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In chemical and food industry, the fluid concentration distribution inspection plays a key role in the control of the production processes. To meet the requirement of process control and by-product reaction suppression in chemical and food industry, advanced fluid concentration measurement techniques are highly desired. Due to its nondestructive and non-radiation features, Ultrasonic tomography (UT) is considered as a promising technique for monitoring the sucrose solution in the container, yielding images of both sound velocity and concentration. In this paper, we investigate the potential of using ultrasound tomography for quantitative fluid concentration imaging. Theoretical Basics of ultrasound tomography are studied, emphasizing aspects of tomographic forward problem, time-of-flight estimation, and the tomographic reconstruction algorithm. The feasibility and effectiveness of the developed methods are validated in numerical simulations.

X-ray tomography and magnetic resonance imaging (MRI) are excellent techniques for non-destructive or non-invasive inspections, however, they have shotcomings including the expensive cost in both the devices themselves and their protection facilities, the harmful side effects of the X-rays to human bodies and to the environment. In view of this argument, it is necessary to develop new, inexpensive, safe and reliable tomographic techniques, especially in medical imaging and non-destructive inspections. There are new tomographic techniques under development such as optical tomography, photo-acoustic tomography, ultrasonic tomography and so on, from which we take ultrasonic tomography as the topic in this paper. We introduce a review of the known ultrasonic tomographic techniques and discuss their future development.

Ultrasound Tomography (UT) is a non-invasive, safe, dynamic and relatively inexpensive imaging technique for abdominal diagnosing and monitoring. With the mature of pulse-echo technique, the Ultrasound Reflection Tomography (URT) is widely used in a variety of applications. However, such methods have the disadvantages of low resolution with limited information contained in received signal when operated in human abdomen. Here, to deal with this issue, a continuous wave UT method is presented to image the lesion in upper human abdomen. A series of numerical simulation are conducted to analyze the human abdominal ultrasound field under continuous wave excitation while the incident frequency is optimized according to the resolution and signal intensity synthetically as indicators. The reconstruction result shows that the proposed method has a preferable accuracy locating primary tumors in the major organs, which proves the feasibility of using continuous wave ultrasonic tomography in the examination of human abdominal cancer.

The work contains a description of studies of composite steel-concrete truss element under cyclic and static load which maximal value was increased from stage to stage up to a moment when the system lost its load capacity. During the loading process, truss deflections and slips between a concrete slab and steel top chord of the truss were measured. Also two methods of non-destructive testing were used between the particular loading cycles for an evaluation of stiffness decrease of truss elements resulting from increasing material defects, i.e. an analysis of free vibrations of the system and ultrasonic tomography tests were conducted. A common analysis of all experimental results aided additionally by FEM calculations enabled a complex evaluation of efficiency of using two aforementioned non-destructive methods in diagnostics of composite steel-concrete truss elements.

Ultrasound Computer Tomography (USCT) is a promising breast imaging modality under development. Comparison to a standard method like mammography is essential for further development. Due to significant differences in image dimensionality and compression state of the breast, correlating USCT images and X-ray mammograms is challenging. In this paper we present a 2D/3D registration method to improve the spatial correspondence and allow direct comparison of the images. It is based on biomechanical modeling of the breast and simulation of the mammographic compression. We investigate the effect of including patient-specific material parameters estimated automatically from USCT images. The method was systematically evaluated using numerical phantoms and in-vivo data. The average registration accuracy using the automated registration was 11.9mm. Based on the registered images a method for analysis of the diagnostic value of the USCT images was developed and initially applied to analyze sound speed and attenuation images based on X-ray mammograms as ground truth. Combining sound speed and attenuation allows differentiating lesions from surrounding tissue. Overlaying this information on mammograms, combines quantitative and morphological information for multimodal diagnosis.

As today's standard screening methods frequently fail to detect breast cancer before metastases have developed, early diagnosis is still a major challenge. With the promise of high-quality volume images, three-dimensional ultrasound computer tomography is likely to improve this situation, but has high computational needs. In this work, we investigate the acceleration of the ray-based transmission reconstruction by a GPU-based implementation of the iterative numerical optimization algorithm TVAL3. We identified the regular and transposed sparse-matrix-vector multiply as the performance limiting operations. For accelerated reconstruction we propose two different concepts and devise a hybrid scheme as optimal configuration. In addition we investigate multi-GPU scalability and derive the optimal number of devices for our two primary use-cases: a fast preview mode and a high-resolution mode. In order to achieve a fair estimation of the speedup, we compare our implementation to an optimized CPU version of the algorithm. Using our accelerated implementation we reconstructed a preview 3D volume with 24,576 unknowns, a voxel size of (8?mm)3 and approximately 200,000 equations in 0.5?s. A high-resolution volume with 1,572,864 unknowns, a voxel size of (2mm)3 and approximately 1.6 million equations was reconstructed in 23?s. This constitutes an acceleration of over one order of magnitude in comparison to the optimized CPU version. We accelerate a ray-based 3D ultrasound CT reconstruction by GPU processing.By use-case optimized SpMV variants a speedup of one order of magnitude is obtained.We derive the optimal number of GPUs for reconstructions that do not fit on one GPU.A 3D-preview is reconstructed in 0.5 s, a high-resolution volume in 23 s.

