Evaluation of radiation dose and image quality of CT scan for whole-body pediatric PET/CT: A phantom study

2014 ◽  
Vol 41 (9) ◽  
pp. 092505 ◽  
Author(s):  
Ching-Ching Yang ◽  
Shu-Hsin Liu ◽  
Greta S. P. Mok ◽  
Tung-Hsin Wu
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Ct Scan ◽  
Phantom Study ◽  
Whole Body ◽  
Pet Ct

scholarly journals Analisis Perubahan kV dan mAs terhadap Kualitas Gambar dan Dosis Radiasi pada Pemeriksaan Multislice Computed Tomography Abdomen dalam Kasus Tumor Abdomen di Instalasi Radiologi RSUD dr. Saiful Anwar Malang

2016 ◽  
Vol 2 (1) ◽  
pp. 129-133
Author(s):  
Ardi Soesilo Wibowo ◽  
Gatot Murti Wibowo ◽  
Anang Prabowo
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Ct Scan ◽  
Quantitative Research ◽  
Scoring Method ◽  
Tube Voltage ◽  
Abdominal Tumor ◽  
Abdomen Ct ◽  
Voltage Variation

Backgroud: Examination of the abdomen CT scan is often done by using standard protocol, meanwhile the actual parameter can be modified according to local needs considering image quality and radiation dose based on Karabulut and Ariyuek (2016). Abdomen CT Scan by GE 16 slices unit in Radiology Instaallation of Dr. Saiful Anwar Malang Hospital, using exposure factor of 120 kV, 234 mAs and the value of the CTDI dose was 53.04 mGy. While the BAPETEN’s reference of CTDI value, a CT scan of abdomen was 25 mGy.  This study aims to determine the changes of the value of kV and mAs to the image quality and the radiaton dose in the abdomen MSCT examination on abdominal tumor case in Radiology Installation of Dr. Saiful Anwar Malang Hospital.Methods: This research was a quantitative research with an experimental approach. The data were collected from three variations of tube voltage (kV) ie 100 kV, 120 kV and 140 kV and three variations of tube current value and time (mAs) ie, 180 mAs, 195 mAs, and 210 mAs. Radiographs was evaluated by three radiology physicians. Data were analyzed by scoring method of respondent’s assessment to assess MSCT image quality of abdominal tumor, while the radiation dose was obtained by CTDI recording.Results: The results showed that there was influence of tube voltage variation to image quality of abdominal tumor using MSCT unit. The higher kV used, the higher image quality resulted. From the calculation of the percentage from the assessment, the highest score of variation was at 140 kV, while the lowest score of variation was at 100 kV. Based on the recording CTDI radiation dose on the monitor, found that the higher value of kV, the higher radiation resulted. The mAs variations influenced the image quality of abdominal tumor using MSCT unit. Acoording to the percentage of the assessment, the highest score of variation found in 210 mAs, and the lowest score of variation found in 180 mAs. Based on the recording of radiation dose on the monitor, the higher mAs value, the higher radiation dose using MSCT unit. It was recommended to use 195 kV and 120 mAs for MSCT examination of abdominal tumor in Radiology Installation of Dr. Saiful Anwar Malang Hospital.Conclusion: There was influence of kV and mAs variation to anatomical image clarity and radiation dose of abdomen MSCT examination

scholarly journals Optimisation of BMI-based Images for Overweight and Obese Patients – Implications on Image Quality, Quantitative Accuracy and Radiation Dose in Whole Body 18F-FDG PET/CT Imaging.

2020 ◽  
Author(s):  
Yassine Bouchareb ◽  
Naima Tag ◽  
Hajir Sulaiman ◽  
Khulood Al-Riyami ◽  
Humoud Al-Dhuhli
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Fdg Pet ◽  
Ct Imaging ◽  
Added Value ◽  
Whole Body ◽  
Obese Patients ◽  
Large Patient ◽  
Quantitative Accuracy ◽  
Pet Ct

Abstract Background - In PET/CT imaging the amount of 18 F-FDG activity injected to patient is mainly based on the patient body weight (BW) or on body mass index (BMI). Imaging overweight and obese patients using standard protocols results quite often in poor diagnostic images. The purpose of this study was to optimise BMI-based whole body 18 F-FDG PET images obtained from overweight and obese patients and assess the added value in terms of image quality, quantitative accuracy and radiation dose in comparison to BW-based images. Methods - The NEMA-IEC-body phantom was scanned on the mCT 128 slices scanner (Siemens Healthineers). The spheres and background were filed with F-18 activity. Spheres-to-background (2.1kBq/mL) ratio was 4:1. Data was reconstructed using the OSEM-TOF-PSF routine reconstruction (2 iterations, 21 subsets, 3mm Gaussian filter). The optimisation was performed by varying number of iterations, number of subsets, filter’s size and type and matrix size. The phantom images were assessed using contrast recovery coefficients (CRCs). The optimised reconstruction was applied to 17 overweight and obese patients. The optimised BMI-based images and BW-based images were compared visually and using signal-to-noise ratio (SNR), SUVmax and SUVpeak measurements. Results- The visual assessment of the optimised phantom images using 1 iteration, 21 subsets, 3mm Hamming filter showed better image quality and CRC values compared to the routine reconstruction. On patient data, the optimised BMI-based images provided better image quality compared to BW-based images in 87.5% of the overweight cases and 66.7% for obese cases. Compared to BW-based images, the optimised BMI-based images resulted in reduction of 18.6% in SUVmax, 10.6% in SUVpeak and 59% in radiation dose for overweight patients. Similar trends were observed in obese patients. SNR improvement on BMI optimised images over BW images was 55% and 59% on overweight and obese patients, respectively. Conclusions - The optimised BMI-based approach using 1 iteration, 21 subsets, 3mm Hamming filter improves image quality, reduces radiation dose and provides, at least, similar quantitative accuracy compared to the BW-based approach for both overweight and obese patients. These findings are compelling enough support to conducting a full assessment of the approach on a large patient population.

