Bio-Medical Materials and Engineering - Volume 26, issue s1

Authors: Zhang, Yaonan | Sun, Tingting | Teng, Yueyang | Li, Hong | Kang, Yan

Article Type: Research Article

Abstract: Myocardial elastography (ME) is a strain imaging technique used to diagnose myocardial diseases. Axial and lateral displacement calculations are pre-conditions of strain image acquisition in ME. W.N. Lee et al. proposed a normalized cross-correlation (NCC) and recorrelation method to obtain both axial and lateral displacements in ME. However, this method is not noise-resistant and of high computational cost. This paper proposes a predicted fast NCC algorithm based on W.N. Lee’s method, with the additions of sum-table NCC and a displacement prediction algorithm, to obtain efficient and accurate axial and lateral displacements. Compared to experiments based on the NCC and recorrelation …methods, the results indicate that the proposed NCC method is much faster (predicted fast NCC method, 69.75s for a 520×260 image; NCC and recorrelation method, 1092.25s for a 520×260 image) and demonstrates better performance in eliminating decorrelation noise (SNR of the axial and lateral strain using the proposed method, 5.87 and 1.25, respectively; SNR of the axial and lateral strain using the NCC and recorrelation method, 1.48 and 1.09, respectively). Show more

Keywords: Myocardial elastography (ME), displacement estimation, normalized cross-correlation, recorrelation, prediction

DOI: 10.3233/BME-151462

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1633-S1639, 2015

Authors: Chiang, Hsien-Wen | Liu, Ya-Ling | Chen, Tou-Rong | Chen, Chun-Lon | Chiang, Hsien-Jen | Chao, Shin-Yu

Article Type: Research Article

Abstract: This work aimed to investigate the spatial distribution of scattered radiation doses induced by exposure to the portable X-ray, the C-arm machine, and to simulate the radiologist without a shield of lead clothing, radiation doses absorbed by medical staff at 2 m from the central exposure point. Material and method: With the adoption of the Rando Phantom, several frequently X-rayed body parts were exposed to X-ray radiation, and the scattered radiation doses were measured by ionization chamber dosimeters at various angles from the patient. Assuming that the central point of the X-ray was located at the belly button, five detection …points were distributed in the operation room at 1 m above the ground and 1-2 m from the central point horizontally. Results: The radiation dose measured at point B was the lowest, and the scattered radiation dose absorbed by the prosthesis from the X-ray’s vertical projection was 0.07 ±0.03 μ Gy, which was less than the background radiation levels. The Fluke biomedical model 660-5DE (400 cc) and 660-3DE (4 cc) ion chambers were used to detect air dose at a distance of approximately two meters from the central point. The AP projection radiation doses at point B was the lowest (0.07±0.03 μ Gy) and the radiation doses at point D was the highest (0.26±0.08 μ Gy) .Only taking the vertical projection into account, the radiation doses at point B was the lowest (0.52 μ Gy), and the radiation doses at point E was the highest (4 μ Gy).The PA projection radiation at point B was the lowest (0.36 μ Gy) and the radiation doses at point E was the highest(2.77 μ Gy), occupying 10-32% of the maximum doses. The maximum dose in five directions was nine times to the minimum dose. When the PX and the C-arm machine were used, the radiation doses at a distance of 2 m were attenuated to the background radiation level. The radiologist without a lead shield should stand at point B of patient’s feet. Accordingly, teaching materials on radiation safety for radiological interns and clinical technicians were formulated. Show more

Keywords: Portable X-ray machine, dose, exposure, ionization chamber dosimeter

DOI: 10.3233/BME-151463

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1641-S1650, 2015

Authors: Pan, Lung Fa | Erdene, Erdenetsetseg | Chen, Chun Chi | Pan, Lung Kwang

Article Type: Research Article

Abstract: In this study, the phantom imaging quality of 64-slice CT acquisition protocol was quantitatively evaluated using Taguchi. The phantom acrylic line group was designed and assembled with multiple layers of solid water plate in order to imitate the adult abdomen, and scanned with Philips brilliance CT in order to simulate a clinical examination. According to the Taguchi L8 (27 ) orthogonal array, four major factors of the acquisition protocol were optimized, including (A) CT slice thickness, (B) the image reconstruction filter type, (C) the spiral CT pitch, and (D) the matrix size. The reconstructed line group phantom image was counted …by four radiologists for three discrete rounds in order to obtain the averages and standard deviations of the line counts and the corresponding signal to noise ratios (S/N). The quantified S/N values were analyzed and the optimal combination of the four factor settings was determined to be comprised of (A) a 1-mm thickness, (B) a sharp filter type, (C) a 1.172 spiral CT pitch, and (D) a 1024×1024 matrix size. The dominant factors included the (A) filter type and the cross interaction between the filter type and CT slice thickness (A×B). The minor factors were determined to be (C) the spiral CT pitch and (D) the matrix size since neither was capable of yielding a 95% confidence level in the ANOVA test. Show more

