Australasian physical & engineering sciences in medicine最新文献

Size-specific dose estimates for various weighting factors of CTDI equation. CTDI 方程中不同加权因子的具体尺寸剂量估计值。

Australasian physical & engineering sciences in medicine Pub Date : 2019-12-06 DOI: 10.1007/s13246-019-00830-w

Tomonobu Haba, Masanao Kobayashi, Shuji Koyama

{"title":"Size-specific dose estimates for various weighting factors of CTDI equation.","authors":"Tomonobu Haba, Masanao Kobayashi, Shuji Koyama","doi":"10.1007/s13246-019-00830-w","DOIUrl":"https://doi.org/10.1007/s13246-019-00830-w","url":null,"abstract":"Size-specific dose estimate (SSDE) was proposed by the American Association of Physicists in Medicine (AAPM) Task Group 204 to consider the effect of patient size in the x-ray CT dose estimation. Size correction factors to calculate SSDE were derived based on the conventional weighted CT dose index (CTDIw) equation. This study aims to investigate the influence of Bakalyar's and the authors' own CTDIw equations on the size correction factors described by the AAPM Task Group 204, using Monte Carlo simulations. The simulations were performed by modeling four types of x-ray CT scanner designs, to compute the dose values in water for cylindrical phantoms with 8-40 cm diameters. CTDI100 method and the AAPM Task Group 111's proposed method were employed as the CT dosimetry models. Size correction factors were obtained for the computed dose values of various phantom diameters for the conventional, Bakalyar's, and the authors' weighting factors. Maximum difference between the size correction factors for the Bakalyar's weighting factor and those of the AAPM Task Group 204 was 27% for a phantom diameter of 11.2 cm. On the other hand, the size correction factors calculated for the authors' weighting factor were in good agreement with those from the AAPM Task Group 204 report with a maximum difference of 17%. The results indicate that the SSDE values obtained with the authors' weighting factor can be evaluated by using the size correction factors reported by the AAPM Task Group 204, which is currently accepted as a standard.","PeriodicalId":517394,"journal":{"name":"Australasian physical & engineering sciences in medicine","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139975392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Innovative Force-PRO device to measure force and implant position in total hip arthroplasty. 创新的 Force-PRO 设备，用于测量全髋关节置换术中的受力和植入位置。

Australasian physical & engineering sciences in medicine Pub Date : 2019-12-03 DOI: 10.1007/s13246-019-00824-8

Udomporn Manupibul, Chaiyanun Vijittrakarnrung, Paphon Sa-Ngasoongsong, Praman Fuangfa, Suphaneewan Jaovisidha, Warakorn Charoensuk

{"title":"Innovative Force-PRO device to measure force and implant position in total hip arthroplasty.","authors":"Udomporn Manupibul, Chaiyanun Vijittrakarnrung, Paphon Sa-Ngasoongsong, Praman Fuangfa, Suphaneewan Jaovisidha, Warakorn Charoensuk","doi":"10.1007/s13246-019-00824-8","DOIUrl":"https://doi.org/10.1007/s13246-019-00824-8","url":null,"abstract":"Total hip arthroplasty (THA) is the appropriate treatment for hip pain, dislocation, and dysfunction. THA refers to surgery to replace a hip implant, which is an effective way to recover normal hip function. The design of an implant imitates hip functions and allows bone growth in the implant area. However, it should be noted that the implant can dislocate after surgery. The main factor that should be considered during surgery is the correct position of the implant component. The acetabular cup of the hip implant should be positioned at [Formula: see text] anteversion and [Formula: see text] inclination. The evaluation of the implant inclination and anteversion during the operation decrease the risk of the implant dislocation after surgery. Developing a new innovative Force-PRO device can aid the doctor in evaluating the force on the surface of the acetabular liner and the angle of the acetabular liner during the hip implant operation. This device consists of two main sensors-force sensors and inertial measurement unit sensors. Furthermore, the 3D printings of an implant's parts should be specifically designed to integrate with these sensors. To develop the graphical user interface application, C[Formula: see text] should be the programming language of use. The graphical user interface application communicates between the device and user via a wireless communication system. CT-based imaging and force gauge measurement are the methods to evaluate the efficiency of this device. For this purpose, the sterile method is considered.","PeriodicalId":517394,"journal":{"name":"Australasian physical & engineering sciences in medicine","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139975389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assessing the dependency of the uncertainties in the Elekta Agility MLC calibration procedure on the focal spot position. 评估 Elekta Agility MLC 校准程序的不确定性与焦斑位置的关系。