A promising candidate for breast cancer imaging is ultrasound computer tomography (USCT). At Karlsruhe Institute of Technology (KIT) a 3D USCT with a semiellipsoidal aperture consisting of several hundreds of US transducers was built. The utilized imaging methods require accurate and reliable temperature information over the measured space and acquisition time. Several methods were applied which improved the temperature accuracy and reliability beyond the hardware defaults by one order of magnitude from ±1°C to approx. 0.005°C beyond the requirement of 0.1°C.

In our first clinical study with a full 3D Ultrasound Computer Tomography (USCT) system patient data was acquired in eight minutes for one breast. In this paper the patient movement during the acquisition was analyzed quantitatively and as far as possible corrected in the resulting images. The movement was tracked in ten successive reflectivity reconstructions of full breast volumes acquired during 10 s intervals at different aperture positions, which were separated by 41 s intervals. The mean distance between initial and final position was 2.2 mm (standard deviation (STD) ± 0.9 mm, max. 4.1 mm, min. 0.8 mm) and the average sum of all moved distances was 4.9 mm (STD ± 1.9 mm, max. 8.8 mm, min. 2.7 mm). The tracked movement was corrected by summing successive images, which were transformed according to the detected movement. The contrast of these images increased and additional image content became visible.

Ultrasound Computer Tomography (USCT) is a promising new imaging method for breast cancer diagnosis. We developed a 3D USCT system and tested it in a pilot study with encouraging results: 3D USCT was able to depict two carcinomas, which were present in contrast enhanced MRI volumes serving as ground truth. To overcome severe differences in the breast shape, an image registration was applied. We analyzed the correlation between average sound speed in the breast and the breast density estimated from segmented MRIs and found a positive correlation with R=0.70. Based on the results of the pilot study we now carry out a successive clinical study with 200 patients. For this we integrated our reconstruction methods and image post-processing into a comprehensive workflow. It includes a dedicated DICOM viewer for interactive assessment of fused USCT images. A new preview mode now allows intuitive and faster patient positioning. We updated the USCT system to decrease the data acquisition time by approximately factor two and to increase the penetration depth of the breast into the USCT aperture by 1 cm . Furthermore the compute-intensive reflectivity reconstruction was considerably accelerated, now allowing a sub-millimeter volume reconstruction in approximately 16 minutes. The updates made it possible to successfully image first patients in our ongoing clinical study.

Ultrasound Computer Tomography (USCT), developed at KIT, is a promising new imaging system for breast cancer diagnosis, and was successfully tested in a pilot study. The 3D USCT II prototype consists of several hundreds of ultrasound (US) transducers on a semi-ellipsoidal aperture. Spherical waves are sequentially emitted by individual transducers and received in parallel by many transducers. Reflectivity volumes are reconstructed by synthetic aperture focusing (SAFT). However, straight forward SAFT imaging leads to blurred images due to system imperfections. We present an extension of a previously proposed approach to enhance the images. This approach includes additional a priori information and system characteristics. Now spatial phase compensation was included. The approach was evaluated with a simulation and clinical data sets. An increase in the image quality was observed and quantitatively measured by SNR and other metrics.

The incidence of fetal malformation was reviewed and an assessment made of the diagnostics of ultrasound. The prognosis of the related cases, as related to the clinical application of ultrasound was discussed. Forty-seven of 56 malformed fetuses were correctly diagnosed antenatally (84%). Diagnostic accuracy in the case of real-time B scan was 91%, while accuracy in the case of contact compound scan was 73%. The disorders most readily identifiable were those related to the image of cystic patterns and/or deformed body contour. Among the 47 with positive findings, an actual plan of treatment was prepared for 9. Of these 9, 6 could actually be treated and the lives of 3 were saved. Deaths were attributed to diagnostic inadequacy, eventual complications and under-development of organs associated with the malformations.

In four fetuses with gastroduodenal obstructions, different types of lesions were diagnosed prenatally by real-time ultrasonic tomography. Surgery in the early neonatal period confirmed these findings. The sites of obstruction corresponded to the anatomical configuration of the gastroduodenal area. Diagnostic criteria to identify individual lesions are proposed for use in a clinical setting.

