نتایج جستجو برای: noise dose
تعداد نتایج: 502879 فیلتر نتایج به سال:
The aim of the study was to investigate the image quality of low-dose CT images with different reconstruction algorithms including filtered back projection (FBP), hybrid iterative reconstruction (HIR), and iterative model reconstruction (IMR) algorithms by comparison of routine dose images with FBP reconstruction, in patients with malignant obstructive tracheobronchial diseases.In total, 60 pat...
OBJECTIVES To utilize a novel objective approach combining a software phantom and an image quality metric to systematically evaluate the influence of sinogram affirmed iterative reconstruction (SAFIRE) of multidetector computed tomography (MDCT) data on image noise characteristics and low-contrast detectability (LCD). MATERIALS AND METHODS A low-contrast and a high-contrast phantom were exami...
Abstract Purpose Phantom studies in CT emphysema quantification show that iterative reconstruction and deep learning-based noise reduction (DLNR) allow lower radiation dose. We compared on ultra-low-dose (ULDCT) with without reduction, to standard-dose (SDCT) chronic obstructive pulmonary disease (COPD). Method Forty-nine COPD patients underwent ULDCT (third generation dual-source CT; 70ref-mAs...
Organ Dose Modulation or ODM (GE Healthcare, Milwaukee, WI) was evaluated to characterize changes in CTDIvol, image noise, effective dose, and organ dose saving to patients. Three separate investigations were completed: a tube current modulation phantom was scanned with and without ODM, a CTDIvol phantom was scanned with ODM, and Monte Carlo simulations were performed. ODM was found to reduce t...
OBJECTIVES To evaluate the clinical value of noise-based tube current reduction method with iterative reconstruction for obtaining consistent image quality with dose optimization in prospective electrocardiogram (ECG)-triggered coronary CT angiography (CCTA). MATERIALS AND METHODS We performed a prospective randomized study evaluating 338 patients undergoing CCTA with prospective ECG-triggeri...
in recent years noise has been well known as an environmental pollution. particularly its effects will be more serious in some environments including hospitals which patients need a calm and peaceful condition. this study aims to evaluate hospitals noise pollution level. this study is a cross-sectional study. noise measurements were made in all hospital wards in a workday and weekend from 8 to ...
پایان نامه حاضر در مورد امکان سنجی استفاده از مدلسازی آماری مبـتنی برbmd جهت برآورد حجم بحرانی خونریزی درایجاد مقادیر معینی از خطر مرگ ناشی از خونــریزی مــغزی غیرتروماتیک(خود به خودی) می باشد. روشbmd در رابطه با مقدار دوز یا حجم بحرانی یک وضعیت از پیش تعیین شده برای بدست آوردن بهترین پاسخ جهت ارزیابی خطرات سلامتی و بهداشتی و همچنین برآورد مقدار یا حجم بحرانی دوز می باشد. روشbmd یک روش جایگزین...
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