

    International Nuclear Information System (INIS)

    Yi, Chin A.; Lee, Kyung Soo; Shin, Myung-Hee; Cho, Yun Yung; Choi, Yoon-Ho; Kwon, O. Jung; Shin, Kyung Eun

    2015-01-01

    To evaluate the performance of low-dose CT (LDCT) screening for lung cancer (LCA) detection in an Asian population with diverse risks for LCA. LCA screening was performed in 12,427 symptomless Asian subjects using either LDCT (5,771) or chest radiography (CXR) (6,656) in a non-trial setting. Subjects were divided into high-risk and non-high-risk groups. Data were collected on the number of patients with screening-detected LCAs and their survival in order to compare outcomes between LDCT and CXR screening with the stratification of risks considering age, sex and smoking status. In the non-high-risk group, a significant difference was observed for the detection of lung cancer (adjusted OR, 5.07; 95 % CI, 2.72-9.45) and survival (adjusted HR of LCA survival between LDCT vs. CXR group, 0.08; 95 % CI, 0.01-0.62). No difference in detection or survival of LCA was noticed in the high-risk group. LCAs in the non-high-risk group were predominantly adenocarcinomas (96 %), and more likely to be part-solid or non-solid compared with those in the high-risk group (p = 0.023). In the non-high-risk group, LDCT helps detect more LCAs and offers better survival than CXR screening, due to better detection of part solid or non-solid lung adenocarcinomas. (orig.)

  18. Low-dose CT screening in an Asian population with diverse risk for lung cancer: A retrospective cohort study

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Chin A. [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Lee, Kyung Soo [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Shin, Myung-Hee; Cho, Yun Yung [Sungkyunkwan University School of Medicine, Department of Social and Preventive Medicine, Seoul (Korea, Republic of); Choi, Yoon-Ho [Sungkyunkwan University School of Medicine, Center for Health Promotion, Seoul (Korea, Republic of); Kwon, O. Jung [Sungkyunkwan University School of Medicine, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Seoul (Korea, Republic of); Shin, Kyung Eun [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul (Korea, Republic of)

    2015-08-15

    To evaluate the performance of low-dose CT (LDCT) screening for lung cancer (LCA) detection in an Asian population with diverse risks for LCA. LCA screening was performed in 12,427 symptomless Asian subjects using either LDCT (5,771) or chest radiography (CXR) (6,656) in a non-trial setting. Subjects were divided into high-risk and non-high-risk groups. Data were collected on the number of patients with screening-detected LCAs and their survival in order to compare outcomes between LDCT and CXR screening with the stratification of risks considering age, sex and smoking status. In the non-high-risk group, a significant difference was observed for the detection of lung cancer (adjusted OR, 5.07; 95 % CI, 2.72-9.45) and survival (adjusted HR of LCA survival between LDCT vs. CXR group, 0.08; 95 % CI, 0.01-0.62). No difference in detection or survival of LCA was noticed in the high-risk group. LCAs in the non-high-risk group were predominantly adenocarcinomas (96 %), and more likely to be part-solid or non-solid compared with those in the high-risk group (p = 0.023). In the non-high-risk group, LDCT helps detect more LCAs and offers better survival than CXR screening, due to better detection of part solid or non-solid lung adenocarcinomas. (orig.)

  19. Adaptive statistical iterative reconstruction-applied ultra-low-dose CT with radiography- comparable radiation dose: Usefulness for lung nodule detection

    International Nuclear Information System (INIS)

    Yoon, Hyun Jung; Chung, Myung Jin; Hwang, Hye Sun; Lee, Kyung Soo; Moon, Jung Won

    2015-01-01

    To assess the performance of adaptive statistical iterative reconstruction (ASIR)-applied ultra-low-dose CT (ULDCT) in detecting small lung nodules. Thirty patients underwent both ULDCT and standard dose CT (SCT). After determining the reference standard nodules, five observers, blinded to the reference standard reading results, independently evaluated SCT and both subsets of ASIR- and filtered back projection (FBP)-driven ULDCT images. Data assessed by observers were compared statistically. Converted effective doses in SCT and ULDCT were 2.81 ± 0.92 and 0.17 ± 0.02 mSv, respectively. A total of 114 lung nodules were detected on SCT as a standard reference. There was no statistically significant difference in sensitivity between ASIR-driven ULDCT and SCT for three out of the five observers (p = 0.678, 0.735, < 0.01, 0.038, and < 0.868 for observers 1, 2, 3, 4, and 5, respectively). The sensitivity of FBP-driven ULDCT was significantly lower than that of ASIR-driven ULDCT in three out of the five observers (p < 0.01 for three observers, and p = 0.064 and 0.146 for two observers). In jackknife alternative free-response receiver operating characteristic analysis, the mean values of figure-of-merit (FOM) for FBP, ASIR-driven ULDCT, and SCT were 0.682, 0.772, and 0.821, respectively, and there were no significant differences in FOM values between ASIR-driven ULDCT and SCT (p = 0.11), but the FOM value of FBP-driven ULDCT was significantly lower than that of ASIR-driven ULDCT and SCT (p = 0.01 and 0.00). Adaptive statistical iterative reconstruction-driven ULDCT delivering a radiation dose of only 0.17 mSv offers acceptable sensitivity in nodule detection compared with SCT and has better performance than FBP-driven ULDCT

  20. Adaptive statistical iterative reconstruction-applied ultra-low-dose CT with radiography- comparable radiation dose: Usefulness for lung nodule detection

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hyun Jung; Chung, Myung Jin; Hwang, Hye Sun; Lee, Kyung Soo [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Moon, Jung Won [Dept. of Radiology, Kangbuk Samsung Hospital, Seoul (Korea, Republic of)

    2015-10-15

    To assess the performance of adaptive statistical iterative reconstruction (ASIR)-applied ultra-low-dose CT (ULDCT) in detecting small lung nodules. Thirty patients underwent both ULDCT and standard dose CT (SCT). After determining the reference standard nodules, five observers, blinded to the reference standard reading results, independently evaluated SCT and both subsets of ASIR- and filtered back projection (FBP)-driven ULDCT images. Data assessed by observers were compared statistically. Converted effective doses in SCT and ULDCT were 2.81 ± 0.92 and 0.17 ± 0.02 mSv, respectively. A total of 114 lung nodules were detected on SCT as a standard reference. There was no statistically significant difference in sensitivity between ASIR-driven ULDCT and SCT for three out of the five observers (p = 0.678, 0.735, < 0.01, 0.038, and < 0.868 for observers 1, 2, 3, 4, and 5, respectively). The sensitivity of FBP-driven ULDCT was significantly lower than that of ASIR-driven ULDCT in three out of the five observers (p < 0.01 for three observers, and p = 0.064 and 0.146 for two observers). In jackknife alternative free-response receiver operating characteristic analysis, the mean values of figure-of-merit (FOM) for FBP, ASIR-driven ULDCT, and SCT were 0.682, 0.772, and 0.821, respectively, and there were no significant differences in FOM values between ASIR-driven ULDCT and SCT (p = 0.11), but the FOM value of FBP-driven ULDCT was significantly lower than that of ASIR-driven ULDCT and SCT (p = 0.01 and 0.00). Adaptive statistical iterative reconstruction-driven ULDCT delivering a radiation dose of only 0.17 mSv offers acceptable sensitivity in nodule detection compared with SCT and has better performance than FBP-driven ULDCT.

  1. Adaptive Statistical Iterative Reconstruction-Applied Ultra-Low-Dose CT with Radiography-Comparable Radiation Dose: Usefulness for Lung Nodule Detection.

    Science.gov (United States)

    Yoon, Hyun Jung; Chung, Myung Jin; Hwang, Hye Sun; Moon, Jung Won; Lee, Kyung Soo

    2015-01-01

    To assess the performance of adaptive statistical iterative reconstruction (ASIR)-applied ultra-low-dose CT (ULDCT) in detecting small lung nodules. Thirty patients underwent both ULDCT and standard dose CT (SCT). After determining the reference standard nodules, five observers, blinded to the reference standard reading results, independently evaluated SCT and both subsets of ASIR- and filtered back projection (FBP)-driven ULDCT images. Data assessed by observers were compared statistically. Converted effective doses in SCT and ULDCT were 2.81 ± 0.92 and 0.17 ± 0.02 mSv, respectively. A total of 114 lung nodules were detected on SCT as a standard reference. There was no statistically significant difference in sensitivity between ASIR-driven ULDCT and SCT for three out of the five observers (p = 0.678, 0.735, ASIR-driven ULDCT in three out of the five observers (p ASIR-driven ULDCT, and SCT were 0.682, 0.772, and 0.821, respectively, and there were no significant differences in FOM values between ASIR-driven ULDCT and SCT (p = 0.11), but the FOM value of FBP-driven ULDCT was significantly lower than that of ASIR-driven ULDCT and SCT (p = 0.01 and 0.00). Adaptive statistical iterative reconstruction-driven ULDCT delivering a radiation dose of only 0.17 mSv offers acceptable sensitivity in nodule detection compared with SCT and has better performance than FBP-driven ULDCT.

  2. Performance of ultralow-dose CT with iterative reconstruction in lung cancer screening: limiting radiation exposure to the equivalent of conventional chest X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Adrian [University Hospital Inselspital Bern, Department of Diagnostic, Interventional and Paediatric Radiology, Bern (Switzerland); University Hospital Pitie-Salpetriere, Department of Polyvalent and Oncological Radiology, Paris (France); Landau, Julia; Buetikofer, Yanik; Leidolt, Lars; Brela, Barbara; May, Michelle; Heverhagen, Johannes; Christe, Andreas [University Hospital Inselspital Bern, Department of Diagnostic, Interventional and Paediatric Radiology, Bern (Switzerland); Ebner, Lukas [University Hospital Inselspital Bern, Department of Diagnostic, Interventional and Paediatric Radiology, Bern (Switzerland); Duke University Medical Center, Department of Radiology, Durham, NC (United States)

    2016-10-15

    To investigate the detection rate of pulmonary nodules in ultralow-dose CT acquisitions. In this lung phantom study, 232 nodules (115 solid, 117 ground-glass) of different sizes were randomly distributed in a lung phantom in 60 different arrangements. Every arrangement was acquired once with standard radiation dose (100 kVp, 100 references mAs) and once with ultralow radiation dose (80 kVp, 6 mAs). Iterative reconstruction was used with optimized kernels: I30 for ultralow-dose, I70 for standard dose and I50 for CAD. Six radiologists examined the axial 1-mm stack for solid and ground-glass nodules. During a second and third step, three radiologists used maximum intensity projection (MIPs), finally checking with computer-assisted detection (CAD), while the others first used CAD, finally checking with the MIPs. The detection rate was 95.5 % with standard dose (DLP 126 mGy*cm) and 93.3 % with ultralow-dose (DLP: 9 mGy*cm). The additional use of either MIP reconstructions or CAD software could compensate for this difference. A combination of both MIP reconstructions and CAD software resulted in a maximum detection rate of 97.5 % with ultralow-dose. Lung cancer screening with ultralow-dose CT using the same radiation dose as a conventional chest X-ray is feasible. (orig.)

  3. Ultra-low-dose lung screening CT with model-based iterative reconstruction: an assessment of image quality and lesion conspicuity.

    Science.gov (United States)

    Ju, Yun Hye; Lee, Geewon; Lee, Ji Won; Hong, Seung Baek; Suh, Young Ju; Jeong, Yeon Joo

    2018-05-01

    Background Reducing radiation dose inevitably increases image noise, and thus, it is important in low-dose computed tomography (CT) to maintain image quality and lesion detection performance. Purpose To assess image quality and lesion conspicuity of ultra-low-dose CT with model-based iterative reconstruction (MBIR) and to determine a suitable protocol for lung screening CT. Material and Methods A total of 120 heavy smokers underwent lung screening CT and were randomly and equally assigned to one of five groups: group 1 = 120 kVp, 25 mAs, with FBP reconstruction; group 2 = 120 kVp, 10 mAs, with MBIR; group 3 = 100 kVp, 15 mAs, with MBIR; group 4 = 100 kVp, 10 mAs, with MBIR; and group 5 = 100 kVp, 5 mAs, with MBIR. Two radiologists evaluated intergroup differences with respect to radiation dose, image noise, image quality, and lesion conspicuity using the Kruskal-Wallis test and the Chi-square test. Results Effective doses were 61-87% lower in groups 2-5 than in group 1. Image noises in groups 1 and 5 were significantly higher than in the other groups ( P image quality was best in group 1, but diagnostic acceptability of overall image qualities in groups 1-3 was not significantly different (all P values > 0.05). Lesion conspicuities were similar in groups 1-4, but were significantly poorer in group 5. Conclusion Lung screening CT with MBIR obtained at 100 kVp and 15 mAs enables a ∼60% reduction in radiation dose versus low-dose CT, while maintaining image quality and lesion conspicuity.

  4. Clinical value of a one-stop-shop low-dose lung screening combined with 18F-FDG PET/CT for the detection of metastatic lung nodules from colorectal cancer

    International Nuclear Information System (INIS)

    Han, Yeon Hee; Lim, Seok Tae; Jeong, Hwan Jeong; Sohn, Myung Hee

    2016-01-01

    The aim of this study was to evaluate the clinical usefulness of additional low-dose high-resolution lung computed tomography (LD-HRCT) combined with 18F-fluoro-2-deoxyglucose positron emission tomography with CT (18F-FDG PET/CT) compared with conventional lung setting image of 18F-FDG PET/CT for the detection of metastatic lung nodules from colorectal cancer. From January 2011 to September 2011, 649 patients with colorectal cancer underwent additional LD-HRCT at maximum inspiration combined with 18F-FDG PET/CT. Forty-five patients were finally diagnosed to have lung metastasis based on histopathologic study or clinical follow-up. Twenty-five of the 45 patients had ≤5 metastatic lung nodules and the other 20 patients had  >5 metastatic nodules. One hundred and twenty nodules in the 25 patients with ≤5 nodules were evaluated by conventional lung setting image of 18F-FDG PET/CT and by additional LD-HRCT respectively. Sensitivities, specificities, diagnostic accuracies, positive predictive values (PPVs), and negative predictive values (NPVs) of conventional lung setting image of 18F-FDG PET/CT and additional LD-HRCT were calculated using standard formulae. The McNemar test and receiver-operating characteristic (ROC) analysis were performed. Of the 120 nodules in the 25 patients with ≤5 metastatic lung nodules, 66 nodules were diagnosed as metastatic. Eleven of the 66 nodules were confirmed histopathologically and the others were diagnosed by clinical follow-up. Conventional lung setting image of 18F-FDG PET/CT detected 40 of the 66 nodules and additional LD-HRCT detected 55 nodules. All 15 nodules missed by conventional lung setting imaging but detected by additional LD-HRCT were <1 cm in size. The sensitivity, specificity, and diagnostic accuracy of the modalities were 60.6 %, 85.2 %, and 71.1 % for conventional lung setting image and 83.3 %, 88.9 %, and 85.8 % for additional LD-HRCT. By ROC analysis, the area under the ROC curve (AUC) of conventional

  5. Clinical value of a one-stop-shop low-dose lung screening combined with {sup 18}F-FDG PET/CT for the detection of metastatic lung nodules from colorectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yeon Hee; Lim, Seok Tae; Jeong, Hwan Jeong; Sohn, Myung Hee [Dept. of Nuclear Medicine, Research Institute of Clinical Medicine, Chonbuk National University-Biomedical Research Institute, Chonbuk National University Hospital, Cyclotron Research Center, Molecular Imaging and Therapeutic Medicine Research Center, Chonbuk National University Medical School and Hospital, Jeonju (Korea, Republic of)

    2016-06-15

    The aim of this study was to evaluate the clinical usefulness of additional low-dose high-resolution lung computed tomography (LD-HRCT) combined with 18F-fluoro-2-deoxyglucose positron emission tomography with CT (18F-FDG PET/CT) compared with conventional lung setting image of 18F-FDG PET/CT for the detection of metastatic lung nodules from colorectal cancer. From January 2011 to September 2011, 649 patients with colorectal cancer underwent additional LD-HRCT at maximum inspiration combined with 18F-FDG PET/CT. Forty-five patients were finally diagnosed to have lung metastasis based on histopathologic study or clinical follow-up. Twenty-five of the 45 patients had ≤5 metastatic lung nodules and the other 20 patients had  >5 metastatic nodules. One hundred and twenty nodules in the 25 patients with ≤5 nodules were evaluated by conventional lung setting image of 18F-FDG PET/CT and by additional LD-HRCT respectively. Sensitivities, specificities, diagnostic accuracies, positive predictive values (PPVs), and negative predictive values (NPVs) of conventional lung setting image of 18F-FDG PET/CT and additional LD-HRCT were calculated using standard formulae. The McNemar test and receiver-operating characteristic (ROC) analysis were performed. Of the 120 nodules in the 25 patients with ≤5 metastatic lung nodules, 66 nodules were diagnosed as metastatic. Eleven of the 66 nodules were confirmed histopathologically and the others were diagnosed by clinical follow-up. Conventional lung setting image of 18F-FDG PET/CT detected 40 of the 66 nodules and additional LD-HRCT detected 55 nodules. All 15 nodules missed by conventional lung setting imaging but detected by additional LD-HRCT were <1 cm in size. The sensitivity, specificity, and diagnostic accuracy of the modalities were 60.6 %, 85.2 %, and 71.1 % for conventional lung setting image and 83.3 %, 88.9 %, and 85.8 % for additional LD-HRCT. By ROC analysis, the area under the ROC curve (AUC) of conventional

  6. High-resolution CT of the lung in asbestos-exposed subjects. Comparison of low-dose and high-dose HRCT

    International Nuclear Information System (INIS)

    Majurin, M.L.; Varpula, M.; Kurki, T.; Pakkala, L.

    1994-01-01

    The lowest possible mAs settings for high-resolution CT (HRCT) were studied on 45 individuals with suspected asbestos-related lung disease. All patients were investigated with 5 to 6 high-dose HRCT images (120 kVp/160 mA/2 s) at 3-cm intervals. At a selected level 4 additional low-dose images were obtained on each patient with lower mAs settings (100 mA/2 s, 80 mA/2 s, 60 mA/2 s, 30 mA/2 s). Thirty-seven subjects out of 45 had HRCT lesions compatible with asbestosis. HRCT images obtained with as low as 60 mA/2 s settings clearly showed pleural tractions and thickenings, parenchymal bands, honeycombing and subpleural curvilinear shadows, whereas in the evaluation of subpleural short lines and ground glass findings 80 mA/2 s were required. The lowest setting, 30 mA/2 s, was sufficient only in detecting and evaluating pleural tractions and thickenings. We conclude that 160 mAs yield good quality HRCT images, with substantial decrease of radiation dose, for the evaluation of asbestos-related lesions. (orig.)

  7. Perfusion CT of the Brain and Liver and of Lung Tumors: Use of Monte Carlo Simulation for Patient Dose Estimation for Examinations With a Cone-Beam 320-MDCT Scanner.

    Science.gov (United States)

    Cros, Maria; Geleijns, Jacob; Joemai, Raoul M S; Salvadó, Marçal

    2016-01-01

    The purpose of this study was to estimate the patient dose from perfusion CT examinations of the brain, lung tumors, and the liver on a cone-beam 320-MDCT scanner using a Monte Carlo simulation and the recommendations of the International Commission on Radiological Protection (ICRP). A Monte Carlo simulation based on the Electron Gamma Shower Version 4 package code was used to calculate organ doses and the effective dose in the reference computational phantoms for an adult man and adult woman as published by the ICRP. Three perfusion CT acquisition protocols--brain, lung tumor, and liver perfusion--were evaluated. Additionally, dose assessments were performed for the skin and for the eye lens. Conversion factors were obtained to estimate effective doses and organ doses from the volume CT dose index and dose-length product. The sex-averaged effective doses were approximately 4 mSv for perfusion CT of the brain and were between 23 and 26 mSv for the perfusion CT body protocols. The eye lens dose from the brain perfusion CT examination was approximately 153 mGy. The sex-averaged peak entrance skin dose (ESD) was 255 mGy for the brain perfusion CT studies, 157 mGy for the lung tumor perfusion CT studies, and 172 mGy for the liver perfusion CT studies. The perfusion CT protocols for imaging the brain, lung tumors, and the liver performed on a 320-MDCT scanner yielded patient doses that are safely below the threshold doses for deterministic effects. The eye lens dose, peak ESD, and effective doses can be estimated for other clinical perfusion CT examinations from the conversion factors that were derived in this study.

  8. Using YOLO based deep learning network for real time detection and localization of lung nodules from low dose CT scans

    Science.gov (United States)

    Ramachandran S., Sindhu; George, Jose; Skaria, Shibon; V. V., Varun

    2018-02-01

    Lung cancer is the leading cause of cancer related deaths in the world. The survival rate can be improved if the presence of lung nodules are detected early. This has also led to more focus being given to computer aided detection (CAD) and diagnosis of lung nodules. The arbitrariness of shape, size and texture of lung nodules is a challenge to be faced when developing these detection systems. In the proposed work we use convolutional neural networks to learn the features for nodule detection, replacing the traditional method of handcrafting features like geometric shape or texture. Our network uses the DetectNet architecture based on YOLO (You Only Look Once) to detect the nodules in CT scans of lung. In this architecture, object detection is treated as a regression problem with a single convolutional network simultaneously predicting multiple bounding boxes and class probabilities for those boxes. By performing training using chest CT scans from Lung Image Database Consortium (LIDC), NVIDIA DIGITS and Caffe deep learning framework, we show that nodule detection using this single neural network can result in reasonably low false positive rates with high sensitivity and precision.

  9. Clinical Value of a One-Stop-Shop Low-Dose Lung Screening Combined with (18)F-FDG PET/CT for the Detection of Metastatic Lung Nodules from Colorectal Cancer.

    Science.gov (United States)

    Han, Yeon-Hee; Lim, Seok Tae; Jeong, Hwan-Jeong; Sohn, Myung-Hee

    2016-06-01

    The aim of this study was to evaluate the clinical usefulness of additional low-dose high-resolution lung computed tomography (LD-HRCT) combined with (18)F-fluoro-2-deoxyglucose positron emission tomography with CT ((18)F-FDG PET/CT) compared with conventional lung setting image of (18)F-FDG PET/CT for the detection of metastatic lung nodules from colorectal cancer. From January 2011 to September 2011, 649 patients with colorectal cancer underwent additional LD-HRCT at maximum inspiration combined with (18)F-FDG PET/CT. Forty-five patients were finally diagnosed to have lung metastasis based on histopathologic study or clinical follow-up. Twenty-five of the 45 patients had ≤5 metastatic lung nodules and the other 20 patients had >5 metastatic nodules. One hundred and twenty nodules in the 25 patients with ≤5 nodules were evaluated by conventional lung setting image of (18)F-FDG PET/CT and by additional LD-HRCT respectively. Sensitivities, specificities, diagnostic accuracies, positive predictive values (PPVs), and negative predictive values (NPVs) of conventional lung setting image of (18)F-FDG PET/CT and additional LD-HRCT were calculated using standard formulae. The McNemar test and receiver-operating characteristic (ROC) analysis were performed. Of the 120 nodules in the 25 patients with ≤5 metastatic lung nodules, 66 nodules were diagnosed as metastatic. Eleven of the 66 nodules were confirmed histopathologically and the others were diagnosed by clinical follow-up. Conventional lung setting image of (18)F-FDG PET/CT detected 40 of the 66 nodules and additional LD-HRCT detected 55 nodules. All 15 nodules missed by conventional lung setting imaging but detected by additional LD-HRCT were LD-HRCT. By ROC analysis, the area under the ROC curve (AUC) of conventional lung setting image and additional LD-HRCT were 0.712 and 0.827 respectively. Additional LD-HRCT with maximum inspiration was superior to conventional lung setting image of (18)F-FDG PET/CT

  10. SU-C-202-04: Adapting Biologically Optimized Dose Escalation Based On Mid-Treatment PET/CT for Non-Small-Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, P; Kuo, L; Yorke, E; Hu, Y; Lockney, N; Mageras, G; Deasy, J; Rimner, A [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

    2016-06-15

    Purpose: To develop a biological modeling strategy which incorporates the response observed on the mid-treatment PET/CT into a dose escalation design for adaptive radiotherapy of non-small-cell lung cancer. Method: FDG-PET/CT was acquired midway through standard fractionated treatment and registered to pre-treatment planning PET/CT to evaluate radiation response of lung cancer. Each mid-treatment PET voxel was assigned the median SUV inside a concentric 1cm-diameter sphere to account for registration and imaging uncertainties. For each voxel, the planned radiation dose, pre- and mid-treatment SUVs were used to parameterize the linear-quadratic model, which was then utilized to predict the SUV distribution after the full prescribed dose. Voxels with predicted post-treatment SUV≥2 were identified as the resistant target (response arm). An adaptive simultaneous integrated boost was designed to escalate dose to the resistant target as high as possible, while keeping prescription dose to the original target and lung toxicity intact. In contrast, an adaptive target volume was delineated based only on the intensity of mid-treatment PET/CT (intensity arm), and a similar adaptive boost plan was optimized. The dose escalation capability of the two approaches was compared. Result: Images of three patients were used in this planning study. For one patient, SUV prediction indicated complete response and no necessary dose escalation. For the other two, resistant targets defined in the response arm were multifocal, and on average accounted for 25% of the pre-treatment target, compared to 67% in the intensity arm. The smaller response arm targets led to a 6Gy higher mean target dose in the adaptive escalation design. Conclusion: This pilot study suggests that adaptive dose escalation to a biologically resistant target predicted from a pre- and mid-treatment PET/CT may be more effective than escalation based on the mid-treatment PET/CT alone. More plans and ultimately clinical

  11. Lung cancer incidence and mortality in National Lung Screening Trial participants who underwent low-dose CT prevalence screening: a retrospective cohort analysis of a randomised, multicentre, diagnostic screening trial.

    Science.gov (United States)

    Patz, Edward F; Greco, Erin; Gatsonis, Constantine; Pinsky, Paul; Kramer, Barnett S; Aberle, Denise R

    2016-05-01

    Annual low-dose CT screening for lung cancer has been recommended for high-risk individuals, but the necessity of yearly low-dose CT in all eligible individuals is uncertain. This study examined rates of lung cancer in National Lung Screening Trial (NLST) participants who had a negative prevalence (initial) low-dose CT screen to explore whether less frequent screening could be justified in some lower-risk subpopulations. We did a retrospective cohort analysis of data from the NLST, a randomised, multicentre screening trial comparing three annual low-dose CT assessments with three annual chest radiographs for the early detection of lung cancer in high-risk, eligible individuals (aged 55-74 years with at least a 30 pack-year history of cigarette smoking, and, if a former smoker, had quit within the past 15 years), recruited from US medical centres between Aug 5, 2002, and April 26, 2004. Participants were followed up for up to 5 years after their last annual screen. For the purposes of this analysis, our cohort consisted of all NLST participants who had received a low-dose CT prevalence (T0) screen. We determined the frequency, stage, histology, study year of diagnosis, and incidence of lung cancer, as well as overall and lung cancer-specific mortality, and whether lung cancers were detected as a result of screening or within 1 year of a negative screen. We also estimated the effect on mortality if the first annual (T1) screen in participants with a negative T0 screen had not been done. The NLST is registered with ClinicalTrials.gov, number NCT00047385. Our cohort consisted of 26 231 participants assigned to the low-dose CT screening group who had undergone their T0 screen. The 19 066 participants with a negative T0 screen had a lower incidence of lung cancer than did all 26 231 T0-screened participants (371·88 [95% CI 337·97-408·26] per 100 000 person-years vs 661·23 [622·07-702·21]) and had lower lung cancer-related mortality (185·82 [95% CI 162·17

  12. CT dose management

    International Nuclear Information System (INIS)

    Zasheva, Ts.; Georgiev, E.; Kirova, G.

    2013-01-01

    Full text: Introduction: In recent decades Computed Tomography established itself as one of the most common study with a very wide range of applications and techniques of scanning. Best diagnostic value of the method resist to the risks of ionizing radiation, as statistics show that CT is one of the main sources of continuously increasing dose to the population. What you will learn: The physical parameters of the X-ray tube and the principles of image reconstruction; The relationship between variables parameters and the received dose; The ratio between the force and voltage of the current to the image quality, Influence of the used contrast medium to the physical properties of the image, The ratio of patient BMI to image processing, Effective use of knowledge for the optimal CT protocol. Discussions: The goal to reduce the dose received by the patient during a CT scan while keeping the diagnostic quality of the image puts to the test as handset X-ray producers and technicians who need to master the technique of study protocol forming as well as to balance the harm - benefit ratio. Among the most popular techniques are these of dose modulation, low-dose computed tomography at the expense of a reduction of the current or voltage intensity, and control of the number of post-processing algorithms for the image reconstruction. Conclusion: The training of radiologists and X-ray technicians plays a major role in optimizing of technical parameters in view of the reduction of the dose for the patient, while maintaining the diagnostic quality of the image

  13. TU-F-BRF-03: Effect of Radiation Therapy Planning Scan Registration On the Dose in Lung Cancer Patient CT Scans

    International Nuclear Information System (INIS)

    Cunliffe, A; Contee, C; White, B; Justusson, J; Armato, S; Malik, R; Al-Hallaq, H

    2014-01-01

    Purpose: To characterize the effect of deformable registration of serial computed tomography (CT) scans on the radiation dose calculated from a treatment planning scan. Methods: Eighteen patients who received curative doses (≥60Gy, 2Gy/fraction) of photon radiation therapy for lung cancer treatment were retrospectively identified. For each patient, a diagnostic-quality pre-therapy (4–75 days) CT scan and a treatment planning scan with an associated dose map calculated in Pinnacle were collected. To establish baseline correspondence between scan pairs, a researcher manually identified anatomically corresponding landmark point pairs between the two scans. Pre-therapy scans were co-registered with planning scans (and associated dose maps) using the Plastimatch demons and Fraunhofer MEVIS deformable registration algorithms. Landmark points in each pretherapy scan were automatically mapped to the planning scan using the displacement vector field output from both registration algorithms. The absolute difference in planned dose (|ΔD|) between manually and automatically mapped landmark points was calculated. Using regression modeling, |ΔD| was modeled as a function of the distance between manually and automatically matched points (registration error, E), the dose standard deviation (SD-dose) in the eight-pixel neighborhood, and the registration algorithm used. Results: 52–92 landmark point pairs (median: 82) were identified in each patient's scans. Average |ΔD| across patients was 3.66Gy (range: 1.2–7.2Gy). |ΔD| was significantly reduced by 0.53Gy using Plastimatch demons compared with Fraunhofer MEVIS. |ΔD| increased significantly as a function of E (0.39Gy/mm) and SD-dose (2.23Gy/Gy). Conclusion: An average error of <4Gy in radiation dose was introduced when points were mapped between CT scan pairs using deformable registration. Dose differences following registration were significantly increased when the Fraunhofer MEVIS registration algorithm was used

  14. Absorbed dose in CT. Comparison by CT dose index

    International Nuclear Information System (INIS)

    Yamamoto, Kenji; Akazawa, Hiroshi; Andou, Takashi

    2002-01-01

    Few reports have discussed the absorbed dose on CT units with increased scanning capacity even with the current widespread adoption of multi-slice CT units. To compare and investigate the dose indexes among CT units, we measured the absorbed dose on CT units operating in Nagano Prefecture Japan. The measurements showed proportionality between phantom absorbed dose and the exposured mAs values in conventional scanning operation. Further, the measurements showed that the absorbed dose in the center of the phantom differed by about 2.1-fold between the highest and lowest levels on individual CT units. Within a single company, multi-slice CT units of the same company gave absorbed doses of about 1.3 to 1.5 times those of conventional single-slice CT units under the same exposured conditions of conventional scanning. When the scanning pitch was reduced in helical scanning, the absorbed dose at the center of the phantom increased. (author)

  15. Optimal dose levels in screening chest CT for unimpaired detection and volumetry of lung nodules, with and without computer assisted detection at minimal patient radiation.

    Directory of Open Access Journals (Sweden)

    Andreas Christe

    Full Text Available OBJECTIVES: The aim of this phantom study was to minimize the radiation dose by finding the best combination of low tube current and low voltage that would result in accurate volume measurements when compared to standard CT imaging without significantly decreasing the sensitivity of detecting lung nodules both with and without the assistance of CAD. METHODS: An anthropomorphic chest phantom containing artificial solid and ground glass nodules (GGNs, 5-12 mm was examined with a 64-row multi-detector CT scanner with three tube currents of 100, 50 and 25 mAs in combination with three tube voltages of 120, 100 and 80 kVp. This resulted in eight different protocols that were then compared to standard CT sensitivity (100 mAs/120 kVp. For each protocol, at least 127 different nodules were scanned in 21-25 phantoms. The nodules were analyzed in two separate sessions by three independent, blinded radiologists and computer-aided detection (CAD software. RESULTS: The mean sensitivity of the radiologists for identifying solid lung nodules on a standard CT was 89.7% ± 4.9%. The sensitivity was not significantly impaired when the tube and current voltage were lowered at the same time, except at the lowest exposure level of 25 mAs/80 kVp [80.6% ± 4.3% (p = 0.031]. Compared to the standard CT, the sensitivity for detecting GGNs was significantly lower at all dose levels when the voltage was 80 kVp; this result was independent of the tube current. The CAD significantly increased the radiologists' sensitivity for detecting solid nodules at all dose levels (5-11%. No significant volume measurement errors (VMEs were documented for the radiologists or the CAD software at any dose level. CONCLUSIONS: Our results suggest a CT protocol with 25 mAs and 100 kVp is optimal for detecting solid and ground glass nodules in lung cancer screening. The use of CAD software is highly recommended at all dose levels.

  16. Lung nodule detection performance in five observers on computed tomography (CT) with adaptive iterative dose reduction using three-dimensional processing (AIDR 3D) in a Japanese multicenter study: Comparison between ultra-low-dose CT and low-dose CT by receiver-operating characteristic analysis.

    Science.gov (United States)

    Nagatani, Yukihiro; Takahashi, Masashi; Murata, Kiyoshi; Ikeda, Mitsuru; Yamashiro, Tsuneo; Miyara, Tetsuhiro; Koyama, Hisanobu; Koyama, Mitsuhiro; Sato, Yukihisa; Moriya, Hiroshi; Noma, Satoshi; Tomiyama, Noriyuki; Ohno, Yoshiharu; Murayama, Sadayuki

    2015-07-01

    To compare lung nodule detection performance (LNDP) in computed tomography (CT) with adaptive iterative dose reduction using three dimensional processing (AIDR3D) between ultra-low dose CT (ULDCT) and low dose CT (LDCT). This was part of the Area-detector Computed Tomography for the Investigation of Thoracic Diseases (ACTIve) Study, a multicenter research project being conducted in Japan. Institutional Review Board approved this study and informed consent was obtained. Eighty-three subjects (body mass index, 23.3 ± 3.2) underwent chest CT at 6 institutions using identical scanners and protocols. In a single visit, each subject was scanned using different tube currents: 240, 120 and 20 mA (3.52, 1.74 and 0.29 mSv, respectively). Axial CT images with 2-mm thickness/increment were reconstructed using AIDR3D. Standard of reference (SOR) was determined based on CT images at 240 mA by consensus reading of 2 board-certificated radiologists as to the presence of lung nodules with the longest diameter (LD) of more than 3mm. Another 5 radiologists independently assessed and recorded presence/absence of lung nodules and their locations by continuously-distributed rating in CT images at 20 mA (ULDCT) and 120 mA (LDCT). Receiver-operating characteristic (ROC) analysis was used to evaluate LNDP of both methods in total and also in subgroups classified by LD (>4, 6 and 8 mm) and nodular characteristics (solid and ground glass nodules). For SOR, 161 solid and 60 ground glass nodules were identified. No significant difference in LNDP for entire solid nodules was demonstrated between both methods, as area under ROC curve (AUC) was 0.844 ± 0.017 in ULDCT and 0.876 ± 0.026 in LDCT (p=0.057). For ground glass nodules with LD 8mm or more, LNDP was similar between both methods, as AUC 0.899 ± 0.038 in ULDCT and 0.941 ± 0.030 in LDCT. (p=0.144). ULDCT using AIDR3D with an equivalent radiation dose to chest x-ray could have comparable LNDP to LDCT with AIDR3D except for smaller ground

  17. Automated assessment of aortic and main pulmonary arterial diameters using model-based blood vessel segmentation for predicting chronic thromboembolic pulmonary hypertension in low-dose CT lung screening

    Science.gov (United States)

    Suzuki, Hidenobu; Kawata, Yoshiki; Niki, Noboru; Sugiura, Toshihiko; Tanabe, Nobuhiro; Kusumoto, Masahiko; Eguchi, Kenji; Kaneko, Masahiro

    2018-02-01

    Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by obstruction of the pulmonary vasculature by residual organized thrombi. A morphological abnormality inside mediastinum of CTEPH patient is enlargement of pulmonary artery. This paper presents an automated assessment of aortic and main pulmonary arterial diameters for predicting CTEPH in low-dose CT lung screening. The distinctive feature of our method is to segment aorta and main pulmonary artery using both of prior probability and vascular direction which were estimated from mediastinal vascular region using principal curvatures of four-dimensional hyper surface. The method was applied to two datasets, 64 lowdose CT scans of lung cancer screening and 19 normal-dose CT scans of CTEPH patients through the training phase with 121 low-dose CT scans. This paper demonstrates effectiveness of our method for predicting CTEPH in low-dose CT screening.

  18. WE-FG-207B-07: Feasibility of Low Dose Lung Cancer Screening with a Whole-Body Photon Counting CT: First Human Results

    International Nuclear Information System (INIS)

    Symons, R; Cork, T; Folio, L; Bluemke, D; Pourmorteza, A

    2016-01-01

    Purpose: To evaluate the feasibility of using a whole-body photon counting detector (PCD) CT scanner for low dose lung cancer screening compared to a conventional energy integrating detector (EID) system. Methods: Radiation dose-matched EID and PCD scans of the COPDGene 2 phantom and 2 human volunteers were acquired. Phantom images were acquired at different radiation dose levels (CTDIvol: 3.0, 1.5, and 0.75 mGy) and different tube voltages (120, 100, and 80 kVp), while human images were acquired at vendor recommended low-dose lung cancer screening settings. EID and PCD images were compared for quantitative Hounsfield unit accuracy, noise levels, and contrast-to-noise ratios (CNR) for detection of ground-glass nodules (GGNs) and emphysema. Results: The PCD Hounsfield unit accuracy was better for water at all scan parameters, and for lung, GGN and emphysema equivalent regions of interest (ROIs) at 1.5 and 0.75 mGy. PCD attenuation accuracy was more consistent for all scan parameters (all P<0.01), while Hounsfield units for lung, GGN and emphysema ROIs changed significantly for EID with decreasing dose (all P<0.001). PCD showed lower noise levels at the lowest dose setting at 120, 100 and 80 kVp (15.2±0.3 vs 15.8±0.2, P=0.03; 16.1±0.3 vs 18.0±0.4, P=0.003; and 16.1±0.3 vs 17.9±0.3, P=0.001, respectively), resulting in superior CNR for the detection of GGNs and emphysema at 100 and 80 kVp. Significantly lower PCD noise levels were confirmed in volunteer images. Conclusion: PCD provided better Hounsfield unit accuracy for lung, ground-glass, and emphysema-equivalent foams at 1.5 and 0.75 mGy with less variability than EID. Additionally, PCD showed less noise, and higher CNR at 0.75 mGy for both 100 and 80 kVp. PCD technology may help reduce radiation exposure in lung cancer screening while maintaining diagnostic quality.

  19. WE-FG-207B-07: Feasibility of Low Dose Lung Cancer Screening with a Whole-Body Photon Counting CT: First Human Results

    Energy Technology Data Exchange (ETDEWEB)

    Symons, R; Cork, T; Folio, L; Bluemke, D; Pourmorteza, A [National Institutes of Health Clinical Center, Bethesda, MD (United States)

    2016-06-15

    Purpose: To evaluate the feasibility of using a whole-body photon counting detector (PCD) CT scanner for low dose lung cancer screening compared to a conventional energy integrating detector (EID) system. Methods: Radiation dose-matched EID and PCD scans of the COPDGene 2 phantom and 2 human volunteers were acquired. Phantom images were acquired at different radiation dose levels (CTDIvol: 3.0, 1.5, and 0.75 mGy) and different tube voltages (120, 100, and 80 kVp), while human images were acquired at vendor recommended low-dose lung cancer screening settings. EID and PCD images were compared for quantitative Hounsfield unit accuracy, noise levels, and contrast-to-noise ratios (CNR) for detection of ground-glass nodules (GGNs) and emphysema. Results: The PCD Hounsfield unit accuracy was better for water at all scan parameters, and for lung, GGN and emphysema equivalent regions of interest (ROIs) at 1.5 and 0.75 mGy. PCD attenuation accuracy was more consistent for all scan parameters (all P<0.01), while Hounsfield units for lung, GGN and emphysema ROIs changed significantly for EID with decreasing dose (all P<0.001). PCD showed lower noise levels at the lowest dose setting at 120, 100 and 80 kVp (15.2±0.3 vs 15.8±0.2, P=0.03; 16.1±0.3 vs 18.0±0.4, P=0.003; and 16.1±0.3 vs 17.9±0.3, P=0.001, respectively), resulting in superior CNR for the detection of GGNs and emphysema at 100 and 80 kVp. Significantly lower PCD noise levels were confirmed in volunteer images. Conclusion: PCD provided better Hounsfield unit accuracy for lung, ground-glass, and emphysema-equivalent foams at 1.5 and 0.75 mGy with less variability than EID. Additionally, PCD showed less noise, and higher CNR at 0.75 mGy for both 100 and 80 kVp. PCD technology may help reduce radiation exposure in lung cancer screening while maintaining diagnostic quality.

  20. Detection of lung cancer through low-dose CT screening (NELSON): a prespecified analysis of screening test performance and interval cancers.

    Science.gov (United States)

    Horeweg, Nanda; Scholten, Ernst Th; de Jong, Pim A; van der Aalst, Carlijn M; Weenink, Carla; Lammers, Jan-Willem J; Nackaerts, Kristiaan; Vliegenthart, Rozemarijn; ten Haaf, Kevin; Yousaf-Khan, Uraujh A; Heuvelmans, Marjolein A; Thunnissen, Erik; Oudkerk, Matthijs; Mali, Willem; de Koning, Harry J

    2014-11-01

    Low-dose CT screening is recommended for individuals at high risk of developing lung cancer. However, CT screening does not detect all lung cancers: some might be missed at screening, and others can develop in the interval between screens. The NELSON trial is a randomised trial to assess the effect of screening with increasing screening intervals on lung cancer mortality. In this prespecified analysis, we aimed to assess screening test performance, and the epidemiological, radiological, and clinical characteristics of interval cancers in NELSON trial participants assigned to the screening group. Eligible participants in the NELSON trial were those aged 50-75 years, who had smoked 15 or more cigarettes per day for more than 25 years or ten or more cigarettes for more than 30 years, and were still smoking or had quit less than 10 years ago. We included all participants assigned to the screening group who had attended at least one round of screening. Screening test results were based on volumetry using a two-step approach. Initially, screening test results were classified as negative, indeterminate, or positive based on nodule presence and volume. Subsequently, participants with an initial indeterminate result underwent follow-up screening to classify their final screening test result as negative or positive, based on nodule volume doubling time. We obtained information about all lung cancer diagnoses made during the first three rounds of screening, plus an additional 2 years of follow-up from the national cancer registry. We determined epidemiological, radiological, participant, and tumour characteristics by reassessing medical files, screening CTs, and clinical CTs. The NELSON trial is registered at www.trialregister.nl, number ISRCTN63545820. 15,822 participants were enrolled in the NELSON trial, of whom 7915 were assigned to low-dose CT screening with increasing interval between screens, and 7907 to no screening. We included 7155 participants in our study, with

  1. Emphysema quantification on low-dose CT using percentage of low-attenuation volume and size distribution of low-attenuation lung regions: Effects of adaptive iterative dose reduction using 3D processing

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Mizuho, E-mail: nmizuho@med.kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Matsumoto, Sumiaki, E-mail: sumatsu@med.kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Seki, Shinichiro, E-mail: sshin@med.kobe-u.ac.jp [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Koyama, Hisanobu, E-mail: hkoyama@med.kobe-u.ac.jp [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Ohno, Yoshiharu, E-mail: yosirad@kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Fujisawa, Yasuko, E-mail: yasuko1.fujisawa@toshiba.co.jp [Toshiba Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi 324-8550 (Japan); Sugihara, Naoki, E-mail: naoki.sugihara@toshiba.co.jp [Toshiba Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi 324-8550 (Japan); and others

    2014-12-15

    Highlights: • Emphysema quantification (LAV% and D) was affected by image noise on low-dose CT. • For LAV% and D, AIDR 3D improved agreement of quantification on low-dose CT. • AIDR 3D has the potential to quantify emphysema accurately on low-dose CT. - Abstract: Purpose: To evaluate the effects of adaptive iterative dose reduction using 3D processing (AIDR 3D) for quantification of two measures of emphysema: percentage of low-attenuation volume (LAV%) and size distribution of low-attenuation lung regions. Method and materials: : Fifty-two patients who underwent standard-dose (SDCT) and low-dose CT (LDCT) were included. SDCT without AIDR 3D, LDCT without AIDR 3D, and LDCT with AIDR 3D were used for emphysema quantification. First, LAV% was computed at 10 thresholds from −990 to −900 HU. Next, at the same thresholds, linear regression on a log–log plot was used to compute the power law exponent (D) for the cumulative frequency-size distribution of low-attenuation lung regions. Bland–Altman analysis was used to assess whether AIDR 3D improved agreement between LDCT and SDCT for emphysema quantification of LAV% and D. Results: The mean relative differences in LAV% between LDCT without AIDR 3D and SDCT were 3.73%–88.18% and between LDCT with AIDR 3D and SDCT were −6.61% to 0.406%. The mean relative differences in D between LDCT without AIDR 3D and SDCT were 8.22%–19.11% and between LDCT with AIDR 3D and SDCT were 1.82%–4.79%. AIDR 3D improved agreement between LDCT and SDCT at thresholds from −930 to −990 HU for LAV% and at all thresholds for D. Conclusion: AIDR 3D improved the consistency between LDCT and SDCT for emphysema quantification of LAV% and D.

  2. Lung nodule detection performance in five observers on computed tomography (CT) with adaptive iterative dose reduction using three-dimensional processing (AIDR 3D) in a Japanese multicenter study: Comparison between ultra-low-dose CT and low-dose CT by receiver-operating characteristic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nagatani, Yukihiro, E-mail: yatsushi@belle.shiga-med.ac.jp [Department of Radiology, Shiga University of Medical Science, Otsu 520-2192, Shiga (Japan); Takahashi, Masashi; Murata, Kiyoshi [Department of Radiology, Shiga University of Medical Science, Otsu 520-2192, Shiga (Japan); Ikeda, Mitsuru [Department of Radiological and Medical Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Aichi (Japan); Yamashiro, Tsuneo [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa (Japan); Miyara, Tetsuhiro [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa (Japan); Department of Radiology, Okinawa Prefectural Yaeyama Hospital, Ishigaki 907-0022, Okinawa (Japan); Koyama, Hisanobu [Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo (Japan); Koyama, Mitsuhiro [Department of Radiology, Osaka Medical College, Takatsuki 569-8686, Osaka (Japan); Sato, Yukihisa [Department of Radiology, Osaka University Graduate School of Medicine, Suita 565-0871, Osaka (Japan); Department of Radiology, Osaka Medical Center of Cancer and Cardiovascular Diseases, Osaka 537-8511, Osaka (Japan); Moriya, Hiroshi [Department of Radiology, Ohara General Hospital, Fukushima 960-8611 (Japan); Noma, Satoshi [Department of Radiology, Tenri Hospital, Tenri 632-8552, Nara (Japan); Tomiyama, Noriyuki [Department of Radiology, Osaka University Graduate School of Medicine, Suita 565-0871, Osaka (Japan); Ohno, Yoshiharu [Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo (Japan); Murayama, Sadayuki [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa (Japan)

    2015-07-15

    Highlights: • Using AIDR 3D, ULDCT showed comparable LND of solid nodules to LDCT. • Using AIDR 3D, LND of smaller GGN in ULDCT was inferior to that in LDCT. • Effective dose in ULDCT was about only twice of that in chest X-ray. • BMI values in study population were mostly in the normal range body habitus. - Abstract: Purpose: To compare lung nodule detection performance (LNDP) in computed tomography (CT) with adaptive iterative dose reduction using three dimensional processing (AIDR3D) between ultra-low dose CT (ULDCT) and low dose CT (LDCT). Materials and methods: This was part of the Area-detector Computed Tomography for the Investigation of Thoracic Diseases (ACTIve) Study, a multicenter research project being conducted in Japan. Institutional Review Board approved this study and informed consent was obtained. Eighty-three subjects (body mass index, 23.3 ± 3.2) underwent chest CT at 6 institutions using identical scanners and protocols. In a single visit, each subject was scanned using different tube currents: 240, 120 and 20 mA (3.52, 1.74 and 0.29 mSv, respectively). Axial CT images with 2-mm thickness/increment were reconstructed using AIDR3D. Standard of reference (SOR) was determined based on CT images at 240 mA by consensus reading of 2 board-certificated radiologists as to the presence of lung nodules with the longest diameter (LD) of more than 3 mm. Another 5 radiologists independently assessed and recorded presence/absence of lung nodules and their locations by continuously-distributed rating in CT images at 20 mA (ULDCT) and 120 mA (LDCT). Receiver-operating characteristic (ROC) analysis was used to evaluate LNDP of both methods in total and also in subgroups classified by LD (>4, 6 and 8 mm) and nodular characteristics (solid and ground glass nodules). Results: For SOR, 161 solid and 60 ground glass nodules were identified. No significant difference in LNDP for entire solid nodules was demonstrated between both methods, as area under ROC

  3. Prevalance rate of low-dose CT lung cancer screening. Results of a questionnaire survey of member facilities of Japan society of ningen dock with special concerns regarding the actual status and disincentives for implementing such screening

    International Nuclear Information System (INIS)

    Takizawa, Hirotaka

    2012-01-01

    We conducted a survey of member facilities of the Japan Society of Ningen Dock to elucidate the actual status of chest computed tomography (CT) screening and the reasons for not being able to change to low-dose CT. We sent a questionnaire consisting of 9 items to 531 member facilities in July 2010, response by facsimile to obtain an analysis. The prevalence rate of low-dose CT lung cancer screening slightly increased to 35% in comparison with the former survey done in November 2008. Some facilities indicated some shift in tube current to a lower range even though this was insufficient to meet the definition of low-dose CT. This reflects their thinking of ''Even with knowledge, there is strong hesitation to change to low-dose CT''. Among the reasons why they did not change to low-dose CT, a priority for high quality images was the top reason among problems of devices and performance. Informed consent was not yet adequate. It is necessary for manufactures to develop better technology to improve the image quality of low-dose CT and to report enough information to clinicians. On the medical side, perception of the necessity for appropriate reduction of radiation dose and the decision to move to low-dose CT would be of crucial significance for facility heads as well as radiologists and technicians. (author)

  4. Spiral CT and radiation dose

    International Nuclear Information System (INIS)

    Imhof, H.; Schibany, N.; Ba-Ssalamah, A.; Czerny, C.; Hojreh, A.; Kainberger, F.; Krestan, C.; Kudler, H.; Noebauer, I.; Nowotny, R.

    2003-01-01

    Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981. Nowadays there are several modifications of the CTDI values, which may lead to confusion. It is suggested to use the standardized CTDI-100 w. value together with the dose length product in all CT-examinations. These values should be printed on all CT-images and allows an evaluation of the individualized patient dose. Nowadays, radiologist's aim must be to work at the lowest maximal diagnostic acceptable signal to noise ratio. To decrease radiation dose radiologist should use low kV and mA, but high pitches. Newly developed CT-dose-reduction soft-wares and filters should be installed in all CT-machines. We should critically compare the average dose used for a specific examination with the reference dose used in this country and/or Europe. Greater differences should caution the radiologist. Finally, we as radiologists must check very carefully all indications and recommend alternative imaging methods. But we have also to teach our customers--patients and medical doctors who are non-radiologists--that a 'good' image is not that which show all possible information, but that which visualize 'only' the diagnostic necessary information

  5. Identification of early-stage usual interstitial pneumonia from low-dose chest CT scans using fractional high-density lung distribution

    Science.gov (United States)

    Xie, Yiting; Salvatore, Mary; Liu, Shuang; Jirapatnakul, Artit; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2017-03-01

    A fully-automated computer algorithm has been developed to identify early-stage Usual Interstitial Pneumonia (UIP) using features computed from low-dose CT scans. In each scan, the pre-segmented lung region is divided into N subsections (N = 1, 8, 27, 64) by separating the lung from anterior/posterior, left/right and superior/inferior in 3D space. Each subsection has approximately the same volume. In each subsection, a classic density measurement (fractional high-density volume h) is evaluated to characterize the disease severity in that subsection, resulting in a feature vector of length N for each lung. Features are then combined in two different ways: concatenation (2*N features) and taking the maximum in each of the two corresponding subsections in the two lungs (N features). The algorithm was evaluated on a dataset consisting of 51 UIP and 56 normal cases, a combined feature vector was computed for each case and an SVM classifier (RBF kernel) was used to classify them into UIP or normal using ten-fold cross validation. A receiver operating characteristic (ROC) area under the curve (AUC) was used for evaluation. The highest AUC of 0.95 was achieved by using concatenated features and an N of 27. Using lung partition (N = 27, 64) with concatenated features had significantly better result over not using partitions (N = 1) (p-value < 0.05). Therefore this equal-volume partition fractional high-density volume method is useful in distinguishing early-stage UIP from normal cases.

  6. Reliable categorisation of visual scoring of coronary artery calcification on low-dose CT for lung cancer screening: validation with the standard Agatston score

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yi-Luan; Wu, Fu-Zong; Wang, Yen-Chi [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung 813 (China); National Yang Ming University, Faculty of Medicine, School of Medicine, Taipei (China); Ju, Yu-Jeng [National Taiwan University, Department of Psychology, Taipei (China); Mar, Guang-Yuan [Kaohsiung Veterans General Hospital, Division of Cardiology, Department of Medicine, Kaohsiung 813 (China); Chuo, Chiung-Chen [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung 813 (China); Lin, Huey-Shyan [Fooyin University, School of Nursing, Kaohsiung (China); Wu, Ming-Ting [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung 813 (China); National Yang Ming University, Faculty of Medicine, School of Medicine, Taipei (China); National Yang Ming University, Institute of Clinical Medicine, Taipei (China)

    2013-05-15

    To validate the reliability of the visual coronary artery calcification score (VCACS) on low-dose CT (LDCT) for concurrent screening of CAC and lung cancer. We enrolled 401 subjects receiving LDCT for lung cancer screening and ECG-gated CT for the Agatston score (AS). LDCT was reconstructed with 3- and 5-mm slice thickness (LDCT-3mm and LDCT-5mm respectively) for VCACS to obtain VCACS-3mm and VCACS-5mm respectively. After a training session comprising 32 cases, two observers performed four-scale VCACS (absent, mild, moderate, severe) of 369 data sets independently, the results were compared with four-scale AS (0, 1-100, 101-400, >400). CACs were present in 39.6 % (146/369) of subjects. The sensitivity of VCACS-3mm was higher than for VCACS-5mm (83.6 % versus 74.0 %). The median of AS of the 24 false-negative cases in VCACS-3mm was 2.3 (range 1.1-21.1). The false-negative rate for detecting AS {>=} 10 on LDCT-3mm was 1.9 %. VCACS-3mm had higher concordance with AS than VCACS-5mm (k = 0.813 versus k = 0.685). An extended test of VCACS-3mm for four junior observers showed high inter-observer reliability (intra-class correlation = 0.90) and good concordance with AS (k = 0.662-0.747). This study validated the reliability of VCACS on LDCT for lung cancer screening and showed that LDCT-3mm was more feasible than LDCT-5mm for CAD risk stratification. (orig.)

  7. Patient dose in CT fluoroscopy examinations

    International Nuclear Information System (INIS)

    Ito, Yusuke; Kobayashi, Masanao; Kataoka, Yumi; Ida, Yoshihiro; Kato, Ryoichi; Katada, Kazuhiro; Asada, Yasuki; Suzuki, Shoichi

    2008-01-01

    CT fluoroscopy(CTF) results in a high dose for the area under investigation in comparison with other types of examination. On the basis of data from April 2005 to March 2008, we measured the X-ray doses at the target site in CTF of the lungs, lumbar vertebrae, and pelvis as well as the X-ray dose to the female reproductive organs, and calculated the effective dose. The CT equipment used was an Aquilion 16. TLDs were inserted into an anthropomorphic phantom in positions corresponding to the target sites and the reproductive organs. Standard tube voltage and tube current were used as measurement conditions, and the scanning time used was the average value for each type of examination during the two years. Dose measurements were taken in the following order: scanography, helical scan, CTF, helical scan. X-ray element calibration was carried out through reciprocal comparison made between an ionization chamber dosimeter corrected according to government standards and the TLD for each tube voltage used for measurement. Dose estimation software was used to calculate the effective doses. During the two years there were 136 CTF examinations. These included 43 scans of the lungs, 13 of lumbar vertebrae, and 18 of the pelvis. The X-ray doses were 0.1 mGy at both the ovaries and the uterus for lung scans, 2 mGy at the ovaries and 1 mGy at the uterus for lumbar vertebrae scans, and 40 mGy at the ovaries and 20 mGy at the uterus for pelvic scans. The effective dose was highest for the lumbar vertebrae, followed by the lungs and finally the pelvis. (author)

  8. Mass preserving image registration for lung CT

    DEFF Research Database (Denmark)

    Gorbunova, Vladlena; Sporring, Jon; Lo, Pechin Chien Pau

    2012-01-01

    This paper presents a mass preserving image registration algorithm for lung CT images. To account for the local change in lung tissue intensity during the breathing cycle, a tissue appearance model based on the principle of preservation of total lung mass is proposed. This model is incorporated...... on four groups of data: 44 pairs of longitudinal inspiratory chest CT scans with small difference in lung volume; 44 pairs of longitudinal inspiratory chest CT scans with large difference in lung volume; 16 pairs of expiratory and inspiratory CT scans; and 5 pairs of images extracted at end exhale and end...

  9. CT dose reduction in children

    International Nuclear Information System (INIS)

    Vock, Peter

    2005-01-01

    World wide, the number of CT studies in children and the radiation exposure by CT increases. The same energy dose has a greater biological impact in children than in adults, and scan parameters have to be adapted to the smaller diameter of the juvenile body. Based on seven rules, a practical approach to paediatric CT is shown: Justification and patient preparation are important steps before scanning, and they differ from the preparation of adult patients. The subsequent choice of scan parameters aims at obtaining the minimal signal-to-noise ratio and volume coverage needed in a specific medical situation; exposure can be divided in two aspects: the CT dose index determining energy deposition per rotation and the dose-length product (DLP) determining the volume dose. DLP closely parallels the effective dose, the best parameter of the biological impact. Modern scanners offer dose modulation to locally minimise exposure while maintaining image quality. Beyond the selection of the physical parameters, the dose can be kept low by scanning the minimal length of the body and by avoiding any non-qualified repeated scanning of parts of the body. Following these rules, paediatric CT examinations of good quality can be obtained at a reasonable cost of radiation exposure. (orig.)