Currently, breast cancer is one of the most common cancers in women all over the world. A novel 3D breast ultrasound imaging ring system using the linear array transducer is proposed to decrease costs, reduce processing difficulties, and improve patient comfort as compared to modern day breast screening systems. The 1 × 128 Piezoelectric Micromachined Ultrasonic Transducer (PMUT) linear array is placed 90 degrees cross-vertically. The transducer surrounds the mammary gland, which allows for non-contact detection. Once the experimental platform is built, the breast model is placed through the electric rotary table opening and into a water tank that is at a constant temperature of 32 °C. The electric rotary table performs a 360° scan either automatically or mechanically. Pulse echo signals are captured through a circular scanning method at discrete angles. Subsequently, an ultrasonic tomography algorithm is designed, and a horizontal slice imaging is realized. The experimental results indicate that the preliminary detection of mass is realized by using this ring system. Circular scanning imaging is obtained by using a rotatable linear array instead of a cylindrical array, which allows the size and location of the mass to be recognized. The resolution of breast imaging is improved through the adjustment of the angle interval (>0.05°) and multiple slices are gained through different transducer array elements (1 × 128). These results validate the feasibility of the system design as well as the algorithm, and encourage us to implement our concept with a clinical study in the future.

After osteoclastic trepanations of the posterior fossa for cystic or solid processes of the cerebellum and the cerebellopontine angle, ultrasonic tomography is a suitable imaging procedure. A mechanical sector probe with a frequency of 3.5 MHz is recommended as transducer. The postoperative ultrasonic findings are the basis for the sonographic observation of the further evolution. Cystic and solid processes can be localized and their dimensions metrically determined by means of multiple plane cross-sectional imaging. Ultrasonic tomography is recommended as a primary diagnostic method owing to its lack of invasivity and radiation exposure, simple handling and repeatability. As a consequence, CT examinations can be better aimed.

We present a fruitful combination of geophysical tests (Ultrasonic Measurements) and photogrammetric processing (Structure from Motion) for the analysis of the integrity of a couple of statues from the Egyptian Museum of Turin. Aim of the study was to investigate the persistence of the exterior widespread fractures within the sculptures. More than one hundred ultrasonic measurements were acquired on selected travel-paths across each statue, using an ultrasonic pulse velocity instrument. Dealing with complex-shape objects of restrained dimensions, it was very important to accurately define the three-dimensional coordinates of sources and receivers, in order to precisely measure their distances. A 3-D model of the statues was obtained from photogrammetric techniques. The acquired data were analyzed with both a statistical approach and tomographic processing, comparing the use of classical and staggered grids, in order to obtain the best fit of the local resolution. The final results revealed a valuable tool to guide the procedures for the mobilization, transport and restoration of the sculptures.

3D Ultrasound Computer Tomography (USCT) is a new imaging method for breast cancer diagnosis. In the current state of development it is essential to correlate USCT with a known imaging modality like MRI to evaluate how different tissue types are depicted. Due to different imaging conditions, e.g. with the breast subject to buoyancy in USCT, a direct correlation is demanding. We present a 3D image registration method to reduce positioning differences and allow direct side-by-side comparison of USCT and MRI volumes. It is based on a two-step approach including a buoyancy simulation with a biomechanical model and free form deformations using cubic B-Splines for a surface refinement. Simulation parameters are optimized patient-specifically in a simulated annealing scheme. The method was evaluated with in-vivo datasets resulting in an average registration error below 5mm. Correlating tissue structures can thereby be located in the same or nearby slices in both modalities and three-dimensional non-linear deformations due to the buoyancy are reduced. Image fusion of MRI volumes and USCT sound speed volumes was performed for intuitive display. By applying the registration to data of our first in-vivo study with the KIT 3D USCT, we could correlate several tissue structures in MRI and USCT images and learn how connective tissue, carcinomas and breast implants observed in the MRI are depicted in the USCT imaging modes.

The inspection system is crucial to ensure the system is always in a good condition. A technique that can be used for inspection system is process tomography. By promising non-destructive approach; various types of process tomography applied in civil, manufacturing and electrical applications. The purpose of this paper is to review the types of process tomography such as ultrasonic tomography, x-ray tomography, optical tomography, electrical resistance tomography, and electrical impedance tomography that had been applied to the inspection system. Variety techniques of inspection based on those sensors briefly discussed in this paper. The result showed that the process tomography expanded tremendously in the inspection system. Finally, a potential future research on the inspection system in the civil application proposed in this paper.