Australasian physical & engineering sciences in medicine Pub Date : 2019-12-02 DOI: 10.1007/s13246-019-00821-x

Jacek M Chojnowski, Lee M Taylor, Jonathan R Sykes, David I Thwaites

{"title":"Assessing the dependency of the uncertainties in the Elekta Agility MLC calibration procedure on the focal spot position.","authors":"Jacek M Chojnowski, Lee M Taylor, Jonathan R Sykes, David I Thwaites","doi":"10.1007/s13246-019-00821-x","DOIUrl":"https://doi.org/10.1007/s13246-019-00821-x","url":null,"abstract":"The effectiveness of radiotherapy treatments depends on the accuracy of the dose delivery process. The majority of radiotherapy courses are delivered on linear accelerators with a Multi Leaf Collimator (MLC) in 3D conformal Radiation Therapy, Intensity Modulated Radiation Therapy (IMRT) or Volumetric Modulated Arc Therapy (VMAT) modes that require accurate MLC positioning. This study investigates the MLC calibration accuracy, following manufacturer procedures for an Elekta Synergy linac with the Agility head, against the radiation focal spot offset (alignment with the collimator axis of rotation). If the radiation focal spot is not aligned ideally with the collimator axis of rotation then a systematic error can be introduced into the calibration procedure affecting absolute MLC leaf positions. Calibration of diaphrams is equally affected; however they are not investigated here. The results indicate that an estimated 0.15 mm MLC uncertainty in all MLC leaves positions can be introduced due to uncertainty of the radiation focal spot position of 0.21 mm.","PeriodicalId":517394,"journal":{"name":"Australasian physical & engineering sciences in medicine","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139975388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The potential of photoplethysmogram and galvanic skin response in emotion recognition using nonlinear features. 利用非线性特征识别情绪中的光敏肌电图和皮肤电反应的潜力。

Australasian physical & engineering sciences in medicine Pub Date : 2019-11-27 DOI: 10.1007/s13246-019-00825-7

Atefeh Goshvarpour, Ateke Goshvarpour

{"title":"The potential of photoplethysmogram and galvanic skin response in emotion recognition using nonlinear features.","authors":"Atefeh Goshvarpour, Ateke Goshvarpour","doi":"10.1007/s13246-019-00825-7","DOIUrl":"10.1007/s13246-019-00825-7","url":null,"abstract":"Recently, developing an accurate automatic emotion recognition system using a minimum number of bio-signals has become a challenging issue in \"affective computing.\" This study aimed to propose a reliable system by examining nonlinear dynamics of photoplethysmogram (PPG) and galvanic skin response (GSR). To address this goal, two strategies were adopted. First, the efficiency of each signal in valence/arousal based emotion categorization was examined. Then, the proficiency of a hybrid feature, by combining both GSR and PPG features was studied. Lyapunov exponents, lagged Poincare's measures, and approximate entropy were extracted to characterize the irregularity and chaotic behavior of the phase space. To discriminate two levels of arousal and two levels of the valence, a probabilistic neural network (PNN) with different sigma adjustment parameter was examined. The results showed that the phase space geometry and consequently, the signal dynamics are influenced by the emotional music video. Additionally, distinctive patterns of the phase space behavior were observed under the influence of different lags. For both signals, the most irregularity was observed during the high valence, and the least irregularity was seen during the low valence. Consequently, signals' irregularity is affected by the valence dimension. The results showed that the fusion has more potential for emotion recognition than that of using each signal separately. For sigma = 0.1, the highest recognition rate was 100% in a subject-dependent mode. In a subject-independent mode, the maximum accuracies of 88.57 and 86.8% were obtained for arousal and valence dimensions, respectively.","PeriodicalId":517394,"journal":{"name":"Australasian physical & engineering sciences in medicine","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139975393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Method to calculate frequency characteristics of reconstruction filter kernel in X-ray computed tomography. 计算 X 射线计算机断层扫描中重建滤波器内核频率特性的方法。