  10. Screenings of lung cancer with low dose spiral CT: results of a three year pilot study and design of the randomised controlled trial Italung-CT; Screening della neoplasia polmonare con TC spirale a bassa dose: risultati di uno studio pilota triennale e disegno dello studio clinico randomizzato Italung-CT

    Energy Technology Data Exchange (ETDEWEB)

    Picozzi, Giulia [Firenze Univ., Firenze (Italy). Radiodiagnostica I-Dipartimento di Fisiopatologia Clinica; Paci, Enrico [Azienda Ospedaliera Universitaria di Careggi, Firenze (Italy). Unita' di Epidemiologia Clinica e Descrittiva Centro per lo Studio e la Prevenzione Oncologica; Lopes Pegna, Andrea [Azienda Ospedaliera Universitaria di Careggi, Firenze (Italy). U.O. Pneumologia] [and others

    2005-02-01

    Purpose: To report the results of a three-year observational pilot study of lung cancer screening with low dose computed tomography (CT) and to present the study design of a randomised clinical trial named as Italung CT. Materials and methods: Sixty (47 males and 13 females, mean age 64{+-}4.5 years) heavy smokers (at least 20 packs-year) underwent three low-dose spiral CT screening tests one year apart on a single slice or multislice CT scanner. Indeterminate nodules were managed according to the recommendations of the Early Lung Cancer Action Project. Results: Indeterminate nodules were observed in 33 (55%) of the subjects (60% at the baseline screening test, 24% at the first annual test and 16% at the second annual test). The size of the largest indeterminate nodule was <5mm in diameter in 20 subjects. 10 of whom showed the nodule at the baseline test. Forty-five subjects (75%) completed the first annual test and 42 (70%) the second annual test. One (1.6%) prevalent lung cancer (adenosquamous carcinoma) and one (2.2%) incident lung cancer (small cell cancer at the first annual examination) were observed, as well as pulmonary localisation of Hodgkin's lymphoma (at the second annual test). In addition, one subject underwent lung surgery for a chondromatous hamartoma. Conclusions: The results of the pilot study are substantially in line with those of other observational studies of greater sample size. This justifies optimism about the reliability of the results in the screened arm of the Italung Ct trial which hast just began. [Italian] Scopo: Riportare i risultati di uno studio pilota osservazionale di screening della neoplasia polmonare con TC a bassa dose della durata di tre anni e presentare il disegno dello studio clinico randomizzato Italung-CT. Materiale e metodi: Sessanta (47 uomini e 13 donne, eta' media 64{+-}4,5 anni) forti fumatori (almeno 20 pacchetti/anno) sono stati sottoposti ad un esame basale e a due controlli annuali con TC single o

  11. Combined use of positron emission tomography and volume doubling time in lung cancer screening with low-dose CT scanning

    DEFF Research Database (Denmark)

    Ashraf, H; Dirksen, A; Jakobsen, Annika Loft

    2011-01-01

    In lung cancer screening the ability to distinguish malignant from benign nodules is a key issue. This study evaluates the ability of positron emission tomography (PET) and volume doubling time (VDT) to discriminate between benign and malignant nodules.......In lung cancer screening the ability to distinguish malignant from benign nodules is a key issue. This study evaluates the ability of positron emission tomography (PET) and volume doubling time (VDT) to discriminate between benign and malignant nodules....

  12. Reliability analysis of visual ranking of coronary artery calcification on low-dose CT of the thorax for lung cancer screening: comparison with ECG-gated calcium scoring CT.

    Science.gov (United States)

    Kim, Yoon Kyung; Sung, Yon Mi; Cho, So Hyun; Park, Young Nam; Choi, Hye-Young

    2014-12-01

    Coronary artery calcification (CAC) is frequently detected on low-dose CT (LDCT) of the thorax. Concurrent assessment of CAC and lung cancer screening using LDCT is beneficial in terms of cost and radiation dose reduction. The aim of our study was to evaluate the reliability of visual ranking of positive CAC on LDCT compared to Agatston score (AS) on electrocardiogram (ECG)-gated calcium scoring CT. We studied 576 patients who were consecutively registered for health screening and undergoing both LDCT and ECG-gated calcium scoring CT. We excluded subjects with an AS of zero. The final study cohort included 117 patients with CAC (97 men; mean age, 53.4 ± 8.5). AS was used as the gold standard (mean score 166.0; range 0.4-3,719.3). Two board-certified radiologists and two radiology residents participated in an observer performance study. Visual ranking of CAC was performed according to four categories (1-10, 11-100, 101-400, and 401 or higher) for coronary artery disease risk stratification. Weighted kappa statistics were used to measure the degree of reliability on visual ranking of CAC on LDCT. The degree of reliability on visual ranking of CAC on LDCT compared to ECG-gated calcium scoring CT was excellent for board-certified radiologists and good for radiology residents. A high degree of association was observed with 71.6% of visual rankings in the same category as the Agatston category and 98.9% varying by no more than one category. Visual ranking of positive CAC on LDCT is reliable for predicting AS rank categorization.

  13. The Danish randomized lung cancer CT screening trial

    DEFF Research Database (Denmark)

    Pedersen, Jesper H; Ashraf, Haseem; Dirksen, Asger

    2009-01-01

    INTRODUCTION: Lung cancer screening with low dose computed tomography (CT) has not yet been evaluated in randomized clinical trials, although several are underway. METHODS: In The Danish Lung Cancer Screening Trial, 4104 smokers and previous smokers from 2004 to 2006 were randomized to either...... lung cancer. Ten of these had stage I disease. Eleven of 17 lung cancers at baseline were treated surgically, eight of these by video assisted thoracic surgery resection. CONCLUSIONS: Screening may facilitate minimal invasive treatment and can be performed with a relatively low rate of false......-positive screen results compared with previous studies on lung cancer screening....

  14. Radiation dose and cancer risk from pediatric CT examinations on 64-slice CT: A phantom study

    International Nuclear Information System (INIS)

    Feng Shiting; Law, Martin Wai-Ming; Huang Bingsheng; Ng, Sherry; Li Ziping; Meng Quanfei; Khong, Pek-Lan

    2010-01-01

    Objective: To measure the radiation dose from CT scans in an anthropomorphic phantom using a 64-slice MDCT, and to estimate the associated cancer risk. Materials and methods: Organ doses were measured with a 5-year-old phantom and thermoluminescent dosimeters. Four protocols; head CT, thorax CT, abdomen CT and pelvis CT were studied. Cancer risks, in the form of lifetime attributable risk (LAR) of cancer incidence, were estimated by linear extrapolation using the organ radiation doses and the LAR data. Results: The effective doses for head, thorax, abdomen and pelvis CT, were 0.7 mSv, 3.5 mSv, 3.0 mSv, 1.3 mSv respectively. The organs with the highest dose were; for head CT, salivary gland (22.33 mGy); for thorax CT, breast (7.89 mGy); for abdomen CT, colon (6.62 mGy); for pelvis CT, bladder (4.28 mGy). The corresponding LARs for boys and girls were 0.015-0.053% and 0.034-0.155% respectively. The organs with highest LARs were; for head CT, thyroid gland (0.003% for boys, 0.015% for girls); for thorax CT, lung for boys (0.014%) and breast for girls (0.069%); for abdomen CT, colon for boys (0.017%) and lung for girls (0.016%); for pelvis CT, bladder for both boys and girls (0.008%). Conclusion: The effective doses from these common pediatric CT examinations ranged from 0.7 mSv to 3.5 mSv and the associated lifetime cancer risks were found to be up to 0.16%, with some organs of higher radiosensitivity including breast, thyroid gland, colon and lungs.

  15. Low-dose dental CT

    International Nuclear Information System (INIS)

    Rustemeyer, P.; Eich, H.T.; John-Mikolajewski, V.; Mueller, R.D.

    1999-01-01

    Purpose: The intention of this study was to reduce patient dose during dental CT in the planning for osseointegrated implants. Methods and Materials: Dental CTs were performed with a spiral CT (Somatom Plus 4, Siemens) and a dental software package. Use of the usual dental CT technique (120 kVp; 165 mA, 1 s rotation time, 165 mAs; pitch factor 1) was compared with a new protocol (120 kVp; 50 mA; 0.7 s rotation time; 35 mAs; pitch factor 2) which delivered the best image quality at the lowest possible radiation dose, as tested in a preceding study. Image quality was analysed using a human anatomic head preparation. Four radiologists analysed the images independently. A Wilcoxon rank pair-test was used for statistic evaluation. The doses to the thyroid gland, the active bone marrow, the salivary glands, and the eye lens were determined in a tissue-equivalent phantom (Alderson-Rando Phantom) with lithium fluoride thermoluminescent dosimeters at the appropriate locations. Results: By mAs reduction from 165 to 35 and using a pitch factor of 2, the radiation dose could be reduced by a factor of nine (max.) (e.g., the bone marrow dose could be reduced from 23.6 mSv to 2.9 mSv, eye lens from 0.5 mSv to 0.3 mSv, thyroid gland from 2.5 mSv to 0.5 mSv, parotid glands from 2.3 mSv to 0.4 mSv). The dose reduction did not lead to an actual loss of image quality or diagnostic information. Conclusion: A considerable dose reduction without loss of diagnostic information is achievable in dental CT. Dosereducing examination protocols like the one presented may further expand the use of preoperative dental CT. (orig.) [de

  16. [CT-Screening for Lung Cancer - what is the Evidence?

    Science.gov (United States)

    Watermann, Iris; Reck, Martin

    2018-04-01

    In patients with lung cancer treatment opportunities and prognosis are correlated to the stage of disease with a chance for curative treatment in patients with early stage disease. Therefore, early detection of lung cancer is of paramount importance for improving the prognosis of lung cancer patients.The National Lung Screening Trial (NLST) has already shown that low-dose CT increases the number of identified early stage lung cancer patients and reduces lung cancer related mortality. Critically considered in terms of CT-screening are false-positive results, overdiagnosis and unessential invasive clarification. Preliminary results of relatively small European trials haven´t yet confirmed the results of the NLST-study.Until now Lung Cancer Screening by low dose CT-scan or other methods is neither approved nor available in Germany.To improve the efficacy of CT-Screening and to introduce early detection of lung cancer in standard practice, additional, complementing methods should be further evaluated. One option might be the supplementary analysis of biomarkers in liquid biopsies or exhaled breath condensates. In addition, defining the high-risk population is of great relevance to identify candidates who might benefit of early detection programs. © Georg Thieme Verlag KG Stuttgart · New York.

  17. The mean lung dose (MLD). Predictive criterion for lung damage

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, Peter; Appold, Steffen [Dresden University of Technology (TU Dresden), Clinic and Polyclinic for Radiotherapy and Radiation Oncology, Carl Gustav Carus Medical Faculty, Dresden (Germany); Herrmann, Thomas

    2015-07-15

    The purpose of this work was to prove the validity of the mean lung dose (MLD), widely used in clinical practice to estimate the lung toxicity of a treatment plan, by reevaluating experimental data from mini pigs. A total of 43 mini pigs were irradiated in one of four dose groups (25, 29, 33, and 37 Gy). Two regimens were applied: homogeneous irradiation of the right lung or partial irradiation of both lungs - including parts with lower dose - but with similar mean lung doses. The animals were treated with five fractions with a linear accelerator applying a CT-based treatment plan. The clinical lung reaction (breathing frequency) and morphological changes in CT scans were examined frequently during the 48 weeks after irradiation. A clear dose-effect relationship was found for both regimens of the trial. However, a straightforward relationship between the MLD and the relative number of responders with respect to different grades of increased breathing frequency for both regimens was not found. A morphologically based parameter NTCP{sub lung} was found to be more suitable for this purpose. The dependence of this parameter on the MLD is markedly different for the two regimens. In clinical practice, the MLD can be used to predict lung toxicity of a treatment plan, except for dose values that could lead to severe side effects. In the latter mentioned case, limitations to the predictive value of the MLD are possible. Such severe developments of a radiation-induced pneumopathy are better predicted by the NTCP{sub lung} formalism. The predictive advantage of this parameter compared to the MLD seems to remain in the evaluation and comparison of widely differing dose distributions, like in the investigated trial. (orig.) [German] Es soll unter Reevaluation von Tierversuchsdaten am Minischwein geprueft werden, ob die in der klinischen Praxis zur Beurteilung der Lungentoxizitaet eines Bestrahlungsregims regelhaft verwendete mittlere Lungendosis (MLD) eine zuverlaessige

  18. Lung cancer mimicking lung abscess formation on CT images.

    Science.gov (United States)

    Taira, Naohiro; Kawabata, Tsutomu; Gabe, Atsushi; Ichi, Takaharu; Kushi, Kazuaki; Yohena, Tomofumi; Kawasaki, Hidenori; Yamashiro, Toshimitsu; Ishikawa, Kiyoshi

    2014-01-01

    Male, 64 FINAL DIAGNOSIS: Lung pleomorphic carcinoma Symptoms: Cough • fever - Clinical Procedure: - Specialty: Oncology. Unusual clinical course. The diagnosis of lung cancer is often made based on computed tomography (CT) image findings if it cannot be confirmed on pathological examinations, such as bronchoscopy. However, the CT image findings of cancerous lesions are similar to those of abscesses.We herein report a case of lung cancer that resembled a lung abscess on CT. We herein describe the case of 64-year-old male who was diagnosed with lung cancer using surgery. In this case, it was quite difficult to distinguish between the lung cancer and a lung abscess on CT images, and a lung abscess was initially suspected due to symptoms, such as fever and coughing, contrast-enhanced CT image findings showing a ring-enhancing mass in the right upper lobe and the patient's laboratory test results. However, a pathological diagnosis of lung cancer was confirmed according to the results of a rapid frozen section biopsy of the lesion. This case suggests that physicians should not suspect both a lung abscesses and malignancy in cases involving masses presenting as ring-enhancing lesions on contrast-enhanced CT.

  19. Relationship between radiation dose and lung function in patients with lung cancer receiving radiotherapy

    International Nuclear Information System (INIS)

    Harsaker, V.; Dale, E.; Bruland, O.S.; Olsen, D.R.

    2003-01-01

    In patients with inoperable non-small cell lung cancer (NSCLC), radical radiotherapy is the treatment of choice. The dose is limited by consequential pneumonitis and lung fibrosis. Hence, a better understanding of the relationship between the dose-volume distributions and normal tissue side effects is needed. CT is a non-invasive method to monitor the development of fibrosis and pneumonitis, and spirometry is an established tool to measure lung function. NSCLC patients were included in a multicenter trial and treated with megavoltage conformal radiotherapy. In a subgroup comprising 16 patients, a total dose of 59-63 Gy with 1.8-1.9 Gy per fraction was given. Dose-volume histograms were calculated and corrected according to the linear-quadratic formula using alpha/beta=3 Gy. The patients underwent repetitive CT examinations (mean follow-up, 133 days) following radiotherapy, and pre and post treatment spirometry (mean follow-up, 240 days). A significant correlation was demonstrated between local lung dose and changes in CT numbers >30 days after treatment (p 40 Gy Gy there was a sudden increase in CT numbers at 70-90 days. Somewhat unexpectedly, the highest mean lung doses were found in patients with the least reductions in lung function (peak expiratory flow; p<0.001). The correlation between CT numbers, radiation dose and time after treatment show that CT may be used to monitor development of lung fibrosis/pneumonitis after radiotherapy for lung cancer. Paradoxically, the patients with the highest mean lung doses experienced the minimum deterioration of lung function. This may be explained by reduction in the volume of existing tumour masses obstructing the airways, leading to relief of symptoms. This finding stresses the role of radiotherapy for lung cancer, especially where the treatment aim is palliative

  20. Lung cancer mimicking lung abscess formation on CT images

    OpenAIRE

    Taira, Naohiro; Kawabata, Tsutomu; Gabe, Atsushi; Ichi, Takaharu; Kushi, Kazuaki; Yohena, Tomofumi; Kawasaki, Hidenori; Yamashiro, Toshimitsu; Ishikawa, Kiyoshi

    2014-01-01

    Patient: Male, 64 Final Diagnosis: Lung pleomorphic carcinoma Symptoms: Cough • fever Medication: — Clinical Procedure: — Specialty: Oncology Objective: Unusual clinical course Background: The diagnosis of lung cancer is often made based on computed tomography (CT) image findings if it cannot be confirmed on pathological examinations, such as bronchoscopy. However, the CT image findings of cancerous lesions are similar to those of abscesses.We herein report a case of lung cancer that resemble...

  1. Estimation of absorbed and effective dose in {sup 18}F-FDG em PET- CT exams for diagnosis of lung cancer; Estimativa de dose absorvida e efetiva em exames de {sup 18}F-FDG em PET- CT para diagnostico de cancer de pulmao

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Guilherme Neto de Pinho; Santana, Priscila do Carmo, E-mail: guinpc1@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Anatomia e Imagem; Oliveira, Paulo Marcio Campos de; Reis, Lucas Paixao dos [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-04-15

    This paper presents an evaluation of tissues and organs absorbed doses as well as the effective dose resulting from PET-CT scans performed with {sup 18}F-FDG radiopharmaceutical for lung cancer diagnosis in whole body scans. The ICRP-106 biokinetic model was used to estimate the absorbed and effective doses from the radiopharmaceutical for both male and female patient according to the characteristics of anthropomorphic Alderson Rando® simulators. Computer Tomography doses were evaluated using thermoluminescent detectors inserted in the same anthropomorphic simulators. Optimization protocols for image acquisition and the use of automatic exposure control were used in order to reduce patient doses, taking into account the equipment model and its system. The effective dose in female patients was 5.8 mSv. The effective dose in male patients was 8.4 mSv. The dose values estimated for the {sup 18}F-FDG PET-CT scan are below the values described in the literature. This is because the CT was not used for diagnostic but for morphological mapping. (author)

  2. High resolution CT in diffuse lung disease

    International Nuclear Information System (INIS)

    Webb, W.R.

    1995-01-01

    High resolution CT (computerized tomography) was discussed in detail. The conclusions were HRCT is able to define lung anatomy at the secondary lobular level and define a variety of abnormalities in patients with diffuse lung diseases. Evidence from numerous studies indicates that HRCT can play a major role in the assessment of diffuse infiltrative lung disease and is indicate clinically (95 refs.)

  3. High resolution CT in diffuse lung disease

    Energy Technology Data Exchange (ETDEWEB)

    Webb, W R [California Univ., San Francisco, CA (United States). Dept. of Radiology

    1996-12-31

    High resolution CT (computerized tomography) was discussed in detail. The conclusions were HRCT is able to define lung anatomy at the secondary lobular level and define a variety of abnormalities in patients with diffuse lung diseases. Evidence from numerous studies indicates that HRCT can play a major role in the assessment of diffuse infiltrative lung disease and is indicate clinically (95 refs.).

  4. CT findings of inoperable lung carcinoma

    International Nuclear Information System (INIS)

    Gay, S.B.; Black, W.C.

    1987-01-01

    CT is useful in the evaluation of patients with newly diagnosed or highly suspected lung cancer. The principal role of CT is to screen those patients with metastatic disease beyond the hili from an attempt at curative thoracotomy. While CT is regarded as very sensitive, it is not considered highly specific, and thus a surgical procedure is usually recommended for definitive diagnosis of most ''positive'' CT findings. However, the authors demonstrate a few characteristic CT findings that are highly predictive of unresectable metastatic disease. These CT findings include massive mediastinal lymphadenopathy, diffuse mediastinal infiltration, pericardial involvement, vascular encasement, and advanced chest wall invasion

  5. Lung studies with spiral CT. pitch 1 versus pitch 2

    International Nuclear Information System (INIS)

    Sartoni Galloni, S.; Miceli, M.; Lipparino, M.; Burzi, M.; Gigli, F.; Rossi, M.S.; Santoli, G.; Guidarelli, G.

    1999-01-01

    In Spiral CT, the pitch is the ratio of the distance to tabletop travels per 360 degrees rotation to nominal slice width, expressed in mm. Performing Spiral CT examination with pitch 2 allows to reduce examination time, exposure and contrast dose, and X-ray tube overload. The authors investigated the yield of pitch 2 in lung parenchyma studies, particular relative to diagnostic image quality [it

  6. New approach to lung cancer screening with helical volume CT

    International Nuclear Information System (INIS)

    Midorikawa, S.; Hashimoto, N.; Katakura, T.; Suzuki, K.

    1990-01-01

    This paper evaluates the relationship between reducing radiation dose to the patient and maintaining the clinical quality of the chest image in lung cancer screening by helical-volume CT (HVCT). The authors evaluated the changing relationship between radiation dose and clinical quality after changing the HVCY scanning conditions (such as stroke of patient transport and section thickness) as well as adding copper filters of various thickness and using high-voltage x-ray examination to complement CT examinations. The authors were able to reduce radiation dose by changing the HVCT scanning conditions (eg, stroke of 20 mm/sec, with a section thickness of 10 mm)

  7. Systemic Air Embolism After CT-guided Lung Biopsy

    Science.gov (United States)

    2017-11-27

    Patients Who Underwent Percutaneous Lung Biopsy Under CT Guidance; Patients Who Presented Systemic Air Embolism After Percutaneous Lung Biopsy Under CT Guidance Depicted at the Time of the Procedure on a Whole Thoracic CT

  8. Low-dose Dental-CT

    International Nuclear Information System (INIS)

    Gahleitner, A.; Imhof, H.; Homolka, P.; Fuerhauser, R.; Freudenthaler, J.; Watzek, G.

    2000-01-01

    Dental-CT is a relatively new, increasingly used investigation technique in dental radiology. Several authors have stated that the indication for Dental-CT has to be chosen on a strict basis, due to high dose values. This article describes the technique of performing dental-CT and calculates the effective dose based on published data and own measurements as well as the dose reduction potential to achieve an optimized protocol for Dental-CT investigations. (orig.) [de

  9. Dose calculation with respiration-averaged CT processed from cine CT without a respiratory surrogate

    International Nuclear Information System (INIS)

    Riegel, Adam C.; Ahmad, Moiz; Sun Xiaojun; Pan Tinsu

    2008-01-01

    Dose calculation for thoracic radiotherapy is commonly performed on a free-breathing helical CT despite artifacts caused by respiratory motion. Four-dimensional computed tomography (4D-CT) is one method to incorporate motion information into the treatment planning process. Some centers now use the respiration-averaged CT (RACT), the pixel-by-pixel average of the ten phases of 4D-CT, for dose calculation. This method, while sparing the tedious task of 4D dose calculation, still requires 4D-CT technology. The authors have recently developed a means to reconstruct RACT directly from unsorted cine CT data from which 4D-CT is formed, bypassing the need for a respiratory surrogate. Using RACT from cine CT for dose calculation may be a means to incorporate motion information into dose calculation without performing 4D-CT. The purpose of this study was to determine if RACT from cine CT can be substituted for RACT from 4D-CT for the purposes of dose calculation, and if increasing the cine duration can decrease differences between the dose distributions. Cine CT data and corresponding 4D-CT simulations for 23 patients with at least two breathing cycles per cine duration were retrieved. RACT was generated four ways: First from ten phases of 4D-CT, second, from 1 breathing cycle of images, third, from 1.5 breathing cycles of images, and fourth, from 2 breathing cycles of images. The clinical treatment plan was transferred to each RACT and dose was recalculated. Dose planes were exported at orthogonal planes through the isocenter (coronal, sagittal, and transverse orientations). The resulting dose distributions were compared using the gamma (γ) index within the planning target volume (PTV). Failure criteria were set to 2%/1 mm. A follow-up study with 50 additional lung cancer patients was performed to increase sample size. The same dose recalculation and analysis was performed. In the primary patient group, 22 of 23 patients had 100% of points within the PTV pass γ criteria

  10. Nutrient intake and nutrient patterns and risk of lung cancer among heavy smokers: results from the COSMOS screening study with annual low-dose CT

    International Nuclear Information System (INIS)

    Gnagnarella, Patrizia; Maisonneuve, Patrick; Bellomi, Massimo; Rampinelli, Cristiano; Bertolotti, Raffaella; Spaggiari, Lorenzo; Palli, Domenico; Veronesi, Giulia

    2013-01-01

    The role of nutrients in lung cancer aetiology remains controversial and has never been evaluated in the context of screening. Our aim was to investigate the role of single nutrients and nutrient patterns in the aetiology of lung cancer in heavy smokers. Asymptomatic heavy smokers (≥20 pack-years) were invited to undergo annual low-dose computed tomography. We assessed diet using a self-administered food frequency questionnaire and collected information on multivitamin supplement use. We performed principal component analysis identifying four nutrient patterns and used Cox proportional Hazards regression to assess the association between nutrients and nutrients patterns and lung cancer risk. During a mean follow-up of 5.7 years, 178 of 4,336 participants were diagnosed with lung cancer by screening. We found a significant risk reduction of lung cancer with increasing vegetable fat consumption (HR for highest vs. lowest quartile = 0.50, 95 % CI = 0.31–0.80; P-trend = 0.02). Participants classified in the high “vitamins and fiber” pattern score had a significant risk reduction of lung cancer (HR = 0.57; 95 % CI = 0.36–0.90, P-trend = 0.01). Among heavy smokers enrolled in a screening trial, high vegetable fat intake and adherence to the “vitamin and fiber” nutrient pattern were associated with reduced lung cancer incidence.

  11. Segmentation of Lung Structures in CT

    DEFF Research Database (Denmark)

    Lo, Pechin Chien Pau

    This thesis proposes and evaluates new algorithms for segmenting various lung structures in computed tomography (CT) images, namely the lungs, airway trees and vessel trees. The main objective of these algorithms is to facilitate a better platform for studying Chronic Obstructive Pulmonary Disease......, 200 randomly selected CT scans were manually evaluated by medical experts, and only negligible or minor errors were found in nine scans. The proposed algorithm has been used to study how changes in smoking behavior affect CT based emphysema quantification. The algorithms for segmenting the airway...

  12. Monte Carlo dose calibration in CT scanner

    International Nuclear Information System (INIS)

    Yadav, Poonam; Ramasubramanian, V.; Subbaiah, K.V.; Thayalan, K.

    2008-01-01

    Computed Tomography (CT) scanner is a high radiation imaging modality compared to radiography. The dose from a CT examination can vary greatly depending on the particular CT scanner used, the area of the body examined, and the operating parameters of the scan. CT is a major contributor to collective effective dose in diagnostic radiology. Apart from the clinical benefits, the widespread use of multislice scanner is increasing radiation level to patient in comparison with conventional CT scanner. So, it becomes necessary to increase awareness about the CT scanner. (author)

  13. Radiation dose reduction in pediatric CT

    International Nuclear Information System (INIS)

    Robinson, A.E.; Hill, E.P.; Harpen, M.D.

    1986-01-01

    The relationship between image noise and radiation dose was investigated in computed tomography (CT) images of a pediatric abdomen phantom. A protocol which provided a minimum absorbed dose consistent with acceptable image noise criteria was determined for a fourth generation CT scanner. It was found that pediatric abdominal CT scans could maintain diagnostic quality with at least a 50% reduction in dose from the manufacturers' suggested protocol. (orig.)

  14. Neglectable benefit of searching for incidental findings in the Dutch-Belgian lung cancer screening trial (NELSON) using low-dose multidetector CT

    International Nuclear Information System (INIS)

    Wiel, J.C.M. van de; Wang, Y.; Xu, D.M.; Zaag-Loonen, H.J. van der; Jagt, E.J. van der; Oudkerk, M.; Klaveren, R.J. van

    2007-01-01

    The purpose of this study was to prospectively determine the frequency and spectrum of incidental findings (IFs) and their clinical implications in a high risk population for lung cancer undergoing low-dose multidetector computed tomography (MDCT) screening for lung cancer. Scans of 1,929 participants were evaluated for lung lesions and IFs by two radiologists. IFs were categorised as not clinically relevant or possibly clinically relevant. Findings were considered possibly clinically relevant if they could require further evaluation or could have substantial clinical implications. All possibly clinically relevant IFs were reviewed by a third radiologist, who determined its clinical relevance. Of all 1,929 participants, 1,410 (73%) had not clinically relevant IFs and 163 (8%) had possibly clinically relevant IFs of which 129 (79%) were indeed considered clinically relevant. Additional imaging was performed mainly by ultrasound (112 of 118, 96%). All but one lesion were concluded to be benign, mostly cysts (n = 115, 80%). Only 21 (1%) participants had findings with clinical implications. In one participant a malignancy was found, yet without any clinical benefit since no curative treatment was possible. Based on our results, we advise against systematically searching for and reporting of IFs in lung cancer screening studies using low-dose MDCT. (orig.)

  15. A practical approach to radiological evaluation of CT lung cancer screening examinations

    NARCIS (Netherlands)

    Xie, Xueqian; Heuvelmans, Marjolein A.; van Ooijen, Peter M. A.; Oudkerk, Matthijs; Vliegenthart, Rozemarijn

    2013-01-01

    Lung cancer is the most common cause of cancer-related death in the world. The Dutch-Belgian Randomized Lung Cancer Screening Trial (Dutch acronym: NELSON) was launched to investigate whether screening for lung cancer by low-dose multidetector computed tomography (CT) in high-risk patients will lead

  16. Resectable stage III lung cancer: CT, surgical, and pathologic correlation

    International Nuclear Information System (INIS)

    Scott, I.R.; Muller, N.L.; Miller, R.R.; Evans, K.G.; Nelems, B.

    1987-01-01

    Patients with stage IIIa lung cancer have improved survival following surgery. The authors reviewed the CT, surgical, and pathologic findings in 26 patients with completely resected stage IIIa lung cancer. These include examples of the different subsets of stage IIIa disease. CT correctly predicted chest-wall invasion in only two of ten patients, pericardial involvement in one of three, and tumor extension to within 2 cm of the carina in one of three patients. It detected mediastinal nodal disease in eight of 11 patients. CT is of limited value in assessing chest-wall or pericardial extension; however, such extension does not preclude complete resection. Ipsilateral nodal involvement also doses not preclude surgery

  17. CT triage for lung malignancy

    DEFF Research Database (Denmark)

    Kusk, Martin Weber; Karstoft, Jens; Mussmann, Bo

    2015-01-01

    Background: Generation of multiplanar reformation (MPR) images has become automatic on most modern computed tomography (CT) scanners, potentially increasing the workload of the reporting radiologists. It is not always clear if this increases diagnostic performance in all clinical tasks. Purpose...

  18. Respiratory gated lung CT using 320-row area detector CT

    International Nuclear Information System (INIS)

    Sakamoto, Ryo; Noma, Satoshi; Higashino, Takanori

    2010-01-01

    Three hundred and twenty-row Area Detector CT (ADCT) has made it possible to scan whole lung field with prospective respiratory gated wide volume scan. We evaluated whether the respiratory gated wide volume scan enables to reduce motion induced artifacts in the lung area. Helical scan and respiratory gated wide volume scan were performed in 5 patients and 10 healthy volunteers under spontaneous breathing. Significant reduction of motion artifact and superior image quality were obtained in respiratory gated scan in comparison with helical scan. Respiratory gated wide volume scan is an unique method using ADCT, and is able to reduce motion artifacts in lung CT scans of patients unable to suspend respiration in clinical scenes. (author)

  19. High resolution CT of the lung

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Harumi (Kyoto Univ. (Japan). Faculty of Medicine)

    1991-02-01

    The emergence of computed tomography (CT) in the early 1970s has greatly contributed to diagnostic radiology. The brain was the first organ examined with CT, followed by the abdomen. For the chest, CT has also come into use shortly after the introduction in the examination of the thoracic cavity and mediastinum. CT techniques were, however, of limited significance in the evaluation of pulmonary diseases, especially diffuse pulmonary diseases. High-resolution CT (HRCT) has been introduced in clinical investigations of the lung field. This article is designed to present chest radiographic and conventional tomographic interpretations and to introduce findings of HRCT corresponding to the same shadows, with a summation of the significance of HRCT and issues of diagnostic imaging. Materials outlined are tuberculosis, pneumoconiosis, bronchopneumonia, mycoplasma pneumonia, lymphangitic carcinomatosis, sarcoidosis, diffuse panbronchiolitis, interstitial pneumonia, and pulmonary emphysema. Finally, an overview of basic investigations evolved from HRCT is given. (N.K.) 140 refs.

  20. Automatic lung segmentation in functional SPECT images using active shape models trained on reference lung shapes from CT.

    Science.gov (United States)

    Cheimariotis, Grigorios-Aris; Al-Mashat, Mariam; Haris, Kostas; Aletras, Anthony H; Jögi, Jonas; Bajc, Marika; Maglaveras, Nicolaos; Heiberg, Einar

    2018-02-01

    Image segmentation is an essential step in quantifying the extent of reduced or absent lung function. The aim of this study is to develop and validate a new tool for automatic segmentation of lungs in ventilation and perfusion SPECT images and compare automatic and manual SPECT lung segmentations with reference computed tomography (CT) volumes. A total of 77 subjects (69 patients with obstructive lung disease, and 8 subjects without apparent perfusion of ventilation loss) performed low-dose CT followed by ventilation/perfusion (V/P) SPECT examination in a hybrid gamma camera system. In the training phase, lung shapes from the 57 anatomical low-dose CT images were used to construct two active shape models (right lung and left lung) which were then used for image segmentation. The algorithm was validated in 20 patients, comparing its results to reference delineation of corresponding CT images, and by comparing automatic segmentation to manual delineations in SPECT images. The Dice coefficient between automatic SPECT delineations and manual SPECT delineations were 0.83 ± 0.04% for the right and 0.82 ± 0.05% for the left lung. There was statistically significant difference between reference volumes from CT and automatic delineations for the right (R = 0.53, p = 0.02) and left lung (R = 0.69, p automatic quantification of wide range of measurements.

  1. Estimates of effective dose in adult CT examinations

    International Nuclear Information System (INIS)

    Mohamed, Mustafa Awad Elhaj.

    2015-12-01

    The goal of study was to estimate effective dose (E) in adult CT examinations for Toshiba X64 slice using CT. Exp version 2.5 software in Sudan. Using of CT in medical diagnosis delivers radiation doses to patients that are higher than those from other radiological procedures. lack of optimized protocols could be an additional source of increased dose in developing countries. In order to achieve these objectives, data of CT-scanner has been collected from three hospitals ( ANH, ZSH and MMH). Data collected included equipment information and scan parameters for individual patients, who were used to asses. 300 adult patients underwent head, chest, abdomen-pelvis and peivis CT examinations. The CT1_w , CTD1_vol, DLP, patient effective dos and organ doses were estimated, using CT exposure parameters and CT Exp version 2.5 software. A large variation of mean effective dose and organ doses among hospitals was observed for similar CT examinations. These variations largely originated from different CT scanning protocols used in different hospitals and scan length. The mean effective dose in this study in the Brain, PNS, Chest, pulmonary, Abdomen-pelvis, Pelvis, KUB and CTU were 3.2 mSv, 2.6 mSv, 18.9 mSv 17.6 mSv 27.1 mSv, 11.2 mSv, 9.6 mSv and 23.7 mSv respectively, and organ equivalent, doses presented in this study in this study for the eye lens (for head), lungs and thymus ( for chest) , liver, kidney and small intest ( for abdomen t-pelvis), bladder, uterus and gonads ( for pelvis), were 62.9 mSv, 39.5 mSv, 34.1 mSv, 53.9 mSv, 52.6 mSv, 58.1 mSv, 37 mSv, and 34.6 mSv, respectively. These values were mostly comparable to and slightly higher than the values of effective doses reported from similar studies the United Kingdom, Tanzania, Australia, Canada and Sudan. It was concluded that patient effective dose and organ doses could be substantially minimized through careful selection of scanning parameters based on clinical indications of study, patient size, and body

  2. Mass Preserving Registration for lung CT

    DEFF Research Database (Denmark)

    Gorbunova, Vladlena; Lo, Pechin Chien Pau; Loeve, Martin

    2009-01-01

    intensities due to differences in inspiration level, we propose to adjust the intensity of lung tissue according to the local expansion or compression. An image registration method without intensity adjustment is compared to the proposed method. Both approaches are evaluated on a set of 10 pairs of expiration...... and inspiration CT scans of children with cystic fibrosis lung disease. The proposed method with mass preserving adjustment results in significantly better alignment of the vessel trees. Analysis of local volume change for regions with trapped air compared to normally ventilated regions revealed larger...

  3. CT findings of adenocarcinoma of the lung

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, T. J.; Kim, S. J.; Lee, D. Y.; Ahn, C. M [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-03-01

    To evaluate CT findings of primary adenocarcinoma of the lung and to assess distant metastasis at the time of diagnosis. CT findings of 150 patients with adenocarcinoma, confirmed by histopathologic methods, were classified as central or peripheral lesion and pattern analysis of typical findings noted in this cancer was carried out. Intra and extrathoracic metastases of adenocarcinoma were also investigated. Of 150 cases of adenocarcinoma of the lung, 121 were found to be of the peripheral type and 29 were of the central type. These peripheral lesions comprised 105 nodules, 11 consolidations, four cavities and one linear lesion, while the central lesions consisted of 19 cases of atelectasis and tens of branchial wall thickening. lung to lung(nine cases), lymphangitic(five cases), and pleural metastasis(16 cases) were presented as intrathoracic metastasis, while bone(17), brain,(six), liver(two) and adrenal metastasis(one case)were presented as extrathoracic metastasis. The most common radiologic finding of adenocarcinoma is a peripheral single mass or nodule but consolidation, cavity or tubular lesions, as well as atelectasis or bronchial wall thickening alone can be presented as unusual findings of adenocarcinoma. As a consequence, it is in many cases difficult to differentially diagnose. Distant metastasis was also noted in many cases of early T-stage lesion, so to successfully manage the patient, careful evaluation of the metastasis is essential.

  4. CT findings of adenocarcinoma of the lung

    International Nuclear Information System (INIS)

    Jeon, T. J.; Kim, S. J.; Lee, D. Y.; Ahn, C. M

    1996-01-01

    To evaluate CT findings of primary adenocarcinoma of the lung and to assess distant metastasis at the time of diagnosis. CT findings of 150 patients with adenocarcinoma, confirmed by histopathologic methods, were classified as central or peripheral lesion and pattern analysis of typical findings noted in this cancer was carried out. Intra and extrathoracic metastases of adenocarcinoma were also investigated. Of 150 cases of adenocarcinoma of the lung, 121 were found to be of the peripheral type and 29 were of the central type. These peripheral lesions comprised 105 nodules, 11 consolidations, four cavities and one linear lesion, while the central lesions consisted of 19 cases of atelectasis and tens of branchial wall thickening. lung to lung(nine cases), lymphangitic(five cases), and pleural metastasis(16 cases) were presented as intrathoracic metastasis, while bone(17), brain,(six), liver(two) and adrenal metastasis(one case)were presented as extrathoracic metastasis. The most common radiologic finding of adenocarcinoma is a peripheral single mass or nodule but consolidation, cavity or tubular lesions, as well as atelectasis or bronchial wall thickening alone can be presented as unusual findings of adenocarcinoma. As a consequence, it is in many cases difficult to differentially diagnose. Distant metastasis was also noted in many cases of early T-stage lesion, so to successfully manage the patient, careful evaluation of the metastasis is essential

  5. Patient-specific dose estimation for pediatric chest CT

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P. [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Global Applied Science Laboratory, GE Healthcare, Waukesha, Wisconsin 53188 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham North Carolina 27710 (United States)

    2008-12-15

    Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ

  6. Dose reduction strategies for cardiac CT

    International Nuclear Information System (INIS)

    Midgley, S.M.; Einsiedel, P.; Langenberg, F.; Lui, E.

    2010-01-01

    Full text: Recent advances in CT technology have produced brighter X-ray sources. gantries capable of increased rotation speeds, faster scintil lation materials arranged into multiple rows of detectors, and associated advances in 3D reconstruction methods. These innovations have allowed multi-detector CT to be turned to the diagnosis of cardiac abnormalities and compliment traditional imaging techniques such as coronary angiography. This study examines the cardiac imaging solution offered by the Siemens Somatom Definition Dual Source 64 slice CT scanner. Our dose reduction strategies involve optimising the data acquisition protocols according to diagnostic task, patient size and heart rate. The relationship between scan parameters, image quality and patient dose is examined and verified against measurements with phantoms representing the standard size patient. The dose reduction strategies are reviewed with reference to survey results of patient dose. Some cases allow the insertion of shielding to protect radiosensitive organs, and results are presented to quantify the dose saving.

  7. Time evolution of regional CT density changes in normal lung after IMRT for NSCLC

    International Nuclear Information System (INIS)

    Bernchou, Uffe; Schytte, Tine; Bertelsen, Anders; Bentzen, Søren M.; Hansen, Olfred; Brink, Carsten

    2013-01-01

    Purpose: This study investigates the clinical radiobiology of radiation induced lung disease in terms of regional computed tomography (CT) density changes following intensity modulated radiotherapy (IMRT) for non-small-cell lung cancer (NSCLC). Methods: A total of 387 follow-up CT scans in 131 NSCLC patients receiving IMRT to a prescribed dose of 60 or 66 Gy in 2 Gy fractions were analyzed. The dose-dependent temporal evolution of the density change was analyzed using a two-component model, a superposition of an early, transient component and a late, persistent component. Results: The CT density of healthy lung tissue was observed to increase significantly (p 12 months. Conclusions: The radiobiology of lung injury may be analyzed in terms of CT density change. The initial transient change in density is consistent with radiation pneumonitis, while the subsequent stabilization of the density is consistent with pulmonary fibrosis

  8. Quantitative assessment of smoking-induced emphysema progression in longitudinal CT screening for lung cancer

    Science.gov (United States)

    Suzuki, H.; Mizuguchi, R.; Matsuhiro, M.; Kawata, Y.; Niki, N.; Nakano, Y.; Ohmatsu, H.; Kusumoto, M.; Tsuchida, T.; Eguchi, K.; Kaneko, M.; Moriyama, N.

    2015-03-01

    Computed tomography has been used for assessing structural abnormalities associated with emphysema. It is important to develop a robust CT based imaging biomarker that would allow quantification of emphysema progression in early stage. This paper presents effect of smoking on emphysema progression using annual changes of low attenuation volume (LAV) by each lung lobe acquired from low-dose CT images in longitudinal screening for lung cancer. The percentage of LAV (LAV%) was measured after applying CT value threshold method and small noise reduction. Progression of emphysema was assessed by statistical analysis of the annual changes represented by linear regression of LAV%. This method was applied to 215 participants in lung cancer CT screening for five years (18 nonsmokers, 85 past smokers, and 112 current smokers). The results showed that LAV% is useful to classify current smokers with rapid progression of emphysema (0.2%/year, pemphysema in CT screening for lung cancer.

  9. Organ dose evaluation for CT scans based on in-phantom measurements

    International Nuclear Information System (INIS)

    Liu Haikuan; Zhuo Weihai; Chen Bo; Yi Yanling; Li Dehong

    2009-01-01

    Objective: To explore the organ doses and their distributions in different projections of CT scans. Methods: The CT values were measured and the linear absorption coefficients were derived for the main organs of the anthropomorphic phantom to compare with the normal values of human beings. The radiophotoluminescent glass dosimeters were set into various tissues or organs of the phantom for mimic measurements of the organ doses undergoing the head, chest, abdomen and pelvis CT scans, respectively. Results: The tissue equivalence of the phantom used in this study was good. The brain had the largest organ dose undergoing the head CT scan. The organ doses in thyroid, breast, lung and oesophagus were relatively large in performing the chest CT scan, while the liver, stomach, colon and lung had relatively hrge organ doses in abdomen CT practice. The doses in bone surface and colon exceeded by 50 mGy in a single pelvis CT scan. Conclusions: The organ doses and their distributions largely vary with different projections of CT scans. The organ doses of colon, bone marrow,gonads and bladder are fairly large in performing pelvis CT scan, which should be paid attention in the practice. (authors)

  10. Dose assessment in patients undergoing lung examinations by computed tomography

    International Nuclear Information System (INIS)

    Gonzaga, Natalia B.; Silva, Teogenes A. da; Magalhaes, Marcos J.

    2011-01-01

    In the last fifteen years, the use of computed tomography (CT) has increased alongside other radiology technologies technologies. Its contribution has already achieved 34% in terms of doses undergone by patients. Radiation protection of patients submitted to CT examinations is based on the knowledge of internationally defined dosimetric quantities as the CT air kerma-length product (P K,L ) and weighted CT air kerma index (C w ). In Brazil, those dosimetric quantities are not routinely used and the optimization criteria are based only upon the MSAD - the average dose in multislices. In this work, the dosimetric quantities P K,L and C w were assessed by the CT Expo program for seven protocols used daily for lung examinations in adults with the use of Siemens and Philips scanners in Belo Horizonte. Results showed that P K,L values varied from 163 to 558 mGy.cm and the C w from 9.6 to 17.5 mGy. All results were found to be lower than the reference values internationally recommended by ICRP 87 and the European Community 16262 (30 mGy and 650 mGy.cm). The large dose ranges suggest that optimization of patient dose reduction is still possible without losses in the image quality and new reference dose levels could be recommended after a large survey to be carried out in the region. (author)

  11. The relationship between image quality and CT dose index of multi-slice low-dose chest CT

    International Nuclear Information System (INIS)

    Zhu Xiaohua; Shao Jiang; Shi Jingyun; You Zhengqian; Li Shijun; Xue Yongming

    2003-01-01

    Objective: To explore the rationality and possibility of multi-slice low-dose CT scan in the examination of the chest. Methods: (1) X-ray dose index measurement: 120 kV tube voltage, 0.75 s rotation, 8 mm and 3 mm slice thickness, and the tube current setting of 115.0, 40.0, 25.0, and 7.5 mAs were employed in every section. The X-ray radiation dose was measured and compared statistically. (2) phantom measurement of homogeneity and noise: The technical parameters were 120 kV, 0.75 s, 8 mm and 3 mm sections, and every slice was scanned using tube current of 115.0, 40.0, 25.0, and 7.5 mAs. Five same regions of interest were measured on every image. The homogeneity and noise level of CT were appraised. (3) The multi-slice low-dose CT in patients: 30 patients with mass and 30 with patch shadow in the lung were selected randomly. The technical parameters were 120 kV, 0.75 s, 8 mm and 3 mm slice thickness. 115.0, 40.0, 25.0, 15.0, and 7.5 mAs tube current were employed in each same slice. Otherwise, 15 cases with helical scan were examined using 190, 150, 40, 25, and 15 mAs tube current. The reconstruction images of MIP, MPR, CVR, HRCT, 3D, CT virtual endoscopy, and variety of interval reconstruction were compared. (4) Evaluation of image quality: CT images were evaluated by four doctors using single-blind method, and 3 degrees including normal image, image with few artifact, and image with excessive artifact, were employed and analyzed statistically. Results: (1) The CT dose index with 115.0 mAs tube current exceeded those of 40.0, 25.0, and 7.5 mAs by about 60%, 70%, and 85%, respectively. (2) The phantom measurement showed that the lower of CT dose the lower of homogeneity, the lower of CT dose the higher of noise level. (3) Result of image quality evaluation: The percentage of the normal image had no significant difference between 8 and 3 mm in 115, 40, and 25 mAs (P>0.05). Conclusion: Multi-slice low-dose chest CT technology may protect the patients and guarantee the

  12. Computer-aided pulmonary nodule detection. Performance of two CAD systems at different CT dose levels

    International Nuclear Information System (INIS)

    Hein, Patrick Alexander; Rogalla, P.; Klessen, C.; Lembcke, A.; Romano, V.C.

    2009-01-01

    Purpose: To evaluate the impact of dose reduction on the performance of computer-aided lung nodule detection systems (CAD) of two manufacturers by comparing respective CAD results on ultra-low-dose computed tomography (ULD-CT) and standard dose CT (SD-CT). Materials and Methods: Multi-slice computed tomography (MSCT) data sets of 26 patients (13 male and 13 female, patients 31 - 74 years old) were retrospectively selected for CAD analysis. Indication for CT examination was staging of a known primary malignancy or suspected pulmonary malignancy. CT images were consecutively acquired at 5 mAs (ULD-CT) and 75 mAs (SD-CT) with 120kV tube voltage (1 mm slice thickness). The standard of reference was determined by three experienced readers in consensus. CAD reading algorithms (pre-commercial CAD system, Philips, Netherlands: CAD-1; LungCARE, Siemens, Germany: CAD-2) were applied to the CT data sets. Results: Consensus reading identified 253 nodules on SD-CT and ULD-CT. Nodules ranged in diameter between 2 and 41 mm (mean diameter 4.8 mm). Detection rates were recorded with 72% and 62% (CAD-1 vs. CAD-2) for SD-CT and with 73% and 56% for ULD-CT. Median also positive rates per patient were calculated with 6 and 5 (CAD-1 vs. CAD-2) for SD-CT and with 8 and 3 for ULD-CT. After separate statistical analysis of nodules with diameters of 5 mm and greater, the detection rates increased to 83% and 61% for SD-CT and to 89% and 67% for ULD-CT (CAD-1 vs. CAD-2). For both CAD systems there were no significant differences between the detection rates for standard and ultra-low-dose data sets (p>0.05). Conclusion: Dose reduction of the underlying CT scan did not significantly influence nodule detection performance of the tested CAD systems. (orig.)

  13. WE-B-207-02: CT Lung Cancer Screening and the Medical Physicist: A Dosimetry Summary of CT Participants in the National Lung Cancer Screening Trial (NLST)

    International Nuclear Information System (INIS)

    Lee, C.

    2015-01-01

    The US National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a low-dose CT (LDCT) to posterior-anterior (PA) chest x-ray (CXR) in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. Funded by the National Cancer Institute this trial demonstrated that LDCT screening reduced lung cancer mortality. The US Preventive Services Task Force (USPSTF) cited NLST findings and conclusions in its deliberations and analysis of lung cancer screening. Under the 2010 Patient Protection and Affordable Care Act, the USPSTF favorable recommendation regarding lung cancer CT screening assisted in obtaining third-party payers coverage for screening. The objective of this session is to provide an introduction to the NLST and the trial findings, in addition to a comprehensive review of the dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations. Session presentations will review and discuss the findings of two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray exams that were performed on 92 chest imaging systems of which 66,157 participant examinations were used. The CT organ dosimetry investigation collected scan parameters from 23,773 CT examinations; a subset of the 75,133 CT examinations performed using 97 multi-detector CT scanners. Organ dose conversion coefficients were calculated using a Monte Carlo code. An experimentally-validated CT scanner simulation was coupled with 193 adult hybrid computational phantoms representing the height and weight of the current U.S. population. The dose to selected organs was calculated using the organ dose library and the abstracted scan

  14. WE-B-207-02: CT Lung Cancer Screening and the Medical Physicist: A Dosimetry Summary of CT Participants in the National Lung Cancer Screening Trial (NLST)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C. [National Cancer Institute (United States)

    2015-06-15

    The US National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a low-dose CT (LDCT) to posterior-anterior (PA) chest x-ray (CXR) in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. Funded by the National Cancer Institute this trial demonstrated that LDCT screening reduced lung cancer mortality. The US Preventive Services Task Force (USPSTF) cited NLST findings and conclusions in its deliberations and analysis of lung cancer screening. Under the 2010 Patient Protection and Affordable Care Act, the USPSTF favorable recommendation regarding lung cancer CT screening assisted in obtaining third-party payers coverage for screening. The objective of this session is to provide an introduction to the NLST and the trial findings, in addition to a comprehensive review of the dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations. Session presentations will review and discuss the findings of two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray exams that were performed on 92 chest imaging systems of which 66,157 participant examinations were used. The CT organ dosimetry investigation collected scan parameters from 23,773 CT examinations; a subset of the 75,133 CT examinations performed using 97 multi-detector CT scanners. Organ dose conversion coefficients were calculated using a Monte Carlo code. An experimentally-validated CT scanner simulation was coupled with 193 adult hybrid computational phantoms representing the height and weight of the current U.S. population. The dose to selected organs was calculated using the organ dose library and the abstracted scan

  15. Clinical value of CARE dose 4D technique in decreasing CT scanning dose of adult chest

    International Nuclear Information System (INIS)

    Wu Aiqin; Zheng Wenlong; Xu Chongyong; Fang Bidong; Ge Wen

    2011-01-01

    Objective: To investigate the value of CARE Dose 4D technique in decreasing radiation dose and improving image quality of multi-slice spiral CT in adult chest scanning. Methods: 100 patients of chest CT scanning were equally divided into study group and control group randomly. CARE Dose 4D Technique was used in study group. Effective mAs value, volume CT dose index (CTDI vol ) and dose length product (DLP) were displayed automatically in machine while chest scanning; those values and actual mAs value of every image were recorded respectively. The image quality at apex of lung, lower edge of aorta arch, middle area of left atrium and base of lung on every image of 400 images was judged and classified as three level (excellent, good, poor) by two deputy chief physicians with double blind method, the image noise at corresponding parts was measured. Results: While setting 80 mAs for quality reference mAs, the effective mAs value in study group most decreased 44 mAs than control group with an average decrease of 9.60 (12.0%), CTDI vol with 4.75 mGy with an average decrease of 0.95 mCy (11.0%), DLP 99.50% in study group, with 98.0% in control group. But it was higher at apex of lung and base of lung, lower at middle area of left atrium, and similar at lower edge of aorta arch in study group than contrast group. The image noise were lower at apex of lung and base of lung in study group than control group (t =6.299 and 2.332, all P<0.05), higher at middle area of left atrium in study group than control group (t=3.078, P<0.05) and similar at lower edge of aorta arch in study group than control group (t=1.191, P>0.05). Conclusions: CARE Dose 4D technique provides a function regulated mAs real-time on line, it not only raises utilization rate of radiation and decreases radiation dose, but also promises and increases image quality in chest CT scanning, and has some clinical significance. (authors)

  16. SU-E-J-87: Ventilation Weighting Effect On Mean Doses of Both Side Lungs for Patients with Advanced Stage Lung Cancer

    International Nuclear Information System (INIS)

    Qu, H; Xia, P; Yu, N

    2015-01-01

    Purpose: To study ventilation weighting effect on radiation doses to both side lungs for patients with advanced stage lung cancer. Methods: Fourteen patients with advanced stage lung cancer were included in this retrospective study. Proprietary software was developed to calculate the lung ventilation map based on 4DCT images acquired for radiation therapy. Two phases of inhale (0%) and exhale (50%) were used for the lung ventilation calculations. For each patient, the CT images were resampled to the same dose calculation resolution of 3mmx3mmx3mm. The ventilation distribution was then normalized by the mean value of the ventilation. The ventilation weighted dose was calculated by applying linearly weighted ventilation to the dose of each pixel. The lung contours were automatically delineated from patient CT image with lung window, excluding the tumor and high density tissues. For contralateral and ipsilateral lungs, the mean lung doses from the original plan and ventilation weighted mean lung doses were compared using two tail t-Test. Results: The average of mean dose was 6.1 ±3.8Gy for the contralateral lungs, and 26.2 ± 14.0Gy for the ipsilateral lungs. The average of ventilation weighted dose was 6.3± 3.8Gy for the contralateral lungs and 24.6 ± 13.1Gy for the ipsilateral lungs. The statistics analysis shows the significance of the mean dose increase (p<0.015) for the contralateral lungs and decrease (p<0.005) for the ipsilateral lungs. Conclusion: Ventilation weighted doses were greater than the un-weighted doses for contralateral lungs and smaller for ipsilateral lungs. This Result may be helpful to understand the radiation dosimetric effect on the lung function and provide planning guidance for patients with advance stage lung cancer

  17. WE-D-207-00: CT Lung Cancer Screening and the Medical Physicist: Moving Forward

    International Nuclear Information System (INIS)

    2015-01-01

    In the United States, Lung Cancer is responsible for more cancer deaths than the next four cancers combined. In addition, the 5 year survival rate for lung cancer patients has not improved over the past 40 to 50 years. To combat this deadly disease, in 2002 the National Cancer Institute launched a very large Randomized Control Trial called the National Lung Screening Trial (NLST). This trial would randomize subjects who had substantial risk of lung cancer (due to age and smoking history) into either a Chest X-ray arm or a low dose CT arm. In November 2010, the National Cancer Institute announced that the NLST had demonstrated 20% fewer lung cancer deaths among those who were screened with low-dose CT than with chest X-ray. In December 2013, the US Preventive Services Task Force recommended the use of Lung Cancer Screening using low dose CT and a little over a year later (Feb. 2015), CMS announced that Medicare would also cover Lung Cancer Screening using low dose CT. Thus private and public insurers are required to provide Lung Cancer Screening programs using CT to the appropriate population(s). The purpose of this Symposium is to inform medical physicists and prepare them to support the implementation of Lung Screening programs. This Symposium will focus on the clinical aspects of lung cancer screening, requirements of a screening registry for systematically capturing and tracking screening patients and results (such as required Medicare data elements) as well as the role of the medical physicist in screening programs, including the development of low dose CT screening protocols. Learning Objectives: To understand the clinical basis and clinical components of a lung cancer screening program, including eligibility criteria and other requirements. To understand the data collection requirements, workflow, and informatics infrastructure needed to support the tracking and reporting components of a screening program. To understand the role of the medical physicist in

  18. PET/CT in malignant melanoma: contrast-enhanced CT versus plain low-dose CT

    International Nuclear Information System (INIS)

    Pfluger, Thomas; Schneider, Vera; Fougere, Christian la; Bartenstein, Peter; Weiss, Mayo; Melzer, Henriette Ingrid; Coppenrath, Eva; Berking, Carola

    2011-01-01

    The aim of this study was to evaluate the diagnostic value of contrast-enhanced CT (CECT) versus non-enhanced low-dose CT (NECT) in the staging of advanced malignant melanoma with 18 F-fluordeoxyglucose (FDG) positron emission tomography (PET)/CT. In total, 50 18 F-FDG PET/CT examinations were performed in 50 patients with metastasized melanoma. For attenuation correction, whole-body NECT was performed followed by diagnostic CECT with contrast agent. For the whole-body PET, 18 F-FDG was applied. Criteria for evaluation were signs of vital tumour tissue (extent of lesions, contrast enhancement, maximum standardized uptake value >2.5). Findings suspicious for melanoma were considered lesions. NECT, CECT and 18 F-FDG PET were evaluated separately, followed by combined analysis of PET/NECT and PET/CECT. Findings were verified histologically and/or by follow-up (>6 months). Overall, 232 lesions were analysed, and 151 proved to be metastases. The sensitivity of NECT, CECT, PET, PET/NECT and PET/CECT was 62, 85, 90, 97 and 100%, and specificity was 52, 63, 88, 93 and 93%, respectively. Compared to CECT, NECT obtained additional false-negative results: lymph node (n = 19) and liver/spleen metastases (n = 9). Misinterpreted physiological structures mainly caused additional false-positive findings (n = 17). In combined analysis of PET/NECT, six false-positive [other tumours (n = 2), inflammatory lymph nodes (n = 2), inflammatory lung lesion (n = 1), blood vessel (n = 1)] and five false-negative findings [liver (n = 3), spleen (n = 1), lymph node metastases (n = 1)] remained. On PET/CECT, six false-positive [inflammatory lymph nodes (n = 3), other tumours (n = 2), inflammatory lung lesion (n = 1)] and no false-negative findings occurred. However, additional false findings on PET/NECT (6 of 232) did not change staging compared to PET/CECT. Our results indicate that it is justified to perform PET/NECT instead of PET/CECT for melanoma staging. (orig.)

  19. Uncertainties on lung doses from inhaled plutonium.

    Science.gov (United States)

    Puncher, Matthew; Birchall, Alan; Bull, Richard K

    2011-10-01

    In a recent epidemiological study, Bayesian uncertainties on lung doses have been calculated to determine lung cancer risk from occupational exposures to plutonium. These calculations used a revised version of the Human Respiratory Tract Model (HRTM) published by the ICRP. In addition to the Bayesian analyses, which give probability distributions of doses, point estimates of doses (single estimates without uncertainty) were also provided for that study using the existing HRTM as it is described in ICRP Publication 66; these are to be used in a preliminary analysis of risk. To infer the differences between the point estimates and Bayesian uncertainty analyses, this paper applies the methodology to former workers of the United Kingdom Atomic Energy Authority (UKAEA), who constituted a subset of the study cohort. The resulting probability distributions of lung doses are compared with the point estimates obtained for each worker. It is shown that mean posterior lung doses are around two- to fourfold higher than point estimates and that uncertainties on doses vary over a wide range, greater than two orders of magnitude for some lung tissues. In addition, we demonstrate that uncertainties on the parameter values, rather than the model structure, are largely responsible for these effects. Of these it appears to be the parameters describing absorption from the lungs to blood that have the greatest impact on estimates of lung doses from urine bioassay. Therefore, accurate determination of the chemical form of inhaled plutonium and the absorption parameter values for these materials is important for obtaining reliable estimates of lung doses and hence risk from occupational exposures to plutonium.