A promising candidate for improved imaging of breast cancer is ultrasound computer tomography (USCT). The aim of this work was to design a new aperture for our full 3D USCT which extends the properties of the current aperture to a larger ROI fitting the buoyant breast in water and decreasing artifacts in transmission tomography. The optimization resulted in a larger opening angle of the transducers, a larger diameter of the aperture and an approximately homogeneous distribution of the transducers, with locally random distances. The developed optimization methods allow us to automatically generate an optimized aperture for given diameters of apertures and transducer arrays, as well as quantitative comparison to other arbitrary apertures. Thus, during the design phase of the next generation KIT 3D USCT, the image quality can be balanced against the specification parameters and given hardware and cost limitations. The methods can be applied for general aperture optimization, only limited by the assumptions of a hemispherical aperture and circular transducer arrays.

A new technique using ultrasound computed tomography is explained. Reconstruction of pictures follows basically the algorithm of radiology CT in one plane. The computed data of several scan planes with different angles of the same subject are used for image reconstruction. In this manner, poor lateral resolution of reflections is eliminated. The improved quality of the CT ultrasound images is shown.

The purpose of this study was to investigate the clinical usefulness of the measurement of ultrasonic obstetric conjugate.In 209 pregnant women, ultrasonic obstetric conjugate was measured twice at 28 and 36 weeks of pregnancy. In 26 of these patients the measurement of obstetric conjugate by x-ray pelvimetry was also performed at 36 weeks of pregnancy because of medical indications. Obstetric outcome was investigated in association with ultrasonic obstetric conjugate. The relationship between ultrasonic obstetric conjugate and x-ray pelvimetry was investigated.Ultrasonic obstetric conjugate ranged from 10.7 to 15.1 cm. In 12 patients (5.7%) ultrasonic obstetric conjugate was less than 12 cm. Six of them (50.0%) underwent cesarean section because of dystocia. This percentage was significantly higher than 7.1% of the cesarean section rate (14 of 197) in patients with ultrasonic obstetric conjugate more than 12 cm (P.001). A close positive correlation was observed between ultrasonic obstetric conjugate and x-ray pelvimetry (r = 0.91; P.0001).We conclude that ultrasonic obstetric conjugate measurement is a safe and useful procedure in the prediction of dystocia.

Ultrasound Computer Tomography (USCT) is a promising 3D modality for early breast cancer detection, which is expected to provide quantitative imaging. The aim of this paper is to evaluate the quantitative diagnostic value of the USCT images, i.e. sound speed and attenuation images, using X-ray mammograms as ground truth. For this purpose we applied our 2D/3D registration method, which is based on biomechanical modeling of the breast. Mammograms were segmented into fatty, glandular and tumorous tissue. For each tissue, the average sound speed and attenuation in the corresponding USCT images was calculated. Tumorous tissue could be separated from fatty and glandular tissue using a fixed absolute sound speed threshold in all regarded datasets. By combining sound speed and attenuation, the separation between fatty and glandular tissue could be improved. By overlaying sound speed and attenuation information on the mammogram, quantitative and morphological information can be combined for multimodal diagnosis. This may benefit early breast cancer detection in future.

Ultrasound Computer Tomography is an upcoming imaging modality for early breast cancer detection. For evaluation of the method, comparison with the standard method X-ray mammography is of strongest interest. To overcome the significant differences in dimensionality and compression state of the breast, in earlier work a registration method based on biomechanical modeling of the breast was proposed. However only homogeneous models could be applied, i.e. inner structures of the breast were neglected. In this work we extend the biomechanical modeling of the breast by estimating patient-specific tissue parameters automatically from the speed of sound volume. Two heterogeneous models are proposed modeling a quadratic and an exponential relationship between speed of sound and tissue stiffness. The models were evaluated using phantom images and clinical data. The size of all lesions is better preserved using heterogeneous models, especially using an exponential relationship. The presented approach yields promising results and gives a physical justification to our registration method. It can be considered as a first step towards a realistic modeling of the breast.

3D ultrasound computer tomography (3D USCT) promises reproducible high-resolution images for early detection of breast tumors. The synthetic aperture focusing technique (SAFT) used for image reconstruction is highly computeintensive but suitable for an accelerated execution on GPUs. In this paper we investigate how a previous implementation of the SAFT algorithm in CUDA C can be further accelerated and integrated into the existing MATLAB signal and image processing chain for 3D USCT. The focus is on an efficient preprocessing and preparation of data blocks in MATLAB as well as an improved utilisation of special hardware like the texture fetching units on GPUs. For 64 slices with 1024×1024 pixels each the overall runtime of the reconstruction including data loading and preprocessing could be decreased from 35 hours with CPU to 2.4 hours with eight GPUs.