Advantages of Application of Whole-Body Low-Dose Computed Tomography in Multiple Myeloma

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Chen J ◽  
◽  
Li M ◽  
Gao Z ◽  
Liu S ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Image Quality ◽  
Radiation Dose ◽  
Ct Scan ◽  
Reconstruction Algorithm ◽  
Objective Evaluation ◽  
Whole Body ◽  
Significant Difference ◽  
Group A ◽  
Group B

Aim: This study was designed to investigate the application of whole-body low-dose computed tomography in the examination of multiple myeloma. Method: 40 patients with multiple myeloma admitted to our hospital were prospectively selected as the study subjects. All patients were pathologically confirmed and/or clinically diagnosed with multiple myeloma. Patients were randomly divided into two groups: Group A (n=20) received whole-body lowdose CT scan with SAFIR iterative reconstruction algorithm; Group B (n=20) underwent whole body conventional dose CT scan combined with conventional reconstruction algorithm. The image quality was scored subjectively, and the objective evaluation indexes (including CT value and noise of neck, chest, abdomen, pelvic cavity and lower extremities, signal-to-noise ratio and image quality index) were measured and recorded, and the radiation dose was recorded. Mann-Whitney U test (to evaluate the subjective score) and t test (to evaluate the objective evaluation index and radiation dose) were used to compare the differences of the above indexes between group A and group B. Result: All the images met the diagnostic requirements. There was no statistical significance in the scores between group A and group B (P>0.05). Significant differences in CT value, noise and SNR of neck, chest, abdomen, pelvis and lower extremities between group A and group B (P<0.05) were identified. For the image quality index (figure of merit, FOM), the FOM of chest, abdomen and pelvis was not statistically significantly changed (P<0.05). The radiation dose of group A decreased by 56.77% (3.06/5.39) compared to group B with a statistically significant difference (P<0.05). The Kappa values of subjective scores of the two groups showed no statistically significant difference (respectively, 0.68 and o.69, P>0.05). Conclusion: Compared to conventional CT examination, whole-body lowdose CT scan combined with SAFIR iterative reconstruction algorithm can effectively reduce noise, reduce X-ray radiation dose, and obtain ideal image quality in multiple myeloma examination, which has a certain application value.

scholarly journals Evaluation of image quality at the detector’s edge of dedicated breast positron emission tomography

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yoko Satoh ◽  
Utaroh Motosugi ◽  
Masamichi Imai ◽  
Yoshie Omiya ◽  
Hiroshi Onishi
Keyword(s):  
Image Quality ◽  
Chest Wall ◽  
Clinical Studies ◽  
Breast Imaging ◽  
Phantom Study ◽  
Breast Lesions ◽  
Clinical Images ◽  
Dedicated Breast Pet ◽  
Pet Ct ◽  
Significant Difference

Abstract Background Using phantoms and clinical studies in prone hanging breast imaging, we assessed the image quality of a commercially available dedicated breast PET (dbPET) at the detector’s edge, where mammary glands near the chest wall are located. These are compared to supine PET/CT breast images of the same clinical subjects. Methods A breast phantom with four spheres (16-, 10-, 7.5-, and 5-mm diameter) was filled with 18F-fluorodeoxyglucose solution (sphere-to-background activity concentration ratio, 8:1). The spheres occupied five different positions from the top edge to the centre of the detector and were scanned for 5 min in each position. Reconstructed images were visually evaluated, and the contrast-to-noise ratio (CNR), contrast recovery coefficient (CRC) for all spheres, and coefficient of variation of the background (CVB) were calculated. Subsequently, clinical images obtained with standard supine PET/CT and prone dbPET were retrospectively analysed. Tumour-to-background ratios (TBRs) between breast cancer near the chest wall (close to the detector’s edge; peripheral group) and at other locations (non-peripheral group) were compared. The TBR of each lesion was compared between dbPET and PET/CT. Results Closer to the detector’s edge, the CNR and CRC of all spheres decreased while the CVB increased in the phantom study. The disadvantages of this placement were visually confirmed. Regarding clinical images, TBR of dbPET was significantly higher than that of PET/CT in both the peripheral (12.38 ± 6.41 vs 6.73 ± 3.5, p = 0.0006) and non-peripheral (12.44 ± 5.94 vs 7.71 ± 7.1, p = 0.0183) groups. There was no significant difference in TBR of dbPET between the peripheral and non-peripheral groups. Conclusion The phantom study revealed poorer image quality at < 2-cm distance from the detector’s edge than at other more central parts. In clinical studies, however, the visibility of breast lesions with dbPET was the same regardless of the lesion position, and it was higher than that in PET/CT. dbPET has a great potential for detecting breast lesions near the chest wall if they are at least 2 cm from the edge of the FOV, even in young women with small breasts.

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