  20. Low-dose non-enhanced CT versus full-dose contrast-enhanced CT in integrated PET/CT studies for the diagnosis of uterine cancer recurrence

    Energy Technology Data Exchange (ETDEWEB)

    Kitajima, Kazuhiro [Institute of Biomedical Research and Innovation, Department of PET Diagnosis, Kobe (Japan); Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Suzuki, Kayo [Institute of Biomedical Research and Innovation, Department of PET Diagnosis, Kobe (Japan); Nakamoto, Yuji [Kyoto University Hospital, Department of Diagnostic Radiology, Kyoto (Japan); Onishi, Yumiko; Sakamoto, Setsu; Sugimura, Kazuro [Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Senda, Michio [Institute of Biomedical Research and Innovation, Department of Molecular Imaging, Kobe (Japan); Kita, Masato [Kobe City Medical Center General Hospital, Department of Obstetrics and Gynecology, Kobe (Japan)

    2010-08-15

    To evaluate low-dose non-enhanced CT (ldCT) and full-dose contrast-enhanced CT (ceCT) in integrated {sup 18}F-fluorodeoxyglucose (FDG) PET/CT studies for restaging of uterine cancer. A group of 100 women who had undergone treatment for uterine cervical (n=55) or endometrial cancer (n=45) underwent a conventional PET/CT scans with ldCT, and then a ceCT scan. Two observers retrospectively reviewed and interpreted the PET/ldCT and PET/ceCT images in consensus using a three-point grading scale (negative, equivocal, or positive) per patient and per lesion. Final diagnoses were obtained by histopathological examination, or clinical follow-up for at least 6 months. Patient-based analysis showed that the sensitivity, specificity and accuracy of PET/ceCT were 90% (27/30), 97% (68/70) and 95% (95/100), respectively, whereas those of PET/ldCT were 83% (25/30), 94% (66/70) and 91% (91/100), respectively. Sensitivity, specificity and accuracy did not significantly differ between two methods (McNemar test, p=0.48, p=0.48, and p=0.13, respectively). There were 52 sites of lesion recurrence: 12 pelvic lymph node (LN), 11 local recurrence, 8 peritoneum, 7 abdominal LN, 5 lung, 3 supraclavicular LN, 3 liver, 2 mediastinal LN, and 1 muscle and bone. The grading results for the 52 sites of recurrence were: negative 5, equivocal 0 and positive 47 for PET/ceCT, and negative 5, equivocal 4 and positive 43 for PET/ldCT, respectively. Four equivocal regions by PET/ldCT (local recurrence, pelvic LN metastasis, liver metastasis and muscle metastasis) were correctly interpreted as positive by PET/ceCT. PET/ceCT is an accurate imaging modality for the assessment of uterine cancer recurrence. Its use reduces the frequency of equivocal interpretations. (orig.)

  1. Automated quantification of emphysema in CT studies of the lung

    International Nuclear Information System (INIS)

    Archer, D.C.; deKemp, R.A.; Coblentz, C.L.; Nahmias, C.

    1991-01-01

    Emphysema by definition is a pathologic diagnosis. Recently, in vivo quantification of emphysema from CT with point counting and with a GE 9800 CT scanner program called Density Mask has been described. These methods are laborious and time-consuming, making them unsuitable for screening. The propose of this paper is to create a screening test for emphysema. The authors developed a computer program that quantifies the amount of emphysema from standard CT-scans. The computer was programmed to recognize the lung edges on each section by identifying abrupt changes in CT numbers; grow regions within each lung to identify and separate the lungs from other structures; count regions of lung containing CT numbers measuring <-900 HU corresponding to areas of emphysema; and calculation the percentage of emphysema present from the volume of normal emphysematous lung. The programs were written in C and urn on a Sun 4/100 workstation

  2. Automated size-specific CT dose monitoring program: Assessing variability in CT dose

    International Nuclear Information System (INIS)

    Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan

    2012-01-01

    Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED adj ). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED adj between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED adj that differed by up to 44% from effective dose estimates that were not

  3. Automated size-specific CT dose monitoring program: Assessing variability in CT dose

    Energy Technology Data Exchange (ETDEWEB)

    Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan [Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States) and Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2012-11-15

    Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED{sub adj}). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED{sub adj} between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED{sub adj} that differed by up to 44% from effective dose

  4. [Evaluation of Organ Dose Estimation from Indices of CT Dose Using Dose Index Registry].

    Science.gov (United States)

    Iriuchijima, Akiko; Fukushima, Yasuhiro; Ogura, Akio

    Direct measurement of each patient organ dose from computed tomography (CT) is not possible. Most methods to estimate patient organ dose is using Monte Carlo simulation with dedicated software. However, dedicated software is too expensive for small scale hospitals. Not every hospital can estimate organ dose with dedicated software. The purpose of this study was to evaluate the simple method of organ dose estimation using some common indices of CT dose. The Monte Carlo simulation software Radimetrics (Bayer) was used for calculating organ dose and analysis relationship between indices of CT dose and organ dose. Multidetector CT scanners were compared with those from two manufactures (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare). Using stored patient data from Radimetrics, the relationships between indices of CT dose and organ dose were indicated as each formula for estimating organ dose. The accuracy of estimation method of organ dose was compared with the results of Monte Carlo simulation using the Bland-Altman plots. In the results, SSDE was the feasible index for estimation organ dose in almost organs because it reflected each patient size. The differences of organ dose between estimation and simulation were within 23%. In conclusion, our estimation method of organ dose using indices of CT dose is convenient for clinical with accuracy.

  5. In search of the relevant lung dose

    International Nuclear Information System (INIS)

    Fisher, D.R.

    1982-12-01

    Researchers have traditionally been inconsistent in their methods of determining and reporting dose to the lung from inhaled radionuclides - a situation which has led to difficulties in later comparing results and deriving dose-response relationships. The dose quantities which at present are most generally assumed to be related to risk of stochastic radiation effects (such as lung cancer) are (1) mean dose equivalent to the bronchial epithelium basal cell layer for radon daughters, and (2) mean dose equivalent to the whole lung (including tracheobronchial lymph nodes) for all other radionuclides. The average radiation dose is calculated by assuming that the energy is homogeneously impared to the entire tissue mass. However, the actual dose received by a cell which becomes transformed or tumorigenic is likely to be very much different than the smear dose to the entire organ. This realization has led to further study of stochastic energy deposition processes in single cells or cell nuclei from internal emitters. The end product of the stochastic approach to dosimetry, sometimes called microdosimetry, is a probability density in specific energy. For alpha-emitting radionuclides in the lung, a concept that may be more important than dose is the probability that a cell is hit by an alpha particle

  6. CT findings of primary lung cancer

    International Nuclear Information System (INIS)

    Park, Yeon Won; Kim, So Seon; Woo, Young Hoon; Kim, Ho Joon; Chun, Byung Hee; Suh, Jung Hyek; Suh, Soo Jhi

    1985-01-01

    Authors retrospectively analyzed the CT findings of 102 cases of histologically proven bronchogenic carcinoma during last 4 years from January 1980 to July 1984 at Kosin Medical College. The results were as follows: 1. The sex ratio was 86 males to 16 females and the greatest number (66.7%) of cases were seen in fourth and fifth decades. 2. The distribution of histologic types of primary lung cancer as follows: Squamous cell carcinoma 66 cases, Adenocarcinoma 10 cases, Small cell carcinoma 7 cases, Large cell carcinoma 5 cases, Bronchioloalveolar cell carcinoma 1 case, Unclassified 13 cases. 3. Location of primary lesions as follows: Right lung 61 cases, Left lung 40 cases. In both lungs, the greatest number of cases were found in the upper lobes. Ratio between central and peripheral mass was 2.5:1, except adenocarcinoma (6:4). 4. CT findings were as follows: Hilar or central mass (75 cases), Peripheral mass (26), Bronchial abnormalities such as narrowing, obstruction, or displacement (60), Thickening of the posterior wall of the right upper lobe bronchus, bronchus intermedius, or left main bronchus (17), Post-obstructive changes; Atelectasis, Pneumonitis, Emphysema (34, 17, 1 respectively), Hilar adenopathy (21), Mediastinal lymph node enlargement (50), Mediastinal invasion (51), Pericardial thickening (5), SVC syndrome with collateral vessels (3), Pleural effusion (27), Pleural thickening or invasion (14), Chest wall invasion (2), Distant metastasis (26). 5. In most of patients (92 cases), the size of mass was above 3cm, but in 9 cases below 3cm. Margins of the masses were serrated or lobulated in most cases. In 5 cases, cavitary formations were noted, walls of which were thick and irregular, and air-fluid level was noted in 1 case. In 2 cases, eccentric calcification were noted within mass. 6. Among 51 cases of whom direct mediastinal invasion was suspected, 8 cases were operated upon, and this revealed that the masses were not resectable. Among the patients in

  7. Radiation exposure during paediatric CT in Sudan: CT dose, organ and effective doses

    International Nuclear Information System (INIS)

    Suliman, I.I.; Khamis, H.M.; Ombada, T.H.; Alzimami, K.; Alkhorayef, M.; Sulieman, A.

    2015-01-01

    The purpose of this study was to assess the magnitude of radiation exposure during paediatric CT in Sudanese hospitals. Doses were determined from CT acquisition parameters using CT-Expo 2.1 dosimetry software. Doses were evaluated for three patient ages (0-1, 1-5 and 5-10 y) and two common procedures (head and abdomen). For children aged 0-1 y, volume CT air kerma index (C vol ), air Kerma-length product and effective dose (E) values were 19.1 mGy, 265 mGy.cm and 3.1 mSv, respectively, at head CT and those at abdominal CT were 8.8 mGy, 242 mGy.cm and 7.7 mSv, respectively. Those for children aged 1-5 y were 22.5 mGy, 305 mGy.cm and 1.1 mSv, respectively, at head CT and 12.6 mGy, 317 mGy.cm, and 5.1 mSv, respectively, at abdominal CT. Dose values and variations were comparable with those reported in the literature. Organ equivalent doses vary from 7.5 to 11.6 mSv for testes, from 9.0 to 10.0 mSv for ovaries and from 11.1 to 14.3 mSv for uterus in abdominal CT. The results are useful for dose optimisation and derivation of national diagnostic reference levels. (authors)

  8. Microdosimetric approach for lung dose assessments

    International Nuclear Information System (INIS)

    Hofmann, W.; Steinhausler, F.; Pohl, E.; Bernroider, G.

    1980-01-01

    In the macroscopic region the term ''organ dose'' is related to an uniform energy deposition within a homogeneous biological target. Considering the lung, inhaled radioactive nuclides, however, show a significant non-uniform distribution pattern throughout the respiratory tract. For the calculation of deposition and clearance of inhaled alpha-emitting radionuclides within different regions of this organ, a detailed compartment model, based on the Weibel model A was developed. Since biological effects (e.g. lung cancer initiation) are primarily caused at the cellular level, the interaction of alpha particles with different types of cells of the lung tissue was studied. The basic approach is to superimpose alpha particle tracks on magnified images of randomly selected tissue slices, simulating alpha emitting sources. Particle tracks are generated by means of a specially developed computer program and used as input data for an on-line electronic image analyzer (Quantimet-720). Using adaptive pattern recognition methods the different cells in the lung tissue can be identified and their distribution within the whole organ determined. This microdosimetric method is applied to soluble radon decay products as well as to insoluble, highly localized, plutonium particles. For a defined microdistribution of alpha emitters, the resulting dose, integrated over all cellular dose values, is compared to the compartmental doses of the ICRP lung model. Furthermore this methodology is also applicable to other organs and tissues of the human body for dose calculations in practical health physics. (author)

  9. Mid-ventilation position planning: Optimal model for dose distribution in lung tumour

    International Nuclear Information System (INIS)

    Benchalal, M.; Leseur, J.; Chajon, E.; Cazoulat, G.; Haigron, P.; Simon, A.; Bellec, J.; Lena, H.; Crevoisier, R. de

    2012-01-01

    Purpose. - The dose distribution for lung tumour is estimated using a 3D-CT scan, and since a person breathes while the images are captured, the dose distribution doesn't reflect the reality. A 4D-CT scan integrates the motion of the tumour during breathing and, therefore, provides us with important information regarding tumour's motion in all directions, the motion volume (ITV) and the time-weighted average position (MVP). Patient and methods. - Based on these two concepts, we have estimated, for a lung carcinoma case a 3D dose distribution from a 3D-CT scan, and a 4D dose distribution from a 4-D CT scan. To this, we have applied a non-rigid registration to estimate the cumulative dose. Results. - Our study shows that the 4D dose estimation of the GTV is almost the same when made using MVP and ITV concepts, but sparring of the healthy lung is better done using the MPV model (MVP), as compared to the ITV model. This improvement of the therapeutic index allows, from a projection on the theoretical maximal dose to PTV (strictly restricted to doses for the lungs and the spinal cord), for an increase of about 11% on the total dose (maximal dose of 86 Gy for the ITV and 96 Gy for the MVP). Conclusion. - Further studies with more patients are needed to confirm our data. (authors)

  10. Dose optimization in CT examination of children

    International Nuclear Information System (INIS)

    Hojreh, A.; Prosch, H.

    2012-01-01

    Problems arise due to the increased clinical use of computed tomography (CT) and the high radiosensitivity of children. The ALARA concept (as low as reasonably achievable) prevails in pediatric radiology. Justified indications and full utilization of available dose optimization methods. Medical physicists and the manufacturers should support pediatric radiology in the implementation of the ALARA concept. The referring physicians and radiology staff should be integrated into training programs. Sufficient diagnostic image quality is paramount and not the pretty images. (orig.) [de

  11. Usefulness of low-dose CT in the detection of pulmonary metastasis of gestational trophoblastic tumours

    International Nuclear Information System (INIS)

    Xu, X.J.; Lou, F.L.; Zhang, M.M.; Pan, Z.M.; Zhang, L.

    2007-01-01

    Aim: To determine whether a low-dose spiral chest computed tomography (CT) examination could replace standard-dose chest CT in detecting pulmonary metastases in patients with gestational trophoblastic tumour (GTT). Materials and methods: In a prospective investigation, 67 chest CT examinations of 39 GTT patients were undertaken. All the patients underwent CT examinations using standard-dose (150 mAs, pitch 1, standard reconstruction algorithm) and low-dose (40 mAs, pitch 2, bone reconstruction algorithm) protocols. Two radiologists interpreted images independently. A metastasis was defined as a nodule within lung parenchyma that could not be attributed to a pulmonary vessel. The number of metastases detected with each protocol was recorded. The size of each lesion was measured and categorized as <5, 5-9.9, and ≥10 mm. Wilcoxon's signed rank test was used to assess the difference between the numbers of lesion detected by the two protocols. Results: The CT dose index (CTDI) for the standard-dose and low-dose CT protocols was 10.4 mGy and 1.4 mGy, respectively. One thousand, six hundred, and eighty-two metastases were detected by standard-dose CT, and 1460 lesions by the low-dose protocol. The numbers detected by low-dose CT were significantly less than those detected by standard-dose CT (Z = -3.776, p < 0.001), especially for nodules smaller than 5 mm (Z = -4.167, p < 0.001). However, the disease staging and risk score of the patients were not affected by use of the low-dose protocol. Conclusion: Low-dose chest CT can be used as a staging and follow-up procedure for patients with GTT

  12. Introduction of guidance dose levels inpaediatrics CT

    International Nuclear Information System (INIS)

    Verdun, F.R.; Valley, J.F.; Bernasconi, M.; Schnyder, P.; Gudinchet, F.

    2001-01-01

    The purpose of this work is to present a methodology in order to define reference levels for chest or abdominal CT examinations performed on children. For children aged from 0 to 6 the CTDI w measured in the head test object (i.e. diameter 16 cm) should be used as a dose indicator. For children older than 12 years old the CTDI w measured in the body test object (i.e. 32 cm) should be used as a dose indicator. For children aged between 6 to 12 we propose to use an intermediate CTDI w in order to avoid an over or underestimation of the dose delivered in the slices. Finally a set of dose length products (DLP) measured in our centre for standard abdominal acquisitions will be given. (author)

  13. Feasibility of using intravenous contrast-enhanced computed tomography (CT) scans in lung cancer treatment planning

    International Nuclear Information System (INIS)

    Xiao Jianghong; Zhang Hong; Gong Youling; Fu Yuchuan; Tang Bin; Wang Shichao; Jiang Qingfeng; Li Ping

    2010-01-01

    Background and purpose: To investigate the feasibility of using intravenous contrast-enhanced computed tomography (CT) scans in 3-dimensional conformal radiotherapy (3D-CRT), stereotactic body radiation therapy (SBRT) and intensity-modulated radiotherapy (IMRT) treatment planning for lung cancers, respectively. Materials and methods: Twelve patients with bulky lung tumors and 14 patients with small lung tumors were retrospectively analyzed. Each patient took two sets of CT in the same position with active breathing control (ABC) technique before and after intravenous contrast agent (CA) injections. Bulky tumors were planned with 3D-CRT, while SBRT plans were generated for patients with small tumors based on CT scans with intravenous CA. In addition, IMRT plans were generated for patients with bulky tumors to continue on a planning study. All plans were copied and replaced on the scans without intravenous CA. The radiation doses calculated from the two sets of CTs were compared with regard to planning volumes (PTV), the organ at-risk (OAR) and the lungs using Wilcoxon's signed rank test. Results: In comparisons for 3D-CRT plans, CT scans with intravenous CA reduced the mean dose and the maximum dose of PTV with significant differences (p 95 ) for targets, respectively (p < 0.05). There was no statistical significance for lung parameters between two sets of scans in SBRT plans and IMRT plans. Conclusions: The enhanced CT scans can be used for both target delineation and treatment planning in 3D-CRT. The dose difference caused by intravenous CA is small. But for SBRT and IMRT, the minimum irradiation dose in targets may be estimated to be increased up to 2.71% while the maximum dose may be estimated to be decreased up to 1.36%. However, the difference in dose distribution in most cases were found to be clinical tolerable.

  14. Deep learning for low-dose CT

    Science.gov (United States)

    Chen, Hu; Zhang, Yi; Zhou, Jiliu; Wang, Ge

    2017-09-01

    Given the potential risk of X-ray radiation to the patient, low-dose CT has attracted a considerable interest in the medical imaging field. Currently, the main stream low-dose CT methods include vendor-specific sinogram domain filtration and iterative reconstruction algorithms, but they need to access raw data whose formats are not transparent to most users. Due to the difficulty of modeling the statistical characteristics in the image domain, the existing methods for directly processing reconstructed images cannot eliminate image noise very well while keeping structural details. Inspired by the idea of deep learning, here we combine the autoencoder, deconvolution network, and shortcut connections into the residual encoder-decoder convolutional neural network (RED-CNN) for low-dose CT imaging. After patch-based training, the proposed RED-CNN achieves a competitive performance relative to the-state-of-art methods. Especially, our method has been favorably evaluated in terms of noise suppression and structural preservation.

  15. Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A. [Federal University of Minas Gerais, Program of Nuclear Science and Techniques, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

  16. Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

    International Nuclear Information System (INIS)

    Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A.

    2015-10-01

    Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

  17. Effect of Localizer Radiography Projection on Organ Dose at Chest CT with Automatic Tube Current Modulation.

    Science.gov (United States)

    Saltybaeva, Natalia; Krauss, Andreas; Alkadhi, Hatem

    2017-03-01

    Purpose To calculate the effect of localizer radiography projections to the total radiation dose, including both the dose from localizer radiography and that from subsequent chest computed tomography (CT) with tube current modulation (TCM). Materials and Methods An anthropomorphic phantom was scanned with 192-section CT without and with differently sized breast attachments. Chest CT with TCM was performed after one localizer radiographic examination with anteroposterior (AP) or posteroanterior (PA) projections. Dose distributions were obtained by means of Monte Carlo simulations based on acquired CT data. For Monte Carlo simulations of localizer radiography, the tube position was fixed at 0° and 180°; for chest CT, a spiral trajectory with TCM was used. The effect of tube start angles on dose distribution was investigated with Monte Carlo simulations by using TCM curves with fixed start angles (0°, 90°, and 180°). Total doses for lungs, heart, and breast were calculated as the sum of the dose from localizer radiography and CT. Image noise was defined as the standard deviation of attenuation measured in 14 circular regions of interest. The Wilcoxon signed rank test, paired t test, and Friedman analysis of variance were conducted to evaluate differences in noise, TCM curves, and organ doses, respectively. Results Organ doses from localizer radiography were lower when using a PA instead of an AP projection (P = .005). The use of a PA projection resulted in higher TCM values for chest CT (P chest CT. © RSNA, 2016 Online supplemental material is available for this article.

  18. Radiation dosage of various CT-methods in lung diagnostics

    International Nuclear Information System (INIS)

    Heinz-Peer, G.; Weninger, F.; Nowotny, R.; Herold, C.J.

    1996-01-01

    Introduction of the computed tomography index CTDI and the multiple scan average dose (MSAD) has led to standardization of the dose description in CT examinations. Despite the use of these dose parameters, many different dosages are reported in the literature for different CT methods. In addition, there is still a wide range of radiation dosimetry results reported for conventional CT, helical CT, and HRCT used in chest examinations. The variations in dosage are mainly due to difference in factors affecting the dose, i.e. beam geometry, beam quality, scanner geometry ('generation'), and operating parameters. In addition, CT dosimetry instrumentation and methodology make a contribution to dosages. Recent studies calculating differences in factors affecting dosage and CT dosimetry and using similar operating parameters, show similar results in CT dosimetry for conventional and helical CT. On the other hand, dosages for HRCT were greatly reduced. This was mainly caused by narrow beam collimation and increasing section spacing. (orig.) [de

  19. Asbestos Surveillance Program Aachen (ASPA): initial results from baseline screening for lung cancer in asbestos-exposed high-risk individuals using low-dose multidetector-row CT

    International Nuclear Information System (INIS)

    Das, Marco; Muehlenbruch, Georg; Mahnken, Andreas H.; Guenther, Rolf W.; Wildberger, Joachim E.; Hering, K.G.; Sirbu, H.; Zschiesche, W.; Knoll, Lars; Felten, Michael K.; Kraus, Thomas

    2007-01-01

    The purpose of this study was to assess the prevalence of lung cancer in a high-risk asbestos-exposed cohort using low-dose MDCT. Of a population of 5,389 former power-plant workers, 316 were characterized as individuals at highest risk for lung cancer according to a lung-cancer risk model including age, asbestos exposure and smoking habits. Of these 316, 187 (mean age: 66.6 years) individuals were included in a prospective trial. Mean asbestos exposure time was 29.65 years and 89% were smokers. Screening was performed on a 16-slice MDCT (Siemens) with low-dose technique (10/20 mAs eff. ; 1 mm/0.5 mm increment). In addition to soft copy PACS reading analysis on a workstation with a dedicated lung analysis software (LungCARE; Siemens) was performed. One strongly suspicious mass and eight cases of histologically proven lung cancer were found plus 491 additional pulmonary nodules (average volume: 40.72 ml, average diameter 4.62 mm). Asbestos-related changes (pleural plaques, fibrosis) were visible in 80 individuals. Lung cancer screening in this high-risk cohort showed a prevalence of lung cancer of 4.28% (8/187) at baseline screening with an additional large number of indeterminate pulmonary nodules. Low-dose MDCT proved to be feasible in this highly selected population. (orig.)

  20. CT staging of lung cancer: the role of artificial pneumothorax

    International Nuclear Information System (INIS)

    Lee, Jin Seong; Im, Jung Gi; Han, Man Chung

    1991-01-01

    To determine the role of artificially induced pneumothorax in the evaluation of the chest wall and mediastinal invasion in patients with peripheral bronchogenic carcinoma. CT scans of 22 patients obtained after induced pneumothorax were evaluated. All patients had peripheral lung mass abutting the pleura on a routine CT scan. Room air of 200-400ml was introduced through intrathoracic negative pressure initially, followed by pressure injection through the 18 gauge long bevelled needle under fluoroscopic control. Conclusively, CT with artificial pneumothorax added more information than conventional CT in the evaluation of the chest wall or mediastinal invasion by lung cancer without notable risk

  1. Organ doses can be estimated from the computed tomography (CT) dose index for cone-beam CT on radiotherapy equipment.

    Science.gov (United States)

    Martin, Colin J; Abuhaimed, Abdullah; Sankaralingam, Marimuthu; Metwaly, Mohamed; Gentle, David J

    2016-06-01

    Cone beam computed tomography (CBCT) systems are fitted to radiotherapy linear accelerators and used for patient positioning prior to treatment by image guided radiotherapy (IGRT). Radiotherapists' and radiographers' knowledge of doses to organs from CBCT imaging is limited. The weighted CT dose index for a reference beam of width 20 mm (CTDIw,ref) is displayed on Varian CBCT imaging equipment known as an On-Board Imager (OBI) linked to the Truebeam linear accelerator. This has the potential to provide an indication of organ doses. This knowledge would be helpful for guidance of radiotherapy clinicians preparing treatments. Monte Carlo simulations of imaging protocols for head, thorax and pelvic scans have been performed using EGSnrc/BEAMnrc, EGSnrc/DOSXYZnrc, and ICRP reference computational male and female phantoms to derive the mean absorbed doses to organs and tissues, which have been compared with values for the CTDIw,ref displayed on the CBCT scanner console. Substantial variations in dose were observed between male and female phantoms. Nevertheless, the CTDIw,ref gave doses within  ±21% for the stomach and liver in thorax scans and 2  ×  CTDIw,ref can be used as a measure of doses to breast, lung and oesophagus. The CTDIw,ref could provide indications of doses to the brain for head scans, and the colon for pelvic scans. It is proposed that knowledge of the link between CTDIw for CBCT should be promoted and included in the training of radiotherapy staff.

  2. WE-B-207-00: CT Lung Cancer Screening Part 1

    International Nuclear Information System (INIS)

    2015-01-01

    The US National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a low-dose CT (LDCT) to posterior-anterior (PA) chest x-ray (CXR) in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. Funded by the National Cancer Institute this trial demonstrated that LDCT screening reduced lung cancer mortality. The US Preventive Services Task Force (USPSTF) cited NLST findings and conclusions in its deliberations and analysis of lung cancer screening. Under the 2010 Patient Protection and Affordable Care Act, the USPSTF favorable recommendation regarding lung cancer CT screening assisted in obtaining third-party payers coverage for screening. The objective of this session is to provide an introduction to the NLST and the trial findings, in addition to a comprehensive review of the dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations. Session presentations will review and discuss the findings of two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray exams that were performed on 92 chest imaging systems of which 66,157 participant examinations were used. The CT organ dosimetry investigation collected scan parameters from 23,773 CT examinations; a subset of the 75,133 CT examinations performed using 97 multi-detector CT scanners. Organ dose conversion coefficients were calculated using a Monte Carlo code. An experimentally-validated CT scanner simulation was coupled with 193 adult hybrid computational phantoms representing the height and weight of the current U.S. population. The dose to selected organs was calculated using the organ dose library and the abstracted scan

  3. WE-B-207-00: CT Lung Cancer Screening Part 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    The US National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a low-dose CT (LDCT) to posterior-anterior (PA) chest x-ray (CXR) in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. Funded by the National Cancer Institute this trial demonstrated that LDCT screening reduced lung cancer mortality. The US Preventive Services Task Force (USPSTF) cited NLST findings and conclusions in its deliberations and analysis of lung cancer screening. Under the 2010 Patient Protection and Affordable Care Act, the USPSTF favorable recommendation regarding lung cancer CT screening assisted in obtaining third-party payers coverage for screening. The objective of this session is to provide an introduction to the NLST and the trial findings, in addition to a comprehensive review of the dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations. Session presentations will review and discuss the findings of two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray exams that were performed on 92 chest imaging systems of which 66,157 participant examinations were used. The CT organ dosimetry investigation collected scan parameters from 23,773 CT examinations; a subset of the 75,133 CT examinations performed using 97 multi-detector CT scanners. Organ dose conversion coefficients were calculated using a Monte Carlo code. An experimentally-validated CT scanner simulation was coupled with 193 adult hybrid computational phantoms representing the height and weight of the current U.S. population. The dose to selected organs was calculated using the organ dose library and the abstracted scan

  4. 3D Interpolation Method for CT Images of the Lung

    Directory of Open Access Journals (Sweden)

    Noriaki Asada

    2003-06-01

    Full Text Available A 3-D image can be reconstructed from numerous CT images of the lung. The procedure reconstructs a solid from multiple cross section images, which are collected during pulsation of the heart. Thus the motion of the heart is a special factor that must be taken into consideration during reconstruction. The lung exhibits a repeating transformation synchronized to the beating of the heart as an elastic body. There are discontinuities among neighboring CT images due to the beating of the heart, if no special techniques are used in taking CT images. The 3-D heart image is reconstructed from numerous CT images in which both the heart and the lung are taken. Although the outline shape of the reconstructed 3-D heart is quite unnatural, the envelope of the 3-D unnatural heart is fit to the shape of the standard heart. The envelopes of the lung in the CT images are calculated after the section images of the best fitting standard heart are located at the same positions of the CT images. Thus the CT images are geometrically transformed to the optimal CT images fitting best to the standard heart. Since correct transformation of images is required, an Area oriented interpolation method proposed by us is used for interpolation of transformed images. An attempt to reconstruct a 3-D lung image by a series of such operations without discontinuity is shown. Additionally, the same geometrical transformation method to the original projection images is proposed as a more advanced method.

  5. Fetal shielding combined with state of the art CT dose reduction strategies during maternal chest CT

    Energy Technology Data Exchange (ETDEWEB)

    Chatterson, Leslie C., E-mail: lch088@mail.usask.ca [Department of Diagnostic Imaging, University of Saskatchewan (Canada); Leswick, David A.; Fladeland, Derek A. [Department of Diagnostic Imaging, University of Saskatchewan (Canada); Hunt, Megan M.; Webster, Stephen [Saskatchewan Ministry of Labour Relations and Workplace Safety (Canada); Lim, Hyun [Department of Community Health and Epidemiology, College of Medicine, University of Saskatchewan (Canada)

    2014-07-15

    Purpose: Custom bismuth-antimony shields were previously shown to reduce fetal dose by 53% on an 8DR (detector row) CT scanner without dynamic adaptive section collimation (DASC), automatic tube current modulation (ATCM) or adaptive statistical iterative reconstruction (ASiR). The purpose of this study is to compare the effective maternal and average fetal organ dose reduction both with and without bismuth-antimony shields on a 64DR CT scanner using DASC, ATCM and ASiR during maternal CTPA. Materials and methods: A phantom with gravid prosthesis and a bismuth-antimony shield were used. Thermoluminescent dosimeters (TLDs) measured fetal radiation dose. The average fetal organ dose and effective maternal dose were determined using 100 kVp, scanning from the lung apices to the diaphragm utilizing DASC, ATCM and ASiR on a 64DR CT scanner with and without shielding in the first and third trimester. Isolated assessment of DASC was done via comparing a new 8DR scan without DASC to a similar scan on the 64DR with DASC. Results: Average third trimester unshielded fetal dose was reduced from 0.22 mGy ± 0.02 on the 8DR to 0.13 mGy ± 0.03 with the conservative 64DR protocol that included 30% ASiR, DASC and ATCM (42% reduction, P < 0.01). Use of a shield further reduced average third trimester fetal dose to 0.04 mGy ± 0.01 (69% reduction, P < 0.01). The average fetal organ dose reduction attributable to DASC alone was modest (6% reduction from 0.17 mGy ± 0.02 to 0.16 mGy ± 0.02, P = 0.014). First trimester fetal organ dose on the 8DR protocol was 0.07 mGy ± 0.03. This was reduced to 0.05 mGy ± 0.03 on the 64DR protocol without shielding (30% reduction, P = 0.009). Shields further reduced this dose to below accurately detectable levels. Effective maternal dose was reduced from 4.0 mSv on the 8DR to 2.5 mSv on the 64DR scanner using the conservative protocol (38% dose reduction). Conclusion: ASiR, ATCM and DASC combined significantly reduce effective maternal and fetal

  6. Fetal shielding combined with state of the art CT dose reduction strategies during maternal chest CT

    International Nuclear Information System (INIS)

    Chatterson, Leslie C.; Leswick, David A.; Fladeland, Derek A.; Hunt, Megan M.; Webster, Stephen; Lim, Hyun

    2014-01-01

    Purpose: Custom bismuth-antimony shields were previously shown to reduce fetal dose by 53% on an 8DR (detector row) CT scanner without dynamic adaptive section collimation (DASC), automatic tube current modulation (ATCM) or adaptive statistical iterative reconstruction (ASiR). The purpose of this study is to compare the effective maternal and average fetal organ dose reduction both with and without bismuth-antimony shields on a 64DR CT scanner using DASC, ATCM and ASiR during maternal CTPA. Materials and methods: A phantom with gravid prosthesis and a bismuth-antimony shield were used. Thermoluminescent dosimeters (TLDs) measured fetal radiation dose. The average fetal organ dose and effective maternal dose were determined using 100 kVp, scanning from the lung apices to the diaphragm utilizing DASC, ATCM and ASiR on a 64DR CT scanner with and without shielding in the first and third trimester. Isolated assessment of DASC was done via comparing a new 8DR scan without DASC to a similar scan on the 64DR with DASC. Results: Average third trimester unshielded fetal dose was reduced from 0.22 mGy ± 0.02 on the 8DR to 0.13 mGy ± 0.03 with the conservative 64DR protocol that included 30% ASiR, DASC and ATCM (42% reduction, P < 0.01). Use of a shield further reduced average third trimester fetal dose to 0.04 mGy ± 0.01 (69% reduction, P < 0.01). The average fetal organ dose reduction attributable to DASC alone was modest (6% reduction from 0.17 mGy ± 0.02 to 0.16 mGy ± 0.02, P = 0.014). First trimester fetal organ dose on the 8DR protocol was 0.07 mGy ± 0.03. This was reduced to 0.05 mGy ± 0.03 on the 64DR protocol without shielding (30% reduction, P = 0.009). Shields further reduced this dose to below accurately detectable levels. Effective maternal dose was reduced from 4.0 mSv on the 8DR to 2.5 mSv on the 64DR scanner using the conservative protocol (38% dose reduction). Conclusion: ASiR, ATCM and DASC combined significantly reduce effective maternal and fetal

  7. Dosimetric comparison between CT and X-ray simulation of radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Kali Ayguli, Zhang Jinrong; Wang Juwu; Ge Feng; Wang Haifeng; Xu Suling

    2007-01-01

    Objective: To compare radiotherapy plan of conventional X-ray simulation with CT simulation by 3D-TPS for lung cancer. Methods: Thirty-three patients were allotted to receive both conventional X-ray simulation and CT simulation in the same treatment position. 3D-TPS was used to design 4-field conventional plan of X-ray simulation (RT), 4-field two dimensional plan(2D)and three dimensional conformal radiation plan(3DCRT) of CT simulation for all patients. The total dose was 50 Gy. Dose volume histogram(DVH) was applied to evaluate the difference of target coverage, dose distribution and normal tissue protection among the three plans. Results: 3DCRT and 2D based on CT simulation were superior to RT in the target coverage, target conformity index (TCI) and target homogeneity (TH) (P 20 , V 30 and mean lung dose were similar among 3DCRT, 2D and RT plans. Moreover, the maximum doses of spinal cord were significantly different among the three plans. No statistical differences of doses to 30% of the heart and esophagus volume among the three plans were observed. Conclusions: There is significantly better tumour volume coverage in CT simulation when compared with X-ray conventional simulation. Target volume delineation by CT simulation is improved significantly. The dose distribution is improved by using three dimensional treatment planning system. 3DCRT plan is superior to 2D plans in target conformity index and target homogeneity. Doses delivered to organs surrounding the target such as lung and heart were reduced significantly in 3DCRT. (authors)

  8. The Use of 4DCT to Reduce Lung Dose: A Dosimetric Analysis

    International Nuclear Information System (INIS)

    Khan, Fazal; Bell, Glenn; Antony, Jacob; Palmer, Matt; Balter, Peter; Bucci, Kara; Chapman, Melissa Jane

    2009-01-01

    Dosimetric studies on respiratory movement suggest several advantages toward the use of 4-dimensional computed tomography (4DCT) in radiation treatment planning. 4DCT is a method to obtain a series of CT scans each representing a different respiratory phase. The use of 4DCT has provided substantial information on tumor movement in the lung, allowing for the creation of custom planning margins explicitly including respiratory motion. These custom motion margins may result in an increase in the amount of normal lung in the field; however, it is believed less normal lung is irradiated than if generic motion margins were used. Clinical data regarding dose to normal lung by using 4DCT remain rather limited. Thus, a study presenting figures on the change in normal lung dose between planned free breathing CT and 4DCT cases would be useful to the dosimetry community. We have generated plans comparing fast spiral CT and 4DCT in regard to tumor coverage and the resulting dose to normal lung for the clinical target volume (CTV) and planning target volume (PTV) expansions used at our institution. These data were analyzed for free breathing and 4D plans of 6 lung cancer patients using intensity modulated radiation therapy (IMRT). We compared doses to normal lung tissue between free breathing and 4DCT plans.

  9. 18FDG uptake associated with CT density on PET/CT in lungs with and without chronic interstitial lung diseases

    International Nuclear Information System (INIS)

    Inoue, Kentaro; Okada, Ken; Taki, Yasuyuki; Goto, Ryoi; Kinomura, Shigeo; Fukuda, Hiroshi

    2009-01-01

    The dependent-density of computed tomography (CT) images of positron emission tomography (PET)/CT is sometimes difficult to distinguish from chronic interstitial lung disease (ILD) when it accompanies increased 18 F-fluorodeoxy-D-glucose ( 18 FDG) uptake. Though the possible utility of 18 FDG-PET for the diagnosis of active ILD has been reported, the clinical relevance of mild lung 18 FDG uptake in ILD cases without signs and symptoms suggesting acute progression has not been described. This study aimed to test relationships between 18 FDG uptake and lung density on CT using PET/CT in patients with normal lung as well as clinically stable chronic ILD. Thirty-six patients with normal lungs (controls) and 28 patients with chronic ILD (ILD cases) without acute exacerbation were retrospectively selected from 18 FDG PET/CT scans performed in examination of malignant neoplasms. Elliptical regions of interest (ROIs) were placed on the lung. The relationships between CT density and 18 FDG uptake between the control and ILD cases were tested. The CT density and 18 FDG uptake had a linear correlation in both the controls and the ILD cases without a difference in their regression slopes, and they were overlapped between the controls and the ILD cases with higher mean values in the ILD cases. Lung 18 FDG uptake was considered to reflect a gravity-dependent tissue density in the normal lung. Though the lung 18 FDG uptake as well as the CT density tended to be higher in chronic ILD patients, it may be difficult to distinguish them in normal dependent regions from those related to chronic ILD in some cases. (author)

  10. Pericardial Tamponade Following CT-Guided Lung Biopsy

    International Nuclear Information System (INIS)

    Mitchell, Michael J.; Montgomery, Mark; Reiter, Charles G.; Culp, William C.

    2008-01-01

    While not free from hazards, CT-guided biopsy of the lung is a safe procedure, with few major complications. Despite its safety record, however, potentially fatal complications do rarely occur. We report a case of pericardial tamponade following CT-guided lung biopsy. Rapid diagnosis and therapy allowed for complete patient recovery. Physicians who perform this procedure should be aware of the known complications and be prepared to treat them appropriately.

  11. Volumetric expiratory high-resolution CT of the lung

    International Nuclear Information System (INIS)

    Nishino, Mizuki; Hatabu, Hiroto

    2004-01-01

    We developed a volumetric expiratory high-resolution CT (HRCT) protocol that provides combined inspiratory and expiratory volumetric imaging of the lung without increasing radiation exposure, and conducted a preliminary feasibility assessment of this protocol to evaluate diffuse lung disease with small airway abnormalities. The volumetric expiratory high-resolution CT increased the detectability of the conducting airway to the areas of air trapping (P<0.0001), and added significant information about extent and distribution of air trapping (P<0.0001)

  12. Dose performance and image quality: Dual source CT versus single source CT in cardiac CT angiography

    International Nuclear Information System (INIS)

    Wang Min; Qi Hengtao; Wang Ximing; Wang Tao; Chen, Jiu-Hong; Liu Cheng

    2009-01-01

    Objective: To evaluate dose performance and image quality of 64-slice dual source CT (DSCT) in comparison to 64-slice single source CT (SSCT) in cardiac CT angiography (CTA). Methods: 100 patients examined by DSCT and 60 patients scanned by SSCT were included in this study. Objective indices such as image noise, contrast-to-noise ratio and signal-to-noise ratio were analyzed. Subjective image quality was assessed by two cardiovascular radiologists in consensus using a four-point scale (1 = excellent to 4 = not acceptable). Estimation of effective dose was performed on the basis of dose length product (DLP). Results: At low heart rates ( 0.05), but, at high heart rates (>70 bpm), DSCT provided robust image quality (P 70 bpm), DSCT is able to provide robust diagnostic image quality at doses far below that of SSCT.

  13. Interval lung cancer after a negative CT screening examination: CT findings and outcomes in National Lung Screening Trial participants

    International Nuclear Information System (INIS)

    Gierada, David S.; Pinsky, Paul F.; Duan, Fenghai; Garg, Kavita; Hart, Eric M.; Kazerooni, Ella A.; Nath, Hrudaya; Watts, Jubal R.; Aberle, Denise R.

    2017-01-01

    This study retrospectively analyses the screening CT examinations and outcomes of the National Lung Screening Trial (NLST) participants who had interval lung cancer diagnosed within 1 year after a negative CT screen and before the next annual screen. The screening CTs of all 44 participants diagnosed with interval lung cancer (cases) were matched with negative CT screens of participants who did not develop lung cancer (controls). A majority consensus process was used to classify each CT screen as positive or negative according to the NLST criteria and to estimate the likelihood that any abnormalities detected retrospectively were due to lung cancer. By retrospective review, 40/44 cases (91%) and 17/44 controls (39%) met the NLST criteria for a positive screen (P < 0.001). Cases had higher estimated likelihood of lung cancer (P < 0.001). Abnormalities included pulmonary nodules ≥4 mm (n = 16), mediastinal (n = 8) and hilar (n = 6) masses, and bronchial lesions (n = 6). Cancers were stage III or IV at diagnosis in 32/44 cases (73%); 37/44 patients (84%) died of lung cancer, compared to 225/649 (35%) for all screen-detected cancers (P < 0.0001). Most cases met the NLST criteria for a positive screen. Awareness of missed abnormalities and interpretation errors may aid lung cancer identification in CT screening. (orig.)

  14. Interval lung cancer after a negative CT screening examination: CT findings and outcomes in National Lung Screening Trial participants

    Energy Technology Data Exchange (ETDEWEB)

    Gierada, David S. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, Box 8131, St. Louis, MO (United States); Pinsky, Paul F. [National Cancer Institute, Bethesda, MD (United States); Duan, Fenghai [Brown University School of Public Health, Department of Biostatistics and Center for Statistical Sciences, Providence, RI (United States); Garg, Kavita [University of Colorado School of Medicine, Mail Stop F726, Box 6510, Aurora, CO (United States); Hart, Eric M. [Northwestern University, Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Kazerooni, Ella A. [University of Michigan Health System, Department of Radiology, Ann Arbor, MI (United States); Nath, Hrudaya; Watts, Jubal R. [University of Alabama at Birmingham School of Medicine, Department of Radiology-JTN370, Birmingham, AL (United States); Aberle, Denise R. [David Geffen School of Medicine at UCLA, Department of Radiological Sciences, Los Angeles, CA (United States)

    2017-08-15

    This study retrospectively analyses the screening CT examinations and outcomes of the National Lung Screening Trial (NLST) participants who had interval lung cancer diagnosed within 1 year after a negative CT screen and before the next annual screen. The screening CTs of all 44 participants diagnosed with interval lung cancer (cases) were matched with negative CT screens of participants who did not develop lung cancer (controls). A majority consensus process was used to classify each CT screen as positive or negative according to the NLST criteria and to estimate the likelihood that any abnormalities detected retrospectively were due to lung cancer. By retrospective review, 40/44 cases (91%) and 17/44 controls (39%) met the NLST criteria for a positive screen (P < 0.001). Cases had higher estimated likelihood of lung cancer (P < 0.001). Abnormalities included pulmonary nodules ≥4 mm (n = 16), mediastinal (n = 8) and hilar (n = 6) masses, and bronchial lesions (n = 6). Cancers were stage III or IV at diagnosis in 32/44 cases (73%); 37/44 patients (84%) died of lung cancer, compared to 225/649 (35%) for all screen-detected cancers (P < 0.0001). Most cases met the NLST criteria for a positive screen. Awareness of missed abnormalities and interpretation errors may aid lung cancer identification in CT screening. (orig.)

  15. CT imaging of coexisting pulmonary tuberculosis and lung cancer

    International Nuclear Information System (INIS)

    Lv Yan; Xie Ruming; Zhou Xinhua; Zhou Zhen; Xu Jinping; He Wei; Guo Lifang; Ning Fenggang

    2013-01-01

    Objective: To study the CT characteristics of coexisting pulmonary tuberculosis and lung cancer. Methods: One hundred and four patients of coexisting pulmonary tuberculosis and lung cancer proved by histology, cytology or clinical underwent CT examination. All patients were divided into two groups, group Ⅰ were the patients with the lung cancer after tuberculosis or both found simultaneously (group Ⅰ a with peripheral lung cancer and group Ⅰ b with central lung cancer), group Ⅱ with tuberculosis during lung cancer chemotherapy (group Ⅱ a with peripheral lung cancer and group Ⅱ b with central lung cancer). Imaging characteristics of tuberculosis and lung cancer were compared. χ"2 test and t test were used for the statistical analysis. Results: Of 104 patients, there were 92 patients (88.5%) in group Ⅰ and 12 patients (11.5%) in group Ⅱ. Seventy patients (76.1%) of lung cancer and tuberculosis were located in the same lobe and 22 patients (23.9%) in the different lobes in group Ⅰ. There was no significant difference in distribution of tuberculosis between group Ⅰ and group Ⅱ (χ"2 = 4.302, P = 0.507). The fibrous stripes, nodules of calcification and pleural adhesion of tuberculosis were statistically significant between the two groups (χ"2 = 22.737, 15.193, 27.792, P < 0.05). There were 33 central lung cancers and 71 peripheral lung cancers. In group Ⅰ a (64 patients of peripheral lung cancers), 39 patients (60.9%) had typical manifestations and most of the lesions were ≥ 3 cm (n = 49, 76.6%), solid lesions showed variable enhancement. Conclusions: Secondary tuberculosis during lung cancer chemotherapy has the same CT characteristics with the common active tuberculosis. The morphology, enhancement pattern of lesion and follow-up are helpful for the diagnosis of lung cancer after tuberculosis. (authors)

  16. Spinal Cord Doses in Palliative Lung Radiotherapy Schedules

    International Nuclear Information System (INIS)

    Ffrrcsi, F.H.; Parton, C.

    2006-01-01

    Aim: We aim to check the safety of the standard palliative radiotherapy techniques by using the Linear quadratic model for a careful estimation of the doses received by the spinal cord, in all standard palliative lung radiotherapy fields and fractionation. Material and Methods: All patients surveyed at this prospective audit were treated with palliative chest radio-therapy for lung cancer over a period from January to June 2005 by different clinical oncology specialists within the department. Radiotherapy field criteria were recorded and compared with the recommended limits of the MRC trial protocols for the dose and fractionation prescribed. Doses delivered to structures off the field central axis were estimated using a standard CT scan of the chest. Dose estimates were made using an SLPLAN planning system. As unexpected spinal cord toxicity has been reported after hypo fractionated chest radiotherapy, a sagittal view was used to calculate the isodoses along the length of the spinal cord that could lie within the RT field. Equivalent dose estimates are made using the Linear Quadratic Equivalent Dose formula (LQED). The relative radiation sensitivity of spinal cord for myelopathy (the a/b dose) cord has been estimated as a/b = 1 Gy. Results: 17 Gy in 2 fraction and 39 Gy in 13 fraction protocols have spinal cord equivalent doses (using the linear-quadratic model) that lie within the conventional safe limits of 50 Gy in 25 fractions for the 100% isodose. However when the dosimetry is modelled for a 6 MV 100 cm isocentric linac in 3 dimensions, and altered separations and air space inhomogeneity are considered, the D-Max doses consistently fall above this limit on our 3 model patients. Conclusion: The 17 Gy in 2 fraction and 39 Gy in 13 fraction protocol would risk spinal cord damage if the radio therapist was unaware of the potential spinal cord doses. Alterative doses are suggested below 15.5 Gy/ 2 fractions (7 days apart) would be most acceptable

  17. Measurement of lung volumes : usefulness of spiral CT

    International Nuclear Information System (INIS)

    Kang, Ho Yeong; Kwak, Byung Kook; Lee, Sang Yoon; Kim, Soo Ran; Lee, Shin Hyung; Lee, Chang Joon; Park, In Won

    1996-01-01

    To evaluate the usefulness of spiral CT in the measurement of lung volumes. Fifteen healthy volunteers were studied by both spirometer and spiral CT at full inspiration and expiration in order to correlated their results, including total lung capacity (TLC), vital capacity (VC) and residual volume (RV). 3-D images were reconstructed from spiral CT, and we measured lung volumes at a corresponding CT window range ; their volumes were compared with the pulmonary function test (paired t-test). The window range corresponding to TLC was from -1000HU to -150HU (p=0.279, r=0.986), and for VC from -910HU to -800HU (p=0.366, r=0.954) in full-inspiratory CT. The optimal window range for RV in full-expiratory CT was from -1000HU to -450HU (p=0.757, r=0.777), and TLC-VC in full-inspiratory CT was also calculated (p=0.843, r=0.847). Spiral CT at full inspiration can used to lung volumes such as TLC, VC and RV

  18. Ultra-low dose CT attenuation correction for PET/CT

    International Nuclear Information System (INIS)

    Xia Ting; Kinahan, Paul E; Alessio, Adam M; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren

    2012-01-01

    A challenge for positron emission tomography/computed tomography (PET/CT) quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently available, lowest dose CT techniques, extended duration cine CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging. (paper)

  19. Ultra-low dose CT attenuation correction for PET/CT

    Science.gov (United States)

    Xia, Ting; Alessio, Adam M.; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren; Kinahan, Paul E.

    2012-01-01

    A challenge for PET/CT quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently-available, lowest dose CT techniques, extended duration CINE CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. Methods We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. Results CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. Conclusion When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging. PMID:22156174

  20. Radiotherapy dose compensation for lung patients

    International Nuclear Information System (INIS)

    Piyaratna, N.; Arnold, A.; Metcalfe, P.

    1999-01-01

    The purpose of the present paper is to provide a more homogeneous dose distribution in the target volume from compensated anterior and posterior fields while the healthy lung is spared by de-weighting the lateral fields. A compensation computation which used linear iterations to compute the most homogeneous dose distribution across the target volume was applied to produce optimum compensator designs. The equivalent tissue-air ratio (E-TAR) inhomogeneity correction was applied for the computations using a GE target series 11 planning computer. The compensators designed were tested for accuracy in a modified water/lung phantom using a scanning diode and an anthropomorphic phantom using thermoluminescent dosimeters. A comparison has been made between the compensated and uncompensated plans for the first nine patients who we have treated with this technique. The dose profiles produced by the computation agreed with the prediction of the computed isodose plans to within ± 2% at the target depth. The thermoluminescent dosimeter (TLD)-measured results in the anthropomorphic phantom agreed with the planning computer within ± 3%. A comparison of nine compensated plans of radiotherapy patients for large-volume targets in the lung region showed a maximum variation in the target to be 19% uncompensated versus 10% compensated. By providing compensated treatment fields from anterior and posterior treatment portals, a homogeneous dose that conforms well to the target volume is provided. As an added bonus, this enables the lateral lung fields to be significantly de-weighted and the healthy lung is spared considerable dose. Copyright (1999) Blackwell Science Pty Ltd

  1. Systematic Error in Lung Nodule Volumetry : Effect of Iterative Reconstruction Versus Filtered Back Projection at Different CT Parameters

    NARCIS (Netherlands)

    Willemink, Martin J.; Leiner, Tim; Budde, Ricardo P. J.; de Kort, Freek P. L.; Vliegenthart, Rozemarijn; van Ooijen, Peter M. A.; Oudkerk, Matthijs; de Jong, Pim A.

    2012-01-01

    OBJECTIVE. Iterative reconstruction potentially can reduce radiation dose compared with filtered back projection (FBP) for chest CT. This is especially important for repeated CT scanning, as is the case in patients with indeterminate lung nodules. It is currently unknown whether absolute nodule

  2. Iterative reconstruction reduces abdominal CT dose

    International Nuclear Information System (INIS)

    Martinsen, Anne Catrine Trægde; Sæther, Hilde Kjernlie; Hol, Per Kristian; Olsen, Dag Rune; Skaane, Per

    2012-01-01

    Objective: In medical imaging, lowering radiation dose from computed tomography scanning, without reducing diagnostic performance is a desired achievement. Iterative image reconstruction may be one tool to achieve dose reduction. This study reports the diagnostic performance using a blending of 50% statistical iterative reconstruction (ASIR) and filtered back projection reconstruction (FBP) compared to standard FBP image reconstruction at different dose levels for liver phantom examinations. Methods: An anthropomorphic liver phantom was scanned at 250, 185, 155, 140, 120 and 100 mA s, on a 64-slice GE Lightspeed VCT scanner. All scans were reconstructed with ASIR and FBP. Four readers evaluated independently on a 5-point scale 21 images, each containing 32 test sectors. In total 672 areas were assessed. ROC analysis was used to evaluate the differences. Results: There was a difference in AUC between the 250 mA s FBP images and the 120 and 100 mA s FBP images. ASIR reconstruction gave a significantly higher diagnostic performance compared to standard reconstruction at 100 mA s. Conclusion: A blending of 50–90% ASIR and FBP may improve image quality of low dose CT examinations of the liver, and thus give a potential for reducing radiation dose.

  3. Evaluation of radiation doses delivered in different chest CT protocols

    International Nuclear Information System (INIS)

    Gorycki, Tomasz; Lasek, Iwona; Kamiński, Kamil; Studniarek, Michał

    2014-01-01

    There are differences in the reference diagnostic levels for the computed tomography (CT) of the chest as cited in different literature sources. The doses are expressed either in weighted CT dose index (CTDI VOL ) used to express the dose per slice, dose-length product (DLP), and effective dose (E). The purpose of this study was to assess the radiation dose used in Low Dose Computer Tomography (LDCT) of the chest in comparison with routine chest CT examinations as well as to compare doses delivered in low dose chest CT with chest X-ray doses. CTDI VOL and DLP doses were taken to analysis from routine CT chest examinations (64 MDCT TK LIGHT SPEED GE Medical System) performed in 202 adult patients with FBP reconstruction: 51 low dose, 106 helical, 20 angio CT, and 25 high resolution CT protocols, as well as 19 helical protocols with iterative ASIR reconstruction. The analysis of chest X-ray doses was made on the basis of reports from 44 examinations. Mean values of CTDI VOL and DLP were, respectively: 2.1 mGy and 85.1 mGy·cm, for low dose, 9.7 mGy and 392.3 mGy·cm for helical, 18.2 mGy and 813.9 mGy·cm for angio CT, 2.3 mGy and 64.4 mGy·cm for high resolution CT, 8.9 mGy. and 317.6 mGy·cm for helical ASIR protocols. Significantly lower CTDI VOL and DLP values were observed for low dose and high resolution CT versus the remaining CT protocols; doses delivered in CT ASIR protocols were also lower (80–81%). The ratio between medial doses in low dose CT and chest X-ray was 11.56. Radiation dose in extended chest LDCT with parameters allowing for identification of mediastinal structures and adrenal glands is still much lower than that in standard CT protocols. Effective doses predicted for LDCT may exceed those used in chest X-ray examinations by a factor of 4 to 12, depending on LDCT scan parameters. Our results, as well as results from other authors, suggest a possibility of reducing the dose by means of iterative reconstruction. Efforts towards further dose

  4. CT quantification of lung and airways in normal Korean subjects

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Song Soo; Lee, Jeong Eun; Shin, Hye Soo [Dept. of Radiology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon (Korea, Republic of); Jin, Gong Yong; Li, Yuan Zhe [Dept. of Radiology, Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju (Korea, Republic of)

    2017-08-01

    To measure and compare the quantitative parameters of the lungs and airways in Korean never-smokers and current or former smokers (“ever-smokers”). Never-smokers (n = 119) and ever-smokers (n = 45) who had normal spirometry and visually normal chest computed tomography (CT) results were retrospectively enrolled in this study. For quantitative CT analyses, the low attenuation area (LAA) of LAA{sub I-950}, LAA{sub E-856}, CT attenuation value at the 15th percentile, mean lung attenuation (MLA), bronchial wall thickness of inner perimeter of a 10 mm diameter airway (Pi10), total lung capacity (TLC{sub CT}), and functional residual capacity (FRC{sub CT}) were calculated based on inspiratory and expiratory CT images. To compare the results between groups according to age, sex, and smoking history, independent t test, one way ANOVA, correlation test, and simple and multiple regression analyses were performed. The values of attenuation parameters and volume on inspiratory and expiratory quantitative computed tomography (QCT) were significantly different between males and females (p < 0.001). The MLA and the 15th percentile value on inspiratory QCT were significantly lower in the ever-smoker group than in the never-smoker group (p < 0.05). On expiratory QCT, all lung attenuation parameters were significantly different according to the age range (p < 0.05). Pi10 in ever-smokers was significantly correlated with forced expiratory volume in 1 second/forced vital capacity (r = −0.455, p = 0.003). In simple and multivariate regression analyses, TLC{sub CT}, FRC{sub CT}, and age showed significant associations with lung attenuation (p < 0.05), and only TLC{sub CT} was significantly associated with inspiratory Pi10. In Korean subjects with normal spirometry and visually normal chest CT, there may be significant differences in QCT parameters according to sex, age, and smoking history.

  5. Comparative reading support system for lung cancer CT screening

    International Nuclear Information System (INIS)

    Kubo, Mitsuru; Saita, Shinsuke; Kawata, Yoshiki; Niki, Noboru; Suzuki, Hidenobu; Ohmatsu, Hironobu; Eguchi, Kenji; Kaneko, Masahiro; Moriyama, Noriyuki

    2010-01-01

    The comparative reading is performed using current and past images of the same case obtained from lung cancer CT screening. The result of this is useful for the early detection of lung cancer. Our paper describes the efficiency improvement of comparative reading using 10 mm slice thickness CT images by developing the system consists of slice registration method, pulmonary nodule registration method, and quantitative evaluation method of pulmonary nodule's degree of change. The proposed system is applied to CT images scanned for 1107 times of 85 cases with 198 pulmonary nodules and is evaluated by comparing it with the reading result of the doctors. We show the effectiveness of the system. (author)

  6. Evaluation of patient absorbed dose in a PET-CT test

    International Nuclear Information System (INIS)

    Guerra P, F.; Mourao F, A. P.; Santana, P. C.

    2017-10-01

    Images of PET-CT has important diagnostic applications, especially in oncology. This equipment allows overlapping of functional images obtained from the administration of radionuclides and anatomical, generated by X-rays. The PET-CT technique may generate higher doses in patients due to the fact that two diagnostic modalities are used in a single examination. A whole body CT scan is performed and in sequence, a capture of the signal generated by the photons emitted is done. In this study, the absorbed and effective doses generated by the CT scan and incorporated by the administration of the radionuclide were evaluated in 19 organs. To evaluate the CT dose, 32 radiochromic film strips were correctly positioned into the anthropomorphic male phantom. The CT protocol performed was whole-body scanning and a high-resolution lung scan. This protocol is currently used in most services. The calculation of the effective dose from the injected activity in the patient was performed using the ICRP 106 Biokinetic model (ICRP 106, 2008). The activity to be injected may vary according to the patients body mass and with the sensitivity of the detector. The mass of the simulator used is 73.5 kg, then the simulation with and injected activity of 244.76 MBq was used. It was observed that 87.4% of the effective dose in examination PET/CT comes from the CT scans, being 63.8% of the whole body scan and 23.6% of high resolution lung scan. Using activity of 0.09 mCi x kg 18 F-FDG radiopharmaceutical contributes only 12.6% of the final effective dose. As a conclusion, it was observed that the dose in patients submitted to the 18 F-FDG PET-CT examination is high, being of great value efforts for its reduction, such as the use of appropriate image acquisition techniques and promoting the application of the principle of optimization of practice. (Author)

  7. Low-dosage helical CT applications for chest medical checkup and lung cancer screening

    International Nuclear Information System (INIS)

    Wang Ping; Cui Fa; Liang Huanqing; Zheng Minfei

    2005-01-01

    Objective: A discussion on low-dosage helical CT applications on chest medical checkup and lung cancer screening. Methods: On the 100 chest medical check up with three different of protocols, including standard-dosage (the tube current was 230 mAs) were compared with low-dose (tube current was 50 mAs or 30 mAs). Results: Low-dosage helical CT scan provides excellent images. In 100 chest medical checkup, 39 nodules or masses were revealed, enlarged lymph node was noted in 1 case; emphysema or bullae was demonstrated in 3 segments; thickening of bronchial wall was shown in 2 cases; and localized pleural thickening was found in 1 case. Conclusion: In chest checkup or lung cancer screening low-dosage helical CT (tube current 30 mAs) will not only guarantee image quality but also reduce the radiation dose during the examination. (authors)

  8. Automated lung nodule classification following automated nodule detection on CT: A serial approach

    International Nuclear Information System (INIS)

    Armato, Samuel G. III; Altman, Michael B.; Wilkie, Joel; Sone, Shusuke; Li, Feng; Doi, Kunio; Roy, Arunabha S.