Due to parallel advances in signal processing and computer hardware in the last 15 years, quantitative ultrasound techniques have reached maturity, allowing for the construction of quantitative maps or images of soft tissues. This book will focus on 5 modern research topics related to quantitative ultrasound of soft tissues: - Spectral-based methods for tissue characterization, tissue typing, cancer detection, etc.; - Envelope statistics analysis as a means of quantifying and imaging tissue properties; - Ultrasound elastography for quantifying elastic properties of tissues (several clinical ultrasound scanners now display elastography images); - Scanning acoustic microscopy for forming images of mechanical properties of soft tissues with micron resolution (desktop size scanners are now available); and - Ultrasound computer tomography for breast cancer imaging (new ultrasound tomography systems have been developed and are currently under evaluation clinically).

Summary A promising candidate for imaging of breast cancer is ultrasound computer tomography (USCT). The main advantages of a USCT system are simultaneous recording of reproducible reflection, attenuation and speed of sound volumes, high image quality, and fast data acquisition. The here presented 3D USCT prototype realizes for the first time the full potential of such a device. It is ready for a clinical study. Full volumes of a breast can be acquired in four minutes. In this paper images acquired with a clinical breast phantom are presented. The resolution and imaged details of the reflectivity reconstruction are comparable to a 3 tesla MRI volume of the phantom. Image quality and resolution is isotropic in all three dimensions, confirming the successful implementation experimentally.

Ultrasound Computer Tomography (USCT) is an upcoming modality for early breast cancer diagnosis, which provides morphological as well as quantitative imaging. In order to compare USCT images to the standard modality X-ray mammography, a 2D/3D registration has to be applied. To analyze the relevance of sound speed images as a quantitative imaging method for tissue characterization, the aim of this paper is to quantify sound speed values of different types of tissue using mammograms as ground truth. Mammograms are segmented and classified into fat, glandular and tumorous tissue. For each tissue class the average sound speed in the registered sound speed image is calculated. The mean absolute sound speed was 1457 m/s for regions segmented as fatty tissue, 1470 m/s for glandular and 1509 m/s for tumorous tissue. For all ten datasets, the sound speed in tumorous tissue was significantly higher than in glandular and fatty tissue. Also glandular and fatty tissue could be separated easily by the absolute sound speed values. By color-coding sound speed, quantitative information from USCT and morphological information from X-ray mammography are fused for combined diagnosis. We believe this method will help radiologists in gaining experience in the reading of USCT images. The combination of diagnostic information is likely to be beneficial to early breast cancer detection.

To introduce a new three-dimensional (3D) diagnostic imaging technology, termed "multimodal ultrasonic tomography" (MUT), for the detection of breast cancer without ionising radiation or compression.MUT performs 3D tomography of the pendulant breast in a water-bath using transmission ultrasound in a fixed-coordinate system. Specialised electronic hardware and signal processing algorithms are used to construct multimodal images for each coronal slice, corresponding to measurements of refractivity and frequency-dependent attenuation and dispersion. In-plane pixel size is 0.25 mm × 0.25 mm and the inter-slice interval can vary from 1 to 4 mm, depending on clinical requirements. MUT imaging was performed on 25 patients ("off-label" use for research purposes only), presenting lesions with sizes10 mm. Histopathology of biopsy samples, obtained from all patients, were used to evaluate the MUT outcomes.All lesions (21 malignant and four benign) were clearly identified on the MUT images and correctly classified into benign and malignant based on their respective multimodal information. Malignant lesions generally exhibited higher values of refractivity and frequency-dependent attenuation and dispersion.Initial clinical results confirmed the ability of MUT to detect and differentiate all suspicious lesions with sizes10 mm discernible in mammograms of 25 female patients.

Breast cancer is the most common cancer among women. The established screening method to detect breast cancer in an early state is X-ray mammography. However, X-ray frequently provides limited contrast of tumors located within glandular tissue. A new imaging approach is Ultrasound Computer Tomography generating threedimensional volumes of the breast. Three different images are available: reflectivity, attenuation and speed of sound. The correlation of USCT volumes with X-ray mammograms is of interest for evaluation of the new imaging modality as well as for a multimodal diagnosis. Yet, both modalities differ in image dimensionality, patient positioning and deformation state of the breast. In earlier work we proposed a methodology based on Finite Element Method to register speed of sound images with the according mammogram. In this work, we enhanced the methodology to register all three image types provided by USCT. Furthermore, the methodology is now completely automated using image similarity measures to estimate rotations in datasets. A fusion methodology is proposed which combines the information of the three USCT image types with the X-ray mammogram via semitransparent overlay images. The evaluation was done using 13 datasets from a clinical study. The registration accuracy was measured by the displacement of the center of a lesion marked in both modalities. Using the automated rotation estimation, a mean displacement of 10.4 mm was achieved. Due to the clinically relevant registration accuracy, the methodology provides a basis for evaluation of the new imaging device USCT as well as for multimodal diagnosis.

