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Item Metadata only Verification of a commercial monte carlo based organ and effective doses calculation in multi-detector computed tomography using thermoluminescent dosimeter(Mahidol University. Mahidol University Library and Knowledge Center, 2008) Woranut Iampa; Napapong PongnapangItem Metadata only A calculation method for the output factors of irregularly shaped electron fields by a sector-integration method(Mahidol University. Mahidol University Library and Knowledge Center, 2003) Chulee Charoonsantikul; Sivalee Suriyapee; Chotika JumpangernItem Metadata only Experimental comparison of CT image quality with scan protocols for upper abdomen using a Catphan phantom(Mahidol University. Mahidol University Library and Knowledge Center, 2024) Jongwat Cheewakul; Mululee Tuntawiroon; Nopamon SritongkulSeveral commercially available multi-slice CT systems and scan protocols were used to obtain CT images at Siriraj Hospital Imaging Center. This work compared the doses and image qualities produced from different scanners and scan protocols for upper abdomen under standardized exposure conditions. The Catphan 504 phantom was scanned on 3 multislice CT scanners, LightSpeed VCT, and Discovery CT750 HD from GE and Dual source 64 slice CT from Siemens. From phantom experiments performed with different scanning parameters, the acquired CT images from different scanners and scan protocols were analyzed for radiation dose and image quality in terms of noise, uniformity, spatial resolution, contrast resolution, and CT number accuracy. CTDI and Dose Length Product (DLP) values and effective dose were calculated for each scan. Data sets that correspond to the 3-phase daily examination were chosen and scanned three times per one information with Catphan. Noise level of the GE 750HD was higher than the other two scanners. Dual source CT gave the lowest noise. All three scanners demonstrated the same uniformity performance. GE LightSpeed VCT had better low contrast detectability and image resolution than others. The 2 GEs showed similar percentage fluctuation in CT number, but more than 10% in LDPE and PMP. Siemens showed over 10% fluctuation only in LDPE. The 2 GEs gave the same magnitude of radiation dose (16.3 and 15.8 mSv) while the radiation dose from Siemens protocol was 40% higher (22.4 mSv). All scanners produced acceptable level of image quality. However, this study showed that CT scanners and scan protocols which vary among vendors affected radiation dose and image quality. Total effective dose for patient undergoing upper abdominal CT ranges from 15.8 to 22.4 mSv.Item Metadata only The measurements of absorbed dose and effective dose by free-in-air method in multi-detector x-ray computed tomography(Mahidol University. Mahidol University Library and Knowledge Center, 2005) Samrit Kittipayak; Napapong PongnapangItem Metadata only Optimized radiation dose and image quality for abdominal CT protocol : phantom study(Mahidol University. Mahidol University Library and Knowledge Center, 2018) Saimai Siangyai; Malulee Tuntawiroon; Dittapong Songsaengthat factors affecting radiation dose and image quality were Noise Index, slice thickness and reconstruction method. A greater radiation dose is required for larger patients, or to decrease the Noise Index. Thin slices yielded poorer image quality than did... thick slices, but showed details more clearly. The results obtained from this study can be used to make small changes in the selection of an appropriate image processing method for abdominal CT scans which can reduce the dose of radiation used whileItem Metadata only Planning target volume (PTV) margin determination from Marker-based and the Exactrac 6D X-Ray IGRT system in prostate cancer patients(Mahidol University. Mahidol University Library and Knowledge Center, 2018) Siwadol Pleanarom; Lalida Tuntipumiamorn; Pittaya Dankulchai, 936 stereoscopic x-ray images and 271 cone beam computed tomography (CBCT) images from the On-Board Imager system were obtained for the analysis. Data of the setup deviations from three setup techniques, including initial laser setting up, marker... step. Introduction of the margin concept, together with image-guided radiation therapy, was found to be an effective method to correct errors from target delineation, patient setup and organ motion. In this work, prostate cancer patients, with implantedItem Metadata only Eye lens dose measurements in cyclotron based radiopharmaceuticals production(Mahidol University. Mahidol University Library and Knowledge Center, 2024) Pattaravarin Rattanamongkonkul; Putthiporn Charoenphun; Krisanat Chuamsaamarkkee; Anaya Ruangma, such as cyclotron workers, should consider to monitor the eye lens dose. Recently, new type of dosimeter called nanoDot OSL was developed for direct monitoring the eye lens dose. Meanwhile, indirect measurement method has been investigated using OSL dosimeter... doses of cyclotron staff between direct and indirect measurement methods for eye lens doses estimation. The phantom study investigated the effect of positions and angles simultaneously on the nanoDot OSL response to 137Cs source was performed. The sixItem Metadata only Deep Learning Network with Object Shape Information for Efficient Continuous-Wave THz Computed Tomography(2025-01-01) Jintamethasawat R.; Inpuak S.; Kaewhanam K.; Nilruang M.; Choobanna P.; Bunyinkgool K.; Boonyasiriwat C.; Jintamethasawat R.; Mahidol UniversityThis paper presents an efficient continuous-wave THz computed tomography, which can be achieved based on the utilization of deep learning approach together with object shape information. A modified U-Net architecture that can incorporate object... techniques, which, while computationally efficient, struggle to achieve high image quality due to their assumption of straight and narrow ray wave propagation that overlooks such effects and results in strong artifacts in the reconstructed imagesPublication Metadata only Comparison of Baseline, Bone-Subtracted, and Enhanced Chest Radiographs for Detection of Pneumothorax(2020-01-01) Fatemeh Homayounieh; Subba R. Digumarthy; Jennifer A. Febbo; Sherief Garrana; Chayanin Nitiwarangkul; Ramandeep Singh; Ruhani Doda Khera; Matthew Gilman; Mannudeep K. Kalra; Faculty of Medicine, Ramathibodi Hospital, Mahidol University; Harvard Medical Schoolchest computed tomography (CT). Two radiologists reviewed the CXR and chest CT for pneumothorax on baseline CXR (ground truth). All baseline CXR were processed to generate bone-subtracted and enhanced images (ClearRead X-ray). Four radiologists (R1-R4...© The Author(s) 2020. Purpose: To assess and compare detectability of pneumothorax on unprocessed baseline, single-energy, bone-subtracted, and enhanced frontal chest radiographs (chest X-ray, CXR). Method and Materials: Our retrospectivePublication Metadata only Metal artifact reduction and image quality evaluation of lumbar spine CT images using metal sinogram segmentation(2015-12-17) Titipong Kaewlek; Diew Koolpiruck; Saowapak Thongvigitmanee; Manus Mongkolsuk; Sastrawut Thammakittiphan; Siri On Tritrakarn; Pipat Chiewvit; King Mongkuts University of Technology Thonburi; Thailand National Electronics and Computer Technology Center; Rangsit University; Mahidol University© 2015 - IOS Press and the authors. Metal artifacts often appear in the images of computed tomography (CT) imaging. In the case of lumbar spine CT images, artifacts disturb the images of critical organs. These artifacts can affect the diagnosis..., treatment, and follow up care of the patient. One approach to metal artifact reduction is the sinogram completion method. A mixed-variable thresholding (MixVT) technique to identify the suitable metal sinogram is proposed. This technique consists of four
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