    2003-01-01

    We have evaluated the performance of an automated classifier applied to the task of differentiating malignant and benign lung nodules in low-dose helical computed tomography (CT) scans acquired as part of a lung cancer screening program. The nodules classified in this manner were initially identified by our automated lung nodule detection method, so that the output of automated lung nodule detection was used as input to automated lung nodule classification. This study begins to narrow the distinction between the 'detection task' and the 'classification task'. Automated lung nodule detection is based on two- and three-dimensional analyses of the CT image data. Gray-level-thresholding techniques are used to identify initial lung nodule candidates, for which morphological and gray-level features are computed. A rule-based approach is applied to reduce the number of nodule candidates that correspond to non-nodules, and the features of remaining candidates are merged through linear discriminant analysis to obtain final detection results. Automated lung nodule classification merges the features of the lung nodule candidates identified by the detection algorithm that correspond to actual nodules through another linear discriminant classifier to distinguish between malignant and benign nodules. The automated classification method was applied to the computerized detection results obtained from a database of 393 low-dose thoracic CT scans containing 470 confirmed lung nodules (69 malignant and 401 benign nodules). Receiver operating characteristic (ROC) analysis was used to evaluate the ability of the classifier to differentiate between nodule candidates that correspond to malignant nodules and nodule candidates that correspond to benign lesions. The area under the ROC curve for this classification task attained a value of 0.79 during a leave-one-out evaluation

  9. Low dose coronary CT angiography with 256-slice helical CT

    International Nuclear Information System (INIS)

    Zhang Xiaodong; Tang Binghang; Li Fangyun

    2011-01-01

    Objective: To compare the image quality and patient radiation dose of coronary computed tomography angiography (CCTA) received by prospectively-gated step-and-shoot (SAS) technique with those obtained by retrospectively-gated spiral ( RGS) technique on a 256-slice CT scanner. Methods: A total of 200 patients were enrolled in this study. One hundred patients underwent CCTA with SAS mode were subdivided into two groups: (1) 50 patients with an average heart rate (HR) ≤ 70 bpm were scanned with a data acquisition time window centered at the 75% of the R-R cycle (group A) and (2) 50 patients with HR > 70 bpm were scanned with the data acquisition time window centered at the 45% of the R-R cycle, including a phase tolerance of ± 5% (group B). Other 100 patients underwent CCTA with RGS mode and ECG-based tube current modulation were also subdivided into two groups: (3) 50 patients with HR ≤ 70 bpm were scanned with cardiac dose right set to phase of 75% ( group C) and (4) 50 patients with HR > 70 bpm were scanned with cardiac ose Rdight set to phases of 45% and 75% (group D). All patients were grouped in randomized order. The image quality of CCTA were evaluated using a rank scale from 1 to 4 (1: excellent; 4: non-assessable). Radiation dose of the four groups received was also estimated. The image quality between groups was compared by Mann-Whitney U test. The radiation dose between groups was compared by t test. For the 100 patients received by prospective ECG-gated CCTA, the receiver operating characteristic curve (ROC) was used to analyze the CCTA image quality and average heart rate to determine the uppercutoff of HR for obtaining diagnostic coronary images with SAS mode. A Spearman correlation analysis was also performed to analyze the correlation of HR and image quality in patients underwent CCTA with SAS mode. Results: Of 2338 coronary artery segments, excellent or good image quality (score of 1 or 2) was achieved in 96.5% (585 of 606) in group A, 77.7% (445

  10. Dependent lung opacity at thin-section CT: evaluation by spirometrically-gated CT of the influence of lung volume

    International Nuclear Information System (INIS)

    Lee, Ki Nam; Yoon, Seong Kuk; Sohn, Choon Hee; Choi, Pil Jo; Webb, W. Richard

    2002-01-01

    To evaluate the influence of lung volume on dependent lung opacity seen at thin-section CT. In thirteen healthy volunteers, thin-section CT scans were performed at three levels (upper, mid, and lower portion of the lung) and at different lung volumes (10, 30, 50, and 100% vital capacity), using spirometric gated CT. Using a three-point scale, two radiologists determined whether dependent opacity was present, and estimated its degree. Regional lung attenuation at a level 2 cm above the diaphragm was determined using semiautomatic segmentation, and the diameter of a branch of the right lower posterior basal segmental artery was measured at each different vital capacity. At all three anatomic levels, dependent opacity occurred significantly more often at lower vital capacities (10, 30%) than at 100% vital capacity (p = 0.001). Visually estimated dependent opacity was significantly related to regional lung attenuation (p < 0.0001), which in dependent areas progressively increased as vital capacity decreased (p < 0.0001). The presence of dependent opacity and regional lung attenuation of a dependent area correlated significantly with increased diameter of a segmental arterial branch (r = 0.493 and p = 0.0002; r = 0.486 and p 0.0003, respectively). Visual estimation and CT measurements of dependent opacity obtained by semiautomatic segmentation are significantly influenced by lung volume and are related to vascular diameter

  11. CT features of lung cancer associated with idiopathic pulmonary fibrosis

    International Nuclear Information System (INIS)

    Kim, Jun Hyoung; Song, Koun Sik; Lee, Deok Hee; Kim, Jin Suh; Lim, Tae Hwan

    1996-01-01

    It is well known that the incidence of lung cancer is high in patients with idiopathic pulmonary fibrosis(IPF). We analyzed the CT features of lung cancer associated with IPF. Retrospective analyzed the CT features of lung cancer associated with IPF. Retrospective analysis was performed in 23 patients with lung cancer(24 lung cancers) associated with IPF. The diagnosis of IPF was made by clinical and CT findings, and lung cancer was confirmed pathologically. We divided the location of lung cancer by lobar distribution and central or peripheral lung zone, and measured the size of mass. We classified the mediastinal lymph node enlargement by American Thoracic Society (ATS) mapping scheme. We evaluated the CT pattern of IPF. The subjects consisted of 6 cases of small cell carcinoma and 18 cases of non-small cell lung cancer. Non-small cell lung cancers were located in the right upper lobe in 5 cases, left upper lobe in 6 cases, right middle lobe in 1 case, right lower lobe in 9 cases, and left lower lobe in 3 cases. Twenty cancers(85%) were located in the peripheral lung zone. Eighteen cancers(73%) were surrounded by fibrotic lung. The size of the mass ranged from 1 to 12 cm, and in 12 cases it was below 3cm in diameter. Mediastinal lymph nodes were enlarged in 22 cases(92%) and classified as N2 or N3 in 15 cases out of 18 non-small cell lung. The size of the mass ranged from 1 to 12 cm, and in 12 cases it was below 3 cm in diameter. Mediastinal lymph nodes were enlarged in 22 cases(92%) and classified as N2 or N3 in 15 cases out of 18 non-small cell lung cancers. CT patterns of underlying IPF were honey-combing in 18 patients(78%) and mixed honey-combing and ground-glass opacity in 5 patients(22%). The lung cancer associated with IPF shows variable cell types. Most of the lung cancers were located peripherally, surrounded by end-stage fibrosis, and were associated with mediastinal lymph node enlargement

  12. CT features of lung cancer associated with idiopathic pulmonary fibrosis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Hyoung; Song, Koun Sik; Lee, Deok Hee; Kim, Jin Suh; Lim, Tae Hwan [Ulsan Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-01-01

    It is well known that the incidence of lung cancer is high in patients with idiopathic pulmonary fibrosis(IPF). We analyzed the CT features of lung cancer associated with IPF. Retrospective analyzed the CT features of lung cancer associated with IPF. Retrospective analysis was performed in 23 patients with lung cancer(24 lung cancers) associated with IPF. The diagnosis of IPF was made by clinical and CT findings, and lung cancer was confirmed pathologically. We divided the location of lung cancer by lobar distribution and central or peripheral lung zone, and measured the size of mass. We classified the mediastinal lymph node enlargement by American Thoracic Society (ATS) mapping scheme. We evaluated the CT pattern of IPF. The subjects consisted of 6 cases of small cell carcinoma and 18 cases of non-small cell lung cancer. Non-small cell lung cancers were located in the right upper lobe in 5 cases, left upper lobe in 6 cases, right middle lobe in 1 case, right lower lobe in 9 cases, and left lower lobe in 3 cases. Twenty cancers(85%) were located in the peripheral lung zone. Eighteen cancers(73%) were surrounded by fibrotic lung. The size of the mass ranged from 1 to 12 cm, and in 12 cases it was below 3cm in diameter. Mediastinal lymph nodes were enlarged in 22 cases(92%) and classified as N2 or N3 in 15 cases out of 18 non-small cell lung. The size of the mass ranged from 1 to 12 cm, and in 12 cases it was below 3 cm in diameter. Mediastinal lymph nodes were enlarged in 22 cases(92%) and classified as N2 or N3 in 15 cases out of 18 non-small cell lung cancers. CT patterns of underlying IPF were honey-combing in 18 patients(78%) and mixed honey-combing and ground-glass opacity in 5 patients(22%). The lung cancer associated with IPF shows variable cell types. Most of the lung cancers were located peripherally, surrounded by end-stage fibrosis, and were associated with mediastinal lymph node enlargement.

  13. CT evaluation of complications of cryoablation treatment in lung cancer

    International Nuclear Information System (INIS)

    Zhu Caiqiao; Chen Yao; Zhang Zhitian; Su Jinzhan; Huang Zhen; Bao Kaikai

    2011-01-01

    Objective: To assess the complications of percutaneous targeted Argon-Helium cryoablation treatment in patients with lung cancer on CT. Methods: Ten patients with unresectable lung cancer were treated by cryotherapy under CT guidance with Argon-Helium cryoablation system. Dynamic contrast-enhanced CT was performed to assess changes before and after treatment, complications and treatment response. Results: Ice ball coverage immediately after surgery was satisfactory in all patients. There were a few complications including worsening hoarseness (1), small pneumothorax (1), and small amount of bleeding at the site of probe puncture (1). Conclusion: Percutaneous targeted Argon-Helium cryoablation guided by CT is an effective treatment for lung cancer without severe complications. (authors)

  14. Low-dose computed tomography volumetry for subtyping chronic lung allograft dysfunction.

    Science.gov (United States)

    Saito, Tomohito; Horie, Miho; Sato, Masaaki; Nakajima, Daisuke; Shoushtarizadeh, Hassan; Binnie, Matthew; Azad, Sassan; Hwang, David M; Machuca, Tiago N; Waddell, Thomas K; Singer, Lianne G; Cypel, Marcelo; Liu, Mingyao; Paul, Narinder S; Keshavjee, Shaf

    2016-01-01

    The long-term success of lung transplantation is challenged by the development of chronic lung allograft dysfunction (CLAD) and its distinct subtypes of bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). However, the current diagnostic criteria for CLAD subtypes rely on total lung capacity (TLC), which is not always measured during routine post-transplant assessment. Our aim was to investigate the utility of low-dose 3-dimensional computed tomography (CT) lung volumetry for differentiating RAS from BOS. This study was a retrospective evaluation of 63 patients who had developed CLAD after bilateral lung or heart‒lung transplantation between 2006 and 2011, including 44 BOS and 19 RAS cases. Median post-transplant follow-up was 65 months in BOS and 27 months in RAS. The median interval between baseline and the disease-onset time-point for CT volumetry was 11 months in both BOS and RAS. Chronologic changes and diagnostic accuracy of CT lung volume (measured as percent of baseline) were investigated. RAS showed a significant decrease in CT lung volume at disease onset compared with baseline (mean 3,916 ml vs 3,055 ml when excluding opacities, p volumetry is a useful tool to differentiate patients who develop RAS from those who develop BOS. Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  15. Current concepts in F18 FDG PET/CT-based Radiation Therapy planning for Lung Cancer

    Directory of Open Access Journals (Sweden)

    Percy eLee

    2012-07-01

    Full Text Available Radiation therapy is an important component of cancer therapy for early stage as well as locally advanced lung cancer. The use of F18 FDG PET/CT has come to the forefront of lung cancer staging and overall treatment decision-making. FDG PET/CT parameters such as standard uptake value and metabolic tumor volume provide important prognostic and predictive information in lung cancer. Importantly, FDG PET/CT for radiation planning has added biological information in defining the gross tumor volume as well as involved nodal disease. For example, accurate target delineation between tumor and atelectasis is facilitated by utilizing PET and CT imaging. Furthermore, there has been meaningful progress in incorporating metabolic information from FDG PET/CT imaging in radiation treatment planning strategies such as radiation dose escalation based on standard uptake value thresholds as well as using respiratory gated PET and CT planning for improved target delineation of moving targets. In addition, PET/CT based follow-up after radiation therapy has provided the possibility of early detection of local as well as distant recurrences after treatment. More research is needed to incorporate other biomarkers such as proliferative and hypoxia biomarkers in PET as well as integrating metabolic information in adaptive, patient-centered, tailored radiation therapy.

  16. Evaluation of variation of voltage (kV) absorbed dose in chest CT scans

    International Nuclear Information System (INIS)

    Mendonca, Bruna G.A.; Mourao, Arnaldo P.

    2013-01-01

    Computed tomography (CT) is one of the most important diagnostic techniques images today. The increasing utilization of CT implies a significant increase of population exposure to ionizing radiation. Optimization of practice aims to reduce doses to patients because the image quality is directly related to the diagnosis. You can decrease the amount of dose to the patient, and maintain the quality of the image. There are several parameters that can be manipulated in a CT scan and these parameters can be used to reduce the energy deposited in the patient. Based on this, we analyzed the variation of dose deposited in the lungs, breasts and thyroid, by varying the supply voltage of the tube. Scans of the thorax were performed following the protocol of routine chest with constant and variable current for the same applied voltage. Moreover, a female phantom was used and thermoluminescent dosimeters (TLD-100), model bat, were used to record the specific organ doses. Scans were performed on a GE CT scanner, model 64 Discovery channels. Higher doses were recorded for the voltage of 120 kV with 200 mAs in the lungs (22.46 mGy) and thyroid (32.22 mGy). For scans with automatic mAs, variable between 100 and 440, this same tension contributed to the higher doses. The best examination in terms of the dose that was used with automatic 80 kV mAs, whose lungs and thyroid received lower dose. For the best breast exam was 100 kV. Since the increase in the 80 kV to 100 kV no impact so much the dose deposited in the lungs, it can be concluded that lowering the applied voltage to 100 kV resulted in a reduction in the dose absorbed by the patient. These results can contribute to optimizing scans of the chest computed tomography

  17. Helical CT for secondary screening of lung cancer

    International Nuclear Information System (INIS)

    Mori, Kiyoshi; Onishi, Tsukasa; Tominaga, Keigo; Kishiro, Izumi; Yokoyama, Kohki.

    1995-01-01

    Helical CT was used on a trial basis for secondary screening of lung cancer, and its clinical usefulness is discussed in this report. The subjects of 157 patients with abnormal shadows on plain chest X-ray images were chosen between November 1993 and August 1994. Imaging parameters used for screening CT were as follows: 50 mA, 120 kV, a couch-top movement speed of 20 mm/s, and a beam width of 10 mm. The entire lung field was scanned during a single breath-hold. Reconstructed images were generated at 10-mm intervals by the 180deg interpolation method, and films were produced. Images of the entire lung field were made during a single breath-hold in all patients. Abnormal shadows were detected in 73 of 157 patients by screening CT. These 73 patients included 14 with lung cancer, 53 with benign lesions, one under observation, and five others. The average diameter of the tumors was 11.1 mm. The lung cancers detected all arose in the periphery, and were classified into stage I (10 patients), stage IIIA (3 patients), and stage IV with bone metastases (1 patient). Lung cancers in clinical stage I (3 patients) and stage IV (1 patient) were difficult to see on plain chest X-ray films. We conclude that screening CT is useful for early diagnosis of lung cancer because the entire lung field can be imaged during a single breath-hold. Therefore, helical CT can be expected to be useful in screening for lung cancer. (author)

  18. Visual assessment of early emphysema and interstitial abnormalities on CT is useful in lung cancer risk analysis

    DEFF Research Database (Denmark)

    Wille, Mathilde M. W.; Thomsen, Laura H.; Petersen, Jens

    2016-01-01

    Objectives: Screening for lung cancer should be limited to a high-risk-population, and abnormalities in low-dose computed tomography (CT) screening images may be relevant for predicting the risk of lung cancer. Our aims were to compare the occurrence of visually detected emphysema and interstitial...... abnormalities in subjects with and without lung cancer in a screening population of smokers. Methods: Low-dose chest CT examinations (baseline and latest possible) of 1990 participants from The Danish Lung Cancer Screening Trial were independently evaluated by two observers who scored emphysema and interstitial...... abnormalities. Emphysema (lung density) was also measured quantitatively. Results: Emphysema was seen more frequently and its extent was greater among participants with lung cancer on baseline (odds ratio (OR), 1.8, p = 0.017 and p = 0.002) and late examinations (OR 2.6, p

  19. Study of metastatic foci by CT in autopsied lung cancer

    International Nuclear Information System (INIS)

    Koga, Mitsuru; Nobe, Yoshifumi; Fujii, Kyoichi.

    1983-01-01

    The authors reexamined all of the image diagnoses made during whole hospitalization in 11 lung cancer cases with autopsy. Of 39 metastatic foci observed at autopsy in the liver, kidney, pancreas, adrenal and brain, 12 had been diagnosed on transverse CT images before death. Three foci were missed at initial readings. The period from CT to autopsy was less than 3 months for 9 of 12 correctly diagnosed foci. For 13 of 27 foci undetected by CT, CT was conducted more than 3 months before death. (Chiba, N)

  20. Impact of new technologies on dose reduction in CT

    International Nuclear Information System (INIS)

    Lee, Ting-Yim; Chhem, Rethy K.

    2010-01-01

    The introduction of slip ring technology enables helical CT scanning in the late 1980's and has rejuvenated CT's role in diagnostic imaging. Helical CT scanning has made possible whole body scanning in a single breath hold and computed tomography angiography (CTA) which has replaced invasive catheter based angiography in many cases because of its easy of operation and lesser risk to patients. However, a series of recent articles and accidents have heightened the concern of radiation risk from CT scanning. Undoubtedly, the radiation dose from CT studies, in particular, CCTA studies, are among the highest dose studies in diagnostic imaging. Nevertheless, CT has remained the workhorse of diagnostic imaging in emergent and non-emergent situations because of their ubiquitous presence in medical facilities from large academic to small regional hospitals and their round the clock accessibility due to their ease of use for both staff and patients as compared to MR scanners. The legitimate concern of radiation dose has sparked discussions on the risk vs benefit of CT scanning. It is recognized that newer CT applications, like CCTA and perfusion, will be severely curtailed unless radiation dose is reduced. This paper discusses the various hardware and software techniques developed to reduce radiation dose to patients in CT scanning. The current average effective dose of a CT study is ∼10 mSv, with the implementation of dose reduction techniques discussed herein; it is realistic to expect that the average effective dose may be decreased by 2-3 fold.

  1. Comparison of CT number calibration techniques for CBCT-based dose calculation

    International Nuclear Information System (INIS)

    Dunlop, Alex; McQuaid, Dualta; Nill, Simeon; Hansen, Vibeke N.; Oelfke, Uwe; Murray, Julia; Bhide, Shreerang; Harrington, Kevin; Poludniowski, Gavin; Nutting, Christopher; Newbold, Kate

    2015-01-01

    The aim of this work was to compare and validate various computed tomography (CT) number calibration techniques with respect to cone beam CT (CBCT) dose calculation accuracy. CBCT dose calculation accuracy was assessed for pelvic, lung, and head and neck (H and N) treatment sites for two approaches: (1) physics-based scatter correction methods (CBCT r ); (2) density override approaches including assigning water density to the entire CBCT (W), assignment of either water or bone density (WB), and assignment of either water or lung density (WL). Methods for CBCT density assignment within a commercially available treatment planning system (RS auto ), where CBCT voxels are binned into six density levels, were assessed and validated. Dose-difference maps and dose-volume statistics were used to compare the CBCT dose distributions with the ground truth of a planning CT acquired the same day as the CBCT. For pelvic cases, all CTN calibration methods resulted in average dose-volume deviations below 1.5 %. RS auto provided larger than average errors for pelvic treatments for patients with large amounts of adipose tissue. For H and N cases, all CTN calibration methods resulted in average dose-volume differences below 1.0 % with CBCT r (0.5 %) and RS auto (0.6 %) performing best. For lung cases, WL and RS auto methods generated dose distributions most similar to the ground truth. The RS auto density override approach is an attractive option for CTN adjustments for a variety of anatomical sites. RS auto methods were validated, resulting in dose calculations that were consistent with those calculated on diagnostic-quality CT images, for CBCT images acquired of the lung, for patients receiving pelvic RT in cases without excess adipose tissue, and for H and N cases. (orig.) [de

  2. Percutaneous CT-guided lung biopsy: sequential versus spiral scanning. A randomized prospective study

    International Nuclear Information System (INIS)

    Ghaye, B.; Dondelinger, R.F.; Dewe, W.

    1999-01-01

    The aim of this study was to evaluate in a prospective and randomized study spiral versus sequential scanning in the guidance of percutaneous lung biopsy. Fifty thoracic lesions occurring in 48 patients were biopsied by a senior and a junior operator. Six different time segments of the procedure were measured. Scanning mode versus length of procedure, pathological results, irradiation and complications were evaluated. Total duration of the procedure and of the first sampling was significantly longer with spiral CT for the senior operator (p < 0.004). No significant time difference was observed for the junior operator. Diameter of the lesion, depth of location, position of the patient and needle entry site did not influence the results. The sensitivity was 90.9, specificity 100, positive predictive value 100 and negative predictive value 60 % for spiral CT, and 94.7, 100, 100 and 85.7 % for sequential CT, respectively. Eleven pneumothoraces and ten perinodular hemorrhages were seen with spiral CT and six and ten, respectively, with sequential CT. The mean dose of irradiation was 4027 mAs for spiral CT and 2358 mAs for conventional CT. Spiral CT does neither reduce procedure time nor the rate of complications. Pathological results do not differ compared with sequential CT, and total dose of irradiation is higher with spiral scanning. (orig.)

  3. Strategies to reduce radiation dose in cardiac PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tung Hsin; Wu, Nien-Yun [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Wang, Shyh-Jen [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Wu, Jay [Institute of Radiological science, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Mok, Greta S.P. [Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Macau (China); Yang, Ching-Ching, E-mail: g39220003@yahoo.com.tw [Department of Radiological Technology, Tzu Chi College of Technology, 880, Sec.2, Chien-kuo Rd. Hualien 970, Taiwan (China); Huang, Tzung-Chi, E-mail: tzungchi.huang@mail.cmu.edu.tw [Department of Biomedical Imaging and Radiological Science, China Medical University, No.91 Hsueh-Shih Road, Taichung 40402, Taiwan (China)

    2011-08-21

    Background: Our aim was to investigate CT dose reduction strategies on a hybrid PET/CT scanner for cardiac applications. Materials: Image quality and dose estimation of different CT scanning protocols for CT coronary angiography (CTCA), and CT-based attenuation correction for PET imaging were investigated. Fifteen patients underwent CTCA, perfusion PET imaging at rest and under stress, and FDG PET for myocardial viability. These patients were divided into three groups based on the CTCA technique performed: retrospectively gated helical (RGH), ECG tube current modulation (ETCM), and prospective gated axial (PGA) acquisitions. All emission images were corrected for photon attenuation using CT images obtained by default setting and an ultra-low dose CT (ULDCT) scan. Results: Radiation dose in RGH technique was 22.2{+-}4.0 mSv. It was reduced to 10.95{+-}0.82 and 4.13{+-}0.31 mSv using ETCM and PGA techniques, respectively. Radiation dose in CT transmission scan was reduced by 96.5% (from 4.53{+-}0.5 to 0.16{+-}0.01 mSv) when applying ULDCT as compared to the default CT. No significant difference in terms of image quality was found among various protocols. Conclusion: The proposed CT scanning strategies, i.e. ETCM or PGA for CTCA and ULDCT for PET attenuation correction, could reduce radiation dose up to 47% without degrading imaging quality in an integrated cardiac PET/CT coronary artery examination.

  4. Risk-benefit analysis and cost-effectiveness analysis of lung cancer screening by spiral CT

    International Nuclear Information System (INIS)

    Iinuma, Takeshi

    1999-01-01

    Mass screening of lung cancer has been widely performed using indirect chest X-ray method in Japan. However reduction of the mortality for lung cancer is questioned. We have proposed that recently developed spiral CT should be adopted for the screening of lung cancer, since CT has an excellent detectability for small nodule. Lung Cancer Screening CT (LSCT) has been developed by author's group using spiral CT with low dose and light weight in order to make a mobile unit. In this paper risk-benefit analysis and cost-effectiveness analysis are described for the LSCT screening of lung cancer. As a risk, radiation carcinogenesis due to exposure from LSCT are compared with gain of life-expectancy by screening and men of 40 years or more and women of 45 years or more are justified. The cost per person-year is estimated for LSCT screening which is better than that of present method, although total cost is higher. The LSCT screening could be recommended if total cost is affordable. (author)

  5. Improved quantitation and reproducibility in multi-PET/CT lung studies by combining CT information.

    Science.gov (United States)

    Holman, Beverley F; Cuplov, Vesna; Millner, Lynn; Endozo, Raymond; Maher, Toby M; Groves, Ashley M; Hutton, Brian F; Thielemans, Kris

    2018-06-05

    Matched attenuation maps are vital for obtaining accurate and reproducible kinetic and static parameter estimates from PET data. With increased interest in PET/CT imaging of diffuse lung diseases for assessing disease progression and treatment effectiveness, understanding the extent of the effect of respiratory motion and establishing methods for correction are becoming more important. In a previous study, we have shown that using the wrong attenuation map leads to large errors due to density mismatches in the lung, especially in dynamic PET scans. Here, we extend this work to the case where the study is sub-divided into several scans, e.g. for patient comfort, each with its own CT (cine-CT and 'snap shot' CT). A method to combine multi-CT information into a combined-CT has then been developed, which averages the CT information from each study section to produce composite CT images with the lung density more representative of that in the PET data. This combined-CT was applied to nine patients with idiopathic pulmonary fibrosis, imaged with dynamic 18 F-FDG PET/CT to determine the improvement in the precision of the parameter estimates. Using XCAT simulations, errors in the influx rate constant were found to be as high as 60% in multi-PET/CT studies. Analysis of patient data identified displacements between study sections in the time activity curves, which led to an average standard error in the estimates of the influx rate constant of 53% with conventional methods. This reduced to within 5% after use of combined-CTs for attenuation correction of the study sections. Use of combined-CTs to reconstruct the sections of a multi-PET/CT study, as opposed to using the individually acquired CTs at each study stage, produces more precise parameter estimates and may improve discrimination between diseased and normal lung.

  6. Accuracy of low dose CT in the diagnosis of appendicitis in childhood and comparison with USG and standard dose CT.

    Science.gov (United States)

    Yi, Dae Yong; Lee, Kyung Hoon; Park, Sung Bin; Kim, Jee Taek; Lee, Na Mi; Kim, Hyery; Yun, Sin Weon; Chae, Soo Ahn; Lim, In Seok

    Computed tomography should be performed after careful consideration due to radiation hazard, which is why interest in low dose CT has increased recently in acute appendicitis. Previous studies have been performed in adult and adolescents populations, but no studies have reported on the efficacy of using low-dose CT in children younger than 10 years. Patients (n=475) younger than 10 years who were examined for acute appendicitis were recruited. Subjects were divided into three groups according to the examinations performed: low-dose CT, ultrasonography, and standard-dose CT. Subjects were categorized according to age and body mass index (BMI). Low-dose CT was a contributive tool in diagnosing appendicitis, and it was an adequate method, when compared with ultrasonography and standard-dose CT in terms of sensitivity (95.5% vs. 95.0% and 94.5%, p=0.794), specificity (94.9% vs. 80.0% and 98.8%, p=0.024), positive-predictive value (96.4% vs. 92.7% and 97.2%, p=0.019), and negative-predictive value (93.7% vs. 85.7% and 91.3%, p=0.890). Low-dose CT accurately diagnosed patients with a perforated appendix. Acute appendicitis was effectively diagnosed using low-dose CT in both early and middle childhood. BMI did not influence the accuracy of detecting acute appendicitis on low-dose CT. Low-dose CT is effective and accurate for diagnosing acute appendicitis in childhood, as well as in adolescents and young adults. Additionally, low-dose CT was relatively accurate, irrespective of age or BMI, for detecting acute appendicitis. Therefore, low-dose CT is recommended for assessing children with suspected acute appendicitis. Copyright © 2017. Published by Elsevier Editora Ltda.

  7. Lung Nodule Detection in CT Images using Neuro Fuzzy Classifier

    Directory of Open Access Journals (Sweden)

    M. Usman Akram

    2013-07-01

    Full Text Available Automated lung cancer detection using computer aided diagnosis (CAD is an important area in clinical applications. As the manual nodule detection is very time consuming and costly so computerized systems can be helpful for this purpose. In this paper, we propose a computerized system for lung nodule detection in CT scan images. The automated system consists of two stages i.e. lung segmentation and enhancement, feature extraction and classification. The segmentation process will result in separating lung tissue from rest of the image, and only the lung tissues under examination are considered as candidate regions for detecting malignant nodules in lung portion. A feature vector for possible abnormal regions is calculated and regions are classified using neuro fuzzy classifier. It is a fully automatic system that does not require any manual intervention and experimental results show the validity of our system.

  8. Computer aided detection system for Osteoporosis using low dose thoracic 3D CT images

    Science.gov (United States)

    Tsuji, Daisuke; Matsuhiro, Mikio; Suzuki, Hidenobu; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Harada, Masafumi; Kusumoto, Masahiko; Tsuchida, Takaaki; Eguchi, Kenji; Kaneko, Masahiro

    2018-02-01

    The patient of osteoporosis is about 13 million people in Japan and it is one of healthy life problems in the aging society. It is necessary to do early stage detection and treatment in order to prevent the osteoporosis. Multi-slice CT technology has been improving the three dimensional (3D) image analysis with higher resolution and shorter scan time. The 3D image analysis of thoracic vertebra can be used for supporting to diagnosis of osteoporosis. This analysis can be used for lung cancer detection at the same time. We develop method of shape analysis and CT values of spongy bone for the detection osteoporosis. Osteoporosis and lung cancer screening show high extraction rate by the thoracic vertebral evaluation CT images. In addition, we created standard pattern of CT value per thoracic vertebra for male age group using 298 low dose data.

  9. Effect of staff training on radiation dose in pediatric CT

    Energy Technology Data Exchange (ETDEWEB)

    Hojreh, Azadeh, E-mail: azadeh.hojreh@meduniwien.ac.at [Medical University of Vienna, Department of Biological Imaging and Image-guided Therapy, Division of General and Paediatric Radiology, Waehringer Guertel 18–20, A-1090 Vienna (Austria); Weber, Michael, E-mail: michael.Weber@Meduniwien.Ac.At [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of General and Paediatric Radiology, Waehringer Guertel 18–20, A-1090 Vienna (Austria); Homolka, Peter, E-mail: peter.Homolka@Meduniwien.Ac.At [Medical University of Vienna, Centre for Medical Physics and Biomedical Engineering, Waehringer Guertel 18–20, A-1090 Vienna (Austria)

    2015-08-15

    Highlights: • Pediatric patient CT doses were compared before and after staff training. • Staff training increasing dose awareness resulted in patient dose reduction. • Application of DRL reduced number of CT's with unusually high doses. • Continuous education and training are effective regarding dose optimization. - Abstract: Objective: To evaluate the efficacy of staff training on radiation doses applied in pediatric CT scans. Methods: Pediatric patient doses from five CT scanners before (1426 scans) and after staff training (2566 scans) were compared statistically. Examinations included cranial CT (CCT), thoracic, abdomen–pelvis, and trunk scans. Dose length products (DLPs) per series were extracted from CT dose reports archived in the PACS. Results: A pooled analysis of non-traumatic scans revealed a statistically significant reduction in the dose for cranial, thoracic, and abdomen/pelvis scans (p < 0.01). This trend could be demonstrated also for trunk scans, however, significance could not be established due to low patient frequencies (p > 0.05). The percentage of scans performed with DLPs exceeding the German DRLs was reduced from 41% to 7% (CCT), 19% to 5% (thorax-CT), from 9% to zero (abdominal–pelvis CT), and 26% to zero (trunk; DRL taken as summed DRLs for thorax plus abdomen–pelvis, reduced by 20% accounting for overlap). Comparison with Austrian DRLs – available only for CCT and thorax CT – showed a reduction from 21% to 3% (CCT), and 15 to 2% (thorax CT). Conclusions: Staff training together with application of DRLs provide an efficient approach for optimizing radiation dose in pediatric CT practice.

  10. CT analysis of lung density changes in patients undergoing total body irradiation prior to bone marrow transplantation

    International Nuclear Information System (INIS)

    Lee, J.Y.; Shank, B.; Bonfiglio, P.; Reid, A.

    1984-01-01

    Sequential changes in lung density measured by CT are potentially sensitive and convenient monitors of lung abnormalities following total body irradiation (TBI). Methods have been developed to compare pre- and post-TBI CT of lung. The average local features of a cross-sectional lung slice are extracted from three peripheral regions of interest in the anterior, posterior, and lateral portions of the CT image. Also, density profiles across a specific region may be obtained. These may be compared first for verification of patient position and breathing status and then for changes between pre- and post-TBI. These may also be compared with radiation dose profiles through the lung. A preliminary study on 21 leukemia patients undergoing total body irradiation indicates the following: (a) Density gradients of patients' lungs in the antero-posterior direction show a marked heterogeneity before and after transplantation compared with normal lungs. The patients with departures from normal density gradients pre-TBI correlate with later pulmonary complications. (b) Measurements of average peripheral lung densities have demonstrated that the average lung density in the younger age group is substantially higher: pre-TBI, the average CT number (1,000 scale) is -638 +/- 39 Hounsfield unit (HU) for 0-10 years old and -739 +/- 53 HU for 21-40 years old. (c) Density profiles showed no post-TBI regional changes in lung density corresponding to the dose profile across the lung, so no differentiation of a radiation-specific effect has yet been possible. Computed tomographic density profiles in the antero-posterior direction are successfully used to verify positioning of the CT slice and the breathing level of the lung

  11. Algorithm of pulmonary emphysema extraction using low dose thoracic 3D CT images

    Science.gov (United States)

    Saita, S.; Kubo, M.; Kawata, Y.; Niki, N.; Nakano, Y.; Omatsu, H.; Tominaga, K.; Eguchi, K.; Moriyama, N.

    2006-03-01

    Recently, due to aging and smoking, emphysema patients are increasing. The restoration of alveolus which was destroyed by emphysema is not possible, thus early detection of emphysema is desired. We describe a quantitative algorithm for extracting emphysematous lesions and quantitatively evaluate their distribution patterns using low dose thoracic 3-D CT images. The algorithm identified lung anatomies, and extracted low attenuation area (LAA) as emphysematous lesion candidates. Applying the algorithm to 100 thoracic 3-D CT images and then by follow-up 3-D CT images, we demonstrate its potential effectiveness to assist radiologists and physicians to quantitatively evaluate the emphysematous lesions distribution and their evolution in time interval changes.

  12. How to choose PET-CT or CT in the diagnosis and staging of lung cancer. Practical experience in China

    International Nuclear Information System (INIS)

    Jiang, T.; Tao, X.; Liu, H.; Liu, S.; Zheng, X.

    2010-01-01

    How to use CT and PET-CT rationally to raise diagnosis, staging and prognostic assessment of lung cancer to a higher level at the best cost-effect ratio is a subject that Chinese clinicians and radiologists should face conscientiously. We review the rational application of CT and PET-CT in four aspects of lung cancer, including screening and detection, morphologic evaluation, haemodynamic or metabolic feature evaluation, and follow-up, staging and prognostic evaluation. As PET-CT is only available in class III-A hospitals today, CT is the most popular equipment in China. PET-CT is more valuable only in cases where CT presentation of lung cancer is atypical or difficult to determine, or in cases where the diagnosis of lung cancer has been initially confirmed, for which clinical staging and decision concerning on therapeutic regimens are needed. We also recommend the current strategies of CT and PET-CT managing of SPN in China. (orig.)

  13. WE-D-207-03: CT Protocols for Screening and the ACR Designated Lung Screening Program

    International Nuclear Information System (INIS)

    McNitt-Gray, M.

    2015-01-01

    In the United States, Lung Cancer is responsible for more cancer deaths than the next four cancers combined. In addition, the 5 year survival rate for lung cancer patients has not improved over the past 40 to 50 years. To combat this deadly disease, in 2002 the National Cancer Institute launched a very large Randomized Control Trial called the National Lung Screening Trial (NLST). This trial would randomize subjects who had substantial risk of lung cancer (due to age and smoking history) into either a Chest X-ray arm or a low dose CT arm. In November 2010, the National Cancer Institute announced that the NLST had demonstrated 20% fewer lung cancer deaths among those who were screened with low-dose CT than with chest X-ray. In December 2013, the US Preventive Services Task Force recommended the use of Lung Cancer Screening using low dose CT and a little over a year later (Feb. 2015), CMS announced that Medicare would also cover Lung Cancer Screening using low dose CT. Thus private and public insurers are required to provide Lung Cancer Screening programs using CT to the appropriate population(s). The purpose of this Symposium is to inform medical physicists and prepare them to support the implementation of Lung Screening programs. This Symposium will focus on the clinical aspects of lung cancer screening, requirements of a screening registry for systematically capturing and tracking screening patients and results (such as required Medicare data elements) as well as the role of the medical physicist in screening programs, including the development of low dose CT screening protocols. Learning Objectives: To understand the clinical basis and clinical components of a lung cancer screening program, including eligibility criteria and other requirements. To understand the data collection requirements, workflow, and informatics infrastructure needed to support the tracking and reporting components of a screening program. To understand the role of the medical physicist in

  14. Quantitative assessment of emphysema from whole lung CT scans: comparison with visual grading

    Science.gov (United States)

    Keller, Brad M.; Reeves, Anthony P.; Apanosovich, Tatiyana V.; Wang, Jianwei; Yankelevitz, David F.; Henschke, Claudia I.

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema and for visual assessment by radiologists of the extent present in the lungs. Several measures have been introduced for the quantification of the extent of disease directly from CT data in order to add to the qualitative assessments made by radiologists. In this paper we compare emphysema index, mean lung density, histogram percentiles, and the fractal dimension to visual grade in order to evaluate the predictability of radiologist visual scoring of emphysema from low-dose CT scans through quantitative scores, in order to determine which measures can be useful as surrogates for visual assessment. All measures were computed over nine divisions of the lung field (whole lung, individual lungs, and upper/middle/lower thirds of each lung) for each of 148 low-dose, whole lung scans. In addition, a visual grade of each section was also given by an expert radiologist. One-way ANOVA and multinomial logistic regression were used to determine the ability of the measures to predict visual grade from quantitative score. We found that all measures were able to distinguish between normal and severe grades (p<0.01), and between mild/moderate and all other grades (p<0.05). However, no measure was able to distinguish between mild and moderate cases. Approximately 65% prediction accuracy was achieved from using quantitative score to predict visual grade, with 73% if mild and moderate cases are considered as a single class.

  15. Implementation of lung cancer CT screening in the Nordic countries

    DEFF Research Database (Denmark)

    Pedersen, Jesper Holst; Sørensen, Jens Benn; Saghir, Zaigham

    2017-01-01

    INTRODUCTION: We review the current knowledge of CT screening for lung cancer and present an expert-based, joint protocol for the proper implementation of screening in the Nordic countries. MATERIALS AND METHODS: Experts representing all the Nordic countries performed literature review...... and concensus for a joint protocol for lung cancer screening. RESULTS AND DISCUSSION: Areas of concern and caution are presented and discussed. We suggest to perform CT screening pilot studies in the Nordic countries in order to gain experience and develop specific and safe protocols for the implementation...

  16. CT reconstruction techniques for improved accuracy of lung CT airway measurement

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, A. [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 (United States); Ranallo, F. N. [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 and Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 (United States); Judy, P. F. [Brigham and Women’s Hospital, Boston, Massachusetts 02115 (United States); Gierada, D. S. [Department of Radiology, Washington University, St. Louis, Missouri 63110 (United States); Fain, S. B., E-mail: sfain@wisc.edu [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 (United States); Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 (United States); Department of Biomedical Engineering,University of Wisconsin School of Engineering, Madison, Wisconsin 53706 (United States)

    2014-11-01

    Purpose: To determine the impact of constrained reconstruction techniques on quantitative CT (qCT) of the lung parenchyma and airways for low x-ray radiation dose. Methods: Measurement of small airways with qCT remains a challenge, especially for low x-ray dose protocols. Images of the COPDGene quality assurance phantom (CTP698, The Phantom Laboratory, Salem, NY) were obtained using a GE discovery CT750 HD scanner for helical scans at x-ray radiation dose-equivalents ranging from 1 to 4.12 mSv (12–100 mA s current–time product). Other parameters were 40 mm collimation, 0.984 pitch, 0.5 s rotation, and 0.625 mm thickness. The phantom was sandwiched between 7.5 cm thick water attenuating phantoms for a total length of 20 cm to better simulate the scatter conditions of patient scans. Image data sets were reconstructed using STANDARD (STD), DETAIL, BONE, and EDGE algorithms for filtered back projection (FBP), 100% adaptive statistical iterative reconstruction (ASIR), and Veo reconstructions. Reduced (half) display field of view (DFOV) was used to increase sampling across airway phantom structures. Inner diameter (ID), wall area percent (WA%), and wall thickness (WT) measurements of eight airway mimicking tubes in the phantom, including a 2.5 mm ID (42.6 WA%, 0.4 mm WT), 3 mm ID (49.0 WA%, 0.6 mm WT), and 6 mm ID (49.0 WA%, 1.2 mm WT) were performed with Airway Inspector (Surgical Planning Laboratory, Brigham and Women’s Hospital, Boston, MA) using the phase congruency edge detection method. The average of individual measures at five central slices of the phantom was taken to reduce measurement error. Results: WA% measures were greatly overestimated while IDs were underestimated for the smaller airways, especially for reconstructions at full DFOV (36 cm) using the STD kernel, due to poor sampling and spatial resolution (0.7 mm pixel size). Despite low radiation dose, the ID of the 6 mm ID airway was consistently measured accurately for all methods other than STD

  17. CT reconstruction techniques for improved accuracy of lung CT airway measurement

    International Nuclear Information System (INIS)

    Rodriguez, A.; Ranallo, F. N.; Judy, P. F.; Gierada, D. S.; Fain, S. B.

    2014-01-01

    Purpose: To determine the impact of constrained reconstruction techniques on quantitative CT (qCT) of the lung parenchyma and airways for low x-ray radiation dose. Methods: Measurement of small airways with qCT remains a challenge, especially for low x-ray dose protocols. Images of the COPDGene quality assurance phantom (CTP698, The Phantom Laboratory, Salem, NY) were obtained using a GE discovery CT750 HD scanner for helical scans at x-ray radiation dose-equivalents ranging from 1 to 4.12 mSv (12–100 mA s current–time product). Other parameters were 40 mm collimation, 0.984 pitch, 0.5 s rotation, and 0.625 mm thickness. The phantom was sandwiched between 7.5 cm thick water attenuating phantoms for a total length of 20 cm to better simulate the scatter conditions of patient scans. Image data sets were reconstructed using STANDARD (STD), DETAIL, BONE, and EDGE algorithms for filtered back projection (FBP), 100% adaptive statistical iterative reconstruction (ASIR), and Veo reconstructions. Reduced (half) display field of view (DFOV) was used to increase sampling across airway phantom structures. Inner diameter (ID), wall area percent (WA%), and wall thickness (WT) measurements of eight airway mimicking tubes in the phantom, including a 2.5 mm ID (42.6 WA%, 0.4 mm WT), 3 mm ID (49.0 WA%, 0.6 mm WT), and 6 mm ID (49.0 WA%, 1.2 mm WT) were performed with Airway Inspector (Surgical Planning Laboratory, Brigham and Women’s Hospital, Boston, MA) using the phase congruency edge detection method. The average of individual measures at five central slices of the phantom was taken to reduce measurement error. Results: WA% measures were greatly overestimated while IDs were underestimated for the smaller airways, especially for reconstructions at full DFOV (36 cm) using the STD kernel, due to poor sampling and spatial resolution (0.7 mm pixel size). Despite low radiation dose, the ID of the 6 mm ID airway was consistently measured accurately for all methods other than STD

  18. Evaluation of organ doses and specific k effective dose of 64-slice CT thorax examination using an adult anthropomorphic phantom

    International Nuclear Information System (INIS)

    Hashim, S.; Karim, M.K.A.; Bakar, K.A.; Sabarudin, A.; Chin, A.W; Saripan, M.I.; Bradley, D.A.

    2016-01-01

    The magnitude of radiation dose in computed tomography (CT) depends on the scan acquisition parameters, investigated herein using an anthropomorphic phantom (RANDO®) and thermoluminescence dosimeters (TLD). Specific interest was in the organ doses resulting from CT thorax examination, the specific k coefficient for effective dose estimation for particular protocols also being determined. For measurement of doses representing five main organs (thyroid, lung, liver, esophagus and skin), TLD-100 (LiF:Mg, Ti) were inserted into selected holes in a phantom slab. Five CT thorax protocols were investigated, one routine (R1) and four that were modified protocols (R2 to R5). Organ doses were ranked from greatest to least, found to lie in the order: thyroid>skin>lung>liver>breast. The greatest dose, for thyroid at 25 mGy, was that in use of R1 while the lowest, at 8.8 mGy, was in breast tissue using R3. Effective dose (E) was estimated using three standard methods: the International Commission on Radiological Protection (ICRP)-103 recommendation (E103), the computational phantom CT-EXPO (E(CTEXPO)) method, and the dose-length product (DLP) based approach. E103 k factors were constant for all protocols, ~8% less than that of the universal k factor. Due to inconsistency in tube potential and pitch factor the k factors from CTEXPO were found to vary between 0.015 and 0.010 for protocols R3 and R5. With considerable variation between scan acquisition parameters and organ doses, optimization of practice is necessary in order to reduce patient organ dose. - Highlights: • Using TLD-100 dosimeters and a RANDO phantom 5 CT thorax protocol organ doses were assessed. • The specific k coefficient for effective dose estimation of protocols differed with approach. • Organ dose was observed to decrease in the order: thyroid>skin>lung>liver>breast. • E103 k factors were constant for all protocols, lower by ~8% compared to the universal k factor.

  19. Diagnosis of malignant pleural effusion and lung cancer with CT

    International Nuclear Information System (INIS)

    Jakimovska, S.; Jakimovska, M.; Jovanovska, S.; Ilieva, S.

    2012-01-01

    Full text: Introduction: A pleural effusion is defined as an abnormal amount of fluid in the space between the layers of tissue (the pleura) that line the lungs. If cancer cells are present in this fluid (pleural cavity) it is called a malignant cancerous pleural effusion. Many benign and malignant disease can cause pleural effusion.The new onset of pleural effusion may herald the presence of a previously undiagnosed malignancy, or more typically, complicate the course of a known lung tumor. Malignant pleural effusions can lead lead to an initial diagnosis of lung cancer in patients.and it was the first symptom of lung cancer. Pleural deposits of tumor cause pleuritic pain. Purpose of this presentation is to show the role of CT in diagnosis of malignant pleural effusion and lung cancer. Material and methods: CT examinations of chest were made to 138 patients for 1 year (1/6/2011- 1/6/2012) with Siemens Somatom Emotion 16 CT Scanner. Patients were at age of 30 -81 years, 93 of them are male and 45 are female. Results: 56 (40.5%) of the patients had pleural effusion. From this group 21 37.5% had malignant pleural effusion and lung cancer. 17 (81%) of them are male, and 4 (19%) are female. 9 (43%) diagnosed lung cancer for first time. Conclusion: Pleural effusion more commonly occur in patient with advanced-stage tumor who frequently have metastases to other organs and long-term survival is uncommon in this group. CT diagnosed malignant pleural effusion and lung cancer and help to choice treatment for these patients

  20. Collateral ventilation to congenital hyperlucent lung lesions assessed on xenon-enhanced dynamic dual-energy CT: an initial experience.

    Science.gov (United States)

    Goo, Hyun Woo; Yang, Dong Hyun; Kim, Namkug; Park, Seung Il; Kim, Dong Kwan; Kim, Ellen Ai-Rhan

    2011-01-01

    We wanted to evaluate the resistance to collateral ventilation in congenital hyperlucent lung lesions and to correlate that with the anatomic findings on xenon-enhanced dynamic dual-energy CT. Xenon-enhanced dynamic dual-energy CT was successfully and safely performed in eight children (median age: 5.5 years, 4 boys and 4 girls) with congenital hyperlucent lung lesions. Functional assessment of the lung lesions on the xenon map was done, including performing a time-xenon value curve analysis and assessing the amplitude of xenon enhancement (A) value, the rate of xenon enhancement (K) value and the time of arrival value. Based on the A value, the lung lesions were categorized into high or low (A value > 10 Hounsfield unit [HU]) resistance to collateral ventilation. In addition, the morphologic CT findings of the lung lesions, including cyst, mucocele and an accessory or incomplete fissure, were assessed on the weighted-average CT images. The xenon-enhanced CT radiation dose was estimated. Five of the eight lung lesions were categorized into the high resistance group and three lesions were categorized into the low resistance group. The A and K values in the normal lung were higher than those in the low resistance group. The time of arrival values were delayed in the low resistance group. Cysts were identified in five lesions, mucocele in four, accessory fissure in three and incomplete fissure in two. Either cyst or an accessory fissure was seen in four of the five lesions showing high resistance to collateral ventilation. The xenon-enhanced CT radiation dose was 2.3 ± 0.6 mSv. Xenon-enhanced dynamic dual-energy CT can help visualize and quantitate various degrees of collateral ventilation to congenital hyperlucent lung lesions in addition to assessing the anatomic details of the lung.

  1. Effective dose and cancer risk in PET/CT exams

    International Nuclear Information System (INIS)

    Pinto, Gabriella M.; Sa, Lidia Vasconcellos de

    2013-01-01

    Due to the use of radiopharmaceutical positron-emitting in PET exam and realization of tomography by x-ray transmission in CT examination, an increase of dose with hybrid PET/CT technology is expected. However, differences of doses have been reported in many countries for the same type of procedure. It is expected that the dose is an influent parameter to standardize the protocols of PET/CT. This study aimed to estimate the effective doses and absorbed in 65 patients submitted to oncological Protocol in a nuclear medicine clinic in Rio de Janeiro, considering the risk of induction of cancer from the scan. The CT exam-related doses were estimated with a simulator of PMMA and simulated on the lmPACT resistance, which for program effective dose, were considered the weight factors of the lCRP 103. The PET exam doses were estimated by multiplying the activity administered to the patient with the ICRP dose 80 factors. The radiological risk for cancer incidence were estimated according to the ICRP 103. The results showed that the effective dose from CT exam is responsible for 70% of the effective total in a PET/CT scan. values of effective dose for the PET/CT exam reached average values of up to 25 mSv leading to a risk of 2, 57 x 10 -4 . Considering that in staging of oncological diseases at least four tests are performed annually, the total risk comes to 1,03x 10 -3

  2. Low-dose respiratory-gated PET/CT: based on 30 mA tube current

    International Nuclear Information System (INIS)

    Wu Ping; Li Sijin; Zhang Yanlan; Hao Xinzhong; Qin Zhixing; Yan Min; Cheng Pengliang; Wu Zhifang

    2013-01-01

    Objective: To establish a low-dose but image-comparable respiratory-gated PET/CT (RG PET/CT) protocol based on 30 mA tube current plus other improved scanning parameters, such as the tube current, the number of respiratory phase and length of breathing cycle. Methods: Twenty-six patients with 18 F-FDG-intaking lung nodules underwent one-bed standard-dose PET/CT (120 mA, 2 min/bed) and low dose RG PET/CT (30 mA, 6 respiratory phases, 1 min/phase). The radiation dose and image quality were analyzed subsequently with signal to noise ratio (SNR) for PET and the homogeneity, noise level for CT in the water phantom respectively. Otherwise the CT images were both visual evaluated by two experienced doctors. In addition, different respiratory cycle was simulated to observe its relation with radiation dose. Results: The effective dose of low-dose RG PET/CT was 4.88∼7.69 mSv [mean (5.68±0.83) mSv]. The PET SNR showed no significance between groups. The homogeneity of 30 mA is good (< 5 HU), although noise level was high, the visual character like lobulation, speculation of lung nodule was superior in some respiratory phases. The radiation dose was positively correlated with respiratory cycle. Conclusions: The performance of low-dose RG PET/CT was comparable to those of standard-dose PET/CT based on a protocol with 30 mA tube current, 6 respiratory phases and breathing state of eupnoea. It produced a much lower radiation exposure and the image quality was enough for clinical use such as delineation of tumor active target, characterization and staging of lung nodules, etc. (authors)

  3. Lung nodule detection by microdose CT versus chest radiography (standard and dual-energy subtracted).

    Science.gov (United States)

    Ebner, Lukas; Bütikofer, Yanik; Ott, Daniel; Huber, Adrian; Landau, Julia; Roos, Justus E; Heverhagen, Johannes T; Christe, Andreas

    2015-04-01

    The purpose of this study was to investigate the feasibility of microdose CT using a comparable dose as for conventional chest radiographs in two planes including dual-energy subtraction for lung nodule assessment. We investigated 65 chest phantoms with 141 lung nodules, using an anthropomorphic chest phantom with artificial lung nodules. Microdose CT parameters were 80 kV and 6 mAs, with pitch of 2.2. Iterative reconstruction algorithms and an integrated circuit detector system (Stellar, Siemens Healthcare) were applied for maximum dose reduction. Maximum intensity projections (MIPs) were reconstructed. Chest radiographs were acquired in two projections with bone suppression. Four blinded radiologists interpreted the images in random order. A soft-tissue CT kernel (I30f) delivered better sensitivities in a pilot study than a hard kernel (I70f), with respective mean (SD) sensitivities of 91.1%±2.2% versus 85.6%±5.6% (p=0.041). Nodule size was measured accurately for all kernels. Mean clustered nodule sensitivity with chest radiography was 45.7%±8.1% (with bone suppression, 46.1%±8%; p=0.94); for microdose CT, nodule sensitivity was 83.6%±9% without MIP (with additional MIP, 92.5%±6%; pmicrodose CT for readers 1, 2, 3, and 4 were 84.3%, 90.7%, 68.6%, and 45.0%, respectively. Sensitivities with chest radiography for readers 1, 2, 3, and 4 were 42.9%, 58.6%, 36.4%, and 90.7%, respectively. In the per-phantom analysis, respective sensitivities of microdose CT versus chest radiography were 96.2% and 75% (pmicrodose CT, the applied dose was 0.1323 mSv. Microdose CT is better than the combination of chest radiography and dual-energy subtraction for the detection of solid nodules between 5 and 12 mm at a lower dose level of 0.13 mSv. Soft-tissue kernels allow better sensitivities. These preliminary results indicate that microdose CT has the potential to replace conventional chest radiography for lung nodule detection.

  4. Techniques and radiation dose in CT examinations of adult patients

    International Nuclear Information System (INIS)

    Elameen, S. E. A.

    2010-06-01

    The use of CT in medical diagnosis delivers radiation dose to patients that are higher than those from other radiological procedures. Lake of optimized protocols could be an additional source of increased dose. The aim of this study was to measure radiation doses in CT examination of the adults in three Sudanese hospitals. Details were obtained from approximately 160 CT examination carried out in 3 hospitals (3 CT scanners). Effective dose was calculated for each examination using CT dose indices. exposure related parameters and CT D1- to- effective dose conversion factors. CT air kerma index (CT D1) and dose length products (DLP) determined were below the established international reference dose levels. The mean effective doses in this study for the head, chest, and abdomen are 0.82, 3.7 and 5.4 mGy respectively. These values were observed that the effective dose per examination was lower in Sudan than in other countries. The report of a CT survey done in these centers indicates that the mean DLP values for adult patients were ranged from 272-460 mGy cm (head) 195-995 mGy cm (chest), 270-459 mGy cm (abdomen). There are a number of observed parameters that greatly need optimization, such as minimize the scan length, without missing any vital anatomical regions, modulation of exposure parameters (kV, mA, exposure time, and slice thickness) based on patient size and age. Another possible method is through use of contrast media only to optimize diagnostic yield. The last possible method is the use of radio protective materials for protection however, in order to achieve the above optimization strategies: there is great demand to educate CT personnel on the effects of scan parameter settings on radiation dose to patients and image quality required for accurate diagnosis. (Author)

  5. Prospective evaluation of the radiologist's hand dose in CT-guided interventions

    International Nuclear Information System (INIS)

    Rogits, B.; Jungnickel, K.; Loewenthal, D.; Dudeck, O.; Pech, M.; Ricke, J.; Kropf, S.; Nekolla, E.A.; Wieners, G.

    2013-01-01

    Purpose: Assessment of radiologist's hand dose in CT-guided interventions and determination of influencing factors. Materials and Methods: The following CT-guided interventions were included: Core biopsy, drainage, periradicular therapy, and celiac plexus neurolysis. The hand dose was measured with an immediately readable dosimeter, the EDD-30 (Unfors, Sweden). The default parameters for CT fluoroscopy were 120 kV, 90 mA and a 4 mm slice thickness. All interventions were performed on a 16-slice CT unit (Aquilion 16 Toshiba, Japan). The tumor size, degree of difficulty (1 - 3), level of experience and device parameters (mAs, dose-length product, scan time) were documented. Results: 138 CT-guided interventions (biopsy n = 99, drainage n = 23, pain therapy n = 16) at different locations (lung n = 41, retroperitoneum n = 53, liver n = 25, spine n = 19) were included. The lesion size was 4 - 240 mm (median: 23 mm). The fluoroscopy time per intervention was 4.6 - 140.2 s (median: 24.2 s). The measured hand dose ranged from 0.001 - 3.02 mSv (median: 0.22 mSv). The median hand dose for lung puncture (n = 41) was slightly higher (median: 0.32 mSv, p = 0.01) compared to that for the liver, retroperitoneum and other. Besides physical influencing factors, the degree of difficulty (p = 0.001) and summed puncture depth (p = 0.004) correlated significantly with the hand dose. Conclusion: The median hand dose for different CT-guided interventions was 0.22 mSv. Therefore, the annual hand dose limit would normally only be reached with about 2000 interventions. (orig.)