A promising candidate for improved imaging of breast cancer is ultrasound computer tomography (USCT). Current experimental USCT systems are still focused in elevation dimension resulting in a large slice thickness, limited depth of field, loss of out-of-plane reflections, and a large number of movement steps to acquire a stack of images. 3DUSCT emitting and receiving spherical wave fronts overcomes these limitations. We built an optimized 3DUSCT with nearly isotropic 3D point spread function, realizing for the first time the full benefits of a 3D system. The 3DUSCT II is based on a semi-ellipsoidal transducer holder cut from polyoxymethylene. The aperture is implemented together with water supply, disinfection unit, temperature control, and movement mechanics in a patient bed. 2041 transducers are mounted in the aperture holder grouped into transducer array systems with embedded amplifiers and emitter electronics. The data acquisition is carried out with 480 parallel channels at 20MHz and with 12 bit resolution. 3.5 million A-Scans with 20 GByte of raw data are acquired for one breast volume. With data acquisition time of less than two minutes for one breast volume, the new system enables the next step of our research: a first clinical study.

At Karlsruhe Institute of Technology a 3D Ultrasound Computer Tomography (USCT) system is under development for early breast cancer detection. With 3.5 million of acquired raw data and up to one billion voxels for one image, the reconstruction of breast volumes may last for weeks in highest possible resolution. The currently applied backprojection algorithm, based on the synthetic aperture focusing technique (SAFT), offers only limited potential for further decrease of the reconstruction time. An alternative reconstruction method could apply signal detected data and rasterizes the backprojected ellipsoids directly. A well-known rasterization algorithm is the Bresenham algorithm, which was originally designed to rasterize lines. In this work an existing Bresenham concept to rasterize circles is extended to comply with the requirements of image reconstruction in USCT: the circle rasterization was adapted to rasterize spheres and extended to floating point parameterization. The evaluation of the algorithm showed that the quality of the rasterization is comparable to the original algorithm. The achieved performance of the circle and sphere rasterization algorithm was 12MVoxel/s and 3.5MVoxel/s. When taking the performance increase due to the reduced A-Scan data into account, an acceleration of factor 28 in comparison to the currently applied algorithm could be reached. For future work the presented rasterization algorithm offers additional potential for further speed up.

Breast cancer is the most common cancer among women. The established screening method to detect breast cancer is X-ray mammography. However, X-ray frequently provides poor contrast of tumors located within glandular tissue. In this case, additional modalities like MRI are used for diagnosis in clinical routine. A new imaging approach is Ultrasound Computer Tomography, generating three-dimensional speed of sound images. High speed of sound values are expected to be an indicator of cancerous structures. Therefore, the combination of speed of sound images and X-ray mammograms may benefit early breast cancer diagnosis. In previous work, we proposed a method based on Finite Elements to automatically register speed of sound images with the according mammograms. The FEM simulation overcomes the challenge that X-ray mammograms show two-dimensional projections of a deformed breast whereas speed of sound images render a three-dimensional undeformed breast in prone position. In this work, 15 datasets from a clinical study were used for further evaluation of the registration quality. The quality of the registration was measured by the displacement of the center of a lesion marked in both modalities. We found a mean displacement of 7.1 mm. For visualization, an overlay technique was developed, which displays speed of sound information directly on the mammogram. Hence, the methodology provides a good basis for multimodal diagnosis using mammograms and speed of sound images. It proposes a guidance tool for radiologists who may benefit from the combined information.

At the Karlsruhe Institute of Technology (KIT) a three-dimensional ultrasound computer tomography (3D USCT) system for early breast cancer diagnosis is being developed. This method promises reproducible volume images of the female breast in 3D. Initial measurements and a simulation based optimization method, which took several physical properties into account, led to a new aperture setup. Yet this simulation is computational too demanding to systematically evaluate the different 'virtual' apertures which can be achieved by rotation and lifting of the system. In optics a Fourier based approach is available to simulate imaging systems as linear systems. For the two apertures used in our project and one hypothetical linear array aperture this concept was evaluated and compared to a reference simulation. An acceptable conformity between the new approach and the reference simulation could be shown. With this approach a fast evaluation of optimal 'virtual' apertures for specific measurement objects and imaging constraints can be carried out within an acceptable time constraint.

Breast cancer is the most common type of cancer for women in Europe and North America. The established standard screening method to detect tumors is X-ray mammography. However, X-ray mammography often has low contrast for tumors located within glandular tissue. A new approach is 3D Ultrasound Computer Tomography (USCT), which is expected to detect small tumors at an early stage. This paper describes the development and the results of Finite Element Method (FEM) simulations of the Transducer Array System (TAS) used in our 3D USCT system. Not all required material parameters were available,so the main challenge of this work was to determine these values. After detailed analysis, a set of material parameters was identified which fits the measured data best. The quality of the simulation was evaluated by comparing the simulated impedance characteristics with measured data of the real TAS. The simulation model provides a powerful tool to analyze the 3D USCT TAS. Furthermore, it is now possible to design and optimize future transducers based on simulation.