Keywords: 64-slice CT, reconstructed imaging, optimization, ANOVA, line phantom

DOI: 10.3233/BME-151464

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1651-S1658, 2015

Authors: Liao, Xiongfei | Wang, Yunlai | Lang, Jinyi | Wang, Pei | Li, Jie | Ge, Ruigang | Yang, Jack

Article Type: Research Article

Abstract: To evaluate the Elekta kilovoltage CBCT doses and the associated technical protocols with patient dosimetry estimation. Image guidance technique with cone-beam CT (CBCT) in radiation oncology on a daily basis can deliver a significant dose to the patient. To evaluate the patient dose from LINAC-integrated kV cone beam CT imaging in image-guided radiotherapy. CT dose index (CTDI) were measured with PTW TM30009 CT ion chamber in air, in head phantom and body phantom, respectively; with different combinations of tube voltage, current, exposure time per frame, collimator and gantry rotation range. Dose length products (DLP) were subsequently calculated to account for …volume integration effects. The CTDI and DLP were also compared to AcQSim™ simulator CT for routine clinical protocols. Both CTDIair and CTDIw depended quadratically on the voltage, while linearly on milliampere x seconds (mAs) settings. It was shown that CTDIw and DLP had very close relationship with the collimator settings and the gantry rotation ranges. Normalized CTDIw for Elekta XVI™ CBCT was lower than that of ACQSim simulator CT owing to its pulsed radiation output characteristics. CTDIw can be used to assess the patient dose in CBCT due to its simplicity for measurement and reproducibility. Regular measurement should be performed in QA & QC program. Optimal image parameters should be chosen to reduce patient dose during CBCT. Show more

Keywords: Cone-beam CT, CT dose index, dose-length product, image-guided radiotherapy

DOI: 10.3233/BME-151465

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1659-S1667, 2015

Authors: Park, S.I. | Lee, J.H. | Ham, H.J. | Jung, Y.J. | Park, M.S. | Lee, J. | Maeng, L.S. | Chung, Y.A. | Jang, K.S.

Article Type: Research Article

Abstract: Liver cirrhosis is a predominant risk factor for hepatocellular carcinoma (HCC). However, the exact mechanism of the progression from cirrhosis to cancer remains unclear. The uptake of 2-[18 F]-fluoro-2-deoxy-D-glucose (18 F-FDG) is widely used as a marker of increased glucose metabolism to monitor the progression of cancer with positron emission tomography (PET)/computed tomography (CT). Here we investigated the feasibility of using 18 F-FDG PET/CT in the diethylnitrosamine (DEN) mediated experimental hepatocellular carcinoma model. Rats received weekly intraperitoneal injections of DEN for 16 weeks for induction of HCC. We recorded starting from 0 days or 0 weeks after the last DEN …injection. The weight and survival rate of rats were then measured. Also, an 18 F-FDG PET scan and serum analysis were performed at minus 2, 0, plus 2, and plus 4 weeks after the last DEN injection. The body weight of rats was maintained between 350 g and 370 g during 14 and 20 weeks, and the rats were euthanized at 35 days after the last DEN injection. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphate (ALP) were significantly higher at zero weeks after the last DEN injection. The 18 F-FDG uptake for the quantitative evaluation of HCC was done by measuring the region of interest (ROI). At minus two weeks after the last DEN injection, the ROI of rats had significantly increased compared to the normal group, in a time-dependent manner. These results suggest that FDG uptake serves as a good screening test to evaluate the feasibility of DEN-induced HCC. Show more

Keywords: Hepatocellular carcinoma, PET/CT, 18F-FDG

DOI: 10.3233/BME-151466

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1669-S1676, 2015

Authors: Tseng, Hsien-Chun | Pan, Lung-Kang | Chen, Hsin-Yu | Liu, Wen-Shan | Hsu, Chang-Chieh | Chen, Chien-Yi

Article Type: Research Article

Abstract: This study is the first to use 10- to 90-kg tissue-equivalent phantoms as patient surrogates to measure peripheral skin doses (Dskin ) in lung cancer treatment through Volumetric Modulated Arc Therapy of the Axesse linac. Five tissue-equivalent and Rando phantoms were used to simulate lung cancer patients using the thermoluminescent dosimetry (TLD-100H) approach. TLD-100H was calibrated using 6 MV photons coming from the Axesse linac. Then it was inserted into phantom positions that closely corresponded with the position of the represented organs and tissues. TLDs were measured using the Harshaw 3500 TLD reader. The ICRP 60 evaluated the mean Dskin …to the lung cancer for 1 fraction (7 Gy) undergoing VMAT. The Dskin of these phantoms ranged from 0.51±0.08 (10-kg) to 0.22±0.03 (90-kg) mSv/Gy. Each experiment examined the relationship between the Dskin and the distance from the treatment field. These revealed strong variations in positions close to the tumor center. The correlation between Dskin and body weight was Dskin (mSv) = -0.0034x + 0.5296, where x was phantom’s weight in kg. R2 is equal to 0.9788. This equation can be used to derive an equation for lung cancer in males. Finally, the results are compared to other published research. These findings are pertinent to patients, physicians, radiologists, and the public. Show more