  6. Ultra-low dose CT attenuation correction for PET/CT: analysis of sparse view data acquisition and reconstruction algorithms

    Science.gov (United States)

    Rui, Xue; Cheng, Lishui; Long, Yong; Fu, Lin; Alessio, Adam M.; Asma, Evren; Kinahan, Paul E.; De Man, Bruno

    2015-01-01

    For PET/CT systems, PET image reconstruction requires corresponding CT images for anatomical localization and attenuation correction. In the case of PET respiratory gating, multiple gated CT scans can offer phase-matched attenuation and motion correction, at the expense of increased radiation dose. We aim to minimize the dose of the CT scan, while preserving adequate image quality for the purpose of PET attenuation correction by introducing sparse view CT data acquisition. Methods We investigated sparse view CT acquisition protocols resulting in ultra-low dose CT scans designed for PET attenuation correction. We analyzed the tradeoffs between the number of views and the integrated tube current per view for a given dose using CT and PET simulations of a 3D NCAT phantom with lesions inserted into liver and lung. We simulated seven CT acquisition protocols with {984, 328, 123, 41, 24, 12, 8} views per rotation at a gantry speed of 0.35 seconds. One standard dose and four ultra-low dose levels, namely, 0.35 mAs, 0.175 mAs, 0.0875 mAs, and 0.04375 mAs, were investigated. Both the analytical FDK algorithm and the Model Based Iterative Reconstruction (MBIR) algorithm were used for CT image reconstruction. We also evaluated the impact of sinogram interpolation to estimate the missing projection measurements due to sparse view data acquisition. For MBIR, we used a penalized weighted least squares (PWLS) cost function with an approximate total-variation (TV) regularizing penalty function. We compared a tube pulsing mode and a continuous exposure mode for sparse view data acquisition. Global PET ensemble root-mean-squares-error (RMSE) and local ensemble lesion activity error were used as quantitative evaluation metrics for PET image quality. Results With sparse view sampling, it is possible to greatly reduce the CT scan dose when it is primarily used for PET attenuation correction with little or no measureable effect on the PET image. For the four ultra-low dose levels

  7. Radiation exposure during CT-guided biopsies: recent CT machines provide markedly lower doses.

    Science.gov (United States)

    Guberina, Nika; Forsting, Michael; Ringelstein, Adrian; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Theysohn, Jens; Wetter, Axel

    2018-03-28

    To examine radiation dose levels of CT-guided interventional procedures of chest, abdomen, spine and extremities on different CT-scanner generations at a large multicentre institute. 1,219 CT-guided interventional biopsies of different organ regions ((A) abdomen (n=516), (B) chest (n=528), (C) spine (n=134) and (D) extremities (n=41)) on different CT-scanners ((I) SOMATOM-Definition-AS+, (II) Volume-Zoom, (III) Emotion6) were included from 2013-2016. Important CT-parameters and standard dose-descriptors were retrospectively examined. Additionally, effective dose and organ doses were calculated using Monte-Carlo simulation, following ICRP103. Overall, radiation doses for CT interventions are highly dependent on CT-scanner generation: the newer the CT scanner, the lower the radiation dose imparted to patients. Mean effective doses for each of four procedures on available scanners are: (A) (I) 9.3mSv versus (II) 13.9mSv (B) (I) 7.3mSv versus (III) 11.4mSv (C) (I) 6.3mSv versus (II) 7.4mSv (D) (I) 4.3mSv versus (II) 10.8mSv. Standard dose descriptors [standard deviation (SD); CT dose index vol (CTDI vol ); dose-length product (DLP body ); size-specific dose estimate (SSDE)] were also compared. Effective dose, organ doses and SSDE for various CT-guided interventional biopsies on different CT-scanner generations following recommendations of the ICRP103 are provided. New CT-scanner generations involve markedly lower radiation doses versus older devices. • Effective dose, organ dose and SSDE are provided for CT-guided interventional examinations. • These data allow identifying organs at risk of higher radiation dose. • Detailed knowledge of radiation dose may contribute to a better individual risk-stratification. • New CT-scanner generations involve markedly lower radiation doses compared to older devices.

  8. Effect of staff training on radiation dose in pediatric CT.

    Science.gov (United States)

    Hojreh, Azadeh; Weber, Michael; Homolka, Peter

    2015-08-01

    To evaluate the efficacy of staff training on radiation doses applied in pediatric CT scans. Pediatric patient doses from five CT scanners before (1426 scans) and after staff training (2566 scans) were compared statistically. Examinations included cranial CT (CCT), thoracic, abdomen-pelvis, and trunk scans. Dose length products (DLPs) per series were extracted from CT dose reports archived in the PACS. A pooled analysis of non-traumatic scans revealed a statistically significant reduction in the dose for cranial, thoracic, and abdomen/pelvis scans (p0.05). The percentage of scans performed with DLPs exceeding the German DRLs was reduced from 41% to 7% (CCT), 19% to 5% (thorax-CT), from 9% to zero (abdominal-pelvis CT), and 26% to zero (trunk; DRL taken as summed DRLs for thorax plus abdomen-pelvis, reduced by 20% accounting for overlap). Comparison with Austrian DRLs - available only for CCT and thorax CT - showed a reduction from 21% to 3% (CCT), and 15 to 2% (thorax CT). Staff training together with application of DRLs provide an efficient approach for optimizing radiation dose in pediatric CT practice. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. SU-G-BRC-08: Evaluation of Dose Mass Histogram as a More Representative Dose Description Method Than Dose Volume Histogram in Lung Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J; Eldib, A; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States); Lin, M [The University of Texas Southwestern Medical Ctr, Dallas, TX (United States); Li, J [Cyber Medical Inc, Xian, Shaanxi (China); Mora, G [Universidade de Lisboa, Codex, Lisboa (Portugal)

    2016-06-15

    Purpose: Dose-volume-histogram (DVH) is widely used for plan evaluation in radiation treatment. The concept of dose-mass-histogram (DMH) is expected to provide a more representative description as it accounts for heterogeneity in tissue density. This study is intended to assess the difference between DVH and DMH for evaluating treatment planning quality. Methods: 12 lung cancer treatment plans were exported from the treatment planning system. DVHs for the planning target volume (PTV), the normal lung and other structures of interest were calculated. DMHs were calculated in a similar way as DVHs expect that the voxel density converted from the CT number was used in tallying the dose histogram bins. The equivalent uniform dose (EUD) was calculated based on voxel volume and mass, respectively. The normal tissue complication probability (NTCP) in relation to the EUD was calculated for the normal lung to provide quantitative comparison of DVHs and DMHs for evaluating the radiobiological effect. Results: Large differences were observed between DVHs and DMHs for lungs and PTVs. For PTVs with dense tumor cores, DMHs are higher than DVHs due to larger mass weighing in the high dose conformal core regions. For the normal lungs, DMHs can either be higher or lower than DVHs depending on the target location within the lung. When the target is close to the lower lung, DMHs show higher values than DVHs because the lower lung has higher density than the central portion or the upper lung. DMHs are lower than DVHs for targets in the upper lung. The calculated NTCPs showed a large range of difference between DVHs and DMHs. Conclusion: The heterogeneity of lung can be well considered using DMH for evaluating target coverage and normal lung pneumonitis. Further studies are warranted to quantify the benefits of DMH over DVH for plan quality evaluation.

  10. Impact of the planning CT scan time on the reflection of the lung tumor motion

    International Nuclear Information System (INIS)

    Kim, Su San; Choi, Eun Kyung; Yi, Byong Yong; Ha, Sung Whan

    2004-01-01

    increased, but remained constant with relative CT scan times above 1.00 T. When setting the planning CT scan time above one respiration period (> 1.00 T), only the set-up margin is needed to delineate the planning target volume. Therefore, therapeutic ratio can be increased by reducing the radiation dose delivered to normal lung tissue

  11. [Lung cancer screening with thoracic X‑ray and CT : Current situation].

    Science.gov (United States)

    von Stackelberg, O; Kauczor, H-U

    2016-09-01

    Attempts at the early detection of lung cancer using imaging methods began as far back as the 1950s. Several studies attempted to demonstrate a reduction of lung cancer mortality by chest radiography screening but all were unsuccessful. Even the first small screening studies using computed tomography (CT) could not demonstrate a reduction in lung cancer-specific mortality until in 2011 the results of the largest randomized controlled low-dose CT screening study in the USA (NLST) were published. The NLST results could show a significant 20 % reduction of lung cancer mortality in elderly and heavy smokers using CT. Confirmation of the NLST results are urgently needed so that the data of the largest European study (NELSON) are eagerly awaited. Pooled with the data from several smaller European studies these results will provide important information and evidence for the establishment of future CT screening programs in Europe. Randomized controlled trials are the basis of evidence-based medicine; therefore, the positive results of the methodologically very good NLST study cannot be ignored, even if it is the only such study completed so far with highly convincing conclusions. The NLST results clearly demonstrate that positive effects for the health of the population can only be expected if the processes are clearly defined and the quality is assured.

  12. Ultralow dose CT for pulmonary nodule detection with chest X-ray equivalent dose - a prospective intra-individual comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Messerli, Michael [University Zurich, Department of Nuclear Medicine, University Hospital Zurich, Zurich (Switzerland); Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Kluckert, Thomas; Knitel, Meinhard; Desbiolles, Lotus; Bauer, Ralf W.; Wildermuth, Simon [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Waelti, Stephan [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University of Montreal, Department of Radiology, CHU Sainte-Justine, Montreal, Quebec (Canada); Rengier, Fabian [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Warschkow, Rene [Cantonal Hospital St. Gallen, Department of Surgery, St. Gallen (Switzerland); Alkadhi, Hatem [University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland); Leschka, Sebastian [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland)

    2017-08-15

    To prospectively evaluate the accuracy of ultralow radiation dose CT of the chest with tin filtration at 100 kV for pulmonary nodule detection. 202 consecutive patients undergoing clinically indicated chest CT (standard dose, 1.8 ± 0.7 mSv) were prospectively included and additionally scanned with an ultralow dose protocol (0.13 ± 0.01 mSv). Standard dose CT was read in consensus by two board-certified radiologists to determine the presence of lung nodules and served as standard of reference (SOR). Two radiologists assessed the presence of lung nodules and their locations on ultralow dose CT. Sensitivity and specificity of the ultralow dose protocol was compared against the SOR, including subgroup analyses of different nodule sizes and types. A mixed effects logistic regression was used to test for independent predictors for sensitivity of pulmonary nodule detection. 425 nodules (mean diameter 3.7 ± 2.9 mm) were found on SOR. Overall sensitivity for nodule detection by ultralow dose CT was 91%. In multivariate analysis, nodule type, size and patients BMI were independent predictors for sensitivity (p < 0.001). Ultralow dose chest CT at 100 kV with spectral shaping enables a high sensitivity for the detection of pulmonary nodules at exposure levels comparable to plain film chest X-ray. (orig.)

  13. The efficacy of low-dose helical CT screening as an option for health examination

    International Nuclear Information System (INIS)

    Kishi, Kazuma; Hara, Shigeko; Kurosaki, Atsuko; Fujii, Takeshi; Yoshimura, Kunihiko

    2007-01-01

    We retrospectively evaluated the results of low-dose helical CT screening as an option for health examinations. From November 2002 to October 2005, CT screening was performed in 2,306 individuals (men 1,766, women 540, mean age 56.1 years). Among them, 71 individuals (3.1%) were diagnosed as having active thoracic diseases consisting of 14 neoplasms and 57 non-neoplastic diseases. Of 14 patients with neoplastic lesions, 13 had lung cancer, 1 of whom had double primary lung cancer, and 1 had atypical adenomatous hyperplasia. The mean diameter of the 14 lung cancers was 14.4 mm. The histology of these lesions was adenocarcinoma in 13 and squamous cell carcinoma in 1. The pathological stage was IA in 12 patients and IIA in 1. All patients underwent surgical resection. On the other hand, emphysema was diagnosed in 40 asymptomatic individuals based on CT and spirometry, and smoking cessation was strongly implemented for those who were current smokers. CT screening is useful for detecting not only early lung cancer but also non-neoplastic lung diseases. (author)

  14. Lung cancer screening with thoracic X-ray and CT. Current situation; Lungenkarzinomscreening mit Roentgenthorax oder CT. Aktuelle Datenlage

    Energy Technology Data Exchange (ETDEWEB)

    Stackelberg, O. von; Kauczor, H.U. [Universitaetsklinikum Heidelberg, Diagnostische und Interventionelle Radiologe, Heidelberg (Germany); Translationales Lungen Forschungszentrum Heidelberg (TLRC), Mitglied des Deutschen Zentrums fuer Lungenforschung (DZL), Heidelberg (Germany)

    2016-09-15

    Attempts at the early detection of lung cancer using imaging methods began as far back as the 1950s. Several studies attempted to demonstrate a reduction of lung cancer mortality by chest radiography screening but all were unsuccessful. Even the first small screening studies using computed tomography (CT) could not demonstrate a reduction in lung cancer-specific mortality until in 2011 the results of the largest randomized controlled low-dose CT screening study in the USA (NLST) were published. The NLST results could show a significant 20 % reduction of lung cancer mortality in elderly and heavy smokers using CT. Confirmation of the NLST results are urgently needed so that the data of the largest European study (NELSON) are eagerly awaited. Pooled with the data from several smaller European studies these results will provide important information and evidence for the establishment of future CT screening programs in Europe. Randomized controlled trials are the basis of evidence-based medicine; therefore, the positive results of the methodologically very good NLST study cannot be ignored, even if it is the only such study completed so far with highly convincing conclusions. The NLST results clearly demonstrate that positive effects for the health of the population can only be expected if the processes are clearly defined and the quality is assured. (orig.) [German] Bestrebungen zur Frueherkennung von Lungenkrebs mit bildgebenden Methoden gibt es schon lange. Alle Studien, die eine Reduktion der Lungenkrebsmortalitaet mittels Roentgenthoraxscreening nachzuweisen versuchten, scheiterten. Auch die ersten kleineren Screeningstudien mit der CT konnten keine Reduktion der Lungenkrebssterblichkeit nachweisen, bis 2011 die Ergebnisse der bisher groessten randomisierten kontrollierten Niedrigdosis-CT-Screeningstudie (NLST) aus den USA veroeffentlicht wurden. Diese konnten eine signifikante 20 %ige Reduktion der Lungenkrebssterblichkeit bei Personen, die aelter und starke

  15. LUDEP: A Lung Dose Evaluation Program

    International Nuclear Information System (INIS)

    Birchall, A.; Bailey, M.R.; James, A.C.

    1990-06-01

    A Task Group of the ICRP is currently reviewing its dosimetric model for the respiratory tract with the aim of producing a more comprehensive and realistic model which can be used both for dosimetry and bioassay purposes. This in turn requires deposition, clearance, and dosimetry to be treated in a more detailed manner in than in the current model. In order to examine the practical application and radiological implications of the proposed model, a microcomputer program has been developed in a modular form so that changes can be easily included as the model develops. LUDEP (Lung Dose Evaluation Program) is a user-friendly menu-driven program which can be operated on any IBM-compatible PC. It enables the user to calculate (a) doses to each region of the respiratory tract and all other body organs, and (b) excretion rates and retention curves for bioassay purposes. 11 refs., 4 figs., 6 tabs

  16. Assessment of airway lesion in obstructive lung diseases by CT

    International Nuclear Information System (INIS)

    Niimi, Akio; Matsumoto, Hisako; Ueda, Tetsuya; Mishima, Michiaki

    2002-01-01

    Airway lesion in obstructive pulmonary diseases, such as asthma or chronic obstructive pulmonary disease (COPD), has recently been assessed quantitatively. Especially in asthma, wall thickening of central airways, and its relation to the severity of disease or airflow obstruction has been clarified. Pathophysiologic importance of peripheral airway lesion has also been highlighted by pathologic or physiologic studies. However, direct evaluation of peripheral airway lesion is beyond resolutional limitation of CT. To assess airway trapping, an indirect CT finding of peripheral airway disease, by quantitative and semiquantitative measures and compare them with clinical indices such as pulmonary function, airway responsiveness, or airway inflammation. Patients with stable asthma (n=20) were studied. HRCT at 3 levels of both lungs were scanned. Low attenuation area (LAA)% and mean lung density were quantitatively assessed by an automatic method. Distribution of mosaic pattern was visually scored semiquantitatively. LAA% and mean lung density at full expiratory phase correlated with the degree of airflow obstruction. Mosaic score at full inspiratory phase correlated with the severity of disease and airflow obstruction. Expiratory/inspiratory ratio of mean lung density was also associated with airway responsiveness or residual volume/total lung capacity (RV/TLC). These CT findings may be useful as markers of asthma pathophysiology. (author)

  17. Simulation of spatiotemporal CT data sets using a 4D MRI-based lung motion model.

    Science.gov (United States)

    Marx, Mirko; Ehrhardt, Jan; Werner, René; Schlemmer, Heinz-Peter; Handels, Heinz

    2014-05-01

    Four-dimensional CT imaging is widely used to account for motion-related effects during radiotherapy planning of lung cancer patients. However, 4D CT often contains motion artifacts, cannot be used to measure motion variability, and leads to higher dose exposure. In this article, we propose using 4D MRI to acquire motion information for the radiotherapy planning process. From the 4D MRI images, we derive a time-continuous model of the average patient-specific respiratory motion, which is then applied to simulate 4D CT data based on a static 3D CT. The idea of the motion model is to represent the average lung motion over a respiratory cycle by cyclic B-spline curves. The model generation consists of motion field estimation in the 4D MRI data by nonlinear registration, assigning respiratory phases to the motion fields, and applying a B-spline approximation on a voxel-by-voxel basis to describe the average voxel motion over a breathing cycle. To simulate a patient-specific 4D CT based on a static CT of the patient, a multi-modal registration strategy is introduced to transfer the motion model from MRI to the static CT coordinates. Differences between model-based estimated and measured motion vectors are on average 1.39 mm for amplitude-based binning of the 4D MRI data of three patients. In addition, the MRI-to-CT registration strategy is shown to be suitable for the model transformation. The application of our 4D MRI-based motion model for simulating 4D CT images provides advantages over standard 4D CT (less motion artifacts, radiation-free). This makes it interesting for radiotherapy planning.

  18. CT findings of pancreatic carcinoma. Evaluation with the combined method of early enhancement CT and high dose enhancement CT

    International Nuclear Information System (INIS)

    Itoh, Shigeki; Endo, Tokiko; Isomura, Takayuki; Ishigaki, Takeo; Ikeda, Mitsuru; Senda, Kouhei.

    1995-01-01

    Computed tomographic (CT) findings of pancreatic ductal adenocarcinoma were studied with the combined method of early enhancement CT and high dose enhancement CT in 72 carcinomas. Common Findings were change in pancreatic contour, abnormal attenuation in a tumor and dilatation of the main pancreatic duct. The incidence of abnormal attenuation and dilatation of the main pancreatic duct and bile duct was constant regardless of tumor size. The finding of hypoattenuation at early enhancement CT was most useful for demonstrating a carcinoma. However, this finding was negative in ten cases, five of which showed inhomogenous hyperattenuation at high dose enhancement CT. The detection of change in pancreatic contour and dilatation of the main pancreatic duct was most frequent at high dose enhancement CT. The finding of change in pancreatic contour and/or abnormal attenuation in a tumor could be detected in 47 cases at plain CT, 66 at early enhancement CT and 65 at high dose enhancement CT. Since the four cases in which neither finding was detected by any CT method showed dilatated main pancreatic duct, there was no case without abnormal CT findings. This combined CT method will be a reliable diagnostic technique in the imaging of pancreatic carcinoma. (author)

  19. CT quantification of lung and airways in normal Korean subjects

    International Nuclear Information System (INIS)

    Kim, Song Soo; Lee, Jeong Eun; Shin, Hye Soo; Jin, Gong Yong; Li, Yuan Zhe

    2017-01-01

    To measure and compare the quantitative parameters of the lungs and airways in Korean never-smokers and current or former smokers (“ever-smokers”). Never-smokers (n = 119) and ever-smokers (n = 45) who had normal spirometry and visually normal chest computed tomography (CT) results were retrospectively enrolled in this study. For quantitative CT analyses, the low attenuation area (LAA) of LAA_I_-_9_5_0, LAA_E_-_8_5_6, CT attenuation value at the 15th percentile, mean lung attenuation (MLA), bronchial wall thickness of inner perimeter of a 10 mm diameter airway (Pi10), total lung capacity (TLC_C_T), and functional residual capacity (FRC_C_T) were calculated based on inspiratory and expiratory CT images. To compare the results between groups according to age, sex, and smoking history, independent t test, one way ANOVA, correlation test, and simple and multiple regression analyses were performed. The values of attenuation parameters and volume on inspiratory and expiratory quantitative computed tomography (QCT) were significantly different between males and females (p < 0.001). The MLA and the 15th percentile value on inspiratory QCT were significantly lower in the ever-smoker group than in the never-smoker group (p < 0.05). On expiratory QCT, all lung attenuation parameters were significantly different according to the age range (p < 0.05). Pi10 in ever-smokers was significantly correlated with forced expiratory volume in 1 second/forced vital capacity (r = −0.455, p = 0.003). In simple and multivariate regression analyses, TLC_C_T, FRC_C_T, and age showed significant associations with lung attenuation (p < 0.05), and only TLC_C_T was significantly associated with inspiratory Pi10. In Korean subjects with normal spirometry and visually normal chest CT, there may be significant differences in QCT parameters according to sex, age, and smoking history

  20. Indeterminate lesions on planar bone scintigraphy in lung cancer patients: SPECT, CT or SPECT-CT?

    International Nuclear Information System (INIS)

    Sharma, Punit; Kumar, Rakesh; Singh, Harmandeep; Bal, Chandrasekhar; Malhotra, Arun; Julka, Pramod Kumar; Thulkar, Sanjay

    2012-01-01

    The objective of the present study was to compare the role of single photon emission computed tomography (SPECT), computed tomography (CT) and SPECT-CT of selected volume in lung cancer patients with indeterminate lesions on planar bone scintigraphy (BS). The data of 50 lung cancer patients (53 ± 10.3 years; range 30-75; male/female 38/12) with 65 indeterminate lesions on planar BS (January 2010 to November 2010) were retrospectively evaluated. All of them underwent SPECT-CT of a selected volume. SPECT, CT and SPECT-CT images were independently evaluated by two experienced readers (experience in musculoskeletal imaging, including CT: 5 and 7 years) in separate sessions. A scoring scale of 1 to 5 was used, in which 1 is definitely metastatic, 2 is probably metastatic, 3 is indeterminate, 4 is probably benign and 5 is definitely benign. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for each modality, taking a score ≤2 as metastatic. With receiver operating characteristic (ROC) curve analysis, areas under the curve (AUC) were calculated for each modality and compared. Clinical and imaging follow-up and/or histopathology were taken as reference standard. For both readers SPECT was inferior to CT (P = 0.004, P = 0.022) and SPECT-CT (P = 0.003, P = 0.037). However, no significant difference was found between CT and SPECT-CT for reader 1 (P = 0.847) and reader 2 (P = 0.592). The findings were similar for lytic as well as sclerotic lesions. Moderate inter-observer agreement was seen for SPECT images (κ = 0.426), while almost perfect agreement was seen for CT (κ = 0.834) and SPECT-CT (κ = 0.971). CT alone and SPECT-CT are better than SPECT for accurate characterisation of indeterminate lesions on planar BS in lung cancer patients. CT alone is not inferior to SPECT-CT for this purpose and might be preferred because of shorter acquisition time and wider availability. (orig.)

  1. Daily fraction dose recalculation based on rigid registration using Cone Beam CT

    Directory of Open Access Journals (Sweden)

    Courtney Bosse

    2014-03-01

    Full Text Available Purpose: To calculate the daily fraction dose for CBCT recalculations based on rigid registration and compare it to the planned CT doses.Methods: For this study, 30 patients that were previously treated (10 SBRT lung, 10 prostate and 10 abdomen were considered. The daily CBCT images were imported into the Pinnacle treatment planning system from Mosaic. Pinnacle was used to re-contour the regions of interest (ROI for the specific CBCT by copying the contours from the original CT plan, planned by the prescribing physician, onto each daily CBCT and then manually reshaping contours to match the ROIs. A new plan is then created with the re-contoured CBCT as primary image in order to calculate the daily dose delivered to each ROI. The DVH values are then exported into Excel and overlaid onto the original CT DVH to produce a graph.Results: For the SBRT lung patients, we found that there were small daily volume changes in the lungs, trachea and esophagus. For almost all regions of interest we found that the dose received each day was less than the predicted dose of the planned CT while the PTV dose was relatively the same each day. The results for the prostate patients were similar, showing slight differences in the DVH values for different days in the rectum and bladder but similar PTV.Conclusion: By comparing daily fraction dose between the re-contoured CBCT images and the original planned CT show that PTV coverage for both prostate and SBRT, it has been shown that for PTV coverage, a planned CT is adequate. However, there are differences between the dose for the organs surrounding the PTV. The dose difference is less than the planned in most instances.-----------------------Cite this article as: Bosse C, Tuohy R, Mavroidis P, Shi Z, Crownover R, Gutierrez A, Papanikolaou N, Stathakis S. Daily fraction dose recalculation based on rigid registration using Cone Beam CT. Int J Cancer Ther Oncol 2014; 2(2:020217. DOI: 10.14319/ijcto.0202.17

  2. WE-B-207-01: CT Lung Cancer Screening and the Medical Physicist: Background, Findings and Participant Dosimetry Summary of the National Lung Screening Trial (NLST)

    International Nuclear Information System (INIS)

    Kruger, R.

    2015-01-01

    The US National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a low-dose CT (LDCT) to posterior-anterior (PA) chest x-ray (CXR) in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. Funded by the National Cancer Institute this trial demonstrated that LDCT screening reduced lung cancer mortality. The US Preventive Services Task Force (USPSTF) cited NLST findings and conclusions in its deliberations and analysis of lung cancer screening. Under the 2010 Patient Protection and Affordable Care Act, the USPSTF favorable recommendation regarding lung cancer CT screening assisted in obtaining third-party payers coverage for screening. The objective of this session is to provide an introduction to the NLST and the trial findings, in addition to a comprehensive review of the dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations. Session presentations will review and discuss the findings of two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray exams that were performed on 92 chest imaging systems of which 66,157 participant examinations were used. The CT organ dosimetry investigation collected scan parameters from 23,773 CT examinations; a subset of the 75,133 CT examinations performed using 97 multi-detector CT scanners. Organ dose conversion coefficients were calculated using a Monte Carlo code. An experimentally-validated CT scanner simulation was coupled with 193 adult hybrid computational phantoms representing the height and weight of the current U.S. population. The dose to selected organs was calculated using the organ dose library and the abstracted scan

  3. WE-B-207-01: CT Lung Cancer Screening and the Medical Physicist: Background, Findings and Participant Dosimetry Summary of the National Lung Screening Trial (NLST)

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, R. [Marshfield Clinic, Marshfield, WI (United States)

    2015-06-15

    The US National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a low-dose CT (LDCT) to posterior-anterior (PA) chest x-ray (CXR) in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. Funded by the National Cancer Institute this trial demonstrated that LDCT screening reduced lung cancer mortality. The US Preventive Services Task Force (USPSTF) cited NLST findings and conclusions in its deliberations and analysis of lung cancer screening. Under the 2010 Patient Protection and Affordable Care Act, the USPSTF favorable recommendation regarding lung cancer CT screening assisted in obtaining third-party payers coverage for screening. The objective of this session is to provide an introduction to the NLST and the trial findings, in addition to a comprehensive review of the dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations. Session presentations will review and discuss the findings of two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray exams that were performed on 92 chest imaging systems of which 66,157 participant examinations were used. The CT organ dosimetry investigation collected scan parameters from 23,773 CT examinations; a subset of the 75,133 CT examinations performed using 97 multi-detector CT scanners. Organ dose conversion coefficients were calculated using a Monte Carlo code. An experimentally-validated CT scanner simulation was coupled with 193 adult hybrid computational phantoms representing the height and weight of the current U.S. population. The dose to selected organs was calculated using the organ dose library and the abstracted scan

  4. Quantitative measurement of lung density with x-ray CT and positron CT, (2). Diseased subjects

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Kengo; Ito, Masatoshi; Kubota, Kazuo

    1985-05-01

    Lung density was quantitatively measured on six diseased patients with X-ray CT (XCT) and Positron CT(PCT). The findings are as follows: In the silicosis, extravascular lung density was found to be remarkably increased compared to normals (0.29gcm/sup 3/), but blood volume was in normal range. In the post-irradiated lung cancers, extravascular lung density increased in the irradiated sites compared to the non-irradiated opposite sites, and blood volume varied in each case. In a patient with chronic heart failure, blood volume decreased (0.11mlcm/sup 3/) with increased extravascular lung density (0.23gcm/sup 3/). In the chronic obstructive pulmonary disease, both extravascular lung density and blood volume decreased (0.11gcm/sup 3/ and 0.10mlcm/sup 3/ respectively). Lung density measured with XCT was constantly lower than that with PCT in all cases. But changes in the values of lung density measured, correlated well with each other. In conclusion, the method presented here may clarify the etiology of the diffuse pulmonary diseases, and be used to differentiate and grade the diseases.

  5. Quantitative measurement of lung density with x-ray CT and positron CT, (2)

    International Nuclear Information System (INIS)

    Ito, Kengo; Ito, Masatoshi; Kubota, Kazuo

    1985-01-01

    Lung density was quantitatively measured on six diseased patients with X-ray CT (XCT) and Positron CT(PCT). The findings are as follows: In the silicosis, extravascular lung density was found to be remarkably increased compared to normals (0.29gcm -3 ), but blood volume was in normal range. In the post-irradiated lung cancers, extravascular lung density increased in the irradiated sites compared to the non-irradiated opposite sites, and blood volume varied in each case. In a patient with chronic heart failure, blood volume decreased (0.11mlcm -3 ) with increased extravascular lung density (0.23gcm -3 ). In the chronic obstructive pulmonary disease, both extravascular lung density and blood volume decreased (0.11gcm -3 and 0.10mlcm -3 respectively). Lung density measured with XCT was constantly lower than that with PCT in all cases. But changes in the values of lung density measured, correlated well with each other. In conclusion, the method presented here may clarify the etiology of the diffuse pulmonary diseases, and be used to differentiate and grade the diseases. (author)

  6. Pulmonary disease in cystic fibrosis: assessment with chest CT at chest radiography dose levels.

    Science.gov (United States)

    Ernst, Caroline W; Basten, Ines A; Ilsen, Bart; Buls, Nico; Van Gompel, Gert; De Wachter, Elke; Nieboer, Koenraad H; Verhelle, Filip; Malfroot, Anne; Coomans, Danny; De Maeseneer, Michel; de Mey, Johan

    2014-11-01

    To investigate a computed tomographic (CT) protocol with iterative reconstruction at conventional radiography dose levels for the assessment of structural lung abnormalities in patients with cystic fibrosis ( CF cystic fibrosis ). In this institutional review board-approved study, 38 patients with CF cystic fibrosis (age range, 6-58 years; 21 patients 18 years) underwent investigative CT (at minimal exposure settings combined with iterative reconstruction) as a replacement of yearly follow-up posteroanterior chest radiography. Verbal informed consent was obtained from all patients or their parents. CT images were randomized and rated independently by two radiologists with use of the Bhalla scoring system. In addition, mosaic perfusion was evaluated. As reference, the previous available conventional chest CT scan was used. Differences in Bhalla scores were assessed with the χ(2) test and intraclass correlation coefficients ( ICC intraclass correlation coefficient s). Radiation doses for CT and radiography were assessed for adults (>18 years) and children (chest CT protocol can replace the two yearly follow-up chest radiographic examinations without major dose penalty and with similar diagnostic quality compared with conventional CT.

  7. Radiation dose-reduction strategies in thoracic CT.

    Science.gov (United States)

    Moser, J B; Sheard, S L; Edyvean, S; Vlahos, I

    2017-05-01

    Modern computed tomography (CT) machines have the capability to perform thoracic CT for a range of clinical indications at increasingly low radiation doses. This article reviews several factors, both technical and patient-related, that can affect radiation dose and discusses current dose-reduction methods relevant to thoracic imaging through a review of current techniques in CT acquisition and image reconstruction. The fine balance between low radiation dose and high image quality is considered throughout, with an emphasis on obtaining diagnostic quality imaging at the lowest achievable radiation dose. The risks of excessive radiation dose reduction are also considered. Inappropriately low dose may result in suboptimal or non-diagnostic imaging that may reduce diagnostic confidence, impair diagnosis, or result in repeat examinations incurring incremental ionising radiation exposure. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  8. Resolution enhancement of lung 4D-CT via group-sparsity

    International Nuclear Information System (INIS)

    Bhavsar, Arnav; Wu, Guorong; Shen, Dinggang; Lian, Jun

    2013-01-01

    Purpose: 4D-CT typically delivers more accurate information about anatomical structures in the lung, over 3D-CT, due to its ability to capture visual information of the lung motion across different respiratory phases. This helps to better determine the dose during radiation therapy for lung cancer. However, a critical concern with 4D-CT that substantially compromises this advantage is the low superior-inferior resolution due to less number of acquired slices, in order to control the CT radiation dose. To address this limitation, the authors propose an approach to reconstruct missing intermediate slices, so as to improve the superior-inferior resolution.Methods: In this method the authors exploit the observation that sampling information across respiratory phases in 4D-CT can be complimentary due to lung motion. The authors’ approach uses this locally complimentary information across phases in a patch-based sparse-representation framework. Moreover, unlike some recent approaches that treat local patches independently, the authors’ approach employs the group-sparsity framework that imposes neighborhood and similarity constraints between patches. This helps in mitigating the trade-off between noise robustness and structure preservation, which is an important consideration in resolution enhancement. The authors discuss the regularizing ability of group-sparsity, which helps in reducing the effect of noise and enables better structural localization and enhancement.Results: The authors perform extensive experiments on the publicly available DIR-Lab Lung 4D-CT dataset [R. Castillo, E. Castillo, R. Guerra, V. Johnson, T. McPhail, A. Garg, and T. Guerrero, “A framework for evaluation of deformable image registration spatial accuracy using large landmark point sets,” Phys. Med. Biol. 54, 1849–1870 (2009)]. First, the authors carry out empirical parametric analysis of some important parameters in their approach. The authors then demonstrate, qualitatively as well as

  9. Automated extraction of radiation dose information from CT dose report images.

    Science.gov (United States)

    Li, Xinhua; Zhang, Da; Liu, Bob

    2011-06-01

    The purpose of this article is to describe the development of an automated tool for retrieving texts from CT dose report images. Optical character recognition was adopted to perform text recognitions of CT dose report images. The developed tool is able to automate the process of analyzing multiple CT examinations, including text recognition, parsing, error correction, and exporting data to spreadsheets. The results were precise for total dose-length product (DLP) and were about 95% accurate for CT dose index and DLP of scanned series.

  10. MRI and CT lung biomarkers: Towards an in vivo understanding of lung biomechanics.

    Science.gov (United States)

    Young, Heather M; Eddy, Rachel L; Parraga, Grace

    2017-09-29

    The biomechanical properties of the lung are necessarily dependent on its structure and function, both of which are complex and change over time and space. This makes in vivo evaluation of lung biomechanics and a deep understanding of lung biomarkers, very challenging. In patients and animal models of lung disease, in vivo evaluations of lung structure and function are typically made at the mouth and include spirometry, multiple-breath gas washout tests and the forced oscillation technique. These techniques, and the biomarkers they provide, incorporate the properties of the whole organ system including the parenchyma, large and small airways, mouth, diaphragm and intercostal muscles. Unfortunately, these well-established measurements mask regional differences, limiting their ability to probe the lung's gross and micro-biomechanical properties which vary widely throughout the organ and its subcompartments. Pulmonary imaging has the advantage in providing regional, non-invasive measurements of healthy and diseased lung, in vivo. Here we summarize well-established and emerging lung imaging tools and biomarkers and how they may be used to generate lung biomechanical measurements. We review well-established and emerging lung anatomical, microstructural and functional imaging biomarkers generated using synchrotron x-ray tomographic-microscopy (SRXTM), micro-x-ray computed-tomography (micro-CT), clinical CT as well as magnetic resonance imaging (MRI). Pulmonary imaging provides measurements of lung structure, function and biomechanics with high spatial and temporal resolution. Imaging biomarkers that reflect the biomechanical properties of the lung are now being validated to provide a deeper understanding of the lung that cannot be achieved using measurements made at the mouth. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Resolution enhancement of lung 4D-CT data using multiscale interphase iterative nonlocal means

    International Nuclear Information System (INIS)

    Zhang Yu; Yap, Pew-Thian; Wu Guorong; Feng Qianjin; Chen Wufan; Lian Jun; Shen Dinggang

    2013-01-01

    Purpose: Four-dimensional computer tomography (4D-CT) has been widely used in lung cancer radiotherapy due to its capability in providing important tumor motion information. However, the prolonged scanning duration required by 4D-CT causes considerable increase in radiation dose. To minimize the radiation-related health risk, radiation dose is often reduced at the expense of interslice spatial resolution. However, inadequate resolution in 4D-CT causes artifacts and increases uncertainty in tumor localization, which eventually results in extra damages of healthy tissues during radiotherapy. In this paper, the authors propose a novel postprocessing algorithm to enhance the resolution of lung 4D-CT data. Methods: The authors' premise is that anatomical information missing in one phase can be recovered from the complementary information embedded in other phases. The authors employ a patch-based mechanism to propagate information across phases for the reconstruction of intermediate slices in the longitudinal direction, where resolution is normally the lowest. Specifically, the structurally matching and spatially nearby patches are combined for reconstruction of each patch. For greater sensitivity to anatomical details, the authors employ a quad-tree technique to adaptively partition the image for more fine-grained refinement. The authors further devise an iterative strategy for significant enhancement of anatomical details. Results: The authors evaluated their algorithm using a publicly available lung data that consist of 10 4D-CT cases. The authors’ algorithm gives very promising results with significantly enhanced image structures and much less artifacts. Quantitative analysis shows that the authors’ algorithm increases peak signal-to-noise ratio by 3–4 dB and the structural similarity index by 3%–5% when compared with the standard interpolation-based algorithms. Conclusions: The authors have developed a new algorithm to improve the resolution of 4D-CT. It

  12. CT screening for lung cancer: Importance of emphysema for never smokers and smokers.

    Science.gov (United States)

    Henschke, Claudia I; Yip, Rowena; Boffetta, Paolo; Markowitz, Steven; Miller, Albert; Hanaoka, Takaomi; Wu, Ning; Zulueta, Javier J; Yankelevitz, David F

    2015-04-01

    To address the prevalence of lung cancer in high and low-risk people according to their smoking history, age, and CT findings of emphysema. We reviewed the baseline low-dose CT scans of 62,124 current, former and never smokers, aged 40-90 to determine the prevalence of lung cancer. We performed logistic regression analysis of the prevalence of lung cancer to determine the odds ratio (OR) for emphysema, conditionally on age, female gender, and ethnicity. The prevalence of lung cancer was 1.4% (95% CI: 1.3-1.6) for current smokers, 1.1% (95% CI: 1.0-1.2) for former smokers, and 0.4% (95% CI: 0.3-0.6) for never smokers. Emphysema was identified in 28.5% (6,684), 20.6% (5,422), and 1.6% (194) of current, former, and never smokers, respectively. The prevalence of lung cancer among current smokers was 1.1% for those without emphysema vs. 2.3% for those with emphysema (odds ratio [OR] 1.8; 95% confidence interval [CI]: 1.4-2.2) and the corresponding difference for former smokers was 0.9% vs. 1.8% (OR: 1.7; 95% CI: 1.3-2.2), and for never smokers, it was 0.4% vs. 2.6% (OR: 6.3; 95% CI: 2.4-16.9). Identification of emphysema in low-dose CT scans increases the risk of lung cancer and is important in determining follow-up of current, former, and never smokers. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. CT diagnosis of the primary lung cancer and usefulness of biopsy under CT

    International Nuclear Information System (INIS)

    Fujisawa, Hidefumi; Kushihashi, Tamio

    2011-01-01

    CT especially plays an important role in imaging diagnosis of lung cancer (LC) which gives quite multiple CT findings and this paper describes details to be noted for CT findings of individual lung lesion and cancer according to 5 classes below, together with usefulness of CT-guided biopsy and positron emission tomography (PET) usage. Explained are as follows: Important points in histopathology and CT findings from adenomatous hyperplasia (AH) to atypical AH (pre-invasive lesion); Differential CT diagnosis of benignity or malignancy of pulmonary nodes and tumors; Typical CT findings of LC of peripheral type of invasive or exclusive proliferative type, and pulmonary hillar type; Atypical CT findings of LC/having atypical inner structure such as presenting atypical calcification and atypical cavity/having atypical morphology such as presenting pneumonia-like finding, exhibiting regular or linear edge, and existing at atypical region like extrapleural lumen /having atypical progression rate such as showing rapid or slow doubling time of the volume and shrinking tentatively during the progress/of juvenile LC/and generated from background lung diseases such as interstitial pneumonia, tuberculosis, pneumoconiosis like asbestosis, pneumosilicosis, and pulmonary emphysema and bulla; and Regional ground glass opacity. As well, authors mention about the usefulness of CT-guided needle biopsy of the pulmonary lesion which enables to take the nodal specimen as small as <10 mm. Most frequent complication of the biopsy is pneumothorax (10-50%). How to use PET for LC examination is also commented with its usability and limitation. (T.T.)

  14. Effective dose calculation in CT using high sensitivity TLDs

    International Nuclear Information System (INIS)

    Brady, Z.; Johnston, P.N.

    2010-01-01

    Full text: To determine the effective dose for common paediatric CT examinations using thermoluminescence dosimetry (TLD) mea surements. High sensitivity TLD chips (LiF:Mg,Cu,P, TLD-IOOH, Thermo Fisher Scientific, Waltham, MA) were calibrated on a linac at an energy of 6 MY. A calibration was also performed on a superricial X-ray unit at a kilovoltage energy to validate the megavoltage cali bration for the purpose of measuring doses in the diagnostic energy range. The dose variation across large organs was assessed and a methodology for TLD placement in a 10 year old anthropomorphic phantom developed. Effective dose was calculated from the TLD measured absorbed doses for typical CT examinations after correcting for the TLD energy response and taking into account differences in the mass energy absorption coefficients for different tissues and organs. Results Using new tissue weighting factors recommended in ICRP Publication 103, the effective dose for a CT brain examination on a 10 year old was 1.6 millisieverts (mSv), 4.9 mSv for a CT chest exa ination and 4.7 mSv for a CT abdomen/pelvis examination. These values are lower for the CT brain examination, higher for the CT chest examination and approximately the same for the CT abdomen/ pelvis examination when compared with effective doses calculated using ICRP Publication 60 tissue weighting factors. Conclusions High sensitivity TLDs calibrated with a radiotherapy linac are useful for measuring dose in the diagnostic energy range and overcome limitations of output reproducibility and uniformity asso ciated with traditional TLD calibration on CT scanners or beam quality matched diagnostic X-ray units.

  15. Radiation dose in CT are meeting the challenge

    International Nuclear Information System (INIS)

    Wang Jun

    2003-01-01

    Despite comprising only 2% of all examinations, CT contributed around 20% of the collective dose to the population from diagnostic imaging. An abdominal examination in an adult with an effective dose of 10 mSv has been estimated to increase the lifetime risk of fatal cancer by 1 in 2000. Children are 10 times more sensitive to the effects of radiation than middle aged adults. Girls are more sensitive than boys. Variations in CT practice, ease of using, urgency in multislice CT, unawaring of the 'uncoupling effect' in CT may be contributing to increasing in radiation dose. We must train and have an awareness of emerging materials and the implied changes in practice, with revision of protocols to take account of advances. The 'as low as reasonably achievable (ALARA) ' principle applies just as much to CT as it does to conventional radiography

  16. Adult head CT scans: the uncertainties of effective dose estimates

    International Nuclear Information System (INIS)

    Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E.

    2008-01-01

    Full Text: CT scanning is a high dose imaging modality. Effective dose estimates from CT scans can provide important information to patients and medical professionals. For example, medical practitioners can use the dose to estimate the risk to the patient, and judge whether this risk is outweighed by the benefits of the CT examination, while radiographers can gauge the effect of different scanning protocols on the patient effective dose, and take this into consideration when establishing routine scan settings. Dose estimates also form an important part of epidemiological studies examining the health effects of medical radiation exposures on the wider population. Medical physicists have been devoting significant effort towards estimating patient radiation doses from diagnostic CT scans for some years. The question arises: How accurate are these effective dose estimates? The need for a greater understanding and improvement of the uncertainties in CT dose estimates is now gaining recognition as an important issue (BEIR VII 2006). This study is an attempt to analyse and quantify the uncertainty components relating to effective dose estimates from adult head CT examinations that are calculated with four commonly used methods. The dose estimation methods analysed are the Nagel method, the ImpaCT method, the Wellhoefer method and the Dose-Length Product (DLP) method. The analysis of the uncertainties was performed in accordance with the International Standards Organisation's Guide to the Expression of Uncertainty in Measurement as discussed in Gregory et al (Australas. Phys. Eng. Sci. Med., 28: 131-139, 2005). The uncertainty components vary, depending on the method used to derive the effective dose estimate. Uncertainty components in this study include the statistical and other errors from Monte Carlo simulations, uncertainties in the CT settings and positions of patients in the CT gantry, calibration errors from pencil ionization chambers, the variations in the organ

  17. Reducing dose to the lungs through loosing target dose homogeneity requirement for radiotherapy of non small cell lung cancer.

    Science.gov (United States)

    Miao, Junjie; Yan, Hui; Tian, Yuan; Ma, Pan; Liu, Zhiqiang; Li, Minghui; Ren, Wenting; Chen, Jiayun; Zhang, Ye; Dai, Jianrong

    2017-11-01

    It is important to minimize lung dose during intensity-modulated radiation therapy (IMRT) of nonsmall cell lung cancer (NSCLC). In this study, an approach was proposed to reduce lung dose by relaxing the constraint of target dose homogeneity during treatment planning of IMRT. Ten NSCLC patients with lung tumor on the right side were selected. The total dose for planning target volume (PTV) was 60 Gy (2 Gy/fraction). For each patient, two IMRT plans with six beams were created in Pinnacle treatment planning system. The dose homogeneity of target was controlled by constraints on the maximum and uniform doses of target volume. One IMRT plan was made with homogeneous target dose (the resulting target dose was within 95%-107% of the prescribed dose), while another IMRT plan was made with inhomogeneous target dose (the resulting target dose was more than 95% of the prescribed dose). During plan optimization, the dose of cord and heart in two types of IMRT plans were kept nearly the same. The doses of lungs, PTV and organs at risk (OARs) between two types of IMRT plans were compared and analyzed quantitatively. For all patients, the lung dose was decreased in the IMRT plans with inhomogeneous target dose. On average, the mean dose, V5, V20, and V30 of lung were reduced by 1.4 Gy, 4.8%, 3.7%, and 1.7%, respectively, and the dose to normal tissue was also reduced. These reductions in DVH values were all statistically significant (P target dose could protect lungs better and may be considered as a choice for treating NSCLC. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  18. Influence of lung CT changes in chronic obstructive pulmonary disease (COPD on the human lung microbiome.

    Directory of Open Access Journals (Sweden)

    Marion Engel

    Full Text Available Changes in microbial community composition in the lung of patients suffering from moderate to severe COPD have been well documented. However, knowledge about specific microbiome structures in the human lung associated with CT defined abnormalities is limited.Bacterial community composition derived from brush samples from lungs of 16 patients suffering from different CT defined subtypes of COPD and 9 healthy subjects was analyzed using a cultivation independent barcoding approach applying 454-pyrosequencing of 16S rRNA gene fragment amplicons.We could show that bacterial community composition in patients with changes in CT (either airway or emphysema type changes, designated as severe subtypes was different from community composition in lungs of patients without visible changes in CT as well as from healthy subjects (designated as mild COPD subtype and control group (PC1, Padj = 0.002. Higher abundance of Prevotella in samples from patients with mild COPD subtype and from controls and of Streptococcus in the severe subtype cases mainly contributed to the separation of bacterial communities of subjects. No significant effects of treatment with inhaled glucocorticoids on bacterial community composition were detected within COPD cases with and without abnormalities in CT in PCoA. Co-occurrence analysis suggests the presence of networks of co-occurring bacteria. Four communities of positively correlated bacteria were revealed. The microbial communities can clearly be distinguished by their associations with the CT defined disease phenotype.Our findings indicate that CT detectable structural changes in the lung of COPD patients, which we termed severe subtypes, are associated with alterations in bacterial communities, which may induce further changes in the interaction between microbes and host cells. This might result in a changed interplay with the host immune system.

  19. Influence of lung CT changes in chronic obstructive pulmonary disease (COPD) on the human lung microbiome.

    Science.gov (United States)

    Engel, Marion; Endesfelder, David; Schloter-Hai, Brigitte; Kublik, Susanne; Granitsiotis, Michael S; Boschetto, Piera; Stendardo, Mariarita; Barta, Imre; Dome, Balazs; Deleuze, Jean-François; Boland, Anne; Müller-Quernheim, Joachim; Prasse, Antje; Welte, Tobias; Hohlfeld, Jens; Subramanian, Deepak; Parr, David; Gut, Ivo Glynne; Greulich, Timm; Koczulla, Andreas Rembert; Nowinski, Adam; Gorecka, Dorota; Singh, Dave; Gupta, Sumit; Brightling, Christopher E; Hoffmann, Harald; Frankenberger, Marion; Hofer, Thomas P; Burggraf, Dorothe; Heiss-Neumann, Marion; Ziegler-Heitbrock, Loems; Schloter, Michael; Zu Castell, Wolfgang

    2017-01-01

    Changes in microbial community composition in the lung of patients suffering from moderate to severe COPD have been well documented. However, knowledge about specific microbiome structures in the human lung associated with CT defined abnormalities is limited. Bacterial community composition derived from brush samples from lungs of 16 patients suffering from different CT defined subtypes of COPD and 9 healthy subjects was analyzed using a cultivation independent barcoding approach applying 454-pyrosequencing of 16S rRNA gene fragment amplicons. We could show that bacterial community composition in patients with changes in CT (either airway or emphysema type changes, designated as severe subtypes) was different from community composition in lungs of patients without visible changes in CT as well as from healthy subjects (designated as mild COPD subtype and control group) (PC1, Padj = 0.002). Higher abundance of Prevotella in samples from patients with mild COPD subtype and from controls and of Streptococcus in the severe subtype cases mainly contributed to the separation of bacterial communities of subjects. No significant effects of treatment with inhaled glucocorticoids on bacterial community composition were detected within COPD cases with and without abnormalities in CT in PCoA. Co-occurrence analysis suggests the presence of networks of co-occurring bacteria. Four communities of positively correlated bacteria were revealed. The microbial communities can clearly be distinguished by their associations with the CT defined disease phenotype. Our findings indicate that CT detectable structural changes in the lung of COPD patients, which we termed severe subtypes, are associated with alterations in bacterial communities, which may induce further changes in the interaction between microbes and host cells. This might result in a changed interplay with the host immune system.

  20. Dose reduction for CT in children with cystic fibrosis: is it feasible to reduce the number of images per scan?

    International Nuclear Information System (INIS)

    Jong, Pim A. de; Tiddens, Harm A.W.M.; Nakano, Yasutaka; Lequin, Maarten H.

    2006-01-01

    Reducing the dose for each CT scan is important for children with cystic fibrosis (CF). To determine whether the number of CT images and therefore the dose per CT scan could be reduced without any significant loss of information in children with CF. A cohort of children with CF was followed with biennial surveillance CT scans, obtained in inspiration after a voluntary breath-hold as 1-mm thick images at 10-mm intervals from lung apex to base. A random set of 20 baseline CT scans and 10 follow-up CT scans were blinded. Sets of every image (10-mm intervals), every second image (20-mm intervals), every third image (30-mm intervals) and a selection of three and five images were scored randomly using a published CT scoring system by one experienced observer. The 20 subjects were 10 years of age with a range of 3.7-17.6 years at baseline. Fewer CT images resulted in a significantly lower (less abnormal) CT score and the number of patients positive for abnormalities decreased subsequently. At intervals greater than 20 mm no significant change in CT score over 2 years could be detected, while the CT scores at 10-mm (P=0.02) and 20-mm (P=0.02) intervals worsened significantly. A reduction in the number of inspiratory CT images by increasing the interval between images to greater than 10 mm is not a valid option for radiation dose reduction in children with CF. (orig.)

  1. Analysis of patient CT dose data using virtualdose

    Science.gov (United States)

    Bennett, Richard

    X-ray computer tomography has many benefits to medical and research applications. Recently, over the last decade CT has had a large increase in usage in hospitals and medical diagnosis. In pediatric care, from 2000 to 2006, abdominal CT scans increased by 49 % and chest CT by 425 % in the emergency room (Broder 2007). Enormous amounts of effort have been performed across multiple academic and government groups to determine an accurate measure of organ dose to patients who undergo a CT scan due to the inherent risks with ionizing radiation. Considering these intrinsic risks, CT dose estimating software becomes a necessary tool that health care providers and radiologist must use to determine many metrics to base the risks versus rewards of having an x-ray CT scan. This thesis models the resultant organ dose as body mass increases for patients with all other related scan parameters fixed. In addition to this,this thesis compares a modern dose estimating software, VirtualDose CT to two other programs, CT-Expo and ImPACT CT. The comparison shows how the software's theoretical basis and the phantom they use to represent the human body affect the range of results in organ dose. CT-Expo and ImPACT CT dose estimating software uses a different model for anatomical representation of the organs in the human body and the results show how that approach dramatically changes the outcome. The results categorizes four datasets as compared to the three software types where the appropriate phantom was available. Modeling was done to simulate chest abdominal pelvis scans and whole body scans. Organ dose difference versus body mass index shows as body mass index (BMI) ranges from 23.5 kg/m 2 to 45 kg/m2 the amount of organ dose also trends a percent change from -4.58 to -176.19 %. Comparing organ dose difference with increasing x-ray tube potential from 120 kVp to 140 kVp the percent change in organ dose increases from 55 % to 65 % across all phantoms. In comparing VirtualDose to CT

  2. Accuracy of radiotherapy dose calculations based on cone-beam CT: comparison of deformable registration and image correction based methods

    Science.gov (United States)

    Marchant, T. E.; Joshi, K. D.; Moore, C. J.

    2018-03-01

    Radiotherapy dose calculations based on cone-beam CT (CBCT) images can be inaccurate due to unreliable Hounsfield units (HU) in the CBCT. Deformable image registration of planning CT images to CBCT, and direct correction of CBCT image values are two methods proposed to allow heterogeneity corrected dose calculations based on CBCT. In this paper we compare the accuracy and robustness of these two approaches. CBCT images for 44 patients were used including pelvis, lung and head & neck sites. CBCT HU were corrected using a ‘shading correction’ algorithm and via deformable registration of planning CT to CBCT using either Elastix or Niftyreg. Radiotherapy dose distributions were re-calculated with heterogeneity correction based on the corrected CBCT and several relevant dose metrics for target and OAR volumes were calculated. Accuracy of CBCT based dose metrics was determined using an ‘override ratio’ method where the ratio of the dose metric to that calculated on a bulk-density assigned version of the same image is assumed to be constant for each patient, allowing comparison to the patient’s planning CT as a gold standard. Similar performance is achieved by shading corrected CBCT and both deformable registration algorithms, with mean and standard deviation of dose metric error less than 1% for all sites studied. For lung images, use of deformed CT leads to slightly larger standard deviation of dose metric error than shading corrected CBCT with more dose metric errors greater than 2% observed (7% versus 1%).

  3. Preoperative staging of lung cancer with combined PET-CT

    DEFF Research Database (Denmark)

    Fischer, Barbara; Lassen, Ulrik; Mortensen, Jann

    2009-01-01

    BACKGROUND: Fast and accurate staging is essential for choosing treatment for non-small-cell lung cancer (NSCLC). The purpose of this randomized study was to evaluate the clinical effect of combined positron-emission tomography and computed tomography (PET-CT) on preoperative staging of NSCLC...... one of the following: a thoracotomy with the finding of pathologically confirmed mediastinal lymph-node involvement (stage IIIA [N2]), stage IIIB or stage IV disease, or a benign lung lesion; an exploratory thoracotomy; or a thoracotomy in a patient who had recurrent disease or death from any cause...

  4. A study of different dose calculation methods and the impact on the dose evaluation protocol in lung stereotactic radiation therapy

    International Nuclear Information System (INIS)

    Takada, Takahiro; Furuya, Tomohisa; Ozawa, Shuichi; Ito, Kana; Kurokawa, Chie; Karasawa, Kumiko; Miura, Kohei

    2008-01-01

    AAA (analytical anisotropic algorithm) dose calculation, which shows a better performance for heterogeneity correction, was tested for lung stereotactic radiation therapy (SBRT) in comparison to conventional PBC (pencil beam convolution method) to evaluate its impact on tumor dose parameters. Eleven lung SBRT patients who were treated with photon 4 MV beams in our department between April 2003 and February 2007 were reviewed. Clinical target volume (CTV) was delineated including the spicula region on planning CT images. Planning target volume (PTV) was defined by adding the internal target volume (ITV) and set-up margin (SM) of 5 mm from CTV, and then an multileaf collimator (MLC) penumbra margin of another 5 mm was also added. Six-port non-coplanar beams were employed, and a total prescribed dose of 48 Gy was defined at the isocenter point with four fractions. The entire treatment for an individual patient was completed within 8 days. Under the same prescribed dose, calculated dose distribution, dose volume histogram (DVH), and tumor dose parameters were compared between two dose calculation methods. In addition, the fractionated prescription dose was repeatedly scaled until the monitor units (MUs) calculated by AAA reached a level of MUs nearly identical to those achieved by PBC. AAA resulted in significantly less D95 (irradiation dose that included 95% volume of PTV) and minimal dose in PTV compared to PBC. After rescaling of each MU for each beam in the AAA plan, there was no revision of the isocenter of the prescribed dose required. However, when the PTV volume was less than 20 cc, a 4% lower prescription resulted in nearly identical MUs between AAA and PBC. The prescribed dose in AAA should be the same as that in PBC, if the dose is administered at the isocenter point. However, planners should compare DVHs and dose distributions between AAA and PBC for a small lung tumor with a PTV volume less than approximately 20 cc. (author)

  5. SU-E-T-500: Dose Escalation Strategy for Lung Cancer Patients Using a Biologically- Guided Target Definition

    International Nuclear Information System (INIS)

    Shusharina, N; Khan, F; Choi, N; Sharp, G

    2014-01-01

    Purpose: Dose escalation strategy for lung cancer patients can lead to late symptoms such as pneumonitis and cardiac injury. We propose a strategy to increase radiation dose for improving local tumor control while simultaneously striving to minimize the injury of organs at risk (OAR). Our strategy is based on defining a small, biologically-guided target volume for receiving additional radiation dose. Methods: 106 patients with lung cancer treated with radiotherapy were selected for patients diagnosed with stage II and III disease. Previous research has shown that 50% of the maximum SUV threshold in FDG-PET imaging is appropriate for delineation of the most aggressive part of a tumor. After PET- and CT-derived targets were contoured, an IMRT treatment plan was designed to deliver 60 Gy to the GTV as delineated on a 4D CT (Plan 1). A second plan was designed with additional dose of 18 Gy to the PET-derived volume (Plan 2). A composite plan was generated by the addition of Plan 1 and Plan 2. Results: Plan 1 was compared to the composite plan and increases in OAR dose were assessed. For seven patients on average, lung V5 was increased by 1.4% and V20 by 4.2% for ipsilateral lung and by 13.5% and 7% for contralateral lung. For total lung, V5 and V20 were increased by 4.5% and 4.8% respectively. Mean lung dose was increased by 9.7% for the total lung. The maximum dose to the spinal cord increased by 16% on average. For the heart, V20 increased by 4.2% and V40 by 5.2%. Conclusion: It seems feasible that an additional 18 Gy of radiation dose can be delivered to FDG PET-derived subvolume of the CT-based GTV of the primary tumor without significant increase in total dose to the critical organs such as lungs, spinal cord and heart

  6. SU-E-T-500: Dose Escalation Strategy for Lung Cancer Patients Using a Biologically- Guided Target Definition

    Energy Technology Data Exchange (ETDEWEB)

    Shusharina, N; Khan, F; Choi, N; Sharp, G [Massachusetts General Hospital, Boston, MA (United States)

    2014-06-01

    Purpose: Dose escalation strategy for lung cancer patients can lead to late symptoms such as pneumonitis and cardiac injury. We propose a strategy to increase radiation dose for improving local tumor control while simultaneously striving to minimize the injury of organs at risk (OAR). Our strategy is based on defining a small, biologically-guided target volume for receiving additional radiation dose. Methods: 106 patients with lung cancer treated with radiotherapy were selected for patients diagnosed with stage II and III disease. Previous research has shown that 50% of the maximum SUV threshold in FDG-PET imaging is appropriate for delineation of the most aggressive part of a tumor. After PET- and CT-derived targets were contoured, an IMRT treatment plan was designed to deliver 60 Gy to the GTV as delineated on a 4D CT (Plan 1). A second plan was designed with additional dose of 18 Gy to the PET-derived volume (Plan 2). A composite plan was generated by the addition of Plan 1 and Plan 2. Results: Plan 1 was compared to the composite plan and increases in OAR dose were assessed. For seven patients on average, lung V5 was increased by 1.4% and V20 by 4.2% for ipsilateral lung and by 13.5% and 7% for contralateral lung. For total lung, V5 and V20 were increased by 4.5% and 4.8% respectively. Mean lung dose was increased by 9.7% for the total lung. The maximum dose to the spinal cord increased by 16% on average. For the heart, V20 increased by 4.2% and V40 by 5.2%. Conclusion: It seems feasible that an additional 18 Gy of radiation dose can be delivered to FDG PET-derived subvolume of the CT-based GTV of the primary tumor without significant increase in total dose to the critical organs such as lungs, spinal cord and heart.