1. 1. To evaluate the distribution patterns of subcutaneous fat and muscle 679 male and 950 female Japanese volunteers were investigated by means of ultrasonic tomography. 2. 2. With an increase in age the thickness of the anterior thigh muscle decreased, whilst subscapula muscle thickness was independent of age. 3. 3. In comparing a resident in a city (Tokyo) to a country resident (farmer in Yamagata) the arm muscle of a farmer was thicker than that of a cityman, while the thigh muscle was lower in the farmer. 4. 4. Muscle thickness is related to its cross-sectional area and the muscle area is affected by activity level in daily physical exercise. 5. 5. The present data indicate that the farmer makes less use of his legs than does the city dweller. 6. 6. There were significant correlation coefficients between fat thickness and HDL-C, i.e. the highest correlation was observed at the abdomen, suggesting that the fat thickness of the abdomen is one of the important factors for evaluating serum cholesterol level.

咽頭癌の頸部リンパ節転移107例のうち, 超音波断層法で検索できたリンパ節201個について種々の検討を加え, つぎの結論を得た。1. 転移の好発部位は何れの癌も, 上内深頸リンパ節, 中内深頸リンパ節で, 上・中咽頭癌はこのほか副神経リンパ節にも多くみられた。2. 大きさは上咽頭癌は112～2499mm3, 中咽頭癌が112～2,499mm3のものが多く, 下咽癌は1,000～4,999mm3の大きさで, 前二者より大きい傾向を示した。3. 咽頭癌のリンパ節転移の病像を正しく把握するには超音波断層法による画像診断が有用である。その場合, 転移部位, 大きさを判断する必要がある。

Objectives We propose an automatic breast mass detection algorithm in three-dimensional (3D) ultrasound (US) images using the Hough transform technique. Methods One hundred twenty-five cropped images containing 68 benign and 60 malignant masses are acquired with clinical diagnosis by an experienced radiologist. The 3D US images are masked, subsampled, contrast-adjusted, and median-filtered as preprocessing steps before the Hough transform is used. Thereafter, we perform 3D Hough transform to detect spherical hyperplanes in 3D US breast image volumes, generate Hough spheres, and sort them in the order of votes. In order to reduce the number of the false positives in the breast mass detection algorithm, the Hough sphere with a mean or grey level value of the centroid higher than the mean of the 3D US image is excluded, and the remaining Hough sphere is converted into a circumscribing parallelepiped cube as breast mass lesion candidates. Finally, we examine whether or not the generated Hough cubes were overlapping each other geometrically, and the resulting Hough cubes are suggested as detected breast mass candidates. Results An automatic breast mass detection algorithm is applied with mass detection sensitivity of 96.1% at 0.84 false positives per case, quite comparable to the results in previous research, and we note that in the case of malignant breast mass detection, every malignant mass is detected with false positives per case at a rate of 0.62. Conclusions The breast mass detection efficiency of our algorithm is assessed by performing a ROC analysis.

Ultrasound computer tomography (USCT) is an ultrasound imaging method capable of producing volume images with high spatial resolution and image quality. The long term goal of the system under construction is high quality imaging in 3D for early breast cancer diagnosis. In this paper the first images of an experimental 3D-prototype are presented and discussed in respect to further modifications of our system.

Ultrasound computer tomography (USCT) is an imaging method capable of producing volume images with sub-millimeter resolution and high image quality. The long term goal of the system under construction is 3D imaging for early breast cancer diagnosis. In this paper the first images of a clinical breast phantom are presented and discussed in respect to further modifications of our system

Ultrasonic computed tomography (UCT) is one of the methods capable of tissue characterization. It is expected to provide not only a quantitative image but also diagnostic information. As in X-ray CT, UCT requires a projection data to reconstruct a cross-sectional image. The projection data of ultrasonic tomography is based on measurement the time delay, which is time difference between ultrasound traverse with and without object. In this paper, we investigate two different types of quantitative UCT image, refractive-index and sound-velocity image. We purpose the new method of measurement the time delay by converting the received ultrasonic pulse to frequency domain and measuring the phase shift of the center frequency of the broadband pulse. The method seems more robust to noise. Two image reconstruction techniques are used for comparison purpose including traditional filtered back-projection and simultaneous algebraic reconstruction technique (SART).