Australasian physical & engineering sciences in medicine Pub Date : 2019-11-21 DOI: 10.1007/s13246-019-00819-5

Kazuhiro Sato, Yu Tomita, Ryota Kageyama, Yumi Takane, Shingo Kayano, Haruo Saito

{"title":"Method to calculate frequency characteristics of reconstruction filter kernel in X-ray computed tomography.","authors":"Kazuhiro Sato, Yu Tomita, Ryota Kageyama, Yumi Takane, Shingo Kayano, Haruo Saito","doi":"10.1007/s13246-019-00819-5","DOIUrl":"https://doi.org/10.1007/s13246-019-00819-5","url":null,"abstract":"A computed tomography (CT) image is generally reconstructed by a filtered back projection (FBP) algorithm. In an FBP algorithm, the image quality primarily depends on a reconstruction filter kernel. Although the details of the filter kernel are not disclosed to users, the frequency response of the filter kernel can theoretically be calculated using the relational formula of the filter kernel and the modulation transfer function (MTF) of the reconstruction algorithm (MTFA). In this study, we proposed a method to determine the frequency response of a filter kernel and verify its validity. Two clinical CT scanners were used to derive the filter kernel. The MTF was obtained and subsequently separated to the MTF of the scanner system and MTFA. Using the relational formula of the filter kernel and MTFA, we calculated the frequency response of the filter kernel. To verify the calculated result, we measured the noise power spectrum (NPS). Additionally, the filter kernel was calculated using the relational formula of the filter kernel and NPS. In both CT scanners, the filter kernels calculated by the two methods showed good agreement, and we confirmed the validity of the results and the effectiveness of the proposed method. Furthermore, the inherent image quality performance of the CT scanner could be clarified by the reconstruction filter kernel.","PeriodicalId":517394,"journal":{"name":"Australasian physical & engineering sciences in medicine","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139975390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Muscle and bone dose in paediatric limb digital radiography: a Monte Carlo evaluation. 儿科四肢数字放射摄影中的肌肉和骨骼剂量：蒙特卡罗评估。

Australasian physical & engineering sciences in medicine Pub Date : 2019-11-20 DOI: 10.1007/s13246-019-00820-y

Yuri V Matyagin, Donald W McRobbie

{"title":"Muscle and bone dose in paediatric limb digital radiography: a Monte Carlo evaluation.","authors":"Yuri V Matyagin, Donald W McRobbie","doi":"10.1007/s13246-019-00820-y","DOIUrl":"https://doi.org/10.1007/s13246-019-00820-y","url":null,"abstract":"The proliferation of digital radiography (DR) has led to a re-evaluation of exposure parameters and image quality. Currently, there is a move towards reducing X-ray tube voltage (kVp) in paediatric exposures down to 40 kVp to achieve better images. However, the effect on patient dose of these modifications is uncertain. The main aims of this phantom study were to evaluate the effect of reducing the kVp in paediatric limb DR exposures on contrast-to-noise ratio (CNR) and patient dose. For this purpose, Monte Carlo simulations of radiographic exposures on a paediatric limb phantom were performed. The phantom included muscle tissue and bone segments of five different densities in the range of 1.12 to 1.48 g/cm3. The overall thickness of the phantom varied between 1 and 12 cm. Dependence of the CNR at constant limb phantom muscle and bone doses and dependence of the CNR per unit of muscle and bone dose at constant detector dose on radiographic exposure factors and limb thickness were calculated. X-ray tube current-time product (mAs) values required to achieve equal detector dose versus limb thickness for different kVp were calculated, as well as muscle and bone doses for the limb phantom of varying thickness. Present work has shown that reducing the kVp in paediatric radiography of the extremities can result in a significant increase in radiation dose, particularly for thicker limbs. Low kVp radiography requires justification for use on the extremities.","PeriodicalId":517394,"journal":{"name":"Australasian physical & engineering sciences in medicine","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139975391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0