  7. CT dose profiles and MSAD calculation in a chest phantom

    International Nuclear Information System (INIS)

    Oliveira, Bruno Beraldo; Silva, Teogenes Augusto da

    2011-01-01

    For optimizing patient doses in computed tomography (CT), the Brazilian legislation has only established diagnostic reference levels (DRLs) in terms of Multiple Scan Average Dose (MSAD) in a typical adult as a quality control parameter for CT scanners. Compliance with the DRLs can be verified by measuring the Computed Tomography Air Kerma Index with a calibrated pencil ionization chamber or by obtaining the dose distribution in CT scans. An analysis of the quality of five CT scanners in Belo Horizonte was done in terms of dose profile of chest scans and MSAD determinations. Measurements were done with rod shape lithium fluoride thermoluminescent dosimeters (TLD-100) distributed in cylinders positioned in peripheral and central regions of a polymethylmethacrylate chest phantom. The peripheral regions presented higher dose values. The longitudinal dose variation can be observed and the maximum dose was recorded at the edges of the phantom at the midpoint of the longitudinal axis. The MSAD results were in according to the DRL of 25 mGy established by Brazilian legislation. The results contribute to disseminate to hospitals and radiologists the proper procedure to use the thermoluminescent dosimeters for the calculation of the MSAD from the CT dose profiles and to notice the compliance with the DRLs. (author)

  8. Evaluation of patient absorbed dose in a PET-CT test

    Energy Technology Data Exchange (ETDEWEB)

    Guerra P, F.; Mourao F, A. P. [Federal University of Minas Gerais, Department of Nuclear Engineering, Av. Antonio Carlos 6627, CEP 31270-901, Pampulha, Belo Horizonte, Minas Gerais (Brazil); Santana, P. C., E-mail: fgpaiva92@gmail.com [Federal University of Minas Gerais, Medical School, Av. Prof. Alfredo Balena 190, CEP 30123970, Santa Efigenia, Belo Horizonte, Minas Gerais (Brazil)

    2017-10-15

    Images of PET-CT has important diagnostic applications, especially in oncology. This equipment allows overlapping of functional images obtained from the administration of radionuclides and anatomical, generated by X-rays. The PET-CT technique may generate higher doses in patients due to the fact that two diagnostic modalities are used in a single examination. A whole body CT scan is performed and in sequence, a capture of the signal generated by the photons emitted is done. In this study, the absorbed and effective doses generated by the CT scan and incorporated by the administration of the radionuclide were evaluated in 19 organs. To evaluate the CT dose, 32 radiochromic film strips were correctly positioned into the anthropomorphic male phantom. The CT protocol performed was whole-body scanning and a high-resolution lung scan. This protocol is currently used in most services. The calculation of the effective dose from the injected activity in the patient was performed using the ICRP 106 Biokinetic model (ICRP 106, 2008). The activity to be injected may vary according to the patients body mass and with the sensitivity of the detector. The mass of the simulator used is 73.5 kg, then the simulation with and injected activity of 244.76 MBq was used. It was observed that 87.4% of the effective dose in examination PET/CT comes from the CT scans, being 63.8% of the whole body scan and 23.6% of high resolution lung scan. Using activity of 0.09 mCi x kg {sup 18}F-FDG radiopharmaceutical contributes only 12.6% of the final effective dose. As a conclusion, it was observed that the dose in patients submitted to the {sup 18}F-FDG PET-CT examination is high, being of great value efforts for its reduction, such as the use of appropriate image acquisition techniques and promoting the application of the principle of optimization of practice. (Author)

  9. Studies on diagnosis of lung emphysema by CT image using experimental models and clinical cases

    International Nuclear Information System (INIS)

    Nakatani, Seiki

    1998-01-01

    Since the detailed report between the degree of functional disorder in lung emphysema and the analysis of CT image is quite unknown, the present study was attempted to produce the experimental model of lung emphysema with various stages by the administration of papain to the focal lobe in canine lung. Using this model or clinical lung emphysema, the relationship between the degree of destruction of alveolar walls, clinical pulmonary functions and CT images was investigated. CT scan was performed at the level of 50% vital capacity in both experimental models and clinical subjects by using spirometric gating CT. CT density histogram was obtained from CT image which was produced by using the developed software for this purpose. Densitometric parameters, such as mean CT value, %LAA, the peak in the histogram and 5% tile were selected from CT image. Papain solution of 5 mg/kg body weight was cumulatively administered to the left lower lobe in canine lung, resulting in the destruction of lung alveolar walls in parallel to the increasing dosage of papain. There was a significant correlation between not only the increasing dosage of papain, but also %FEV 1.0 and CT densitometric parameters, indicating that the histological changes of alveolar walls and the lung function in lung emphysema could be estimated by analysis of CT image. These experimental and clinical studies suggest that the analysis of CT image can reflect the pathophysiological changes in the lung and be useful for precise clinical diagnosis of lung emphysema. (author)

  10. Lung cancer screening beyond low-dose computed tomography: the role of novel biomarkers.

    Science.gov (United States)

    Hasan, Naveed; Kumar, Rohit; Kavuru, Mani S

    2014-10-01

    Lung cancer is the most common and lethal malignancy in the world. The landmark National lung screening trial (NLST) showed a 20% relative reduction in mortality in high-risk individuals with screening low-dose computed tomography. However, the poor specificity and low prevalence of lung cancer in the NLST provide major limitations to its widespread use. Furthermore, a lung nodule on CT scan requires a nuanced and individualized approach towards management. In this regard, advances in high through-put technology (molecular diagnostics, multi-gene chips, proteomics, and bronchoscopic techniques) have led to discovery of lung cancer biomarkers that have shown potential to complement the current screening standards. Early detection of lung cancer can be achieved by analysis of biomarkers from tissue samples within the respiratory tract such as sputum, saliva, nasal/bronchial airway epithelial cells and exhaled breath condensate or through peripheral biofluids such as blood, serum and urine. Autofluorescence bronchoscopy has been employed in research setting to identify pre-invasive lesions not identified on CT scan. Although these modalities are not yet commercially available in clinic setting, they will be available in the near future and clinicians who care for patients with lung cancer should be aware. In this review, we present up-to-date state of biomarker development, discuss their clinical relevance and predict their future role in lung cancer management.

  11. CT findings of small bowel metastases from primary lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Wook; Ha, Hyun Kwon; Kim, Ah Young; Kim, Gab Choul; Kim, Tae Kyoung; Kim, Pyo Nyun; Lee, Moon Gyu [Ulsan University College of Medicine, Seoul (Korea, Republic of)

    2002-11-01

    To evaluate the CT findings of small bowel metastases from primary lung cancer. Of the 1468 patients with primary lung cancer between 1990 and 2000, 13 patients who had metastasis to the small intestine were collected. Of these 13 patients, nine who underwent CT scan were included for analysis. The pathologic diagnoses of primary lung cancer in these nine patients were squamous cell carcinoma in six, adenocarcinoma in two, and large cell carcinoma in one. CT scans were analyzed with regard to the site and patterns (intraluminal mass/bowel wall thickening/bowel implants) of metastatic masses, and the presence or absence of complication such as intussusception, obstruction, or perforation of the small bowel. The medical records of the patients were also reviewed retrospectively for evaluation of presenting abdominal symptom and time interval of metastases from initial diagnosis of lung cancer. Metastatic lesions were distributed throughout the small intestine: the duodenum in five, the jejunum in four, the ileum in six, and both jejunum and ileum in one patient. The size of metastatic masses of small bowel ranged from 1.3 cm to 5.0 cm (mean size, 2.6 cm) On CT, the small bowel was involved with intraluminal masses (mean size, 3.4 cm) in eight patients, diffuse wall thickening (mean thickness, 1.6 cm) in five, and bowel implants (mean size, 2.2 cm) in two. Complications occurred in seven patients, including intussusceptions without obstruction in two patients and with obstruction in two, obstruction without intussusceptions in two, and bowel perforation in one. Of 9 patients, 6 had at least one symptom referable to the small bowel including abdominal pain in 4, anemia in 3, vomiting in 1, and jaundice in 1. Lung cancer and small bowel lesions were detected simultaneously in four patients and the time interval of metastases from initial diagnosis of lung cancer ranged from 10 days to 30 months (median interval, 54 days) in patients. CT helps in defining the extent and

  12. CT findings of small bowel metastases from primary lung cancer

    International Nuclear Information System (INIS)

    Kim, Jae Wook; Ha, Hyun Kwon; Kim, Ah Young; Kim, Gab Choul; Kim, Tae Kyoung; Kim, Pyo Nyun; Lee, Moon Gyu

    2002-01-01

    To evaluate the CT findings of small bowel metastases from primary lung cancer. Of the 1468 patients with primary lung cancer between 1990 and 2000, 13 patients who had metastasis to the small intestine were collected. Of these 13 patients, nine who underwent CT scan were included for analysis. The pathologic diagnoses of primary lung cancer in these nine patients were squamous cell carcinoma in six, adenocarcinoma in two, and large cell carcinoma in one. CT scans were analyzed with regard to the site and patterns (intraluminal mass/bowel wall thickening/bowel implants) of metastatic masses, and the presence or absence of complication such as intussusception, obstruction, or perforation of the small bowel. The medical records of the patients were also reviewed retrospectively for evaluation of presenting abdominal symptom and time interval of metastases from initial diagnosis of lung cancer. Metastatic lesions were distributed throughout the small intestine: the duodenum in five, the jejunum in four, the ileum in six, and both jejunum and ileum in one patient. The size of metastatic masses of small bowel ranged from 1.3 cm to 5.0 cm (mean size, 2.6 cm) On CT, the small bowel was involved with intraluminal masses (mean size, 3.4 cm) in eight patients, diffuse wall thickening (mean thickness, 1.6 cm) in five, and bowel implants (mean size, 2.2 cm) in two. Complications occurred in seven patients, including intussusceptions without obstruction in two patients and with obstruction in two, obstruction without intussusceptions in two, and bowel perforation in one. Of 9 patients, 6 had at least one symptom referable to the small bowel including abdominal pain in 4, anemia in 3, vomiting in 1, and jaundice in 1. Lung cancer and small bowel lesions were detected simultaneously in four patients and the time interval of metastases from initial diagnosis of lung cancer ranged from 10 days to 30 months (median interval, 54 days) in patients. CT helps in defining the extent and

  13. High-resolution pulmonary ventilation and perfusion PET/CT allows for functionally adapted intensity modulated radiotherapy in lung cancer

    International Nuclear Information System (INIS)

    Siva, Shankar; Thomas, Roshini; Callahan, Jason; Hardcastle, Nicholas; Pham, Daniel; Kron, Tomas; Hicks, Rodney J.; MacManus, Michael P.; Ball, David L.; Hofman, Michael S.

    2015-01-01

    Background and purpose: To assess the utility of functional lung avoidance using IMRT informed by four-dimensional (4D) ventilation/perfusion (V/Q) PET/CT. Materials and methods: In a prospective clinical trial, patients with non-small cell lung cancer (NSCLC) underwent 4D-V/Q PET/CT scanning before 60 Gy of definitive chemoradiation. Both “highly perfused” (HPLung) and “highly ventilated” (HVLung) lung volumes were delineated using a 70th centile SUV threshold, and a “ventilated lung volume” (VLung) was created using a 50th centile SUV threshold. For each patient four IMRT plans were created, optimised to the anatomical lung, HPLung, HVLung and VLung volumes, respectively. Improvements in functional dose volumetrics when optimising to functional volumes were assessed using mean lung dose (MLD), V5, V10, V20, V30, V40, V50 and V60 parameters. Results: The study cohort consisted of 20 patients with 80 IMRT plans. Plans optimised to HPLung resulted in a significant reduction of functional MLD by a mean of 13.0% (1.7 Gy), p = 0.02. Functional V5, V10 and V20 were improved by 13.2%, 7.3% and 3.8% respectively (p-values < 0.04). There was no significant sparing of dose to functional lung when adapting to VLung or HVLung. Plan quality was highly consistent with a mean PTV D95 and D5 ranging from 60.8 Gy to 61.0 Gy and 63.4 Gy to 64.5 Gy, respectively, and mean conformity and heterogeneity index ranging from 1.11 to 1.17 and 0.94 to 0.95, respectively. Conclusion: IMRT plans adapted to perfused but not ventilated lung on 4D-V/Q PET/CT allowed for reduced dose to functional lung whilst maintaining consistent plan quality

  14. Predictors of pneumothorax after CT-guided transthoracic needle lung biopsy: the role of quantitative CT.

    Science.gov (United States)

    Chami, H A; Faraj, W; Yehia, Z A; Badour, S A; Sawan, P; Rebeiz, K; Safa, R; Saade, C; Ghandour, B; Shamseddine, A; Mukherji, D; Haydar, A A

    2015-12-01

    To evaluate the association of quantitative computed tomography (CT) measures of emphysema with the occurrence of pneumothorax after CT-guided needle lung biopsy (NLB) accounting for other risk factors. One hundred and sixty-three CT-guided NLBs performed between 2008 and 2013 with available complete chest CT within 30 days were reviewed for the occurrence of post-procedure pneumothorax. Percent emphysema was determined quantitatively as the percentage of lung voxels below -950 HU on chest CT images using automated software. Multivariable regression was used to assess the association of percent emphysema volume with the occurrence of post-procedure pneumothorax. The association of percent emphysema volume with the pneumothorax size and need for chest tube placement after NLB was also explored. Percent emphysema was significantly associated with the incidence of post-NLB pneumothorax (OR=1.10 95% confidence interval: 1.01-1.15; p=0.03) adjusting for lower-lobe lesion location, needle path length, lesion size, number of passes, and pleural needle trajectory angle. Percent emphysema was not associated with the size of the pneumothorax, nor the need for chest tube placement after NLB. Percent emphysema determined quantitatively from chest CT is a significant predictor of post-NLB pneumothorax. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  15. Fully automated gynecomastia quantification from low-dose chest CT

    Science.gov (United States)

    Liu, Shuang; Sonnenblick, Emily B.; Azour, Lea; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2018-02-01

    Gynecomastia is characterized by the enlargement of male breasts, which is a common and sometimes distressing condition found in over half of adult men over the age of 44. Although the majority of gynecomastia is physiologic or idiopathic, its occurrence may also associate with an extensive variety of underlying systemic disease or drug toxicity. With the recent large-scale implementation of annual lung cancer screening using low-dose chest CT (LDCT), gynecomastia is believed to be a frequent incidental finding on LDCT. A fully automated system for gynecomastia quantification from LDCT is presented in this paper. The whole breast region is first segmented using an anatomyorientated approach based on the propagation of pectoral muscle fronts in the vertical direction. The subareolar region is then localized, and the fibroglandular tissue within it is measured for the assessment of gynecomastia. The presented system was validated using 454 breast regions from non-contrast LDCT scans of 227 adult men. The ground truth was established by an experienced radiologist by classifying each breast into one of the five categorical scores. The automated measurements have been demonstrated to achieve promising performance for the gynecomastia diagnosis with the AUC of 0.86 for the ROC curve and have statistically significant Spearman correlation r=0.70 (p early detection as well as the treatment of both gynecomastia and the underlying medical problems, if any, that cause gynecomastia.

  16. CT screening for lung cancer. Update 2008

    International Nuclear Information System (INIS)

    Henschke, C.I.; Yip, R.; Yankelevitz, D.F.

    2009-01-01

    Screening for a cancer should be considered when the cancer is significant in terms of incidence and mortality, treatment of early stage disease is better than treatment of late stage disease, and there is a screening regimen that provides for earlier diagnosis rather than later, symptom-prompted diagnosis. Lung cancer qualifies as it kills more people than any other cancer worldwide. In the United States it kills more people than colon, breast, and prostate cancer combined and more women than breast cancer. The fundamental concepts of screening are presented. Screening for a cancer is a repetitive process, starting with the baseline round followed by repeat rounds of screening at set intervals. The regimen of screening defines the initial diagnostic test and the sequence of tests to be performed leading to a rule-in diagnosis of the cancer. The regimen should provide lead time of the diagnosis of the cancer. The regimen for the first, baseline round may be different from the regimen for the repeat rounds as the former is inherently different from the subsequent repeat rounds. Baseline screening identifies a greater proportion of cancers with a longer latent (asymptomatic) phase than repeat screening, called length bias. Length bias exists for any screening program, regardless of the design of the study or the cancer. Repeat rounds of screening identify the same proportion of cancer diagnoses found in absence of screening for people having the same risk of the cancer and these repeat rounds of screening can be pooled. It is also a consequence of length bias that cancers found in repeat rounds are earlier in their latent phase than those of the baseline round, a less frequently mentioned consequence. Overdiagnosis bias, another bias of screening, can occur in two ways: a cancer' detected by the screening, pathologically proven, that is not life-threatening even when not resected and a genuine life-threatening cancer that is diagnosed and treated but the person dies

  17. CT of chronic infiltrative lung disease: Prevalence of mediastinal lymphadenopathy

    Energy Technology Data Exchange (ETDEWEB)

    Niimi, Hiroshi; Kang, Eun-Young; Kwong, S. [Univ. of British Columbia and Vancouver Hospital and Health Sciences Centre (Canada)] [and others

    1996-03-01

    Our goal was to determine the prevalence of mediastinal lymph node enlargement at CT in patients with diffuse infiltrative lung disease. The study was retrospective and included 175 consecutive patients with diffuse infiltrative lung diseases. Diagnoses included idiopathic pulmonary fibrosis (IPF) (n = 61), usual interstitial pneumonia associated with collagen vascular disease (CVD) (n = 20), idiopathic bronchiolitis obliterans organizing pneumonia (BOOP) (n = 22), extrinsic allergic alveolitis (EAA) (n = 17), and sarcoidosis (n = 55). Fifty-eight age-matched patients with CT of the chest performed for unrelated conditions served as controls. The presence, number, and sites of enlarged nodes (short axis {ge}10 mm in diameter) were recorded. Enlarged mediastinal nodes were present in 118 of 175 patients (67%) with infiltrative lung disease and 3 of 58 controls (5%) (p < 0.001). The prevalence of enlarged nodes was 84% (46 of 55) in sarcoidosis, 67% (41 of 61) in IPF, 70% (14 of 20) in CVD, 53% (9 of 17) in EAA, and 36% (8 of 22) in BOOP. The mean number of enlarged nodes was higher in sarcoidosis (mean 3.2) than in the other infiltrative diseases (mean 1.2) (p < 0.001). Enlarged nodes were most commonly present in station 10R, followed by 7, 4R, and 5. Patients with infiltrative lung disease frequently have enlarged mediastinal lymph nodes. However, in diseases other than sarcoid, usually only one or two nodes are enlarged and their maximal short axis diameter is <15 mm. 11 refs., 2 figs., 1 tab.

  18. Table incremental slow injection CE-CT in lung cancer

    International Nuclear Information System (INIS)

    Yoshida, Shoji; Maeda, Tomoho; Morita, Masaru

    1988-01-01

    The purpose of this study is to evaluate tumor enhancement in lung cancer under the table incremental study with slow injection of contrast media. The early serial 8 sliced images during the slow injection (1.5 ml/sec) of contrant media were obtained. Following the early images, delayed 8 same sliced images were taken in 2 minutes later. Chacteristic enhanced patterns of the primary cancer and metastatic mediastinal lymphnode were recognized in this study. Enhancement of the primary lesion was classified in 4 patterns, irregular geographic pattern, heterogeneous pattern, homogeneous pattern and rim-enhanced pattern. In mediastinal metastatic lymphadenopathy, three enhanced patterns were obtained, heterogeneous, homogeneous and ring enhanced pattern. Some characteristic enhancement patterns according to the histopathological finding of the lung cancer were obtained. With using this incremental slow injection CE-CT, precise information about the relationship between lung cancer and adjacent mediastinal structure, and obvious staining patterns of the tumor and mediastinal lymphnode were recognized. (author)

  19. PET/CT. Dose-escalated image fusion?

    International Nuclear Information System (INIS)

    Brix, G.; Beyer, T.

    2005-01-01

    Clinical studies demonstrate a gain in diagnostic accuracy by employing combined PET/CT instead of separate CT and PET imaging. However, whole-body PET/CT examinations result in a comparatively high radiation burden to patients and thus require a proper justification and optimization to avoid repeated exposure or over-exposure of patients. This review article summarizes relevant data concerning radiation exposure of patients resulting from the different components of a combined PET/CT examination and presents different imaging strategies that can help to balance the diagnostic needs and the radiation protection requirements. In addition various dose reduction measures are discussed, some of which can be adopted from CT practice, while others mandate modifications to the existing hard- and software of PET/CT systems. (orig.)

  20. Effects of Respiration-Induced Density Variations on Dose Distributions in Radiotherapy of Lung Cancer

    International Nuclear Information System (INIS)

    Mexner, Vanessa; Wolthaus, Jochem W.H.; Herk, Marcel van; Damen, Eugene M.F.; Sonke, Jan-Jakob

    2009-01-01

    Purpose: To determine the effect of respiration-induced density variations on the estimated dose delivered to moving structures and, consequently, to evaluate the necessity of using full four-dimensional (4D) treatment plan optimization. Methods and Materials: In 10 patients with large tumor motion (median, 1.9 cm; range, 1.1-3.6 cm), the clinical treatment plan, designed using the mid-ventilation ([MidV]; i.e., the 4D-CT frame closest to the time-averaged mean position) CT scan, was recalculated on all 4D-CT frames. The cumulative dose was determined by transforming the doses in all breathing phases to the MidV geometry using deformable registration and then averaging the results. To determine the effect of density variations, this cumulative dose was compared with the accumulated dose after similarly deforming the planned (3D) MidV-dose in each respiratory phase using the same transformation (i.e., 'blurring the dose'). Results: The accumulated tumor doses, including and excluding density variations, were almost identical. Relative differences in the minimum gross tumor volume (GTV) dose were less than 2% for all patients. The relative differences were even smaller in the mean lung dose and the V20 (<0.5% and 1%, respectively). Conclusions: The effect of respiration-induced density variations on the dose accumulated over the respiratory cycle was very small, even in the presence of considerable respiratory motion. A full 4D-dose calculation for treatment planning that takes into account such density variations is therefore not required. Planning using the MidV-CT derived from 4D-CT with an appropriate margin for geometric uncertainties is an accurate and safe method to account for respiration-induced anatomy variations.

  1. Quantitative study on lung volume and lung perfusion using SPECT and CT in thoracal tumors

    International Nuclear Information System (INIS)

    Beyer-Enke, S.A.; Goerich, J.; Strauss, L.G.

    1988-01-01

    22 patients with space occupying lesions in the thoracal region were investigated by computer tomography and by perfusion scintigraphy using SPECT. In order to evaluate the CT images quantitatively, the lung volume was determined using approximation method and compared with the perfusion in the SPECT study. For this, anatomically equivalent transaxial SPECT slices had been coordinated to the CT slices. Between the determined lung volumes and the activity in the ocrresponding layers, a statistically significant correlation was found. It could be shown that the stronger perfusion, frequently observed at the right side of the healthy lung, may be explained by an higher volume of the right pulmonary lobe. Whereas in benign displacing processes the relation activity to volume was similar to the one of the healthy lung, a strongly reduced perfusion together with inconspicuous lung volumes became apparent with malignant tumors. In addition to the great morphological evidence of CT and SPECT studies, additional informations regarding the dignity of displacing processes may be derived from the quantitative evaluation of both methods. (orig.) [de

  2. Methods of in-vivo mouse lung micro-CT

    Science.gov (United States)

    Recheis, Wolfgang A.; Nixon, Earl; Thiesse, Jacqueline; McLennan, Geoffrey; Ross, Alan; Hoffman, Eric

    2005-04-01

    Micro-CT will have a profound influence on the accumulation of anatomical and physiological phenotypic changes in natural and transgenetic mouse models. Longitudinal studies will be greatly facilitated, allowing for a more complete and accurate description of events if in-vivo studies are accomplished. The purpose of the ongoing project is to establish a feasible and reproducible setup for in-vivo mouse lung micro-computed tomography (μCT). We seek to use in-vivo respiratory-gated μCT to follow mouse models of lung disease with subsequent recovery of the mouse. Methodologies for optimizing scanning parameters and gating for the in-vivo mouse lung are presented. A Scireq flexiVent ventilated the gas-anesthetized mice at 60 breaths/minute, 30 cm H20 PEEP, 30 ml/kg tidal volume and provided a respiratory signal to gate a Skyscan 1076 μCT. Physiologic monitoring allowed the control of vital functions and quality of anesthesia, e.g. via ECG monitoring. In contrary to longer exposure times with ex-vivo scans, scan times for in-vivo were reduced using 35μm pixel size, 158ms exposure time and 18μm pixel size, 316ms exposure time to reduce motion artifacts. Gating via spontaneous breathing was also tested. Optimal contrast resolution was achieved at 50kVp, 200μA, applying an aluminum filter (0.5mm). There were minimal non-cardiac related motion artifacts. Both 35μm and 1μm voxel size images were suitable for evaluation of the airway lumen and parenchymal density. Total scan times were 30 and 65 minutes respectively. The mice recovered following scanning protocols. In-vivo lung scanning with recovery of the mouse delivered reasonable image quality for longitudinal studies, e.g. mouse asthma models. After examining 10 mice, we conclude μCT is a feasible tool evaluating mouse models of lung pathology in longitudinal studies with increasing anatomic detail available for evaluation as one moves from in-vivo to ex-vivo studies. Further developments include automated

  3. Dose reduction in pediatric abdominal CT: use of iterative reconstruction techniques across different CT platforms

    International Nuclear Information System (INIS)

    Khawaja, Ranish Deedar Ali; Singh, Sarabjeet; Otrakji, Alexi; Padole, Atul; Lim, Ruth; Nimkin, Katherine; Westra, Sjirk; Kalra, Mannudeep K.; Gee, Michael S.

    2015-01-01

    Dose reduction in children undergoing CT scanning is an important priority for the radiology community and public at large. Drawbacks of radiation reduction are increased image noise and artifacts, which can affect image interpretation. Iterative reconstruction techniques have been developed to reduce noise and artifacts from reduced-dose CT examinations, although reconstruction algorithm, magnitude of dose reduction and effects on image quality vary. We review the reconstruction principles, radiation dose potential and effects on image quality of several iterative reconstruction techniques commonly used in clinical settings, including 3-D adaptive iterative dose reduction (AIDR-3D), adaptive statistical iterative reconstruction (ASIR), iDose, sinogram-affirmed iterative reconstruction (SAFIRE) and model-based iterative reconstruction (MBIR). We also discuss clinical applications of iterative reconstruction techniques in pediatric abdominal CT. (orig.)

  4. Dose reduction in pediatric abdominal CT: use of iterative reconstruction techniques across different CT platforms

    Energy Technology Data Exchange (ETDEWEB)

    Khawaja, Ranish Deedar Ali; Singh, Sarabjeet; Otrakji, Alexi; Padole, Atul; Lim, Ruth; Nimkin, Katherine; Westra, Sjirk; Kalra, Mannudeep K.; Gee, Michael S. [MGH Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States)

    2015-07-15

    Dose reduction in children undergoing CT scanning is an important priority for the radiology community and public at large. Drawbacks of radiation reduction are increased image noise and artifacts, which can affect image interpretation. Iterative reconstruction techniques have been developed to reduce noise and artifacts from reduced-dose CT examinations, although reconstruction algorithm, magnitude of dose reduction and effects on image quality vary. We review the reconstruction principles, radiation dose potential and effects on image quality of several iterative reconstruction techniques commonly used in clinical settings, including 3-D adaptive iterative dose reduction (AIDR-3D), adaptive statistical iterative reconstruction (ASIR), iDose, sinogram-affirmed iterative reconstruction (SAFIRE) and model-based iterative reconstruction (MBIR). We also discuss clinical applications of iterative reconstruction techniques in pediatric abdominal CT. (orig.)

  5. Visual assessment of early emphysema and interstitial abnormalities on CT is useful in lung cancer risk analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wille, Mathilde M.W.; Dirksen, Asger; Shaker, Saher B. [Gentofte Hospital, Department of Respiratory Medicine, Hellerup (Denmark); Thomsen, Laura H. [Hvidovre Hospital, Department of Respiratory Medicine, Hvidovre (Denmark); Petersen, Jens [University of Copenhagen, Department of Computer Science, DIKU, Koebenhavn Oe (Denmark); Bruijne, Marleen de [University of Copenhagen, Department of Computer Science, DIKU, Koebenhavn Oe (Denmark); Erasmus MC -University Medical Center Rotterdam, Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Rotterdam (Netherlands); Pedersen, Jesper H. [Copenhagen University Hospital, Department of Thoracic Surgery, Rigshospitalet, Koebenhavn Oe (Denmark)

    2016-02-15

    Screening for lung cancer should be limited to a high-risk-population, and abnormalities in low-dose computed tomography (CT) screening images may be relevant for predicting the risk of lung cancer. Our aims were to compare the occurrence of visually detected emphysema and interstitial abnormalities in subjects with and without lung cancer in a screening population of smokers. Low-dose chest CT examinations (baseline and latest possible) of 1990 participants from The Danish Lung Cancer Screening Trial were independently evaluated by two observers who scored emphysema and interstitial abnormalities. Emphysema (lung density) was also measured quantitatively. Emphysema was seen more frequently and its extent was greater among participants with lung cancer on baseline (odds ratio (OR), 1.8, p = 0.017 and p = 0.002) and late examinations (OR 2.6, p < 0.001 and p < 0.001). No significant difference was found using quantitative measurements. Interstitial abnormalities were more common findings among participants with lung cancer (OR 5.1, p < 0.001 and OR 4.5, p < 0.001).There was no association between presence of emphysema and presence of interstitial abnormalities (OR 0.75, p = 0.499). Even early signs of emphysema and interstitial abnormalities are associated with lung cancer. Quantitative measurements of emphysema - regardless of type - do not show the same association. (orig.)

  6. Visual assessment of early emphysema and interstitial abnormalities on CT is useful in lung cancer risk analysis

    International Nuclear Information System (INIS)

    Wille, Mathilde M.W.; Dirksen, Asger; Shaker, Saher B.; Thomsen, Laura H.; Petersen, Jens; Bruijne, Marleen de; Pedersen, Jesper H.

    2016-01-01

    Screening for lung cancer should be limited to a high-risk-population, and abnormalities in low-dose computed tomography (CT) screening images may be relevant for predicting the risk of lung cancer. Our aims were to compare the occurrence of visually detected emphysema and interstitial abnormalities in subjects with and without lung cancer in a screening population of smokers. Low-dose chest CT examinations (baseline and latest possible) of 1990 participants from The Danish Lung Cancer Screening Trial were independently evaluated by two observers who scored emphysema and interstitial abnormalities. Emphysema (lung density) was also measured quantitatively. Emphysema was seen more frequently and its extent was greater among participants with lung cancer on baseline (odds ratio (OR), 1.8, p = 0.017 and p = 0.002) and late examinations (OR 2.6, p < 0.001 and p < 0.001). No significant difference was found using quantitative measurements. Interstitial abnormalities were more common findings among participants with lung cancer (OR 5.1, p < 0.001 and OR 4.5, p < 0.001).There was no association between presence of emphysema and presence of interstitial abnormalities (OR 0.75, p = 0.499). Even early signs of emphysema and interstitial abnormalities are associated with lung cancer. Quantitative measurements of emphysema - regardless of type - do not show the same association. (orig.)

  7. IMRT treatment plans and functional planning with functional lung imaging from 4D-CT for thoracic cancer patients

    Directory of Open Access Journals (Sweden)

    Huang Tzung-Chi

    2013-01-01

    Full Text Available Abstract Background and purpose Currently, the inhomogeneity of the pulmonary function is not considered when treatment plans are generated in thoracic cancer radiotherapy. This study evaluates the dose of treatment plans on highly-functional volumes and performs functional treatment planning by incorporation of ventilation data from 4D-CT. Materials and methods Eleven patients were included in this retrospective study. Ventilation was calculated using 4D-CT. Two treatment plans were generated for each case, the first one without the incorporation of the ventilation and the second with it. The dose of the first plans was overlapped with the ventilation and analyzed. Highly-functional regions were avoided in the second treatment plans. Results For small targets in the first plans (PTV  Conclusion Radiation treatments affect functional lung more seriously in large tumor cases. With compromise of dose to other critical organs, functional treatment planning to reduce dose in highly-functional lung volumes can be achieved

  8. Comparing Effective Doses During Image-Guided Core Needle Biopsies with Computed Tomography Versus C-Arm Cone Beam CT Using Adult and Pediatric Phantoms

    International Nuclear Information System (INIS)

    Ben-Shlomo, A.; Cohen, D.; Bruckheimer, E.; Bachar, G. N.; Konstantinovsky, R.; Birk, E.; Atar, E.

    2016-01-01

    PurposeTo compare the effective doses of needle biopsies based on dose measurements and simulations using adult and pediatric phantoms, between cone beam c-arm CT (CBCT) and CT.MethodEffective doses were calculated and compared based on measurements and Monte Carlo simulations of CT- and CBCT-guided biopsy procedures of the lungs, liver, and kidney using pediatric and adult phantoms.ResultsThe effective doses for pediatric and adult phantoms, using our standard protocols for upper, middle and lower lungs, liver, and kidney biopsies, were significantly lower under CBCT guidance than CT. The average effective dose for a 5-year old for these five biopsies was 0.36 ± 0.05 mSv with the standard CBCT exposure protocols and 2.13 ± 0.26 mSv with CT. The adult average effective dose for the five biopsies was 1.63 ± 0.22 mSv with the standard CBCT protocols and 8.22 ± 1.02 mSv using CT. The CT effective dose was higher than CBCT protocols for child and adult phantoms by 803 and 590 % for upper lung, 639 and 525 % for mid-lung, and 461 and 251 % for lower lung, respectively. Similarly, the effective dose was higher by 691 and 762 % for liver and 513 and 608 % for kidney biopsies.ConclusionsBased on measurements and simulations with pediatric and adult phantoms, radiation effective doses during image-guided needle biopsies of the lung, liver, and kidney are significantly lower with CBCT than with CT.

  9. Comparing Effective Doses During Image-Guided Core Needle Biopsies with Computed Tomography Versus C-Arm Cone Beam CT Using Adult and Pediatric Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Shlomo, A. [Soreq NRC, Radiation Protection Domain (Israel); Cohen, D.; Bruckheimer, E. [Schneider Children’s Medical Center, Section of Pediatric Cardiology (Israel); Bachar, G. N.; Konstantinovsky, R. [Rabin Medical Center, Department of Diagnostic Radiology (Israel); Birk, E. [Schneider Children’s Medical Center, Section of Pediatric Cardiology (Israel); Atar, E., E-mail: elia@clalit.org.il [Rabin Medical Center, Department of Diagnostic Radiology (Israel)

    2016-05-15

    PurposeTo compare the effective doses of needle biopsies based on dose measurements and simulations using adult and pediatric phantoms, between cone beam c-arm CT (CBCT) and CT.MethodEffective doses were calculated and compared based on measurements and Monte Carlo simulations of CT- and CBCT-guided biopsy procedures of the lungs, liver, and kidney using pediatric and adult phantoms.ResultsThe effective doses for pediatric and adult phantoms, using our standard protocols for upper, middle and lower lungs, liver, and kidney biopsies, were significantly lower under CBCT guidance than CT. The average effective dose for a 5-year old for these five biopsies was 0.36 ± 0.05 mSv with the standard CBCT exposure protocols and 2.13 ± 0.26 mSv with CT. The adult average effective dose for the five biopsies was 1.63 ± 0.22 mSv with the standard CBCT protocols and 8.22 ± 1.02 mSv using CT. The CT effective dose was higher than CBCT protocols for child and adult phantoms by 803 and 590 % for upper lung, 639 and 525 % for mid-lung, and 461 and 251 % for lower lung, respectively. Similarly, the effective dose was higher by 691 and 762 % for liver and 513 and 608 % for kidney biopsies.ConclusionsBased on measurements and simulations with pediatric and adult phantoms, radiation effective doses during image-guided needle biopsies of the lung, liver, and kidney are significantly lower with CBCT than with CT.

  10. Comparing Effective Doses During Image-Guided Core Needle Biopsies with Computed Tomography Versus C-Arm Cone Beam CT Using Adult and Pediatric Phantoms.

    Science.gov (United States)

    Ben-Shlomo, A; Cohen, D; Bruckheimer, E; Bachar, G N; Konstantinovsky, R; Birk, E; Atar, E

    2016-05-01

    To compare the effective doses of needle biopsies based on dose measurements and simulations using adult and pediatric phantoms, between cone beam c-arm CT (CBCT) and CT. Effective doses were calculated and compared based on measurements and Monte Carlo simulations of CT- and CBCT-guided biopsy procedures of the lungs, liver, and kidney using pediatric and adult phantoms. The effective doses for pediatric and adult phantoms, using our standard protocols for upper, middle and lower lungs, liver, and kidney biopsies, were significantly lower under CBCT guidance than CT. The average effective dose for a 5-year old for these five biopsies was 0.36 ± 0.05 mSv with the standard CBCT exposure protocols and 2.13 ± 0.26 mSv with CT. The adult average effective dose for the five biopsies was 1.63 ± 0.22 mSv with the standard CBCT protocols and 8.22 ± 1.02 mSv using CT. The CT effective dose was higher than CBCT protocols for child and adult phantoms by 803 and 590% for upper lung, 639 and 525% for mid-lung, and 461 and 251% for lower lung, respectively. Similarly, the effective dose was higher by 691 and 762% for liver and 513 and 608% for kidney biopsies. Based on measurements and simulations with pediatric and adult phantoms, radiation effective doses during image-guided needle biopsies of the lung, liver, and kidney are significantly lower with CBCT than with CT.

  11. CT-guided percutaneous conformal cryoablation for lung carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Yueyong, Xiao; Bin, Wu; Xiao, Zhang; Hongjun, Li; Da, Yu; Jie, Li; Jun, Li [Department of Radiology, PLA General Hospital, Beijing (China)

    2010-02-15

    Objective: To investigate the safety, efficacy and feasibility of CT-guided percutaneous conformal cryoablation for lung cancer. Methods: The inclusion criteria were: (1) Poor respiratory function and aged patients who can not bear the thoracic surgical operation. (2) Peripheral lung cancer involving the pleura and chest wall which can not be resected. (3) Residual tumor after other comprehensive treatment. (4) Focal lung cancer but the patient refused surgical resection. The exclusion criteria were: (1) Multifocal lesions. (2) Lesion close to mediastinum with possible risk of vessel injury. (3) Severe impairment of pulmonary functions, the maximum voluntary ventilation is less than 39%. (4) Repeated cough or dyspnea, can not cooperate with the procedure. (5) Poor systemic conditions, cachexia or bleeding. Totally, 76 lung carcinoma lesions on 66 patients were treated by CT-guided percutaneous conformal cryoablation using 17 G cryoprobes. The maximum diameters of the tumors ranged from 1.5 cm to 1.6 cm. For the tumors with the maximum diameter less than 3.0 cm, they were treated by double-needle clamping cryoablation. For those with the maximum diameter between 3.0 and 5.0 cm, they were treated by multiple-needle conformal cryoablation. For those with the maximum diameter larger than 5.0 cm, they were treated with multiple-needle conformal cyroablation, with the needle distance less than 1.5 cm. All the patients were followed-up 6 to 24 months after the procedure using contrast-enhanced CT to evaluate the tumor size and enhancement. Results: For 18 cases with the maximum diameters less than 3.0 cm, CT scan during the procedure showed that the frozen areas extended beyond the edge of the lesions more than 1.0 cm, the lesion attenuated, narrow-band-like encircled translucency around the lesions and 'target sign' with ground-glass density of the peripheral lung tissue. There was no enhancement during the first 1 st, 3 rd month follow-up, only fibrosis scar in 6 th

  12. CT-guided percutaneous conformal cryoablation for lung carcinoma

    International Nuclear Information System (INIS)

    Xiao Yueyong; Wu Bin; Zhang Xiao; Li Hongjun; Yu Da; Li Jie; Li Jun

    2010-01-01

    Objective: To investigate the safety, efficacy and feasibility of CT-guided percutaneous conformal cryoablation for lung cancer. Methods: The inclusion criteria were: (1) Poor respiratory function and aged patients who can not bear the thoracic surgical operation. (2) Peripheral lung cancer involving the pleura and chest wall which can not be resected. (3) Residual tumor after other comprehensive treatment. (4) Focal lung cancer but the patient refused surgical resection. The exclusion criteria were: (1) Multifocal lesions. (2) Lesion close to mediastinum with possible risk of vessel injury. (3) Severe impairment of pulmonary functions, the maximum voluntary ventilation is less than 39%. (4) Repeated cough or dyspnea, can not cooperate with the procedure. (5) Poor systemic conditions, cachexia or bleeding. Totally, 76 lung carcinoma lesions on 66 patients were treated by CT-guided percutaneous conformal cryoablation using 17 G cryoprobes. The maximum diameters of the tumors ranged from 1.5 cm to 1.6 cm. For the tumors with the maximum diameter less than 3.0 cm, they were treated by double-needle clamping cryoablation. For those with the maximum diameter between 3.0 and 5.0 cm, they were treated by multiple-needle conformal cryoablation. For those with the maximum diameter larger than 5.0 cm, they were treated with multiple-needle conformal cyroablation, with the needle distance less than 1.5 cm. All the patients were followed-up 6 to 24 months after the procedure using contrast-enhanced CT to evaluate the tumor size and enhancement. Results: For 18 cases with the maximum diameters less than 3.0 cm, CT scan during the procedure showed that the frozen areas extended beyond the edge of the lesions more than 1.0 cm, the lesion attenuated, narrow-band-like encircled translucency around the lesions and 'target sign' with ground-glass density of the peripheral lung tissue. There was no enhancement during the first 1 st, 3 rd month follow-up, only fibrosis scar in 6 th

  13. Model-based Iterative Reconstruction: Effect on Patient Radiation Dose and Image Quality in Pediatric Body CT

    Science.gov (United States)

    Dillman, Jonathan R.; Goodsitt, Mitchell M.; Christodoulou, Emmanuel G.; Keshavarzi, Nahid; Strouse, Peter J.

    2014-01-01

    Purpose To retrospectively compare image quality and radiation dose between a reduced-dose computed tomographic (CT) protocol that uses model-based iterative reconstruction (MBIR) and a standard-dose CT protocol that uses 30% adaptive statistical iterative reconstruction (ASIR) with filtered back projection. Materials and Methods Institutional review board approval was obtained. Clinical CT images of the chest, abdomen, and pelvis obtained with a reduced-dose protocol were identified. Images were reconstructed with two algorithms: MBIR and 100% ASIR. All subjects had undergone standard-dose CT within the prior year, and the images were reconstructed with 30% ASIR. Reduced- and standard-dose images were evaluated objectively and subjectively. Reduced-dose images were evaluated for lesion detectability. Spatial resolution was assessed in a phantom. Radiation dose was estimated by using volumetric CT dose index (CTDIvol) and calculated size-specific dose estimates (SSDE). A combination of descriptive statistics, analysis of variance, and t tests was used for statistical analysis. Results In the 25 patients who underwent the reduced-dose protocol, mean decrease in CTDIvol was 46% (range, 19%–65%) and mean decrease in SSDE was 44% (range, 19%–64%). Reduced-dose MBIR images had less noise (P > .004). Spatial resolution was superior for reduced-dose MBIR images. Reduced-dose MBIR images were equivalent to standard-dose images for lungs and soft tissues (P > .05) but were inferior for bones (P = .004). Reduced-dose 100% ASIR images were inferior for soft tissues (P ASIR. Conclusion CT performed with a reduced-dose protocol and MBIR is feasible in the pediatric population, and it maintains diagnostic quality. © RSNA, 2013 Online supplemental material is available for this article. PMID:24091359

  14. Lung vessel segmentation in CT images using graph-cuts

    Science.gov (United States)

    Zhai, Zhiwei; Staring, Marius; Stoel, Berend C.

    2016-03-01

    Accurate lung vessel segmentation is an important operation for lung CT analysis. Filters that are based on analyzing the eigenvalues of the Hessian matrix are popular for pulmonary vessel enhancement. However, due to their low response at vessel bifurcations and vessel boundaries, extracting lung vessels by thresholding the vesselness is not sufficiently accurate. Some methods turn to graph-cuts for more accurate segmentation, as it incorporates neighbourhood information. In this work, we propose a new graph-cuts cost function combining appearance and shape, where CT intensity represents appearance and vesselness from a Hessian-based filter represents shape. Due to the amount of voxels in high resolution CT scans, the memory requirement and time consumption for building a graph structure is very high. In order to make the graph representation computationally tractable, those voxels that are considered clearly background are removed from the graph nodes, using a threshold on the vesselness map. The graph structure is then established based on the remaining voxel nodes, source/sink nodes and the neighbourhood relationship of the remaining voxels. Vessels are segmented by minimizing the energy cost function with the graph-cuts optimization framework. We optimized the parameters used in the graph-cuts cost function and evaluated the proposed method with two manually labeled sub-volumes. For independent evaluation, we used 20 CT scans of the VESSEL12 challenge. The evaluation results of the sub-volume data show that the proposed method produced a more accurate vessel segmentation compared to the previous methods, with F1 score 0.76 and 0.69. In the VESSEL12 data-set, our method obtained a competitive performance with an area under the ROC curve of 0.975, especially among the binary submissions.

  15. Patient doses in chest CT examinations: Comparison of various CT scanners

    Directory of Open Access Journals (Sweden)

    Božović Predrag

    2013-01-01

    Full Text Available This paper presents results from study on patient exposure level in chest CT examinations. CT scanners used in this study were various Siemens and General Electric (GE models. Data on patient doses were collected for adult and pediatric patients. Doses measured for adult patients were lower then those determined as Diagnostic Reference Levels (DRL for Europe, while doses for pediatric patients were similar to those found in published data. As for the manufactures, slightly higher doses were measured on GE devices, both for adult and pediatric patients.

  16. MO-DE-207A-09: Low-Dose CT Image Reconstruction Via Learning From Different Patient Normal-Dose Images

    Energy Technology Data Exchange (ETDEWEB)

    Han, H; Xing, L [Stanford University, Palo Alto, CA (United States); Liang, Z [Stony Brook University, Stony Brook, NY (United States)

    2016-06-15

    Purpose: To investigate a novel low-dose CT (LdCT) image reconstruction strategy for lung CT imaging in radiation therapy. Methods: The proposed approach consists of four steps: (1) use the traditional filtered back-projection (FBP) method to reconstruct the LdCT image; (2) calculate structure similarity (SSIM) index between the FBP-reconstructed LdCT image and a set of normal-dose CT (NdCT) images, and select the NdCT image with the highest SSIM as the learning source; (3) segment the NdCT source image into lung and outside tissue regions via simple thresholding, and adopt multiple linear regression to learn high-order Markov random field (MRF) pattern for each tissue region in the NdCT source image; (4) segment the FBP-reconstructed LdCT image into lung and outside regions as well, and apply the learnt MRF prior in each tissue region for statistical iterative reconstruction of the LdCT image following the penalized weighted least squares (PWLS) framework. Quantitative evaluation of the reconstructed images was based on the signal-to-noise ratio (SNR), local binary pattern (LBP) and histogram of oriented gradients (HOG) metrics. Results: It was observed that lung and outside tissue regions have different MRF patterns predicted from the NdCT. Visual inspection showed that our method obviously outperformed the traditional FBP method. Comparing with the region-smoothing PWLS method, our method has, in average, 13% increase in SNR, 15% decrease in LBP difference, and 12% decrease in HOG difference from reference standard for all regions of interest, which indicated the superior performance of the proposed method in terms of image resolution and texture preservation. Conclusion: We proposed a novel LdCT image reconstruction method by learning similar image characteristics from a set of NdCT images, and the to-be-learnt NdCT image does not need to be scans from the same subject. This approach is particularly important for enhancing image quality in radiation therapy.

  17. MO-DE-207A-09: Low-Dose CT Image Reconstruction Via Learning From Different Patient Normal-Dose Images

    International Nuclear Information System (INIS)

    Han, H; Xing, L; Liang, Z

    2016-01-01

    Purpose: To investigate a novel low-dose CT (LdCT) image reconstruction strategy for lung CT imaging in radiation therapy. Methods: The proposed approach consists of four steps: (1) use the traditional filtered back-projection (FBP) method to reconstruct the LdCT image; (2) calculate structure similarity (SSIM) index between the FBP-reconstructed LdCT image and a set of normal-dose CT (NdCT) images, and select the NdCT image with the highest SSIM as the learning source; (3) segment the NdCT source image into lung and outside tissue regions via simple thresholding, and adopt multiple linear regression to learn high-order Markov random field (MRF) pattern for each tissue region in the NdCT source image; (4) segment the FBP-reconstructed LdCT image into lung and outside regions as well, and apply the learnt MRF prior in each tissue region for statistical iterative reconstruction of the LdCT image following the penalized weighted least squares (PWLS) framework. Quantitative evaluation of the reconstructed images was based on the signal-to-noise ratio (SNR), local binary pattern (LBP) and histogram of oriented gradients (HOG) metrics. Results: It was observed that lung and outside tissue regions have different MRF patterns predicted from the NdCT. Visual inspection showed that our method obviously outperformed the traditional FBP method. Comparing with the region-smoothing PWLS method, our method has, in average, 13% increase in SNR, 15% decrease in LBP difference, and 12% decrease in HOG difference from reference standard for all regions of interest, which indicated the superior performance of the proposed method in terms of image resolution and texture preservation. Conclusion: We proposed a novel LdCT image reconstruction method by learning similar image characteristics from a set of NdCT images, and the to-be-learnt NdCT image does not need to be scans from the same subject. This approach is particularly important for enhancing image quality in radiation therapy.

  18. Effect of CT screening on smoking habits at 1-year follow-up in the Danish Lung Cancer Screening Trial (DLCST)

    DEFF Research Database (Denmark)

    Ashraf, H; Tønnesen, P; Holst Pedersen, J

    2008-01-01

    BACKGROUND: The effect of low-dose CT screening for lung cancer on smoking habits has not been reported in large randomised controlled trials. METHODS: This study evaluated the effect on smoking habits of screening with low-dose CT at 1-year follow up in the Danish Lung Cancer Screening Trial...... pack years. Smoking habits were determined at baseline and at annual screening. Smoking status was verified using exhaled carbon monoxide levels. Lung function tests, nicotine dependency and motivation to quit smoking were assessed. Quit rates and relapse rates were determined at 1-year follow...... (DLCST), a 5-year randomised controlled trial comprising 4104 subjects; 2052 subjects received annual low-dose CT scan (CT group) and 2052 received no intervention (control group). Participants were healthy current and former smokers (>4 weeks since smoking cessation) with a tobacco consumption of >20...

  19. WE-AB-207B-05: Correlation of Normal Lung Density Changes with Dose After Stereotactic Body Radiotherapy (SBRT) for Early Stage Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q; Devpura, S; Feghali, K; Liu, C; Ajlouni, M; Movsas, B; Chetty, I [Henry Ford Health System, Detroit, MI (United States)

    2016-06-15

    Purpose: To investigate correlation of normal lung CT density changes with dose accuracy and outcome after SBRT for patients with early stage lung cancer. Methods: Dose distributions for patients originally planned and treated using a 1-D pencil beam-based (PB-1D) dose algorithm were retrospectively recomputed using algorithms: 3-D pencil beam (PB-3D), and model-based Methods: AAA, Acuros XB (AXB), and Monte Carlo (MC). Prescription dose was 12 Gy × 4 fractions. Planning CT images were rigidly registered to the followup CT datasets at 6–9 months after treatment. Corresponding dose distributions were mapped from the planning to followup CT images. Following the method of Palma et al .(1–2), Hounsfield Unit (HU) changes in lung density in individual, 5 Gy, dose bins from 5–45 Gy were assessed in the peri-tumor region, defined as a uniform, 3 cm expansion around the ITV(1). Results: There is a 10–15% displacement of the high dose region (40–45 Gy) with the model-based algorithms, relative to the PB method, due to the electron scattering of dose away from the tumor into normal lung tissue (Fig.1). Consequently, the high-dose lung region falls within the 40–45 Gy dose range, causing an increase in HU change in this region, as predicted by model-based algorithms (Fig.2). The patient with the highest HU change (∼110) had mild radiation pneumonitis, and the patient with HU change of ∼80–90 had shortness of breath. No evidence of pneumonitis was observed for the 3 patients with smaller CT density changes (<50 HU). Changes in CT densities, and dose-response correlation, as computed with model-based algorithms, are in excellent agreement with the findings of Palma et al. (1–2). Conclusion: Dose computed with PB (1D or 3D) algorithms was poorly correlated with clinically relevant CT density changes, as opposed to model-based algorithms. A larger cohort of patients is needed to confirm these results. This work was supported in part by a grant from Varian

  20. China National Lung Cancer Screening Guideline with Low-dose Computed 
Tomography (2018 version

    Directory of Open Access Journals (Sweden)

    Qinghua ZHOU

    2018-02-01

    Full Text Available Background and objective Lung cancer is the leading cause of cancer-related death in China. The results from a randomized controlled trial using annual low-dose computed tomography (LDCT in specific high-risk groups demonstrated a 20% reduction in lung cancer mortality. The aim of tihs study is to establish the China National lung cancer screening guidelines for clinical practice. Methods The China lung cancer early detection and treatment expert group (CLCEDTEG established the China National Lung Cancer Screening Guideline with multidisciplinary representation including 4 thoracic surgeons, 4 thoracic radiologists, 2 medical oncologists, 2 pulmonologists, 2 pathologist, and 2 epidemiologist. Members have engaged in interdisciplinary collaborations regarding lung cancer screening and clinical care of patients with at risk for lung cancer. The expert group reviewed the literature, including screening trials in the United States and Europe and China, and discussed local best clinical practices in the China. A consensus-based guidelines, China National Lung Cancer Screening Guideline (CNLCSG, was recommended by CLCEDTEG appointed by the National Health and Family Planning Commission, based on results of the National Lung Screening Trial, systematic review of evidence related to LDCT screening, and protocol of lung cancer screening program conducted in rural China. Results Annual lung cancer screening with LDCT is recommended for high risk individuals aged 50-74 years who have at least a 20 pack-year smoking history and who currently smoke or have quit within the past five years. Individualized decision making should be conducted before LDCT screening. LDCT screening also represents an opportunity to educate patients as to the health risks of smoking; thus, education should be integrated into the screening process in order to assist smoking cessation. Conclusion A lung cancer screening guideline is recommended for the high-risk population in China

  1. [China National Lung Cancer Screening Guideline with Low-dose Computed 
Tomography (2018 version)].

    Science.gov (United States)

    Zhou, Qinghua; Fan, Yaguang; Wang, Ying; Qiao, Youlin; Wang, Guiqi; Huang, Yunchao; Wang, Xinyun; Wu, Ning; Zhang, Guozheng; Zheng, Xiangpeng; Bu, Hong; Li, Yin; Wei, Sen; Chen, Liang'an; Hu, Chengping; Shi, Yuankai; Sun, Yan

    2018-02-20

    Lung cancer is the leading cause of cancer-related death in China. The results from a randomized controlled trial using annual low-dose computed tomography (LDCT) in specific high-risk groups demonstrated a 20% reduction in lung cancer mortality. The aim of tihs study is to establish the China National lung cancer screening guidelines for clinical practice. The China lung cancer early detection and treatment expert group (CLCEDTEG) established the China National Lung Cancer Screening Guideline with multidisciplinary representation including 4 thoracic surgeons, 4 thoracic radiologists, 2 medical oncologists, 2 pulmonologists, 2 pathologist, and 2 epidemiologist. Members have engaged in interdisciplinary collaborations regarding lung cancer screening and clinical care of patients with at risk for lung cancer. The expert group reviewed the literature, including screening trials in the United States and Europe and China, and discussed local best clinical practices in the China. A consensus-based guidelines, China National Lung Cancer Screening Guideline (CNLCSG), was recommended by CLCEDTEG appointed by the National Health and Family Planning Commission, based on results of the National Lung Screening Trial, systematic review of evidence related to LDCT screening, and protocol of lung cancer screening program conducted in rural China. Annual lung cancer screening with LDCT is recommended for high risk individuals aged 50-74 years who have at least a 20 pack-year smoking history and who currently smoke or have quit within the past five years. Individualized decision making should be conducted before LDCT screening. LDCT screening also represents an opportunity to educate patients as to the health risks of smoking; thus, education should be integrated into the screening process in order to assist smoking cessation. A lung cancer screening guideline is recommended for the high-risk population in China. Additional research , including LDCT combined with biomarkers, is

  2. CT diagnosis of primary lung cancer coexisting with pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Kim, Sun Joo; Kim, Young Sook; Oh, Jae Hee; Kim, Eun Kyoung; Kim, Young Chul

    1992-01-01

    When bronchogenic carcinoma is coexisting with pulmonary tuberculosis, it is difficult to differentiate bronchogenic carcinoma from pulmonary tuberculosis radiographically. Thus, the object of this study is to define differential diagnosis of bronchogenic carcinoma by computed tomography. We analyzed CT scans of 27 patients with radiologic findings of pulmonary tuberculosis and mass of which twelve cases were pulmonary tuberculosis and fifteen cases were primary lung cancer. The location of parenchymal infiltration and the mass was the same in 60%(9/15) of the primary lung cancer in cases and 83%(10/12) of the pulmonary tuberculosis cases. The common location of the mass was the both upper lobes in 92%(11/12) of the pulmonary tuberculosis cases and 53%(8/15) of the primary lung cancer cases. The common locations of the mediastinal lymphadenopathy were 4R, 2R of the pulmonary tuberculosis cases and 4R, 10R of the primary lung cancer cases. In the feature of post enhanced lymph nodes, homogenous increased density was more frequent in primary lung cancer. Measurements of the maximum thickness part of the cavity wall was not a reliable indication of malignancy

  3. Prospective evaluation of the radiologist's hand dose in CT-guided interventions; Prospektive Evaluation der Handdosis des Radiologen im Rahmen von CT-gestuetzten Interventionen

    Energy Technology Data Exchange (ETDEWEB)

    Rogits, B.; Jungnickel, K.; Loewenthal, D.; Dudeck, O.; Pech, M.; Ricke, J. [Magdeburg Univ. (Germany). Radiology and Nuclear Medicine; Kropf, S. [Magdeburg Univ. (Germany). Dept. of Biometry and Medical Informatics; Nekolla, E.A. [The Federal Office for Radiation Protection, Neuherberg (Germany). Dept. of Radiation Protection and Health; Wieners, G. [Charite CVC, Berlin (Germany). Dept. of Radiology

    2013-11-15

    Purpose: Assessment of radiologist's hand dose in CT-guided interventions and determination of influencing factors. Materials and Methods: The following CT-guided interventions were included: Core biopsy, drainage, periradicular therapy, and celiac plexus neurolysis. The hand dose was measured with an immediately readable dosimeter, the EDD-30 (Unfors, Sweden). The default parameters for CT fluoroscopy were 120 kV, 90 mA and a 4 mm slice thickness. All interventions were performed on a 16-slice CT unit (Aquilion 16 Toshiba, Japan). The tumor size, degree of difficulty (1 - 3), level of experience and device parameters (mAs, dose-length product, scan time) were documented. Results: 138 CT-guided interventions (biopsy n = 99, drainage n = 23, pain therapy n = 16) at different locations (lung n = 41, retroperitoneum n = 53, liver n = 25, spine n = 19) were included. The lesion size was 4 - 240 mm (median: 23 mm). The fluoroscopy time per intervention was 4.6 - 140.2 s (median: 24.2 s). The measured hand dose ranged from 0.001 - 3.02 mSv (median: 0.22 mSv). The median hand dose for lung puncture (n = 41) was slightly higher (median: 0.32 mSv, p = 0.01) compared to that for the liver, retroperitoneum and other. Besides physical influencing factors, the degree of difficulty (p = 0.001) and summed puncture depth (p = 0.004) correlated significantly with the hand dose. Conclusion: The median hand dose for different CT-guided interventions was 0.22 mSv. Therefore, the annual hand dose limit would normally only be reached with about 2000 interventions. (orig.)

  4. Quantitative evaluation of emphysematous changes in the lung by computed tomography (CT)

    International Nuclear Information System (INIS)

    Kitahara, Yoshinari; Hirayama, Takanobu; Hiratsuka, Toshihiko; Tanaka, Yasushi; Takamoto, Masahiro; Ishibashi, Tsuneo; Shinoda, Atsushi

    1987-01-01

    The present studies were undertaken to quantitatively evaluate emphysematous changes in the lung by CT scan. CT scans were made at inspiration and expiration at three levels (base, mid thorax and apex). Low density lesion ratio (LL %) was measured as the proportion of the area under -950 Housfield Unit in each lung field at expiration. Each value of LL % was determined in 6 lung fields (both lung fields at three levels). The LL % was calculated from the mean of these six values. The results suggest that LL % of the emphysematous lungs shows significant elevation of the values compared with those of normal lungs and lungs with bronchial asthma. (author)

  5. Predictors of pneumothorax after CT-guided transthoracic needle lung biopsy: the role of quantitative CT

    International Nuclear Information System (INIS)

    Chami, H.A.; Faraj, W.; Yehia, Z.A.; Badour, S.A.; Sawan, P.; Rebeiz, K.; Safa, R.; Saade, C.; Ghandour, B.; Shamseddine, A.; Mukherji, D.; Haydar, A.A.