In this paper the electronic linear-scanning ultrasonography is compared to the mechanical sector scanning method in optic nerve and orbital lesions. Mechanical sector scanners display the optic nerve as if it were wedge-shaped. The posterior enlargement of the diameter is an acoustic artefact. On the contrary, electronic linear scanners show the optic nerve straight as it is. For evaluating orbital tumors, it is important to see the optic nerve accurately, for the purpose of the tumor site determination. Therefore, the electronic linear scanner is considered to be superior to the mechanical sector scanner. This statement is supported by four case reports.

With ultrasonic tomography palatine tonsils (p.t.) and the paratonsillar regions were imaged in viva. The longitudinal and transverse measurements in 65 tonsils were compared with actual size of these tonsillar tissues after tonsillectomy. We also analyzed the images of the tonsils in 165 normal subjects and in 43 patients with palatine tonsillar diseases (39 with recurrent tonsillitis, one with acute tonsillitis and one each with peritonsillitis, peritonsillar abscess and paratine tonsillar tumor).An ultrasonic apparatus, SSD-256 (Aloka Co. Ltd), and a 7.5MHz probe which were commonly used to examine the carotid arteries were employed. After setting the probe on the submandibular area, we analyzed the images of the p.t. The tissue of the p. t. appeared as a low density shadow, and the plugs in the p. t. as high density spots. In the paratonsillar region, the tongue, the superior constrictor muscles of the pharynx, and the tonsillar branches could also be demonstrated ; the images of the tongue and the sup. const. muscle of the pharynx were high density shadows, while the tonsillar branch appeared as a low density shadow.There was a significant correlation between the ultrasonic measurements and the actual longitudinal and transverse diameters in the 65 tonsils.In normal subjects, images of plugs were not visible or were very faint.Patients with recurrent tonsillitis had many plugs, and the image of the tonsillar capsule was wide and clear from the inferior pole to the superior pole.The image of a localized abscess was clear in the patient with peritonsillar abscess, and that of invasive tumor in the patient with tonsillar tumor.Ultrasound imaging is expected to be useful in the diagnosis and therapy of palatine tonsillar disease.

The diagnositc value of ultrasonic tomography of the upper abdominal organs is sometimes limited by bones and gas. Endoscopic ultrasonography (EUST) combines the advantages of the direct visualization of the upper GI tube and the ultrasonic imaging of adjacent organs. The ultrasonic probe consists of a 5 MHz array that generates a good resolution at the acustical focus, the endoscope is a conventional Olympus gastroscope type GFB3. The ultrasonic transducer is firmly attached to the distal end of the endoscope. Combined examinations are performed in 18 patients with biliary, pancreatic and hepatic disorders or postoperative changes. EUST may be of value not only for gastrointestinal but also for retroperitoneal, cardiac, and mediastinal diseases.

A new approach to ultrasonic breast imaging is reported. Two-dimensional velocity distributions in tomographic slices transaxial to the breast are reconstructed from transmission time-of-flight projections. The data are displayed both as video images and in numeric format. Results of a clinical investigation in which both malignant and benign lesions have been observed are presented. The possibility of differential diagnosis of pathologies on the basis of velocity is discussed.

Clinical gynaecological examination and the imaging techniques in present use are insufficient for an accurate diagnosis of changes of the myometrium. The intrauterine ultrasonographic tomography (IUT) permits the differential diagnostic imaging of normal myometrium, leiomyomata, uterine carcinomata and sarcomata . There was good correlation between intra-uterine ultrasonograms and sections at the same level of selected normal and pathological hysterectomy specimens.

当院における10年以上透析の患者33名について超音波診断法により腎の嚢胞形成を観察し, またこれら対象のうち低血圧をしめす症例にangiotensin II (A II) 注入テストを行い嚢胞形成とR-A-A系との関連を考察した. 超音波診断法で観察した33名中31名 (94%) に透析患者の萎縮腎に多嚢胞性変化が認められ, 嚢胞形成様式をI, II, III, IV, V型に分類した. すなわち腎長径が8-9cmで大型嚢胞 (直径1-3cm) で置換されたI型, 腎長径は6cm以下で大型嚢胞で置換されたII型, 同III, IVは腎長径は6cm以下と小さく前者は直径1cm以下の嚢胞が数個存在し, 後者には超音波診断法上嚢胞がみつからないもの. V型は左右で別の型を示すもの. I-V型の別と臨床生化学データおよび原疾患との関連はない. 透析前PRAは大型の嚢胞をもつグループA (I型とII型の和) の方が小さい嚢胞および嚢胞の見つからないグループB (III型とIV型の和) に比べ統計的に有意に高い (P

The report deals with 2 cases of heart tumors in which a commercial ultrasonic diagnostic equipment was used for tomography. In both cases we were successful in demonstrating the lesions. The visualization of subtle diagnostic details is ruled out by the rhythmical movements of the heart which cause blurring and superposition of signals.