Keywords: Axesse linac, skin dose, TLD, tissue-equivalent phantom, ICRP 60

DOI: 10.3233/BME-151467

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1677-S1683, 2015

Authors: Deng, Luzhen | Mi, Deling | He, Peng | Feng, Peng | Yu, Pengwei | Chen, Mianyi | Li, Zhichao | Wang, Jian | Wei, Biao

Article Type: Research Article

Abstract: For lack of directivity in Total Variation (TV) which only uses x-coordinate and y-coordinate gradient transform as its sparse representation approach during the iteration process, this paper brought in Adaptive-weighted Diagonal Total Variation (AwDTV) that uses the diagonal direction gradient to constraint reconstructed image and adds associated weights which are expressed as an exponential function and can be adaptively adjusted by the local image-intensity diagonal gradient for the purpose of preserving the edge details, then using the steepest descent method to solve the optimization problem. Finally, we did two sets of numerical simulation and the results show that the proposed …algorithm can reconstruct high-quality CT images from few-views projection, which has lower Root Mean Square Error (RMSE) and higher Universal Quality Index (UQI) than Algebraic Reconstruction Technique (ART) and TV-based reconstruction method. Show more

Keywords: Computed tomography (CT), sparse projection, adaptive-weighted diagonal total variation (AwDTV), compressive sensing (CS)

DOI: 10.3233/BME-151468

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1685-S1693, 2015

Authors: Ran, Peng | Xiao, Xiaoming | He, Wei | Li, Zhangyong

Article Type: Research Article

Abstract: Because of the need for rapid detection and location of diseases in clinical applications, this work proposes a composite measurement of magnetic induction tomography (MIT) and electrical impedance tomography (EIT). This paper is composed of the following aspects: portable and integral hardware design, stable dual constant-current sources, the composite detection method, cross-plane data acquirement, 3-dimensional image reconstruction and so on. A qualitative evaluation of conductivity, resolution and relative position error were taken by combining the EIT and MIT methods via the experiment model. The sensitivities of both methods were analyzed to improve the imaging results. The reconstruction results reveal that …the system is capable of obtaining better physiological measurements, which is very useful in clinical monitoring, quick medical diagnosing and preliminary screening of community health. Show more

Keywords: Bioelectrical impedance measurement, magnetic induction tomography, cross evaluation and imaging, 3-dimensional image

DOI: 10.3233/BME-151469

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1695-S1702, 2015

Authors: Avcı, Cafer | Akbaş, Ahmet

Article Type: Research Article

Abstract: In this study, an efficient and robust method classifying the minute based occurrence of sleep apnea is aimed. Three respiration signals obtained from abdominal, chest and nasal way extracted from polysomnography recordings. Wavelet transform based on feature extraction methods are applied on the 1 minute length respiration signals. Dimension reduction process is facilitated by using principal component analysis. The features obtained from 8 recordings are used for the classification sleep apnea by using three ensemble classifiers. According to the results, the classification accuracies have been obtained between 92.07-98.43%, 92.75-98.68% and 92.42-98.61% by using three different ensemble classifier based on abdominal, …chest and nasal based analysis, respectively for AdaBoost, Random Forest and Random Subspace. However the best result is obtained analyzing nasal based respiratory signal by using Random Forest method. In this case accuracy is 98.68%. Show more

Keywords: Sleep apnea, respiratory signals, wavelet, ensemble, boosting, bagging

DOI: 10.3233/BME-151470

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1703-S1710, 2015

Authors: Lu, Qibing | Wang, Pan | Guo, Sihai | Sheng, Buyun | Liu, Xingxing | Fan, Zhun

Article Type: Research Article

Abstract: This paper introduces an automatic bond graph design method based on genetic programming for the evolutionary design of micro-resonator. First, the system-level behavioral model is discussed, which based on genetic programming and bond graph. Then, the geometry parameters of components are automatically optimized, by using the genetic algorithm with constraints. To illustrate this approach, a typical device micro-resonator is designed as an example in biomedicine. This paper provides a new idea for the automatic optimization design of biomedical sensors by evolutionary calculation.

Keywords: Genetic programming (GP), bond graph (BG), micro-resonator, evolutionary computation

DOI: 10.3233/BME-151471

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1711-S1719, 2015