    2015-01-01

    Aim: To evaluate the association of quantitative computed tomography (CT) measures of emphysema with the occurrence of pneumothorax after CT-guided needle lung biopsy (NLB) accounting for other risk factors. Materials and methods: One hundred and sixty-three CT-guided NLBs performed between 2008 and 2013 with available complete chest CT within 30 days were reviewed for the occurrence of post-procedure pneumothorax. Percent emphysema was determined quantitatively as the percentage of lung voxels below −950 HU on chest CT images using automated software. Multivariable regression was used to assess the association of percent emphysema volume with the occurrence of post-procedure pneumothorax. The association of percent emphysema volume with the pneumothorax size and need for chest tube placement after NLB was also explored. Results: Percent emphysema was significantly associated with the incidence of post-NLB pneumothorax (OR=1.10 95% confidence interval: 1.01–1.15; p=0.03) adjusting for lower-lobe lesion location, needle path length, lesion size, number of passes, and pleural needle trajectory angle. Percent emphysema was not associated with the size of the pneumothorax, nor the need for chest tube placement after NLB. Conclusion: Percent emphysema determined quantitatively from chest CT is a significant predictor of post-NLB pneumothorax. - Highlights: • Examine the association between quantitative emphysema measures & post NLB pneumothorax. • The risk of post-NLB pneumothorax increases with every unit increase in percent emphysema. • Percent emphysema is a significant predictor of pneumothorax post transthoracic NLB. • Quantitative analysis of chest CT offers clinicians' objective measures to assess pneumothorax risk.

  6. Ambient dose measurement in some CT departments in Khartoum State

    International Nuclear Information System (INIS)

    Mohammed, S. A. H.

    2012-09-01

    Computerized Tomography (CT) is now one of the most important radiological examinations world wide.The frequency of CT examinations is increasing rapidly from 2% of all radiological examinations in some countries a decade age to 10-15% now. During the imaging procedure, staff may expose to a significant dose. Therefore, ambient dose measurement is important in the shortage of regular personal monitoring in sudan. This study intended to evaluate the ambient dose at some CT departments (Medical Military hospital, Alamal National Hospital, Elnelin Diagnostic Center and Modern Medical Centre). These departments were equipped with daul, 16 and 64 multi detector CT machines. A survey meter (Radios) was used to measure ambient doses in three locations: Doors, Control Rooms and Adjacent Rooms. The ambient dose equivalent (scatter dose) was measured at various distances from the isocenter of the CT unit at various angles to establish isodose cartography. The mean and range of radiation at control room is 10.00-0.20 and mean (7.05μSv/hr,) reception 1.0-0 (0.40) and doors 4.00-100.00 (73.5) for height 1 meter above the ground. For height 2 meters at control room 0-10.00 (6,75), reception 0-90.00 (30) at door 9.00-90.00 (49.50). This study confirms that low levels of radiation dose are received by staff during CT imaging and these levels are within safe limits as prescribed by the national and international regulations. (Author)

  7. Radiofrequency ablation of lung and liver lesions using CT fluoroscopy

    International Nuclear Information System (INIS)

    Chai, A.; Glenn, D.

    2002-01-01

    Full text: Tumour ablation with radiofrequency (RF) energy is a relatively new procedure for the treatment of focal malignant disease. At our institution this is currently being used in the treatment of certain liver and lung lesions with the patients involved being enrolled in clinical trials. The poster describes the technique used at our institution for the placement of the radiofrequency ablation electrode using CT fluoroscopy. Criteria for patient selection are included. Complications from the procedure are described, as well as follow up appearances and results. Our results from the treatment of primary and secondary lesions in the liver correlate well with published literature. Treatment is still not as successful as surgical resection but there is significantly less morbidity. Where this method may be appropriate is when the patient is not a candidate for surgical resection. The treatment of colorectal metastases in the lung shows early promise as a possible second line treatment (as for liver) where the patient is not a candidate for surgery. Preliminary results are soon to be published in conjunction with the Department of Surgery at our institution. RF Electrode placement using CT Fluoroscopy is performed at our institution. While still at its early stages, RF Ablation shows promise as a possible second line treatment (with other adjuvant therapy) for the management of focal malignant disease in the lung and liver. Copyright (2002) Blackwell Science Pty Ltd

  8. Comparison of low- and ultralow-dose computed tomography protocols for quantitative lung and airway assessment.

    Science.gov (United States)

    Hammond, Emily; Sloan, Chelsea; Newell, John D; Sieren, Jered P; Saylor, Melissa; Vidal, Craig; Hogue, Shayna; De Stefano, Frank; Sieren, Alexa; Hoffman, Eric A; Sieren, Jessica C

    2017-09-01

    Quantitative computed tomography (CT) measures are increasingly being developed and used to characterize lung disease. With recent advances in CT technologies, we sought to evaluate the quantitative accuracy of lung imaging at low- and ultralow-radiation doses with the use of iterative reconstruction (IR), tube current modulation (TCM), and spectral shaping. We investigated the effect of five independent CT protocols reconstructed with IR on quantitative airway measures and global lung measures using an in vivo large animal model as a human subject surrogate. A control protocol was chosen (NIH-SPIROMICS + TCM) and five independent protocols investigating TCM, low- and ultralow-radiation dose, and spectral shaping. For all scans, quantitative global parenchymal measurements (mean, median and standard deviation of the parenchymal HU, along with measures of emphysema) and global airway measurements (number of segmented airways and pi10) were generated. In addition, selected individual airway measurements (minor and major inner diameter, wall thickness, inner and outer area, inner and outer perimeter, wall area fraction, and inner equivalent circle diameter) were evaluated. Comparisons were made between control and target protocols using difference and repeatability measures. Estimated CT volume dose index (CTDIvol) across all protocols ranged from 7.32 mGy to 0.32 mGy. Low- and ultralow-dose protocols required more manual editing and resolved fewer airway branches; yet, comparable pi10 whole lung measures were observed across all protocols. Similar trends in acquired parenchymal and airway measurements were observed across all protocols, with increased measurement differences using the ultralow-dose protocols. However, for small airways (1.9 ± 0.2 mm) and medium airways (5.7 ± 0.4 mm), the measurement differences across all protocols were comparable to the control protocol repeatability across breath holds. Diameters, wall thickness, wall area fraction

  9. CT analysis of lung cancer and coexistent emphysema

    International Nuclear Information System (INIS)

    Noh, Kyung Hee; Chung, Myung Hee; Sung, Mi Sook; Yoo, Won Jong; Son, Kyung Myung; Son, Jung Min; Park, Seog Hee

    2004-01-01

    To evaluate the relation of the location and cell type of lung cancer to the location and degree in coexistent emphysema on high-resolution computed tomography (HRCT) scans. Ninety-eight of 209 lung cancer patients having HRCT scans were retrospectively analyzed to assess the total lung emphysema and peritumoral regional emphysema. Single and primary lung cancers were included. The clinical data, including sex, age, smoking history and the pathologic cancer subtype, were recorded to correlate with the HRCT findings. The lobar distribution, central-peripheral predominance, surrounding parenchymal abnormality for cancer, cephalocaudal predominance, and subtype for emphysema were analyzed on HRCT. Using a CT scoring method, we scored the whole lung emphysema and peritumoral emphysema, and correlated the grading of emphysema with pulmonary functional values. Sixty-nine of 98 patients with lung cancer (71%) had emphysema. Lung cancer with emphysema was significantly higher in men than in women, and was significantly related to smoking. The mean age of cancer patients without emphysema was significantly lower than that of cancer patients with emphysema (68 yrs vs. 61 yrs, p= 0.0006). Emphysema of grade I (0-25%) was found in 52 cases, grade II (25-50%) in 15, and grade III (50-75%) in 2. Total emphysema score was paralleled to peritumoral emphysema score in 64.3%, while the remaining patients had a higher peritumoral emphysema score (grade II or III) than total emphysema score (grade 0 or I). There was no statistical correlation in the developmental location between the emphysema and the lung cancer (significant correlation was only noted in grade II group of total emphysema score). The incidence of non-small cell carcinoma tended to be higher than that of small cell carcinoma in the two groups. The possibility of lung cancer in patients with pulmonary nodule, coexisting emphysema, and especially in elderly patients having a history of smoking must be clarified on HRCT

  10. Investigation of lung nodule detectability in low-dose 320-slice computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, J. D.; Paul, N. S.; Siewerdsen, J. H. [Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Department of Medical Imaging, Toronto General Hospital, Toronto, Ontario M5G 2C6 (Canada); Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario M5G 2M9 (Canada) and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

    2009-05-15

    Low-dose imaging protocols in chest CT are important in the screening and surveillance of suspicious and indeterminate lung nodules. Techniques that maintain nodule detectability yet permit dose reduction, particularly for large body habitus, were investigated. The objective of this study was to determine the extent to which radiation dose can be minimized while maintaining diagnostic performance through knowledgeable selection of reconstruction techniques. A 320-slice volumetric CT scanner (Aquilion ONE, Toshiba Medical Systems) was used to scan an anthropomorphic phantom at doses ranging from {approx}0.1 mGy up to that typical of low-dose CT (LDCT, {approx}5 mGy) and diagnostic CT ({approx}10 mGy). Radiation dose was measured via Farmer chamber and MOSFET dosimetry. The phantom presented simulated nodules of varying size and contrast within a heterogeneous background, and chest thickness was varied through addition of tissue-equivalent bolus about the chest. Detectability of a small solid lung nodule (3.2 mm diameter, -37 HU, typically the smallest nodule of clinical significance in screening and surveillance) was evaluated as a function of dose, patient size, reconstruction filter, and slice thickness by means of nine-alternative forced-choice (9AFC) observer tests to quantify nodule detectability. For a given reconstruction filter, nodule detectability decreased sharply below a threshold dose level due to increased image noise, especially for large body size. However, nodule detectability could be maintained at lower doses through knowledgeable selection of (smoother) reconstruction filters. For large body habitus, optimal filter selection reduced the dose required for nodule detection by up to a factor of {approx}3 (from {approx}3.3 mGy for sharp filters to {approx}1.0 mGy for the optimal filter). The results indicate that radiation dose can be reduced below the current low-dose (5 mGy) and ultralow-dose (1 mGy) levels with knowledgeable selection of

  11. Converging stereotactic radiotherapy using kilovoltage X-rays: experimental irradiation of normal rabbit lung and dose-volume analysis with Monte Carlo simulation.

    Science.gov (United States)

    Kawase, Takatsugu; Kunieda, Etsuo; Deloar, Hossain M; Tsunoo, Takanori; Seki, Satoshi; Oku, Yohei; Saitoh, Hidetoshi; Saito, Kimiaki; Ogawa, Eileen N; Ishizaka, Akitoshi; Kameyama, Kaori; Kubo, Atsushi

    2009-10-01

    To validate the feasibility of developing a radiotherapy unit with kilovoltage X-rays through actual irradiation of live rabbit lungs, and to explore the practical issues anticipated in future clinical application to humans through Monte Carlo dose simulation. A converging stereotactic irradiation unit was developed, consisting of a modified diagnostic computed tomography (CT) scanner. A tiny cylindrical volume in 13 normal rabbit lungs was individually irradiated with single fractional absorbed doses of 15, 30, 45, and 60 Gy. Observational CT scanning of the whole lung was performed every 2 weeks for 30 weeks after irradiation. After 30 weeks, histopathologic specimens of the lungs were examined. Dose distribution was simulated using the Monte Carlo method, and dose-volume histograms were calculated according to the data. A trial estimation of the effect of respiratory movement on dose distribution was made. A localized hypodense change and subsequent reticular opacity around the planning target volume (PTV) were observed in CT images of rabbit lungs. Dose-volume histograms of the PTVs and organs at risk showed a focused dose distribution to the target and sufficient dose lowering in the organs at risk. Our estimate of the dose distribution, taking respiratory movement into account, revealed dose reduction in the PTV. A converging stereotactic irradiation unit using kilovoltage X-rays was able to generate a focused radiobiologic reaction in rabbit lungs. Dose-volume histogram analysis and estimated sagittal dose distribution, considering respiratory movement, clarified the characteristics of the irradiation received from this type of unit.

  12. Chest CT using spectral filtration: radiation dose, image quality, and spectrum of clinical utility

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Franziska M.; Johnson, Thorsten R.C.; Sommer, Wieland H.; Thierfelder, Kolja M.; Meinel, Felix G. [University Hospital Munich, Institute for Clinical Radiology, Munich (Germany)

    2015-06-01

    To determine the radiation dose, image quality, and clinical utility of non-enhanced chest CT with spectral filtration. We retrospectively analysed 25 non-contrast chest CT examinations acquired with spectral filtration (tin-filtered Sn100 kVp spectrum) compared to 25 examinations acquired without spectral filtration (120 kV). Radiation metrics were compared. Image noise was measured. Contrast-to-noise-ratio (CNR) and figure-of-merit (FOM) were calculated. Diagnostic confidence for the assessment of various thoracic pathologies was rated by two independent readers. Effective chest diameters were comparable between groups (P = 0.613). In spectral filtration CT, median CTDI{sub vol}, DLP, and size-specific dose estimate (SSDE) were reduced (0.46 vs. 4.3 mGy, 16 vs. 141 mGy*cm, and 0.65 vs. 5.9 mGy, all P < 0.001). Spectral filtration CT had higher image noise (21.3 vs. 13.2 HU, P < 0.001) and lower CNR (47.2 vs. 75.3, P < 0.001), but was more dose-efficient (FOM 10,659 vs. 2,231/mSv, P < 0.001). Diagnostic confidence for parenchymal lung disease and osseous pathologies was lower with spectral filtration CT, but no significant difference was found for pleural pathologies, pulmonary nodules, or pneumonia. Non-contrast chest CT using spectral filtration appears to be sufficient for the assessment of a considerable spectrum of thoracic pathologies, while providing superior dose efficiency, allowing for substantial radiation dose reduction. (orig.)

  13. CT Densitometry of the Lung in Healthy Nonsmokers with Normal Pulmonary Function

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Tack Sun; Chae, Eun Jin; Seo, Joon Beom; Jung, Young Ju; Oh, Yeon Mok; Lee, Sang Do [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2012-09-15

    To investigate the upper normal limit of low attenuation area in healthy nonsmokers. A total of 36 nonsmokers with normal pulmonary function test underwent a CT scan. Six thresholds (-980 --930 HU) on inspiration CT and two thresholds (-950 and -910 HU) on expiration CT were used for obtaining low attenuation area. The mean lung density was obtained on both inspiration CT and expiration CT. Descriptive statistics of low attenuation area and the mean lung density, evaluation of difference of low attenuation area and the mean lung density in both sex and age groups, analysis of the relationship between demographic information and CT parameters were performed. Upper normal limit for low attenuation area was 12.96% on inspiration CT (-950 HU) and 9.48% on expiration CT (-910 HU). Upper normal limit for the mean lung density was -837.58 HU on inspiration CT and 686.82 HU on expiration CT. Low attenuation area and the mean lung density showed no significant differences in both sex and age groups. Body mass index (BMI) was negatively correlated with low attenuation area on inspiration CT (-950 HU, r = -0.398, p = 0.016) and positively correlated with the mean lung density on inspiration CT (r 0.539, p = 0.001) and expiration CT (r = 0.432, p = 0.009). Age and body surface area were not correlated with low attenuation area or the mean lung density. Low attenuation area on CT densitometry of the lung could be found in healthy nonsmokers with normal pulmonary function, and showed negative association with BMI. Reference values, such as range and upper normal limit for low attenuation area in healthy subjects could be helpful in quantitative analysis and follow up of early emphysema, using CT densitometry of the lung.

  14. Usefulness evaluation of low-dose for emphysema: Compared with high-resolution CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Jeong [Dept. of Radiological Technology, Daejeon Health Institute of Technology, Daejeon (Korea, Republic of)

    2016-09-15

    The purpose of this study was to evaluate the usefulness of low-dose CT (LDCT) for emphysema compared with high-resolution CT (HRCT). Measurements of radiation dose and noise were repeated 3 times in same exposure condition which was similar with obtaining HRCT and LDCT images. We analysed reading results of 146 subjects. Six images per participants selected for emphysema grading. Emphysema was graded for all 6 zones on the left and right sides of the lungs by the consensus reading of two chest radiologists using a 4-point scale. Between the HRCT and LDCT images, diagnostic differences and agreements for emphysema were analyzed by McNemar's and unweighted kappa tests, and radiation doses and noise by a Mann-Whitney U-test, using the SPSS 19.0 program. Radiation dose from HRCT was significantly higher than that of LDCT, but the noise was significantly lower in HRCT than in LDCT. Diagnostic agreement for emphysema between HRCT and LDCT images was excellent (k-value=0.88). Emphysema grading scores were not significantly different between HRCT and LDCT images for all six lung zones. Emphysema grading scores from LDCT images were significantly correlated with increased scores on HRCT images (r=0.599, p < 0.001). Considering the tradeoff between radiation dose and image noise, LDCT could be used as the gold standard method instead of HRCT for emphysema detection and grading.

  15. Detecting airway remodeling in COPD and emphysema using low-dose CT imaging

    Science.gov (United States)

    Rudyanto, R.; Ceresa, M.; Muñoz-Barrutia, A.; Ortiz-de-Solorzano, C.

    2012-03-01

    In this study, we quantitatively characterize lung airway remodeling caused by smoking-related emphysema and Chronic Obstructive Pulmonary Disease (COPD), in low-dose CT scans. To that end, we established three groups of individuals: subjects with COPD (n=35), subjects with emphysema (n=38) and healthy smokers (n=28). All individuals underwent a low-dose CT scan, and the images were analyzed as described next. First the lung airways were segmented using a fast marching method and labeled according to its generation. Along each airway segment, cross-section images were resampled orthogonal to the airway axis. Next 128 rays were cast from the center of the airway lumen in each crosssection slice. Finally, we used an integral-based method, to measure lumen radius, wall thickness, mean wall percentage and mean peak wall attenuation on every cast ray. Our analysis shows that both the mean global wall thickness and the lumen radius of the airways of both COPD and emphysema groups were significantly different from those of the healthy group. In addition, the wall thickness change starts at the 3rd airway generation in the COPD patients compared with emphysema patients, who display the first significant changes starting in the 2nd generation. In conclusion, it is shown that airway remodeling happens in individuals suffering from either COPD or emphysema, with some local difference between both groups, and that we are able to detect and accurately quantify this process using images of low-dose CT scans.

  16. Radiation dose in cardiac SPECT/CT: An estimation of SSDE and effective dose

    International Nuclear Information System (INIS)

    Abdollahi, Hamid; Shiri, Isaac; Salimi, Yazdan; Sarebani, Maghsoud; Mehdinia, Reza; Deevband, Mohammad Reza; Mahdavi, Seied Rabi; Sohrabi, Ahmad; Bitarafan-Rajabi, Ahmad

    2016-01-01

    Aims: The dose levels for Computed Tomography (CT) localization and attenuation correction of Single Photon Emission Computed Tomography (SPECT) are limited and reported as Volume Computed Tomography Dose Index (CTDIvol) and Dose-Length Product (DLP). This work presents CT dose estimation from Cardiac SPECT/CT based on new American Association of Physicists in Medicine (AAPM) Size Specific Dose Estimation (SSDE) parameter, effective dose, organ doses and also emission dose from nuclear issue. Material and methods: Myocardial perfusion SPECT/CT for 509 patients was included in the study. SSDE, effective dose and organ dose were calculated using AAPM guideline and Impact-Dose software. Data were analyzed using R and SPSS statistical software. Spearman-Pearson correlation test and linear regression models were used for finding correlations and relationships among parameters. Results: The mean CTDIvol was 1.34 mGy ± 0.19 and the mean SSDE was 1.7 mGy ± 0.16. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The spearman test showed that correlation between body size and organ doses is significant except thyroid and red bone marrow. CTDIvol was strongly dependent on patient size, but SSDE was not. Emission dose was strongly dependent on patient weight, but its dependency was lower to effective diameter. Conclusion: The dose parameters including CTDIvol, DLP, SSDE, effective dose values reported here are very low and below the reference level. This data suggest that appropriate CT acquisition parameters in SPECT/CT localization and attenuation correction are very beneficial for patients and lowering cancer risks.

  17. Radiation dose in cardiac SPECT/CT: An estimation of SSDE and effective dose

    Energy Technology Data Exchange (ETDEWEB)

    Abdollahi, Hamid, E-mail: Hamid_rbp@yahoo.com [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shiri, Isaac [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Salimi, Yazdan [Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sarebani, Maghsoud; Mehdinia, Reza [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Deevband, Mohammad Reza [Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Mahdavi, Seied Rabi [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Radiation Biology Research Center, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sohrabi, Ahmad [Department of Biostatistics, School of Public Health, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Bitarafan-Rajabi, Ahmad, E-mail: bitarafan@hotmail.com [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Department of Nuclear Medicine, Rajaei Cardiovascular, Medical and Research Center, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2016-12-15

    Aims: The dose levels for Computed Tomography (CT) localization and attenuation correction of Single Photon Emission Computed Tomography (SPECT) are limited and reported as Volume Computed Tomography Dose Index (CTDIvol) and Dose-Length Product (DLP). This work presents CT dose estimation from Cardiac SPECT/CT based on new American Association of Physicists in Medicine (AAPM) Size Specific Dose Estimation (SSDE) parameter, effective dose, organ doses and also emission dose from nuclear issue. Material and methods: Myocardial perfusion SPECT/CT for 509 patients was included in the study. SSDE, effective dose and organ dose were calculated using AAPM guideline and Impact-Dose software. Data were analyzed using R and SPSS statistical software. Spearman-Pearson correlation test and linear regression models were used for finding correlations and relationships among parameters. Results: The mean CTDIvol was 1.34 mGy ± 0.19 and the mean SSDE was 1.7 mGy ± 0.16. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The spearman test showed that correlation between body size and organ doses is significant except thyroid and red bone marrow. CTDIvol was strongly dependent on patient size, but SSDE was not. Emission dose was strongly dependent on patient weight, but its dependency was lower to effective diameter. Conclusion: The dose parameters including CTDIvol, DLP, SSDE, effective dose values reported here are very low and below the reference level. This data suggest that appropriate CT acquisition parameters in SPECT/CT localization and attenuation correction are very beneficial for patients and lowering cancer risks.

  18. CT evaluation of cavitary lung lesions: focused on lung cancer, tuberculosis and abscess

    International Nuclear Information System (INIS)

    Lee, Young Rahn; Kim, Myung Gyu; Kang, Eun Young; Suh, Won Hyuck

    1992-01-01

    Differential diagnosis of cavitary lung lesions is frequently problematic. We studied 35 patients with cavitary lung lesions, consisting of lung cancer (17 patients), pulmonary tuberculosis (11 patients), and lung abscess (7 patients). We analysed CT scans in terms of irregularities of the cavity wall, maximum wall thickness, the presence of air-fluid level, location of the cavity within the mass, number of cavities within the mass, size of the cavity and the presence of calcification within the mass. Cancer cavity showed irregular inner (100%) and outer margins (100%), and thick wall (mean, 1.94 cm), eccentrical location (94%) and multiplicity within a mass (38%). Tuberculous cavity showed smooth inner (56%) and irregular outer margins (75%), thin wall (mean 0.96 cm), central location (62%), and multiplicity in one patient (36%). Abscess cavity showed irregular inner (57%) and outer margins (91%), relatively thin wall (mean 1.0 cm), central location (57%), and air-fluid level (86%). CT scan could differentiate malignant lesions from benign condition such as tuberculosis and lung abscess by observing characteristics of the cavities

  19. CT evaluation of cavitary lung lesions: focused on lung cancer, tuberculosis and abscess

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Rahn; Kim, Myung Gyu; Kang, Eun Young; Suh, Won Hyuck [College of Medicine, Korea University, Seoul (Korea, Republic of)

    1992-11-15

    Differential diagnosis of cavitary lung lesions is frequently problematic. We studied 35 patients with cavitary lung lesions, consisting of lung cancer (17 patients), pulmonary tuberculosis (11 patients), and lung abscess (7 patients). We analysed CT scans in terms of irregularities of the cavity wall, maximum wall thickness, the presence of air-fluid level, location of the cavity within the mass, number of cavities within the mass, size of the cavity and the presence of calcification within the mass. Cancer cavity showed irregular inner (100%) and outer margins (100%), and thick wall (mean, 1.94 cm), eccentrical location (94%) and multiplicity within a mass (38%). Tuberculous cavity showed smooth inner (56%) and irregular outer margins (75%), thin wall (mean 0.96 cm), central location (62%), and multiplicity in one patient (36%). Abscess cavity showed irregular inner (57%) and outer margins (91%), relatively thin wall (mean 1.0 cm), central location (57%), and air-fluid level (86%). CT scan could differentiate malignant lesions from benign condition such as tuberculosis and lung abscess by observing characteristics of the cavities.

  20. Automated lung volumetry from routine thoracic CT scans: how reliable is the result?

    Science.gov (United States)

    Haas, Matthias; Hamm, Bernd; Niehues, Stefan M

    2014-05-01

    Today, lung volumes can be easily calculated from chest computed tomography (CT) scans. Modern postprocessing workstations allow automated volume measurement of data sets acquired. However, there are challenges in the use of lung volume as an indicator of pulmonary disease when it is obtained from routine CT. Intra-individual variation and methodologic aspects have to be considered. Our goal was to assess the reliability of volumetric measurements in routine CT lung scans. Forty adult cancer patients whose lungs were unaffected by the disease underwent routine chest CT scans in 3-month intervals, resulting in a total number of 302 chest CT scans. Lung volume was calculated by automatic volumetry software. On average of 7.2 CT scans were successfully evaluable per patient (range 2-15). Intra-individual changes were assessed. In the set of patients investigated, lung volume was approximately normally distributed, with a mean of 5283 cm(3) (standard deviation = 947 cm(3), skewness = -0.34, and curtosis = 0.16). Between different scans in one and the same patient the median intra-individual standard deviation in lung volume was 853 cm(3) (16% of the mean lung volume). Automatic lung segmentation of routine chest CT scans allows a technically stable estimation of lung volume. However, substantial intra-individual variations have to be considered. A median intra-individual deviation of 16% in lung volume between different routine scans was found. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  1. Additional value of PET-CT in the staging of lung cancer: comparison with CT alone, PET alone and visual correlation of PET and CT

    International Nuclear Information System (INIS)

    Wever, W. de; Marchal, G.; Bogaert, J.; Verschakelen, J.A.; Ceyssens, S.; Mortelmans, L.; Stroobants, S.

    2007-01-01

    Integrated positron emission tomography (PET) and computed tomography (CT) is a new imaging modality offering anatomic and metabolic information. The purpose was to evaluate retrospectively the accuracy of integrated PET-CT in the staging of a suggestive lung lesion, comparing this with the accuracy of CT alone, PET alone and visually correlated PET-CT. Fifty patients undergoing integrated PET-CT for staging of a suggestive lung lesion were studied. Their tumor, node, metastasis (TNM) statuses were determined with CT, PET, visually correlated PET-CT and integrated PET-CT. These TNM stages were compared with the surgical TNM status. Integrated PET-CT was the most accurate imaging technique in the assessment of the TNM status. Integrated PET-CT predicted correctly the T status, N status, M status and TNM status in, respectively, 86%, 80%, 98%, 70% versus 68%, 66%,88%, 46% with CT, 46%, 70%, 96%, 30% with PET and 72%, 68%, 96%, 54% with visually correlated PET-CT. T status and N status were overstaged, respectively, in 8% and 16% with integrated PET-CT, in 20% and 28% with CT, in 16% and 20% with PET, in 12% and 20% with visually correlated PET-CT and understaged in 6% and 4% with integrated PET-CT, versus 12% and 6% with CT, 38% and 10% with PET and 12% with visually correlated PET-CT. Integrated PET-CT improves the staging of lung cancer through a better anatomic localization and characterization of lesions and is superior to CT alone and PET alone. If this technique is not available, visual correlation of PET and CT can be a valuable alternative. (orig.)

  2. Evaluation of dose according to the volume and respiratory range during SBRT in lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Deuk Hee [Dept. of Radiation Oncology, Busan Paik Hospital, Inje University, Busan (Korea, Republic of); Park, Eun Tae; Kim, Jung Hoon; Kang, Se Seik [Dept. of Radiological Science, College of Health Sciences, Catholic University of Pusan, Busan (Korea, Republic of)

    2016-09-15

    Stereotactic body radiotherapy is effective technic in radiotherapy for low stage lung cancer. But lung cancer is affected by respiratory so accurately concentrate high dose to the target is very difficult. In this study, evaluated the target volume according to how to take the image. And evaluated the dose by photoluminescence glass dosimeter according to how to contour the volume and respiratory range. As a result, evaluated the 4D CT volume was 10.4 cm{sup 3} which was closest value of real size target. And in dose case is internal target volume dose was 10.82, 16.88, 21.90 Gy when prescribed dose was 10, 15, 20 Gy and it was the highest dose. Respiratory gated radiotherapy dose was more higher than internal target volume. But it made little difference by respiratory range. Therefore, when moving cancer treatment, acquiring image by 4D CT, contouring internal target volume and respiratory gated radiotherapy technic would be the best way.

  3. Evaluation of dose according to the volume and respiratory range during SBRT in lung cancer

    International Nuclear Information System (INIS)

    Lee, Deuk Hee; Park, Eun Tae; Kim, Jung Hoon; Kang, Se Seik

    2016-01-01

    Stereotactic body radiotherapy is effective technic in radiotherapy for low stage lung cancer. But lung cancer is affected by respiratory so accurately concentrate high dose to the target is very difficult. In this study, evaluated the target volume according to how to take the image. And evaluated the dose by photoluminescence glass dosimeter according to how to contour the volume and respiratory range. As a result, evaluated the 4D CT volume was 10.4 cm 3 which was closest value of real size target. And in dose case is internal target volume dose was 10.82, 16.88, 21.90 Gy when prescribed dose was 10, 15, 20 Gy and it was the highest dose. Respiratory gated radiotherapy dose was more higher than internal target volume. But it made little difference by respiratory range. Therefore, when moving cancer treatment, acquiring image by 4D CT, contouring internal target volume and respiratory gated radiotherapy technic would be the best way

  4. SU-F-I-38: Patient Organ Specific Dose Assessment in Coronary CT Angiograph Using Voxellaized Volume Dose Index in Monte Carlo Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Fallal, Mohammadi Gh.; Riyahi, Alam N.; Graily, Gh. [Tehran University of Medical Scienced(TUMS), School of Medicine, Department of Nedical Physics and Biomedical Engineering, Tehran (Iran, Islamic Republic of); Paydar, R. [Iran University of Medical Sciences(IUMS), Allied Medicine Faculty, Department of radiation Sciences, Tehran (Iran, Islamic Republic of)

    2016-06-15

    Purpose: Clinical use of multi detector computed tomography(MDCT) in diagnosis of diseases due to high speed in data acquisition and high spatial resolution is significantly increased. Regarding to the high radiation dose in CT and necessity of patient specific radiation risk assessment, the adoption of new method in the calculation of organ dose is completely required and necessary. In this study by introducing a conversion factor, patient organ dose in thorax region based on CT image data using MC system was calculated. Methods: The geometry of x-ray tube, inherent filter, bow tie filter and collimator were designed using EGSnrc/BEAMnrc MC-system component modules according to GE-Light-speed 64-slices CT-scanner geometry. CT-scan image of patient thorax as a specific phantom was voxellised with 6.25mm3 in voxel and 64×64×20 matrix size. Dose to thorax organ include esophagus, lung, heart, breast, ribs, muscle, spine, spinal cord with imaging technical condition of prospectively-gated-coronary CT-Angiography(PGT) as a step and shoot method, were calculated. Irradiation of patient specific phantom was performed using a dedicated MC-code as DOSXYZnrc with PGT-irradiation model. The ratio of organ dose value calculated in MC-method to the volume CT dose index(CTDIvol) reported by CT-scanner machine according to PGT radiation technique has been introduced as conversion factor. Results: In PGT method, CTDIvol was 10.6mGy and Organ Dose/CTDIvol conversion factor for esophagus, lung, heart, breast, ribs, muscle, spine and spinal cord were obtained as; 0.96, 1.46, 1.2, 3.28. 6.68. 1.35, 3.41 and 0.93 respectively. Conclusion: The results showed while, underestimation of patient dose was found in dose calculation based on CTDIvol, also dose to breast is higher than the other studies. Therefore, the method in this study can be used to provide the actual patient organ dose in CT imaging based on CTDIvol in order to calculation of real effective dose(ED) based on organ dose

  5. Radiation dose reduction in parasinus CT by spectral shaping

    Energy Technology Data Exchange (ETDEWEB)

    May, Matthias S.; Brand, Michael; Lell, Michael M.; Uder, Michael; Wuest, Wolfgang [University Hospital Erlangen, Department of Radiology, Erlangen (Germany); Sedlmair, Martin; Allmendinger, Thomas [Siemens Healthcare GmbH, Forchheim (Germany)

    2017-02-15

    Spectral shaping aims to narrow the X-ray spectrum of clinical CT. The aim of this study was to determine the image quality and the extent of radiation dose reduction that can be achieved by tin prefiltration for parasinus CT. All scans were performed with a third generation dual-source CT scanner. A study protocol was designed using 100 kV tube voltage with tin prefiltration (200 mAs) that provides image noise levels comparable to a low-dose reference protocol using 100 kV without spectral shaping (25 mAs). One hundred consecutive patients were prospectively enrolled and randomly assigned to the study or control group. All patients signed written informed consent. The study protocol was approved by the local Institutional Review Board and applies to the HIPAA. Subjective and objective image quality (attenuation values, image noise, and contrast-to-noise ratio (CNR)) were assessed. Radiation exposure was assessed as volumetric CT dose index, and effective dose was estimated. Mann-Whitney U test was performed for radiation exposure and for image noise comparison. All scans were of diagnostic image quality. Image noise in air, in the retrobulbar fat, and in the eye globe was comparable between both groups (all p > 0.05). CNR{sub eye} {sub globe/air} did not differ significantly between both groups (p = 0.7). Radiation exposure (1.7 vs. 2.1 mGy, p < 0.01) and effective dose (0.055 vs. 0.066 mSv, p < 0.01) were significantly reduced in the study group. Radiation dose can be further reduced by 17% for low-dose parasinus CT by tin prefiltration maintaining diagnostic image quality. (orig.)

  6. Radiation dose reduction in parasinus CT by spectral shaping

    International Nuclear Information System (INIS)

    May, Matthias S.; Brand, Michael; Lell, Michael M.; Uder, Michael; Wuest, Wolfgang; Sedlmair, Martin; Allmendinger, Thomas

    2017-01-01

    Spectral shaping aims to narrow the X-ray spectrum of clinical CT. The aim of this study was to determine the image quality and the extent of radiation dose reduction that can be achieved by tin prefiltration for parasinus CT. All scans were performed with a third generation dual-source CT scanner. A study protocol was designed using 100 kV tube voltage with tin prefiltration (200 mAs) that provides image noise levels comparable to a low-dose reference protocol using 100 kV without spectral shaping (25 mAs). One hundred consecutive patients were prospectively enrolled and randomly assigned to the study or control group. All patients signed written informed consent. The study protocol was approved by the local Institutional Review Board and applies to the HIPAA. Subjective and objective image quality (attenuation values, image noise, and contrast-to-noise ratio (CNR)) were assessed. Radiation exposure was assessed as volumetric CT dose index, and effective dose was estimated. Mann-Whitney U test was performed for radiation exposure and for image noise comparison. All scans were of diagnostic image quality. Image noise in air, in the retrobulbar fat, and in the eye globe was comparable between both groups (all p > 0.05). CNR_e_y_e _g_l_o_b_e_/_a_i_r did not differ significantly between both groups (p = 0.7). Radiation exposure (1.7 vs. 2.1 mGy, p < 0.01) and effective dose (0.055 vs. 0.066 mSv, p < 0.01) were significantly reduced in the study group. Radiation dose can be further reduced by 17% for low-dose parasinus CT by tin prefiltration maintaining diagnostic image quality. (orig.)

  7. Radiation Dose Reduction of Chest CT with Iterative Reconstruction in Image Space - Part I: Studies on Image Quality Using Dual Source CT

    International Nuclear Information System (INIS)

    Hwang, Hye Jeon; Seo, Joon Beom; Lee, Jin Seong; Song, Jae Woo; Lee, Hyun Joo; Lim, Chae Hun; Kim, Song Soo

    2012-01-01

    To determine whether the image quality (IQ) is improved with iterative reconstruction in image space (IRIS), and whether IRIS can be used for radiation reduction in chest CT. Standard dose chest CT (SDCT) in 50 patients and low dose chest CT (LDCT) in another 50 patients were performed, using a dual-source CT, with 120 kVp and same reference mAs (50 mAs for SDCT and 25 mAs for LDCT) employed to both tubes by modifying a dual-energy scan mode. Full-dose data were obtained by combining the data from both tubes and half-dose data were separated from a single tube. These were reconstructed by using a filtered back projection (FBP) and IRIS: full-dose FBP (F-FBP); full-dose IRIS (F-IRIS); half-dose FBP (H-FBP) and half-dose IRIS (H-IRIS). Objective noise was measured. The subjective IQ was evaluated by radiologists for the followings: noise, contrast and sharpness of mediastinum and lung. Objective noise was significantly lower in H-IRIS than in F-FBP (p < 0.01). In both SDCT and LDCT, the IQ scores were highest in F-IRIS, followed by F-FBP, H-IRIS and H-FBP, except those for sharpness of mediastinum, which tended to be higher in FBP. When comparing CT images between the same dose and different reconstruction (F-IRIS/F-FBP and H-IRIS/H-FBP) algorithms, scores tended to be higher in IRIS than in FBP, being more distinct in half-dose images. However, despite the use of IRIS, the scores were lower in H-IRIS than in F-FBP. IRIS generally helps improve the IQ, being more distinct at the reduced radiation. However, reduced radiation by half results in IQ decrease even when using IRIS in chest CT.

  8. 3D automatic exposure control for 64-detector row CT: Radiation dose reduction in chest phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Keiko, E-mail: palm_kei@yahoo.co.jp [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Department of Radiology, Yamanashi University, Shimokato, Yamanashi (Japan); Ohno, Yoshiharu; Koyama, Hisanobu; Kono, Atsushi [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Inokawa, Hiroyasu [Toshiba Medical Systems, Ohtawara, Tochigi (Japan); Onishi, Yumiko [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Nogami, Munenobu [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Division of Image-Based Medicine, Institute of Biomedical Research and Innovation, Kobe, Hyogo (Japan); Takenaka, Daisuke [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Araki, Tsutomu [Department of Radiology, Yamanashi University, Shimokato, Yamanashi (Japan); Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan)

    2011-03-15

    Purpose: The purpose of this study was to determine the utility of three-dimensional (3D) automatic exposure control (AEC) for low-dose CT examination in a chest phantom study. Materials and methods: A chest CT phantom including simulated focal ground-glass opacities (GGOs) and nodules was scanned with a 64-detector row CT with and without AEC. Performance of 3D AEC included changing targeted standard deviations (SDs) of image noise from scout view. To determine the appropriate targeted SD number for identification, the capability of overall identification with the CT protocol adapted to each of the targeted SDs was compared with that obtained with CT without AEC by means of receiver operating characteristic analysis. Results: When targeted SD values equal to or higher than 250 were used, areas under the curve (Azs) of nodule identification with CT protocol using AEC were significantly smaller than that for CT protocol without AEC (p < 0.05). When targeted SD numbers at equal to or more than 180 were adapted, Azs of CT protocol with AEC had significantly smaller than that without AEC (p < 0.05). Conclusion: This phantom study shows 3D AEC is useful for low-dose lung CT examination, and can reduce the radiation dose while maintaining good identification capability and good image quality.

  9. Effective radiation dose from semicoronal CT of the sacroiliac joints in comparison with axial CT and conventional radiography

    Energy Technology Data Exchange (ETDEWEB)

    Jurik, Anne Grethe; Boecker Puhakka, Katriina [Department of Radiology R, Aarhus University Hospital, Aarhus Kommunehospital, Noerrebrogade 44, 8000 Aarhus C (Denmark); Hansen, Jolanta [Department of Medical Physics, Aarhus University Hospital, Aarhus Kommunehospital, Noerrebrogade 44, 8000 Aarhus C (Denmark)

    2002-11-01

    The aim of this study was to evaluate the radiation dose given by semicoronal CT of the sacroiliac joints (SIJs) in comparison with axial CT and conventional radiography. The total effective radiation doses given by serial contiguous semicoronal and axial CT, using 5-mm slices, 120 kV and 330 mAs, were determined by measurement of organ doses using an anthropomorphic Rando Alderson phantom paced with thermoluminescence dosimeters. The doses given by conventional antero-posterior (AP) and oblique projections of the SIJs were determined similarly. In a female the total effective dose by semicoronal CT was found to be more than six times lower than by axial CT and 2.5 times lower than the dose use to obtain a conventional AP radiograph, the values being 102, 678, and 255 {mu}Sv, respectively. The effective dose by semicoronal CT was only a little higher than the dose given to obtain two oblique radiographs. In a male with lead protection of the gonads the dose by semicoronal CT was four times lower than by axial CT, but higher than by conventional radiography. In conclusion, the effective dose by semicoronal CT of the SIJs is lower than by axial CT, and in females a semicoronal CT implies a lower effective radiation dose that used to obtain an AP radiograph. (orig.)

  10. The value of FDG-PET/CT in assessing single pulmonary nodules in patients at high risk of lung cancer

    International Nuclear Information System (INIS)

    Kagna, Olga; Solomonov, Anna; Fruchter, Oren; Keidar, Zohar; Bar-Shalom, Rachel; Israel, Ora; Yigla, Mordechai; Guralnik, Luda

    2009-01-01

    To evaluate whether PET/low-dose CT (ldCT) using 18 F-fluorodeoxyglucose (FDG) improves characterization of indeterminate single pulmonary nodules (SPNs) in patients at high risk of lung cancer. Retrospective analysis of 307 patients who underwent FDG-PET/CT for indeterminate SPNs identified 93 (70 men, age range 46-90 years) at high risk of lung cancer (age >40 years, minimum 10 pack-year smokers). SPNs were evaluated for the presence and intensity of FDG avidity and ldCT patterns. The performance of visual and semiquantitative FDG-PET/ldCT algorithms for characterization of SPNs was compared to that of ldCT. Incongruent FDG-PET and ldCT patterns were analyzed for significance in further patient management. Malignancy was diagnosed in 38% patients. FDG avidity defined 33 SPNs as true-positive (TP) and 2 as false-negative (FN) (malignant), and 41 as true-negative (TN) and 17 as false-positive (FP) (benign). For SUVmax of 2.2 (by ROC analysis) there were 27 TP, 8 FN, 48 TN and 10 FP SPNs. LdCT defined 34 TP, 1 FN, 28 TN and 30 FP lesions. Of the FP lesions on ldCT, 60% were FDG-negative. Visual PET/ldCT analysis had a sensitivity of 94%, a specificity of 70%, an accuracy of 80%, a positive predictive value (PPV) of 66%, and a negative predictive value (NPV) of 95% as compared to 77%, 83%, 81%, 73%, 86% for semiquantitative PET/ldCT and 97%, 48%, 66%, 53%, 96% for ldCT, respectively. Both PET/ldCT algorithms had statistically significantly higher specificity and accuracy than ldCT. Semiquantitative analysis showed significantly higher PPV and lower sensitivity and NPV than found with ldCT. A single screening procedure encompassing FDG-PET and ldCT may improve screening for lung cancer in high-risk patients. The significantly improved specificity may potentially reduce FP ldCT results and further unnecessary invasive procedures. (orig.)

  11. SU-E-J-91: Biomechanical Deformable Image Registration of Longitudinal Lung CT Images

    Energy Technology Data Exchange (ETDEWEB)

    Cazoulat, G; Owen, D; Matuszak, M; Balter, J; Brock, K [University of Michigan, Ann Arbor, MI (United States)

    2015-06-15

    Purpose: Spatial correlation of lung tissue across longitudinal images, as the patient responds to treatment, is a critical step in adaptive radiotherapy. The goal of this work is to expand a biomechanical model-based deformable registration algorithm (Morfeus) to achieve accurate registration in the presence of significant anatomical changes. Methods: Four lung cancer patients previously treated with conventionally fractionated radiotherapy that exhibited notable tumor shrinkage during treatment were retrospectively evaluated. Exhale breathhold CT scans were obtained at treatment planning (PCT) and following three weeks (W3CT) of treatment. For each patient, the PCT was registered to the W3CT using Morfeus, a biomechanical model-based deformable registration algorithm, consisting of boundary conditions on the lungs and incorporating a sliding interface between the lung and chest wall. To model the complex response of the lung, an extension to Morfeus has been developed: (i) The vessel tree was segmented by thresholding a vesselness image based on the Hessian matrix’s eigenvalues and the centerline was extracted; (ii) A 3D shape context method was used to find correspondences between the trees of the two images; (ii) Correspondences were used as additional boundary conditions (Morfeus+vBC). An expert independently identified corresponding landmarks well distributed in the lung to compute Target Registration Errors (TRE). Results: The TRE within 15mm of the tumor boundaries (on average 11 landmarks) is: 6.1±1.8, 4.6±1.1 and 3.8±2.3 mm after rigid registration, Morfeus and Morfeus+vBC, respectively. The TRE in the rest of the lung (on average 13 landmarks) is: 6.4±3.9, 4.7±2.2 and 3.6±1.9 mm, which is on the order of the 2mm isotropic dose grid vector (3.5mm). Conclusion: The addition of boundary conditions on the vessels improved the accuracy in modeling the response of the lung and tumor over the course of radiotherapy. Minimizing and modeling these

  12. PET/CT-guided Interventions: Personnel Radiation Dose

    International Nuclear Information System (INIS)

    Ryan, E. Ronan; Thornton, Raymond; Sofocleous, Constantinos T.; Erinjeri, Joseph P.; Hsu, Meier; Quinn, Brian; Dauer, Lawrence T.; Solomon, Stephen B.

    2013-01-01

    PurposeTo quantify radiation exposure to the primary operator and staff during PET/CT-guided interventional procedures.MethodsIn this prospective study, 12 patients underwent PET/CT-guided interventions over a 6 month period. Radiation exposure was measured for the primary operator, the radiology technologist, and the nurse anesthetist by means of optically stimulated luminescence dosimeters. Radiation exposure was correlated with the procedure time and the use of in-room image guidance (CT fluoroscopy or ultrasound).ResultsThe median effective dose was 0.02 (range 0–0.13) mSv for the primary operator, 0.01 (range 0–0.05) mSv for the nurse anesthetist, and 0.02 (range 0–0.05) mSv for the radiology technologist. The median extremity dose equivalent for the operator was 0.05 (range 0–0.62) mSv. Radiation exposure correlated with procedure duration and with the use of in-room image guidance. The median operator effective dose for the procedure was 0.015 mSv when conventional biopsy mode CT was used, compared to 0.06 mSv for in-room image guidance, although this did not achieve statistical significance as a result of the small sample size (p = 0.06).ConclusionThe operator dose from PET/CT-guided procedures is not significantly different than typical doses from fluoroscopically guided procedures. The major determinant of radiation exposure to the operator from PET/CT-guided interventional procedures is time spent in close proximity to the patient

  13. PET/CT-guided Interventions: Personnel Radiation Dose

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, E. Ronan, E-mail: ronan@ronanryan.com; Thornton, Raymond; Sofocleous, Constantinos T.; Erinjeri, Joseph P. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States); Hsu, Meier [Memorial Sloan-Kettering Cancer Center, Department of Epidemiology and Biostatistics (United States); Quinn, Brian; Dauer, Lawrence T. [Memorial Sloan-Kettering Cancer Center, Department of Medical Physics (United States); Solomon, Stephen B. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States)

    2013-08-01

    PurposeTo quantify radiation exposure to the primary operator and staff during PET/CT-guided interventional procedures.MethodsIn this prospective study, 12 patients underwent PET/CT-guided interventions over a 6 month period. Radiation exposure was measured for the primary operator, the radiology technologist, and the nurse anesthetist by means of optically stimulated luminescence dosimeters. Radiation exposure was correlated with the procedure time and the use of in-room image guidance (CT fluoroscopy or ultrasound).ResultsThe median effective dose was 0.02 (range 0-0.13) mSv for the primary operator, 0.01 (range 0-0.05) mSv for the nurse anesthetist, and 0.02 (range 0-0.05) mSv for the radiology technologist. The median extremity dose equivalent for the operator was 0.05 (range 0-0.62) mSv. Radiation exposure correlated with procedure duration and with the use of in-room image guidance. The median operator effective dose for the procedure was 0.015 mSv when conventional biopsy mode CT was used, compared to 0.06 mSv for in-room image guidance, although this did not achieve statistical significance as a result of the small sample size (p = 0.06).ConclusionThe operator dose from PET/CT-guided procedures is not significantly different than typical doses from fluoroscopically guided procedures. The major determinant of radiation exposure to the operator from PET/CT-guided interventional procedures is time spent in close proximity to the patient.

  14. Dose reduction in chest CT: Comparison of the adaptive iterative dose reduction 3D, adaptive iterative dose reduction, and filtered back projection reconstruction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Yoshitake, E-mail: yamada@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Jinzaki, Masahiro, E-mail: jinzaki@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Hosokawa, Takahiro, E-mail: hosokawa@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Tanami, Yutaka, E-mail: tanami@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Sugiura, Hiroaki, E-mail: hsugiura@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Abe, Takayuki, E-mail: tabe@z5.keio.jp [Center for Clinical Research, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Kuribayashi, Sachio, E-mail: skuribay@a5.keio.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan)

    2012-12-15

    Objectives: To assess the effectiveness of adaptive iterative dose reduction (AIDR) and AIDR 3D in improving the image quality in low-dose chest CT (LDCT). Materials and methods: Fifty patients underwent standard-dose chest CT (SDCT) and LDCT simultaneously, performed under automatic exposure control with noise index of 19 and 38 (for a 2-mm slice thickness), respectively. The SDCT images were reconstructed with filtered back projection (SDCT-FBP images), and the LDCT images with FBP, AIDR and AIDR 3D (LDCT-FBP, LDCT-AIDR and LDCT-AIDR 3D images, respectively). On all the 200 lung and 200 mediastinal image series, objective image noise and signal-to-noise ratio (SNR) were measured in several regions, and two blinded radiologists independently assessed the subjective image quality. Wilcoxon's signed rank sum test with Bonferroni's correction was used for the statistical analyses. Results: The mean dose reduction in LDCT was 64.2% as compared with the dose in SDCT. LDCT-AIDR 3D images showed significantly reduced objective noise and significantly increased SNR in all regions as compared to the SDCT-FBP, LDCT-FBP and LDCT-AIDR images (all, P ≤ 0.003). In all assessments of the image quality, LDCT-AIDR 3D images were superior to LDCT-AIDR and LDCT-FBP images. The overall diagnostic acceptability of both the lung and mediastinal LDCT-AIDR 3D images was comparable to that of the lung and mediastinal SDCT-FBP images. Conclusions: AIDR 3D is superior to AIDR. Intra-individual comparisons between SDCT and LDCT suggest that AIDR 3D allows a 64.2% reduction of the radiation dose as compared to SDCT, by substantially reducing the objective image noise and increasing the SNR, while maintaining the overall diagnostic acceptability.

  15. SU-E-J-86: Lobar Lung Function Quantification by PET Galligas and CT Ventilation Imaging in Lung Cancer Patients

    International Nuclear Information System (INIS)

    Eslick, E; Kipritidis, J; Keall, P; Bailey, D; Bailey, E

    2014-01-01

    Purpose: The purpose of this study was to quantify the lobar lung function using the novel PET Galligas ([68Ga]-carbon nanoparticle) ventilation imaging and the investigational CT ventilation imaging in lung cancer patients pre-treatment. Methods: We present results on our first three lung cancer patients (2 male, mean age 78 years) as part of an ongoing ethics approved study. For each patient a PET Galligas ventilation (PET-V) image and a pair of breath hold CT images (end-exhale and end-inhale tidal volumes) were acquired using a Siemens Biograph PET CT. CT-ventilation (CT-V) images were created from the pair of CT images using deformable image registration (DIR) algorithms and the Hounsfield Unit (HU) ventilation metric. A comparison of ventilation quantification from each modality was done on the lobar level and the voxel level. A Bland-Altman plot was used to assess the difference in mean percentage contribution of each lobe to the total lung function between the two modalities. For each patient, a voxel-wise Spearmans correlation was calculated for the whole lungs between the two modalities. Results: The Bland-Altman plot demonstrated strong agreement between PET-V and CT-V for assessment of lobar function (r=0.99, p<0.001; range mean difference: −5.5 to 3.0). The correlation between PET-V and CT-V at the voxel level was moderate(r=0.60, p<0.001). Conclusion: This preliminary study on the three patients data sets demonstrated strong agreement between PET and CT ventilation imaging for the assessment of pre-treatment lung function at the lobar level. Agreement was only moderate at the level of voxel correlations. These results indicate that CT ventilation imaging has potential for assessing pre-treatment lobar lung function in lung cancer patients

  16. Acute and repeated inhalation lung injury by 3-methoxybutyl chloroformate in rats: CT-pathologic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Yeon Soo [Department of Radiology, Holy Family Hospital, College of Medicine, Catholic University of Korea, 2, Sosa-dong, Wonmi-gu, Pucheon, Kyung gi-do 420-717 (Korea, Republic of); Chung, Myung Hee [Department of Radiology, Holy Family Hospital, College of Medicine, Catholic University of Korea, 2, Sosa-dong, Wonmi-gu, Pucheon, Kyung gi-do 420-717 (Korea, Republic of)]. E-mail: mhchung@catholic.ac.kr; Park, Seog Hee [Department of Radiology, Kangnam St. Mary Hospital, Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-040 (Korea, Republic of); Kim, Hyeon-Yeong [Industrial Chemicals Research Center, Industrial Safety and Health Research Institute KISCO, 104-8, Moonji-dong, Yusong-gu, Taejon-si 305-380 (Korea, Republic of); Choi, Byung Gil [Department of Radiology, Kangnam St. Mary Hospital, Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-040 (Korea, Republic of); Lim, Hyun Wook [Department of Radiology, Holy Family Hospital, College of Medicine, Catholic University of Korea, 2, Sosa-dong, Wonmi-gu, Pucheon, Kyung gi-do 420-717 (Korea, Republic of); Kim, Jin Ah [Department of Pathology, Holy Family Hospital, Catholic University of Korea, 2, Sosa-dong, Wonmi-gu, Pucheon-si, Kyung gi-do 420-717 (Korea, Republic of); Yoo, Won Jong [Department of Radiology, Holy Family Hospital, College of Medicine, Catholic University of Korea, 2, Sosa-dong, Wonmi-gu, Pucheon, Kyung gi-do 420-717 (Korea, Republic of)

    2007-05-15

    Objectives: To investigate the acute and repeated pulmonary damage in Sprague-Dawley rats caused by the inhalation of 3-methoxybutyl chloroformate (3-MBCF) using computed tomography (CT), and to correlate these results with those obtained from a pathological study. Methods: Sixty, 7-week-old rats were exposed to 3-MBCF vapor via inhalation (6 h/day) for 1 day (N = 20), 3 days (N = 20), and 28 days (5 days/week) (N = 20) using whole body exposure chambers at a concentration of 0 (control), 3, 6 and 12 ppm. CT examinations including densitometry and histopathologic studies were carried out. For the follow-up study, the rats exposed for 3 days were scanned using CT and their pathology was examined at 7, 14, and 28 days. Results: There was a significant decrease in the parenchymal density in the groups exposed to the 3-MBCF vapors for 1 day at 3 ppm (p = 0.022) or 6 ppm (p = 0.010), compared with the control. The parenchymal density of the rats exposed to12 ppm was significantly higher. The pathological findings in this period, the grades of vascular congestion, tracheobronchial exfoliation, and alveolar rupture were significant. In the groups exposed for 3 days, there was a large decrease in the parenchymal density with increasing dose (control: -675.48 {+-} 32.82 HU, 3 ppm: -720.65 {+-} 34.21 HU, 6 ppm: -756.41 {+-} 41.68 HU, 12 ppm: -812.56 {+-} 53.48 HU) (p = 0.000). There were significant density differences between each dose in the groups exposed for 28 days (p = 0.000). The CT findings include an irregular lung surface, areas of multifocal, wedge-shaped increased density, a heterogeneous lung density, bronchial dilatation, and axial peribronchovascular bundle thickening. The histopathology examination revealed the development of alveolar interstitial thickening and vasculitis, and an aggravation of the mainstem bronchial exudates and bronchial inflammation. The alveolar wall ruptures and bronchial dilatation became severe during this period. On the follow

  17. Acute and repeated inhalation lung injury by 3-methoxybutyl chloroformate in rats: CT-pathologic correlation

    International Nuclear Information System (INIS)

    Lim, Yeon Soo; Chung, Myung Hee; Park, Seog Hee; Kim, Hyeon-Yeong; Choi, Byung Gil; Lim, Hyun Wook; Kim, Jin Ah; Yoo, Won Jong

    2007-01-01

    Objectives: To investigate the acute and repeated pulmonary damage in Sprague-Dawley rats caused by the inhalation of 3-methoxybutyl chloroformate (3-MBCF) using computed tomography (CT), and to correlate these results with those obtained from a pathological study. Methods: Sixty, 7-week-old rats were exposed to 3-MBCF vapor via inhalation (6 h/day) for 1 day (N = 20), 3 days (N = 20), and 28 days (5 days/week) (N = 20) using whole body exposure chambers at a concentration of 0 (control), 3, 6 and 12 ppm. CT examinations including densitometry and histopathologic studies were carried out. For the follow-up study, the rats exposed for 3 days were scanned using CT and their pathology was examined at 7, 14, and 28 days. Results: There was a significant decrease in the parenchymal density in the groups exposed to the 3-MBCF vapors for 1 day at 3 ppm (p = 0.022) or 6 ppm (p = 0.010), compared with the control. The parenchymal density of the rats exposed to12 ppm was significantly higher. The pathological findings in this period, the grades of vascular congestion, tracheobronchial exfoliation, and alveolar rupture were significant. In the groups exposed for 3 days, there was a large decrease in the parenchymal density with increasing dose (control: -675.48 ± 32.82 HU, 3 ppm: -720.65 ± 34.21 HU, 6 ppm: -756.41 ± 41.68 HU, 12 ppm: -812.56 ± 53.48 HU) (p = 0.000). There were significant density differences between each dose in the groups exposed for 28 days (p = 0.000). The CT findings include an irregular lung surface, areas of multifocal, wedge-shaped increased density, a heterogeneous lung density, bronchial dilatation, and axial peribronchovascular bundle thickening. The histopathology examination revealed the development of alveolar interstitial thickening and vasculitis, and an aggravation of the mainstem bronchial exudates and bronchial inflammation. The alveolar wall ruptures and bronchial dilatation became severe during this period. On the follow-up study, the

  18. SU-E-J-149: Establishing the Relationship Between Pre-Treatment Lung Ventilation, Dose, and Toxicity Outcome

    International Nuclear Information System (INIS)

    Mistry, N; D'Souza, W; Sornsen de Koste, J; Senan, S

    2014-01-01

    Purpose: Recently, there has been an interest in incorporating functional information in treatment planning especially in thoracic tumors. The rationale is that healthy lung regions need to be spared from radiation if possible to help achieve better control on toxicity. However, it is still unclear whether high functioning regions need to be spared or have more capacity to deal with the excessive radiation as compared to the compromised regions of the lung. Our goal with this work is to establish the tools by which we can establish a relationship between pre-treatment lung function, dose, and radiographic outcomes of lung toxicity. Methods: Treatment planning was performed using a single phase of a 4DCT scan, and follow-up anatomical CT scans were performed every 3 months for most patients. In this study, we developed the pipeline of tools needed to analyze such a large dataset, while trying to establish a relationship between function, dose, and outcome. Pre-treatment lung function was evaluated using a recently published technique that evaluates Fractional Regional Ventilation (FRV). All images including the FRV map and the individual follow-up anatomical CT images were all spatially matched to the planning CT using a diffusion based Demons image registration algorithm. Change in HU value was used as a metric to capture the effects of lung toxicity. To validate the findings, a radiologist evaluated the follow-up anatomical CT images and scored lung toxicity. Results: Initial experience in 1 patient shows a relationship between the pre-treatment lung function, dose and toxicity outcome. The results are also correlated to the findings by the radiologist who was blinded to the analysis or dose. Conclusion: The pipeline we have established to study this enables future studies in large retrospective studies. However, the tools are dependent on the fidelity of 4DCT reconstruction for accurate evaluation of regional ventilation. Patent Pending for the technique

  19. CT image construction of a totally deflated lung using deformable model extrapolation

    International Nuclear Information System (INIS)

    Sadeghi Naini, Ali; Pierce, Greg; Lee, Ting-Yim

    2011-01-01

    Purpose: A novel technique is proposed to construct CT image of a totally deflated lung from a free-breathing 4D-CT image sequence acquired preoperatively. Such a constructed CT image is very useful in performing tumor ablative procedures such as lung brachytherapy. Tumor ablative procedures are frequently performed while the lung is totally deflated. Deflating the lung during such procedures renders preoperative images ineffective for targeting the tumor. Furthermore, the problem cannot be solved using intraoperative ultrasound (U.S.) images because U.S. images are very sensitive to small residual amount of air remaining in the deflated lung. One possible solution to address these issues is to register high quality preoperative CT images of the deflated lung with their corresponding low quality intraoperative U.S. images. However, given that such preoperative images correspond to an inflated lung, such CT images need to be processed to construct CT images pertaining to the lung's deflated state. Methods: To obtain the CT images of deflated lung, we present a novel image construction technique using extrapolated deformable registration to predict the deformation the lung undergoes during full deflation. The proposed construction technique involves estimating the lung's air volume in each preoperative image automatically in order to track the respiration phase of each 4D-CT image throughout a respiratory cycle; i.e., the technique does not need any external marker to form a respiratory signal in the process of curve fitting and extrapolation. The extrapolated deformation field is then applied on a preoperative reference image in order to construct the totally deflated lung's CT image. The technique was evaluated experimentally using ex vivo porcine lung. Results: The ex vivo lung experiments led to very encouraging results. In comparison with the CT image of the deflated lung we acquired for the purpose of validation, the constructed CT image was very similar. The

  20. Application of CT perfusion imaging in radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Xia Guangrong; Liu Guimei; He Wen; Jin Guohua; Xie Ruming; Xu Yongxiang; Li Xiaobo; Li Xuebing

    2011-01-01

    Objective: To investigate the value of CT perfusion imaging in evaluation of therapeutic effect and prognosis in radiotherapy for lung cancer. Methods: Fifty-one cases of lung cancer who were unable or refused to be operated on, 36 males and 15 females, aged 37-80, underwent CT perfusion imaging, 29 of which only before radiotherapy and 22 before and after radiotherapy twice. The images were collected by cine dynamic scanning (5 mm/4 slices) and input into the GE AW4.0 workstation for data processing. The slice positions of CT imaging were determined according to the largest tumor size in CT scan. Regions of interest of tumor were drawn at the region corresponding to the original images of CT perfusion. Radiotherapy was performed after CT perfusion imaging. Relevant parameters, including blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS) were calculated. The treatment response after radiotherapy was evaluated by RECIST. At 2 -4 weeks after the treatment, CT examination was conducted once more. Results: The tests of the 51 patients showed that the BV was 13.6 ml·100 g -1 , the BF was 129.5 ml·min -1 ·100 g -1 , the MTT was 9.1 s, and the PS was 10.0 ml· min -1 · 100 g -1 before radiotherapy. The tests of the 22 of the 51 patients showed that the values of BV and BF after radiotherapy were 7.6 ml· 100 g -1 and 97.8 ml·min -1 · 100 g -1 , respectively, both lower than those before radiotherapy (11.2 and 108.7 ml·min -1 ·100 g -1 , respectively), however, both not significantly (t=1.28, 0.40, P>0.05); and the values of MTT and PS after radiotherapy were 8.9 s and 7.8 ml·min -1 · 100 g -1 , respectively, both not significantly higher than those before radiotherapy (7.2 s and 6.8 ml· min -1 · 100 g -1 , respectively, t=-1.15, -0.57, P>0.05). The mean area of tumor after radiotherapy was 1189.6 mm 2 , significantly less than that before radiotherapy (1920.3 mm 2 , t=3.98, P<0.05). The MTT of the SCLC patients was 12

  1. On the radiation dose to lung tissues from radon daughters

    International Nuclear Information System (INIS)

    Wise, K.N.

    1980-04-01

    The work of Harley and Pasternak on calculating dose conversion factors for radon daughters is re-examined. It is found that their estimates of the deposit of radon daughters on the lung airways are too low and the factor for converting from equilibrium activity of radon daughters on the airways to dose to basal cells is too high; these are re-calculated. However, it is shown that inter-subject variability of the depth of the basal cells leads to considerable uncertainty in the individual dose. Finally average dose conversion factors are re-calculated for atmospheres which may be charactersitic of underground mines; the dose conversion factors range from 8 mGy/WLM to 40 mGy/WLM as calculated from the Weibel lung model and from 3 mGy/WLM to 17 mGy/WLM as calculated from the Landahl lung model

  2. Transatlantic Comparison of CT Radiation Doses in the Era of Radiation Dose-Tracking Software.

    Science.gov (United States)

    Parakh, Anushri; Euler, Andre; Szucs-Farkas, Zsolt; Schindera, Sebastian T

    2017-12-01

    The purpose of this study is to compare diagnostic reference levels from a local European CT dose registry, using radiation-tracking software from a large patient sample, with preexisting European and North American diagnostic reference levels. Data (n = 43,761 CT scans obtained over the course of 2 years) for the European local CT dose registry were obtained from eight CT scanners at six institutions. Means, medians, and interquartile ranges of volumetric CT dose index (CTDI vol ), dose-length product (DLP), size-specific dose estimate, and effective dose values for CT examinations of the head, paranasal sinuses, thorax, pulmonary angiogram, abdomen-pelvis, renal-colic, thorax-abdomen-pelvis, and thoracoabdominal angiogram were obtained using radiation-tracking software. Metrics from this registry were compared with diagnostic reference levels from Canada and California (published in 2015), the American College of Radiology (ACR) dose index registry (2015), and national diagnostic reference levels from local CT dose registries in Switzerland (2010), the United Kingdom (2011), and Portugal (2015). Our local registry had a lower 75th percentile CTDI vol for all protocols than did the individual internationally sourced data. Compared with our study, the ACR dose index registry had higher 75th percentile CTDI vol values by 55% for head, 240% for thorax, 28% for abdomen-pelvis, 42% for thorax-abdomen-pelvis, 128% for pulmonary angiogram, 138% for renal-colic, and 58% for paranasal sinus studies. Our local registry had lower diagnostic reference level values than did existing European and North American diagnostic reference levels. Automated radiation-tracking software could be used to establish and update existing diagnostic reference levels because they are capable of analyzing large datasets meaningfully.

  3. Radiation doses in head CT examinations in Serbia: comparison among different CT units

    International Nuclear Information System (INIS)

    Arandjic, D.; Ciraj-Bjelac, O.; Bozovic, P.; Stankovic, J.; Hadnadjev, D.; Stojanovic, S.

    2012-01-01

    A rapid increase in number of Computed Tomography (CT) examinations has been observed world wide. As haed CT is the most frequent CT examination, the purpose of this study was to collect and analyse patient doses in children and adults in different CT units for this procedure. The study included 8 CT units from three manufacturers (Siemens, Toshiba and General Electric). Data for adults and pediatric patients were collected in terms of CTDIvol and DLP values. The doses were estimated as a mean value of 10 patients on each CT unit. For pediatrics, doses were collected for four age groups (0-1year, >1-5years, >5-10years and >10-15years). Comparing different manufacturers and the same number of detector rows it was observed that, in case of 16 slices units, doses were very similar on Siemens and General Electric scanner. CTDIvol and DLP on Siemens scanner were 60 mGy and 1066 mGy·cm, respectively, while on General Electric those values were 66 mGy and 1050 mGy·cm. However, this trend was not observed in case of 64 slices units. CTDIvol and DLP values collected on Toshiba were much higher (177 mGy and 2109 mGy·cm) than in case of Siemens scanner (59 mGy and 1060 mGy·cm). Doses on 16 and 64 slices Siemens scanners were very similar, while on 4 slices were higher. Except in two units, doses were were in line with DRLs. In case of pediatrics, doses increase with patient age and again Siemens scanner showed the lowest values while the highest were observed on Toshiba. (authors)

  4. High resolution CT for localization of early hilar lung carcinoma

    International Nuclear Information System (INIS)

    Minami, Yuko; Ishikawa, Shigemi; Saida, Yukihisa; Kajitani, Motomasa; Yamamoto, Tatsuo; Sato, Yukio; Onizuka, Masataka; Sakakibara, Yuzuru; Noguchi, Masayuki

    2002-01-01

    The purpose of this study was to analyse the usefulness of high resolution CT (HRCT) for the diagnosis and localization of roentgenographically occult lung cancer. HRCT was performed prospectively on chest X-ray negative patients with bloody sputum or suspicious or positive cells on sputum cytology between 1998 and 2000. After the HRCT scan, white light bronchoscopy and autofluorescence bronchoscopy were performed. HRCT depicted 19 hilar bronchial lesions in 13 cases out of 19 patients, of which 9 lesions were confirmed by white light broncoscope. Of 8 hilar squamous cell carcinomas diagnosed in this study, 7 lesions (87.5%) were depicted by HRCT. One CT-negative case (12.5%) was an in situ carcinoma in left B 1+2 . Four out of 20 lesions which showed bronchoscopic abnormality, could not be depicted by HRCT. HRCT could prospectively detect 80% of the bronchoscopic abnormalities and 87.5% of the hilar squamous cell carcinomas of the tracheobronchial lesions of the lung. Therefore, HRCT can be an effective supplemental means for screening for hilar squamous cell carcinoma. (author)

  5. Lung nodule detection in pediatric chest CT: quantitative relationship between image quality and radiologist performance.

    Science.gov (United States)

    Li, Xiang; Samei, Ehsan; Barnhart, Huiman X; Gaca, Ana Maria; Hollingsworth, Caroline L; Maxfield, Charles M; Carrico, Caroline W T; Colsher, James G; Frush, Donald P

    2011-05-01

    To determine the quantitative relationship between image quality and radiologist performance in detecting small lung nodules in pediatric CT. The study included clinical chest CT images of 30 pediatric patients (0-16 years) scanned at tube currents of 55-180 mA. Calibrated noise addition software was used to simulate cases at three nominal mA settings: 70, 35, and 17.5 mA, resulting in quantum noise of 7-32 Hounsfield Unit (HU). Using a validated nodule simulation technique, lung nodules with diameters of 3-5 mm and peak contrasts of 200-500 HU were inserted into the cases, which were then randomized and rated independently by four experienced pediatric radiologists for nodule presence on a continuous scale from 0 (definitely absent) to 100 (definitely present). The receiver operating characteristic (ROC) data were analyzed to quantify the relationship between diagnostic accuracy (area under the ROC curve, AUC) and image quality (the product of nodule peak contrast and displayed diameter to noise ratio, CDNR display). AUC increased rapidly from 0.70 to 0.87 when CDNR display increased from 60 to 130 mm, followed by a slow increase to 0.94 when CDNR display further increased to 257 mm. For the average nodule diameter (4 mm) and contrast (350 HU), AUC decreased from 0.93 to 0.71 with noise increased from 7 to 28 HU. We quantified the relationship between image quality and the performance of radiologists in detecting lung nodules in pediatric CT. The relationship can guide CT protocol design to achieve the desired diagnostic performance at the lowest radiation dose.

  6. Quantitative CT characterization of pediatric lung development using routine clinical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Jill M.; Brody, Alan S.; Fleck, Robert J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Walkup, Laura L. [Cincinnati Children' s Hospital Medical Center, Center for Pulmonary Imaging Research, Pulmonary Medicine and Radiology, Cincinnati, OH (United States); Woods, Jason C. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Cincinnati Children' s Hospital Medical Center, Center for Pulmonary Imaging Research, Pulmonary Medicine and Radiology, Cincinnati, OH (United States)

    2016-12-15

    The use of quantitative CT analysis in children is limited by lack of normal values of lung parenchymal attenuation. These characteristics are important because normal lung development yields significant parenchymal attenuation changes as children age. To perform quantitative characterization of normal pediatric lung parenchymal X-ray CT attenuation under routine clinical conditions in order to establish a baseline comparison to that seen in pathological lung conditions. We conducted a retrospective query of normal CT chest examinations in children ages 0-7 years from 2004 to 2014 using standard clinical protocol. During these examinations semi-automated lung parenchymal segmentation was performed to measure lung volume and mean lung attenuation. We analyzed 42 CT examinations in 39 children, ages 3 days to 83 months (mean ± standard deviation [SD] = 42 ± 27 months). Lung volume ranged 0.10-1.72 liters (L). Mean lung attenuation was much higher in children younger than 12 months, with values as high as -380 Hounsfield units (HU) in neonates (lung volume 0.10 L). Lung volume decreased to approximately -650 HU by age 2 years (lung volume 0.47 L), with subsequently slower exponential decrease toward a relatively constant value of -860 HU as age and lung volume increased. Normal lung parenchymal X-ray CT attenuation decreases with increasing lung volume and age; lung attenuation decreases rapidly in the first 2 years of age and more slowly thereafter. This change in normal lung attenuation should be taken into account as quantitative CT methods are translated to pediatric pulmonary imaging. (orig.)

  7. Quantitative CT characterization of pediatric lung development using routine clinical imaging

    International Nuclear Information System (INIS)

    Stein, Jill M.; Brody, Alan S.; Fleck, Robert J.; Walkup, Laura L.; Woods, Jason C.

    2016-01-01

    The use of quantitative CT analysis in children is limited by lack of normal values of lung parenchymal attenuation. These characteristics are important because normal lung development yields significant parenchymal attenuation changes as children age. To perform quantitative characterization of normal pediatric lung parenchymal X-ray CT attenuation under routine clinical conditions in order to establish a baseline comparison to that seen in pathological lung conditions. We conducted a retrospective query of normal CT chest examinations in children ages 0-7 years from 2004 to 2014 using standard clinical protocol. During these examinations semi-automated lung parenchymal segmentation was performed to measure lung volume and mean lung attenuation. We analyzed 42 CT examinations in 39 children, ages 3 days to 83 months (mean ± standard deviation [SD] = 42 ± 27 months). Lung volume ranged 0.10-1.72 liters (L). Mean lung attenuation was much higher in children younger than 12 months, with values as high as -380 Hounsfield units (HU) in neonates (lung volume 0.10 L). Lung volume decreased to approximately -650 HU by age 2 years (lung volume 0.47 L), with subsequently slower exponential decrease toward a relatively constant value of -860 HU as age and lung volume increased. Normal lung parenchymal X-ray CT attenuation decreases with increasing lung volume and age; lung attenuation decreases rapidly in the first 2 years of age and more slowly thereafter. This change in normal lung attenuation should be taken into account as quantitative CT methods are translated to pediatric pulmonary imaging. (orig.)

  8. PET/CT Based Dose Planning in Radiotherapy

    DEFF Research Database (Denmark)

    Berthelsen, Anne Kiil; Jakobsen, Annika Loft; Sapru, Wendy

    2011-01-01

    radiotherapy planning with PET/CT prior to the treatment. The PET/CT, including the radiotherapy planning process as well as the radiotherapy process, is outlined in detail. The demanding collaboration between mould technicians, nuclear medicine physicians and technologists, radiologists and radiology......This mini-review describes how to perform PET/CT based radiotherapy dose planning and the advantages and possibilities obtained with the technique for radiation therapy. Our own experience since 2002 is briefly summarized from more than 2,500 patients with various malignant diseases undergoing...... technologists, radiation oncologists, physicists, and dosimetrists is emphasized. We strongly believe that PET/CT based radiotherapy planning will improve the therapeutic output in terms of target definition and non-target avoidance and will play an important role in future therapeutic interventions in many...

  9. Patient doses from CT examinations in the United Arab Emirates

    International Nuclear Information System (INIS)

    Janeczek, J.

    2006-01-01

    Full text of publication follows: The main goal of the study was to estimate effective patient doses from the 6 most common CT examinations for different types of CT scanners within the United Arab Emirates. The results were used to assess future trends in patient CT doses following rapid replacement of axial and single-slice spiral scanners by multi-slice scanners. At present all three types of scanner technology exist: axial, spiral and multi-slice with axial scanners being gradually replaced by multi-slice scanners as the medical infrastructure of the country is modernized. Altogether there are more than 30 CT scanners in the country with a population of 4 million. Out of these 11 scanners are 16-slice models with tube-current modulation system. The majority of larger United Arab Emirates hospitals have at least two CT scanners: a single slice and 4 or 16-slice scanner. The survey was carried out with data collection forms distributed to the majority of CT scanner users in the United Arab Emirates hospitals, both private and government. Effective doses for different examinations were calculated from T.L.D. measurements using an Alderson Rando phantom simulating an average size patient. Our results show that effective doses to patients initially increased with the introduction of 4-slice scanners. Multi-slice scanners with 16 and more slices have tube-current modulation system as a standard. It is routinely used by radiographers in almost all examinations resulting in patient dose reduction up to 40 % in certain examinations. Another factor affecting population dose is the increased number of patients examined using multi-slice scanners. In the United Arab Emirates there was an increase of more than 30 % in the annual number of patients examined using multi-slice scanners in comparison to single-slice scanners. This fact is attributed to the ease and speed of operation of multi-slice scanners. Rapid increase in number of CT examinations is of concern. Medical

  10. WE-G-BRD-07: Investigation of Distal Lung Atelectasis Following Stereotactic Body Radiation Therapy Using Regional Lung Volume Changes Between Pre- and Post- Treatment CT Scans

    Energy Technology Data Exchange (ETDEWEB)

    Diot, Q; Kavanagh, B; Miften, M [University of Colorado School of Medicine, Aurora, CO (United States)

    2014-06-15

    Purpose: To propose a quantitative method using lung deformations to differentiate between radiation-induced fibrosis and potential airway stenosis with distal atelectasis in patients treated with stereotactic body radiation therapy (SBRT) for lung tumors. Methods: Twenty-four lung patients with large radiation-induced density increases outside the high dose region had their pre- and post-treatment CT scans manually registered. They received SBRT treatments at our institution between 2002 and 2009 in 3 or 5 fractions, to a median total dose of 54Gy (range, 30–60). At least 50 anatomical landmarks inside the lung (airway branches) were paired for the pre- and post-treatment scans to guide the deformable registration of the lung structure, which was then interpolated to the whole lung using splines. Local volume changes between the planning and follow-up scans were calculated using the deformation field Jacobian. Hyperdense regions were classified as atelectatic or fibrotic based on correlations between regional density increases and significant volume contractions compared to the surrounding tissues. Results: Out of 24 patients, only 7 demonstrated a volume contraction that was at least one σ larger than the remaining lung average. Because they did not receive high doses, these shrunk hyperdense regions were likely showing distal atelectasis resulting from radiation-induced airway stenosis rather than conventional fibrosis. On average, the hyperdense regions extended 9.2 cm farther than the GTV contours but not significantly more than 8.6 cm for the other patients (p>0.05), indicating that a large offset between the radiation and hyperdense region centers is not a good surrogate for atelectasis. Conclusion: A method based on the relative comparison of volume changes between different dates was developed to identify potential lung regions experiencing distal atelectasis. Such a tool is essential to study which lung structures need to be avoided to prevent

  11. Dose profile study in head CT scans using radiochromic films

    Energy Technology Data Exchange (ETDEWEB)

    Ladino G, A. M.; Prata M, A., E-mail: amlgphys@gmail.com [Universidade Federal de Minas Gerais, Departamento de Engenharia Nuclear, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    Diagnostic images of computed tomography generate higher doses than other methods of diagnostic radiology using X-ray beam attenuation. Clinical applications of CT have been increased by technological advances, what leads to a wide variety of scanner in the Brazilian technological pool. It has been difficult to implement dose reduction strategies because of the lack of proper guidance on computed tomography examinations. However, CT scanners allow adjusting acquisition parameter according to the patients physical profile and diagnostic application for which the scan is intended. The knowledge of the dose distribution is important because changes in image acquisition parameters may provide dose reduction. In this study, it was used a cylindrical head phantom in PMMA with 5 openings, what allows dose measurement in 5 regions. In a GE CT scanner, Discovery model of 64 channels, the central slice of the head phantom was irradiated and the absorbed doses were measured using a pencil ionization chamber. Radiochromic film strips were placed in the peripheral and in the central region of the head phantom and was performed a scan of 10 cm in the phantom central region. The scan was performed using the head scanning protocol of the radiobiology service, with a voltage of 120 kV. After scanning, the radiochromic film strips were digitalized and their digital images were used to have the dose longitudinal profiles. The dose values recorded have variation in a range of 18.66 to 23.57 mGy. In the results it was compared the dose index values obtained by the pencil chamber measurement to the dose longitudinal profiles recorded by the film strips. (Author)

  12. Dose profile study in head CT scans using radiochromic films

    International Nuclear Information System (INIS)

    Ladino G, A. M.; Prata M, A.

    2016-10-01

    Diagnostic images of computed tomography generate higher doses than other methods of diagnostic radiology using X-ray beam attenuation. Clinical applications of CT have been increased by technological advances, what leads to a wide variety of scanner in the Brazilian technological pool. It has been difficult to implement dose reduction strategies because of the lack of proper guidance on computed tomography examinations. However, CT scanners allow adjusting acquisition parameter according to the patients physical profile and diagnostic application for which the scan is intended. The knowledge of the dose distribution is important because changes in image acquisition parameters may provide dose reduction. In this study, it was used a cylindrical head phantom in PMMA with 5 openings, what allows dose measurement in 5 regions. In a GE CT scanner, Discovery model of 64 channels, the central slice of the head phantom was irradiated and the absorbed doses were measured using a pencil ionization chamber. Radiochromic film strips were placed in the peripheral and in the central region of the head phantom and was performed a scan of 10 cm in the phantom central region. The scan was performed using the head scanning protocol of the radiobiology service, with a voltage of 120 kV. After scanning, the radiochromic film strips were digitalized and their digital images were used to have the dose longitudinal profiles. The dose values recorded have variation in a range of 18.66 to 23.57 mGy. In the results it was compared the dose index values obtained by the pencil chamber measurement to the dose longitudinal profiles recorded by the film strips. (Author)

  13. Low-dose multislice CT in febrile neutropenic patients

    International Nuclear Information System (INIS)

    Wendel, F.; Jenett, M.; Hahn, D.; Sandstede, J.; Geib, A.

    2005-01-01

    Purpose: to define the value of low-dose multislice CT in a clinical setting for early detection of pneumonia in neutropenic patients with fever of unknown origin. Materials and methods: thirty-five neutropenic patients suffering from fever of unknown origin with normal chest X-ray underwent unenhanced low-dose CT of the chest (120 kV, 10 eff. mAs, collimation 4 x 1 mm) using a multislice CT scanner. Axial und frontal slices with a thickness of 5 mm were calculated. If no pneumonia was found, standard antibiotics were given and a repeated examination was performed if fever continued. In case of pneumonia, antimycotic therapy was added and a follow-up CT was performed within one week. Regression or progression of pneumonia at follow-up served as evidence of pneumonia; lowering of fever within 48 h or inconspicuous follow-up CT was regarded as absence of pneumonia. Results: ten of 35 patients had pneumonic infiltration, which decreased or increased on follow-up CT in 3 and 6 patients, respectively. One patient revealed leucemic infiltration by bronchoalveolar lavage. Twenty-five of 35 patients had no evidence of pneumonia. Twenty of these patients were free of fever within 48 h under antibiotics; one patient died due to his basic illness. Out of 4 patients with persisting fever, 3 patients had no pneumonia on repeated examination; one patient showed disseminated micronodular infiltration. Frontal reconstructions helped to differentiate infiltration from atelectasis in 4 patients. Sensitivity and specificity for the detection of pneumonia at the first examination were 90% and 96%, negative predictive value was 96%. Conclusion: low-dose multislice CT should be performed in neutropenic patients having a fever of unknown origin and normal chest X-ray. (orig.)

  14. Measurement of lung tumor motion using respiration-correlated CT

    International Nuclear Information System (INIS)

    Mageras, Gig S.; Pevsner, Alex; Yorke, Ellen D.; Rosenzweig, Kenneth E.; Ford, Eric C.; Hertanto, Agung; Larson, Steven M.; Lovelock, D. Michael; Erdi, Yusuf E.; Nehmeh, Sadek A.; Humm, John L.; Ling, C. Clifton

    2004-01-01

    Purpose: We investigate the characteristics of lung tumor motion measured with respiration-correlated computed tomography (RCCT) and examine the method's applicability to radiotherapy planning and treatment. Methods and materials: Six patients treated for non-small-cell lung carcinoma received a helical single-slice computed tomography (CT) scan with a slow couch movement (1 mm/s), while simultaneously respiration is recorded with an external position-sensitive monitor. Another 6 patients receive a 4-slice CT scan in a cine mode, in which sequential images are acquired for a complete respiratory cycle at each couch position while respiration is recorded. The images are retrospectively resorted into different respiration phases as measured with the external monitor (4-slice data) or patient surface displacement observed in the images (single-slice data). The gross tumor volume (GTV) in lung is delineated at one phase and serves as a visual guide for delineation at other phases. Interfractional GTV variation is estimated by scaling diaphragm position variations measured in gated radiographs at treatment with the ratio of GTV:diaphragm displacement observed in the RCCT data. Results: Seven out of 12 patients show GTV displacement with respiration of more than 1 cm, primarily in the superior-inferior (SI) direction; 2 patients show anterior-posterior displacement of more than 1 cm. In all cases, extremes in GTV position in the SI direction are consistent with externally measured extremes in respiration. Three patients show evidence of hysteresis in GTV motion, in which the tumor trajectory is displaced 0.2 to 0.5 cm anteriorly during expiration relative to inspiration. Significant (>1 cm) expansion of the GTV in the SI direction with respiration is observed in 1 patient. Estimated intrafractional GTV motion for gated treatment at end expiration is 0.6 cm or less in all cases; however; interfraction variation estimates (systematic plus random) are more than 1 cm in 3

  15. Exposure dose to gonad and its reduction in CT examinations

    International Nuclear Information System (INIS)

    Suzuki, Shoichi; Menju, Mina; Nakazawa, Masato

    2006-01-01

    Exposure doses to gonad (ovary and uterus) due to scattering at the ordinary CT examinations of head, breast, and abdomen (liver) were measured and their reductions by the protective apron usually used in clinic were evaluated by comparison of the given and International Commission of Radiological Protection (ICRP) data for risk assessment. Multi-slice helical/scanno-helical CT for the regions under ordinary diagnostic conditions was done by the apparatus Toshiba Aquilion 16 for the human body phantom (Alderson) with or without the apron (Hagoromo) equivalent to 0.25 mm thick lead. Doses inside and outside the beam flux were measured by the thermoluminescent dosimeter, of which data were corrected by Radcal Model 300 ionization chamber. The doses in the gonad due to scattering were found to be in the range from 0.01 (head CT) to 1 (liver CT) mGy and to be reduced in 20-30% by the apron. Found dose were far smaller than the ICRP threshold values for inducing teratosis and infertality. (T.I.)

  16. Conventional and CT angiography in children: dosimetry and dose comparisons

    International Nuclear Information System (INIS)

    Frush, Donald P.; Yoshizumi, Terry

    2006-01-01

    Tremendous advances have been made in imaging in children with both congenital and acquired heart disease. These include technical advances in cardiac catheterization and conventional angiography, especially with advancements in interventional procedures, as well as noninvasive imaging with MR and CT angiography. With rapid advances in multidetector CT (MDCT) technology, most recently 64-detector array systems (64-slice MDCT), have come a number of advantages over MR. However, both conventional and CT angiography impart radiation dose to children. Although the presence of radiation exposure to children has long been recognized, it is apparent that our ability to assess this dose, particularly in light of the rapid advancements, has been limited. Traditional methods of dosimetry for both conventional and CT angiography are somewhat cumbersome or involve a potential for substantial uncertainty. Recent developments in dosimetry, including metal oxide semiconductor field effect transistors (MOSFET) and the availability of anthropomorphic, tissue-equivalent phantoms have provided new opportunities for dosimetric assessments. Recent work with this technology in state-of-the-art cardiac angiography suites as well as with MDCT have offered direct comparisons of doses in infants and children undergoing diagnostic cardiac evaluation. It is with these dose data that assessment of risks, and ultimately the assessment of risk-benefit, can be better achieved. (orig.)

  17. Low dose CT simulation using experimental noise model

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Satori; Zamyatin, Alexander A. [Toshiba Medical Systems Corporation, Tochigi, Otawarashi (Japan); Silver, Michael D. [Toshiba Medical Research Institute, Vernon Hills, IL (United States)

    2011-07-01

    We suggest a method to obtain system noise model experimentally without relying on assumptions on statistical distribution of the noise; also, knowledge of DAS gain and electronic noise level are not required. Evaluation with ultra-low dose CT data (5 mAs) shows good match between simulated and real data noise. (orig.)

  18. Estimating effective doses to children from CT examinations

    International Nuclear Information System (INIS)

    Heron, J.C.L.

    2000-01-01

    Full text: Assessing doses to patients in diagnostic radiology is an integral part of implementing optimisation of radiation protection. Sources of normalised data are available for estimating doses to adults undergoing CT examinations, but for children this is not the case. This paper describes a simple method for estimating effective doses arising from paediatric CT examinations. First the effective dose to an adult is calculated, having anatomically matched the scanned regions of the child and the adult and also matched the irradiation conditions. A conversion factor is then applied to the adult effective dose, based on the region of the body being scanned - head, upper or lower trunk. This conversion factor is the child-to-adult ratio of the ratios of effective dose per entrance air kerma (in the absence of the patient) at the FAD. The values of these conversion factors were calculated by deriving effective dose per entrance air kerma at the FAD for new-born, 1, 5, 10, 15 and adult phantoms using four projections (AP, PA, left and right laterals) over a range of beam qualities and FADs.The program PCXMC was used for this purpose. Results to date suggest that the conversion factors to give effective doses for children undergoing CT examinations of the upper trunk are approximately 1.3, 1.2, 1.15, 1.1 and 1.05 for ages 0, 1, 5, 10 and 15 years respectively; CT of the lower trunk - 1.4, 1.3, 1.2, 1.2, 1.1; and CT of the head - 2.3, 2.0, 1.5, 1.3, 1.1. The dependence of these factors on beam quality (HVL from 4 to 10 mm Al) is less than 10%, with harder beams resulting in slightly smaller conversion factors. Dependence on FAD is also less than 10%. Major sources of uncertainties in the conversion factors include matching anatomical regions across the phantoms, and the presence of beam divergence in the z-direction when deriving the factors. The method described provides a simple means of estimating effective doses arising from paediatric CT examinations with

  19. Analysis of fetal dose in CT procedures

    International Nuclear Information System (INIS)

    Ortiz Torres, A.; Plazas, M. C.

    2006-01-01

    It is the miracle of the life, that sublime formation, the given more beautiful gift for heaven's sake to our to exist, and it is consequently our responsibility to look after their protection and care. Today in day the quantity of radiation absorbed by the fetus in the treatments for radiodiagnostic, mainly in the procedures of on-line axial tomography, the fetus absorbs a considerable dose of radiation and the questions generated regarding if these doses, bear to a risk of malformations or if it is necessary the interruption of the pregnancy is very frequent. In most of the cases, the treatment with ionizing radiations that it is beneficial for the mother, is only indirectly it for the fetus that is exposed to a risk. The possibility that a fetus or a small boy contract cancer caused by the radiation it can be three times superior to that of the population in general, of there the importance of analyzing the goods of the prenatal irradiation and the main agents to consider for the estimate of the magnitude of the risk of the exhibitions in uterus. In the different circumstances in that these can happen in treatments of on-line axial tomography computerized. (Author)

  20. Interobserver variability in visual evaluation of thoracic CT scans and comparison with automatic computer measurements of CT lung density

    DEFF Research Database (Denmark)

    Winkler Wille, Mathilde Marie; Thomsen, Laura Hohwü; Dirksen, Asger

    2012-01-01

    lung density measurements, i.e. densitometry. Methods – In a pilot study 60 CT scans were selected from a sample of 3980 CT scans from The Danish Lung Cancer Screening Trial (DLCST). The amount of emphysema in these scans was scored independently by two observers, who were blinded regarding clinical...... information. The lung was segmented automatically by in-house developed computer software, and the percentage of pixels below -950 HU was used as a surrogate marker for emphysema. The observer variability, as well as the correlation with the lung density measurements, was analysed using Spearman’s rank...... in emphysema grading. However, the agreement with the CT lung density measurement was poor, indicating that the two types of evaluation represent different aspects of emphysema. Most likely, they should be seen as complementary rather than competitive evaluations. Future comparison with physiological tests...

  1. Correlation of ultra-low dose chest CT findings with physiologic measures of asbestosis

    Energy Technology Data Exchange (ETDEWEB)

    Manners, David [Sir Charles Gairdner Hospital, Department of Respiratory Medicine, Nedlands, WA (Australia); Wong, Patrick; Murray, Conor; Teh, Joelin [Royal Perth Hospital, Department of Diagnostic Imaging, Perth (Australia); Kwok, Yi Jin [Sir Charles Gairdner Hospital, Department of Diagnostic Imaging, Nedlands, WA (Australia); De Klerk, Nick; Franklin, Peter [University of Western Australia, School of Population Health, Perth, WA (Australia); Alfonso, Helman; Reid, Alison [Curtin University, School of Public Health, Perth, WA (Australia); Musk, A.W.B. [Sir Charles Gairdner Hospital, Department of Respiratory Medicine, Nedlands, WA (Australia); University of Western Australia, School of Population Health, Perth, WA (Australia); University of Western Australia, School of Medicine and Pharmacology, Perth, WA (Australia); Brims, Fraser J.H. [Sir Charles Gairdner Hospital, Department of Respiratory Medicine, Nedlands, WA (Australia); University of Western Australia, School of Population Health, Perth, WA (Australia); Curtin University, Curtin Medical School, Perth (Australia)

    2017-08-15

    The correlation between ultra low dose computed tomography (ULDCT)-detected parenchymal lung changes and pulmonary function abnormalities is not well described. This study aimed to determine the relationship between ULDCT-detected interstitial lung disease (ILD) and measures of pulmonary function in an asbestos-exposed population. Two thoracic radiologists independently categorised prone ULDCT scans from 143 participants for ILD appearances as absent (score 0), probable (1) or definite (2) without knowledge of asbestos exposure or lung function. Pulmonary function measures included spirometry and diffusing capacity to carbon monoxide (DLCO). Participants were 92% male with a median age of 73.0 years. CT dose index volume was between 0.6 and 1.8 mGy. Probable or definite ILD was reported in 63 (44.1%) participants. Inter-observer agreement was good (k = 0.613, p < 0.001). There was a statistically significant correlation between the ILD score and both forced expiratory volume in 1 second (FEV{sub 1}) and forced vital capacity (FVC) (r = -0.17, p = 0.04 and r = -0.20, p = 0.02). There was a strong correlation between ILD score and DLCO (r = -0.34, p < 0.0001). Changes consistent with ILD on ULDCT correlate well with corresponding reductions in gas transfer, similar to standard CT. In asbestos-exposed populations, ULDCT may be adequate to detect radiological changes consistent with asbestosis. (orig.)

  2. Correlation of ultra-low dose chest CT findings with physiologic measures of asbestosis

    International Nuclear Information System (INIS)

    Manners, David; Wong, Patrick; Murray, Conor; Teh, Joelin; Kwok, Yi Jin; De Klerk, Nick; Franklin, Peter; Alfonso, Helman; Reid, Alison; Musk, A.W.B.; Brims, Fraser J.H.

    2017-01-01

    The correlation between ultra low dose computed tomography (ULDCT)-detected parenchymal lung changes and pulmonary function abnormalities is not well described. This study aimed to determine the relationship between ULDCT-detected interstitial lung disease (ILD) and measures of pulmonary function in an asbestos-exposed population. Two thoracic radiologists independently categorised prone ULDCT scans from 143 participants for ILD appearances as absent (score 0), probable (1) or definite (2) without knowledge of asbestos exposure or lung function. Pulmonary function measures included spirometry and diffusing capacity to carbon monoxide (DLCO). Participants were 92% male with a median age of 73.0 years. CT dose index volume was between 0.6 and 1.8 mGy. Probable or definite ILD was reported in 63 (44.1%) participants. Inter-observer agreement was good (k = 0.613, p < 0.001). There was a statistically significant correlation between the ILD score and both forced expiratory volume in 1 second (FEV 1 ) and forced vital capacity (FVC) (r = -0.17, p = 0.04 and r = -0.20, p = 0.02). There was a strong correlation between ILD score and DLCO (r = -0.34, p < 0.0001). Changes consistent with ILD on ULDCT correlate well with corresponding reductions in gas transfer, similar to standard CT. In asbestos-exposed populations, ULDCT may be adequate to detect radiological changes consistent with asbestosis. (orig.)

  3. Intracrainal metastases of lung cancer -CT and histopathologic correlation-

    International Nuclear Information System (INIS)

    Park, Hyun Ju; Kim, Myung Soon; Kang, Myung Jae

    1991-01-01

    The authors retrospectively analyzed high resolution (HR) CT scans of the brain in 23 patients with surgically proved primary lung cancer and intracranial metastatic lesions from April 1986 to March 1990. The purpose of this study was to evaluate the relationship between histopathologic types of primary lung cancer and HRCT findings of brain. The results were as follows: The locations of metastatic lesion were intraaxial in 93% and extraaxial in 7%. In the intraaxial lesions, most were in the supratentorial area (83%) and the remainer in the infratentorial area (10%). Among the supratentorial lesions, the parietal lobe was the most commonly involved (33%), while the second most common location was frontal lobe (22%). The HRCT showed multiple lesions in 52% and solitary lesions in 48%. All cell types except for squamous cell carcinoma showed the same incidence in multiplicity, and the squamous cell carcinoma showed slightly more multiple lesions rather than solitary ones. The degree of peritumoral edema was none in 4%, mild in 25%, moderate in 46%, and severe in 25%. All cell types except for squamous cell carcinoma in general showed a moderate degree of edema, and the squamous cell carcinoma mainly showed mild and severe edema. Precontrast CT scans showed mixed density in 52%, isodensity in 24%, low density in 19%, and high density in 5%. All cell types except for large cell carcinoma showed mixed density, the large cell carcinoma showed a low density unlike the others. Hemorrhages were seen in 24% and noted in all cell types except for large cell carcinoma. Postcontrast CT scans showed ring enhancement in 64%, nodular enhancement in 20%, and inhomogeneous enhancement in 16%. All cell types except for small cell carcinoma generally showed ring enhancement, and the small cell carcinoma showed a variable degree of enhancement

  4. The impact of central lung distance, maximal heart distance, and radiation technique on the volumetric dose of the lung and heart for intact breast radiation

    International Nuclear Information System (INIS)

    Kong, F.-M.; Klein, Eric E.; Bradley, Jeffrey D.; Mansur, David B.; Taylor, Marie E.; Perez, Carlos A.; Myerson, Robert J.; Harms, William B.

    2002-01-01

    Purpose: To investigate the impact of radiographic parameter and radiation technique on the volumetric dose of lung and heart for intact breast radiation. Methods and Materials: Forty patients with both two-dimensional (2D) and computed tomographic (CT) simulations were enrolled in the study. Central lung distance (CLD), maximal heart distance (MHD), and maximal heart length (MHL) were measured under virtual simulation. Four plans were compared for each patient. Plan A used a traditional 2D tangential setup. Plan B used clinical target volume (CTV) based three-dimensional (3D) planning. Both plans C and D used a combination of a medial breast field with shallow tangents. Plan D is a further modification of plan C. Results: Under the traditional tangential setup, the mean ipsilateral lung dose and volume at 20, 30, and 40 Gy correlated linearly with CLD (R = 0.85∼0.91). The mean ipsilateral lung dose (Gy) approximated 4 times the CLD value (cm), whereas the percentage volume (%) of ipsilateral lung at 20, 30, and 40 Gy was about 10 times the CLD (cm). The mean heart dose and percentage volume at 20, 30, and 40 Gy correlated with MHD (R = 0.76∼0.80) and MHL (R 0.65∼0.75). The mean heart dose (Gy) approximated 3 times the MHD value (cm), and the percentage volume (%) of the heart at 10, 20, 30, and 40 Gy was about 6 times MHD (cm). Radiation technique impacted lung and heart dose. The 3D tangential plan (plan B) failed to reduce the volumetric dose of lung and heart from that of the 2D plan (plan A). The medial breast techniques (plans C and D) significantly decreased the volume of lung and heart receiving high doses (30 and 40 Gy). Plan D further decreased the 20 Gy volumes. By use of the medial breast technique, the lung and heart dose were not impacted by original CLD and MHD/MHL. Therefore, the improvement from the tangential technique was more remarkable for patients with CLD ≥ 3.0 cm (p<0.001). Conclusions: The CLD and MHD impact the volumetric dose of

  5. Low dose CT reconstruction via L1 norm dictionary learning using alternating minimization algorithm and balancing principle.

    Science.gov (United States)

    Wu, Junfeng; Dai, Fang; Hu, Gang; Mou, Xuanqin

    2018-04-18

    Excessive radiation exposure in computed tomography (CT) scans increases the chance of developing cancer and has become a major clinical concern. Recently, statistical iterative reconstruction (SIR) with l0-norm dictionary learning regularization has been developed to reconstruct CT images from the low dose and few-view dataset in order to reduce radiation dose. Nonetheless, the sparse regularization term adopted in this approach is l0-norm, which cannot guarantee the global convergence of the proposed algorithm. To address this problem, in this study we introduced the l1-norm dictionary learning penalty into SIR framework for low dose CT image reconstruction, and developed an alternating minimization algorithm to minimize the associated objective function, which transforms CT image reconstruction problem into a sparse coding subproblem and an image updating subproblem. During the image updating process, an efficient model function approach based on balancing principle is applied to choose the regularization parameters. The proposed alternating minimization algorithm was evaluated first using real projection data of a sheep lung CT perfusion and then using numerical simulation based on sheep lung CT image and chest image. Both visual assessment and quantitative comparison using terms of root mean square error (RMSE) and structural similarity (SSIM) index demonstrated that the new image reconstruction algorithm yielded similar performance with l0-norm dictionary learning penalty and outperformed the conventional filtered backprojection (FBP) and total variation (TV) minimization algorithms.

  6. WE-FG-202-03: Quantitative CT-Based Analysis to Assess Lung Injury Following Proton Radiotherapy

    International Nuclear Information System (INIS)

    Underwood, T; Grassberger, C; Willers, H; MacDonald, S; Jimenez, R; Paganetti, H

    2016-01-01

    Purpose: Relative to photon alternatives, the increased dose-conformity associated with proton therapy is expected to reduce the extent of radiation-induced lung toxicity. However, analysis of follow-up data is yet to be published in this area. In this study we retrospectively analyzed late-phase HU changes for proton therapy cohorts of chest wall and lung patients. Methods: From our institution’s register of patients treated using double-scattered protons, all chest wall and stereotactic lung cases (treated 2011–2012 and 2008–2014 respectively) were initially considered. Follow-up CT data were accessible for 10 chest wall cases (prescribed 50.4 GyRBE in 28 fractions) and 16 lung cases (prescribed 42–50 GyRBE in 3–4 fractions). CT time-points ranged from 0.5–3.5 years post-treatment. Planning doses were recalculated using TOPAS Monte Carlo simulations and mapped onto the follow-up images using deformable registration. Excluding internal target volumes, changes in HU between each patient’s planning and follow-up CT(s) were evaluated for dose bins of 2–30 GyRBE (2 GyRBE increments). Results: Linear increases in HU per unit dose, with correlations statistically significant at the 1% level (one-sided Spearman’s rank test), were evident for all 10 chest wall cases and 14/16 lung cases. The mean changes in HU/Gy were: 1.76 (SD=0.73) for the chest wall cohort, and 1.40 (SD=0.87) for the lung cohort. The median scan times post treatment were 21 and 12 months respectively. All 26 patients developed solid consolidation (scar-like radiographic opacities) within the exposed lung(s). Conclusion: Analysis of follow-up CTs revealed statistically significant correlations in HU-change/dose for two proton cohorts (lung and chest wall). Quantitatively, the late-phase changes we report broadly match published photon data. Further analysis of such radiographic changes, particularly via matched cohort studies drawing upon consistent imaging protocols, could play an

  7. WE-FG-202-03: Quantitative CT-Based Analysis to Assess Lung Injury Following Proton Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, T [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); University College London, London (United Kingdom); Grassberger, C; Willers, H; MacDonald, S; Jimenez, R; Paganetti, H [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: Relative to photon alternatives, the increased dose-conformity associated with proton therapy is expected to reduce the extent of radiation-induced lung toxicity. However, analysis of follow-up data is yet to be published in this area. In this study we retrospectively analyzed late-phase HU changes for proton therapy cohorts of chest wall and lung patients. Methods: From our institution’s register of patients treated using double-scattered protons, all chest wall and stereotactic lung cases (treated 2011–2012 and 2008–2014 respectively) were initially considered. Follow-up CT data were accessible for 10 chest wall cases (prescribed 50.4 GyRBE in 28 fractions) and 16 lung cases (prescribed 42–50 GyRBE in 3–4 fractions). CT time-points ranged from 0.5–3.5 years post-treatment. Planning doses were recalculated using TOPAS Monte Carlo simulations and mapped onto the follow-up images using deformable registration. Excluding internal target volumes, changes in HU between each patient’s planning and follow-up CT(s) were evaluated for dose bins of 2–30 GyRBE (2 GyRBE increments). Results: Linear increases in HU per unit dose, with correlations statistically significant at the 1% level (one-sided Spearman’s rank test), were evident for all 10 chest wall cases and 14/16 lung cases. The mean changes in HU/Gy were: 1.76 (SD=0.73) for the chest wall cohort, and 1.40 (SD=0.87) for the lung cohort. The median scan times post treatment were 21 and 12 months respectively. All 26 patients developed solid consolidation (scar-like radiographic opacities) within the exposed lung(s). Conclusion: Analysis of follow-up CTs revealed statistically significant correlations in HU-change/dose for two proton cohorts (lung and chest wall). Quantitatively, the late-phase changes we report broadly match published photon data. Further analysis of such radiographic changes, particularly via matched cohort studies drawing upon consistent imaging protocols, could play an

  8. CT-quantified emphysema distribution is associated with lung function decline

    NARCIS (Netherlands)

    Hoesein, F.A.A.M.; Rikxoort, E.M. van; Ginneken, B. van; de Jong, P. A.; Prokop, M.; Lammers, J.W.; Zanen, P.

    2012-01-01

    Emphysema distribution is associated with COPD. It is however unknown whether CT-quantified emphysema distribution (upper/lower lobe) is associated with lung function decline in heavy (former) smokers.587 male participants underwent lung CT-scanning and pulmonary function testing at baseline and

  9. Dual energy CT of the chest: how about the dose?

    Science.gov (United States)

    Schenzle, Jan C; Sommer, Wieland H; Neumaier, Klement; Michalski, Gisela; Lechel, Ursula; Nikolaou, Konstantin; Becker, Christoph R; Reiser, Maximilian F; Johnson, Thorsten R C

    2010-06-01

    New generation Dual Source computed tomography (CT) scanners offer different x-ray spectra for Dual Energy imaging. Yet, an objective, manufacturer independent verification of the dose required for the different spectral combinations is lacking. The aim of this study was to assess dose and image noise of 2 different Dual Energy CT settings with reference to a standard chest scan and to compare image noise and contrast to noise ratios (CNR). Also, exact effective dose length products (E/DLP) conversion factors were to be established based on the objectively measured dose. An anthropomorphic Alderson phantom was assembled with thermoluminescent detectors (TLD) and its chest was scanned on a Dual Source CT (Siemens Somatom Definition) in dual energy mode at 140 and 80 kVp with 14 x 1.2 mm collimation. The same was performed on another Dual Source CT (Siemens Somatom Definition Flash) at 140 kVp with 0.8 mm tin filter (Sn) and 100 kVp at 128 x 0.6 mm collimation. Reference scans were obtained at 120 kVp with 64 x 0.6 mm collimation at equivalent CT dose index of 5.4 mGy*cm. Syringes filled with water and 17.5 mg iodine/mL were scanned with the same settings. Dose was calculated from the TLD measurements and the dose length products of the scanner. Image noise was measured in the phantom scans and CNR and spectral contrast were determined in the iodine and water samples. E/DLP conversion factors were calculated as ratio between the measured dose form the TLDs and the dose length product given in the patient protocol. The effective dose measured with TLDs was 2.61, 2.69, and 2.70 mSv, respectively, for the 140/80 kVp, the 140 Sn/100 kVp, and the standard 120 kVp scans. Image noise measured in the average images of the phantom scans was 11.0, 10.7, and 9.9 HU (P > 0.05). The CNR of iodine with optimized image blending was 33.4 at 140/80 kVp, 30.7 at 140Sn/100 kVp and 14.6 at 120 kVp. E/DLP conversion factors were 0.0161 mSv/mGy*cm for the 140/80 kVp protocol, 0.0181 m

  10. The effect of inspiration on airway dimensions measured in CT images from the Danish Lung Cancer Screening Trial

    DEFF Research Database (Denmark)

    Petersen, Jens; Wille, Mathilde; Thomsen, Laura

    2013-01-01

    of the same subject using image registration. Mixed effect models were used to predict the relative change in lumen diameter (LD) and wall thickness (WT) in airways of generation 0 (trachea) to 6 based on relative changes in the segmented total lung volume (TLV). Results: On average, 1.0, 2.0, 3.9, 7.6, 15...... and Materials: We selected from the Danish Lung Cancer Screening Trial 978 subjects without COPD who were scanned annually for 5 years with low-dose multi-slice CT. Using in-house developed software, the lungs and airways were automatically segmented and corresponding airway branches were found in all scans......Purpose: Airway dimensions measured from CT are increasingly being used to investigate diseases such as chronic obstructive pulmonary disease (COPD). In this study, we investigate the effect of differences in inspiration level on such measurements in voluntary inspiration breathhold scans. Methods...

  11. The accuracy of CT-based inhomogeneity corrections and in vivo dosimetry for the treatment of lung cancer

    International Nuclear Information System (INIS)

    Essers, M.; Lanson, J.H.; Leunens, G.; Schnabel, T.; Mijnheer, B.J.

    1995-01-01

    Purpose: To determine the accuracy of dose calculations based on CT-densities for lung cancer patients irradiated with an anterioposterior parallel-opposed treatment technique and to evaluate, for this technique, the use of diodes and an Electronic Portal Imaging Device (EPID) for absolute exit dose and relative transmission dose verification, respectively. Materials and methods: Dose calculations were performed using a 3-dimensional treatment planning system, using CT-densities or assuming the patient to be water-equivalent. A simple inhomogeneity correction model was used to take CT-densities into account. For 22 patients, entrance and exit dose calculations at the central beam axis and at several off-axis positions were compared with diode measurements. For 12 patients, diode exit dose measurements and exit dose calculations were compared with EPID transmission dose values. Results: Using water-equivalent calculations, the actual exit dose value under lung was, on average, underestimated by 30%, with an overall spread of 10% (1 SD) in the ratio of measurement and calculation. Using inhomogeneity corrections, the exit dose was, on average, overestimated by 4%, with an overall spread of 6% (1 SD). Only 2% of the average deviation was due to the inhomogeneity correction model. The other 2% resulted from a small inaccuracy in beam fit parameters and the fact that lack of backscatter is not taken into account by the calculation model. Organ motion, resulting from the ventilatory or cardiac cycle, caused an estimated uncertainty in calculated exit dose of 2.5% (1 SD). The most important reason for the large overall spread was, however, the inaccuracy involved in point measurements, of about 4% (1 SD), which resulted from the systematic and random deviation in patient set-up and therefore in the diode position with respect to patient anatomy. Transmission and exit dose values agreed with an average difference of 1.1%. Transmission dose profiles also showed good

  12. Monte Carlo dose calculation of microbeam in a lung phantom

    International Nuclear Information System (INIS)

    Company, F.Z.; Mino, C.; Mino, F.

    1998-01-01

    Full text: Recent advances in synchrotron generated X-ray beams with high fluence rate permit investigation of the application of an array of closely spaced, parallel or converging microplanar beams in radiotherapy. The proposed techniques takes advantage of the hypothesised repair mechanism of capillary cells between alternate microbeam zones, which regenerates the lethally irradiated endothelial cells. The lateral and depth doses of 100 keV microplanar beams are investigated for different beam dimensions and spacings in a tissue, lung and tissue/lung/tissue phantom. The EGS4 Monte Carlo code is used to calculate dose profiles at different depth and bundles of beams (up to 20x20cm square cross section). The maximum dose on the beam axis (peak) and the minimum interbeam dose (valley) are compared at different depths, bundles, heights, widths and beam spacings. Relatively high peak to valley ratios are observed in the lung region, suggesting an ideal environment for microbeam radiotherapy. For a single field, the ratio at the tissue/lung interface will set the maximum dose to the target volume. However, in clinical application, several fields would be involved allowing much greater doses to be applied for the elimination of cancer cells. We conclude therefore that multifield microbeam therapy has the potential to achieve useful therapeutic ratios for the treatment of lung cancer

  13. Dose assessment according to changes in algorithm in cardiac CT

    Science.gov (United States)

    Jang, H. C.; Cho, J. H.; Lee, H. K.; Hong, I. S.; Cho, M. S.; Park, C. S.; Lee, S. Y.; Dong, K. R.; Goo, E. H.; Chung, W. K.; Ryu, Y. H.; Lim, C. S.

    2012-06-01

    The principal objective of this study was to determine the effects of the application of the adaptive statistical iterative reconstruction (ASIR) technique in combination with another two factors (body mass index (BMI) and tube potential) on radiation dose in cardiac computed tomography (CT). For quantitative analysis, regions of interest were positioned on the central region of the great coronary artery, the right coronary artery, and the left anterior descending artery, after which the means and standard deviations of measured CT numbers were obtained. For qualitative analysis, images taken from the major coronary arteries (right coronary, left anterior descending, and left circumflex) were graded on a scale of 1-5, with 5 indicating the best image quality. Effective dose, which was calculated by multiplying the value of the dose length product by a standard conversion factor of 0.017 for the chest, was employed as a measure of radiation exposure dose. In cardiac CT in patients with BMI of less than 25 kg/m2, the use of 40% ASIR in combination with a low tube potential of 100 kVp resulted in a significant reduction in the radiation dose without compromising diagnostic quality. Additionally, the combination of the 120 kVp protocol and the application of 40% ASIR application for patients with BMI higher than 25 kg/m2 yielded similar results.

  14. CT-guided percutaneous lung biopsy: Comparison of conventional CT fluoroscopy to CT fluoroscopy with electromagnetic navigation system in 60 consecutive patients

    Energy Technology Data Exchange (ETDEWEB)

    Grand, David Justin, E-mail: dgrand@lifespan.org [Department of Diagnostic Imaging, Warren Alpert School of Medicine, Brown University, Providence, RI 02903 (United States); Atalay, Michael A., E-mail: matalay@lifespan.org [Department of Diagnostic Imaging, Warren Alpert School of Medicine, Brown University, Providence, RI 02903 (United States); Cronan, John J., E-mail: cronan@lifespan.org [Department of Diagnostic Imaging, Warren Alpert School of Medicine, Brown University, Providence, RI 02903 (United States); Mayo-Smith, William W., E-mail: wmayo-smith@lifespan.org [Department of Diagnostic Imaging, Warren Alpert School of Medicine, Brown University, Providence, RI 02903 (United States); Dupuy, Damian E., E-mail: ddupuy@lifespan.org [Department of Diagnostic Imaging, Warren Alpert School of Medicine, Brown University, Providence, RI 02903 (United States)

    2011-08-15

    Purpose: To determine if use of an electromagnetic navigation system (EMN) decreases radiation dose and procedure time of CT fluoroscopy guided lung biopsy in lesions smaller than 2.5 cm. Materials/methods: 86 consecutive patients with small lung masses (<2.5 cm) were approached. 60 consented and were randomized to undergo biopsy with CT fluoroscopy (CTF) (34 patients) or EMN (26 patients). Technical failure required conversion to CTF in 8/26 EMN patients; 18 patients completed biopsy with EMN. Numerous biopsy parameters were compared as described below. Results: Average fluoroscopy time using CTF was 28.2 s compared to 35.0 s for EMN (p = 0.1). Average radiation dose was 117 mGy using CTF and 123 mGy for EMN (p = 0.7). Average number of needle repositions was 3.7 for CTF and 4.4 for EMN (p = 0.4). Average procedure time was 15 min for CTF and 20 min for EMN (p = 0.01). There were 7 pneumothoracesin the CTF group and 6 pneumothoraces in the EMN group (p = 0.7). One pneumothorax in the CTF group and 3 pneumothoraces in the EMN group required chest tube placement (p = 0.1). One pneumothorax patient in each group required hospital admission. Diagnostic specimens were obtained in 31/34 patients in the CTF group and 22/26 patients in the EMN group (p = 0.4). Conclusions: EMN was not statistically different than CTF for fluoroscopy time, radiation dose, number of needle repositions, incidence of pneumothorax, need for chest tube, or diagnostic yield. Procedure time was increased with EMN.

  15. Comparison of CT number calibration techniques for CBCT-based dose calculation

    Energy Technology Data Exchange (ETDEWEB)

    Dunlop, Alex [The Royal Marsden NHS Foundation Trust, Joint Department of Physics, Institute of Cancer Research, London (United Kingdom); The Royal Marsden Hospital, Sutton, Surrey, Downs Road (United Kingdom); McQuaid, Dualta; Nill, Simeon; Hansen, Vibeke N.; Oelfke, Uwe [The Royal Marsden NHS Foundation Trust, Joint Department of Physics, Institute of Cancer Research, London (United Kingdom); Murray, Julia; Bhide, Shreerang; Harrington, Kevin [The Royal Marsden Hospital, Sutton, Surrey, Downs Road (United Kingdom); The Institute of Cancer Research, London (United Kingdom); Poludniowski, Gavin [Karolinska University Hospital, Department of Medical Physics, Stockholm (Sweden); Nutting, Christopher [The Institute of Cancer Research, London (United Kingdom); Newbold, Kate [The Royal Marsden Hospital, Sutton, Surrey, Downs Road (United Kingdom)

    2015-12-15

    The aim of this work was to compare and validate various computed tomography (CT) number calibration techniques with respect to cone beam CT (CBCT) dose calculation accuracy. CBCT dose calculation accuracy was assessed for pelvic, lung, and head and neck (H and N) treatment sites for two approaches: (1) physics-based scatter correction methods (CBCT{sub r}); (2) density override approaches including assigning water density to the entire CBCT (W), assignment of either water or bone density (WB), and assignment of either water or lung density (WL). Methods for CBCT density assignment within a commercially available treatment planning system (RS{sub auto}), where CBCT voxels are binned into six density levels, were assessed and validated. Dose-difference maps and dose-volume statistics were used to compare the CBCT dose distributions with the ground truth of a planning CT acquired the same day as the CBCT. For pelvic cases, all CTN calibration methods resulted in average dose-volume deviations below 1.5 %. RS{sub auto} provided larger than average errors for pelvic treatments for patients with large amounts of adipose tissue. For H and N cases, all CTN calibration methods resulted in average dose-volume differences below 1.0 % with CBCT{sub r} (0.5 %) and RS{sub auto} (0.6 %) performing best. For lung cases, WL and RS{sub auto} methods generated dose distributions most similar to the ground truth. The RS{sub auto} density override approach is an attractive option for CTN adjustments for a variety of anatomical sites. RS{sub auto} methods were validated, resulting in dose calculations that were consistent with those calculated on diagnostic-quality CT images, for CBCT images acquired of the lung, for patients receiving pelvic RT in cases without excess adipose tissue, and for H and N cases. (orig.) [German] Ziel dieser Arbeit ist der Vergleich und die Validierung mehrerer CT-Kalibrierungsmethoden zur Dosisberechnung auf der Grundlage von Kegelstrahlcomputertomographie

  16. Mucosal dose prescription in endobronchial brachytherapy: a study based on CT-dosimetry

    International Nuclear Information System (INIS)

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