Biomedical Engineering and Bioengineering Commons^™

Cutting Rate Effect On Temperature During Cortical Bone Sawing, Hamid Khalili Parsa, Ger Reilly, Brendan Mccormack

Conference Papers

When bone is cut the occurrence of thermal damage to the bone is of major concern to the surgeon. If the temperature exceeds 44°C for longer than 1 min, bone repair is impaired (Eriksson et al, 1984) and necrosis may occur. Repeated use of cutting blades may reduce the cutting efficiency (Wevers et al, 1987; Toksvig-Larsen et al, 1992). Wevers et al also found that there is a greater force required to cut cortical bone using a blunt saw compared to new one.

Indentation Fracture Of Bovine Cortical Bone: Acoustic Emission Technique, Ashkan Safari, Ger Reilly, Brendan Mccormack

Conference Papers

Indentation cutting may result in microcracking and main crack growth which was previously reported. In this study, we recorded the AE signals produced by cracking processes during cutting on cortical bone, measuring the cutting force and correlating between load-displacement curves and AE activities.

Analysis Of Indentation Loading Of Cortical Bone Using Acoustic Emission Techniques, Ashkan Safari, Ger Reilly, Brendan Mccormack

Conference Papers

In this study, we recorded the number of Acoustic emission (AE) hits and related AE energy during indentation fracture of cortical bone using a PAC PCI-2 card and pico sensor. A threshold value of 43dB was used to filter premature trigger due to background noise. Registered AE hits had more than one count (threshold crossing). Amplifier gain was set at 40dB with a (0.1-1) MHz band pass filter. 8mm cubes of cortical bones were indented in the longitudinal direction at constant crosshead speed of 1 mm min-1 using a large 2D, 50˚ wedge indenter. We hypothesised that signals occurring as …

Ricketts And Steiner Analysis Using Newtom 3g™ Scout Images, James I. Gibson Iii

Loma Linda University Electronic Theses, Dissertations & Projects

NewTom 3G™ scout images have the general appearance of traditional lateral cephalometric radiographs. The purpose of this research was to determine if Ricketts and Steiner analyses could be accomplished on NewTom 3G™ scout images.

This was a retrospective study comparing the use of NewTom 3G™ scans in DICOM (Digital Imaging and Communications in Medicine) format to scout images from 25 consecutive patients of the Loma Linda University School of Dentistry Department of Orthodontics, three of these patients did not meet the inclusion criteria. The DICOM images were used to create controls. The controls and scout images were digitized using QuickCeph™. …

An Experimental Technique For Measurement Of Heat Generated During Bone Sawing, Hamid Khalili Parsa, Ger Reilly, Brendan Mccormack

Conference Papers

Orthopaedic bone cutting processes such as osteotomy and hip arthroplasty involve the cutting of one with the aid of various manual and powered cutting instruments including manual and powered bone saws. The extent of surgically induced bone necrosis at the point of the cutting tool and the bone is mainly due to the frictional heat generated by bone cutting. Bone necrosis has an impact on bone regeneration, and the rate of healing of the bone post operation. The threshold temperature for impaired regeneration of bone is in the range of 44°C to 47°C. Overheating also affects the sharpness life of …

Detection Of Microcracks During Bone Cutting Using Acoustic Emission Techniques, Ashkan Safari, Ger Reilly, Brendan Mccormack

Conference Papers

Surgeons may use a number of cutting instruments such as osteotomes and chisels to cut bone during operative procedures. The initial loading of cortical bone during the cutting process results in the formation of microcracks in the vicinity of the cutting zone with main crack propagation to failure occurring with continued loading; microcracking acts as a stimulus for main crack formation and has also been shown to occur during the propagation of the main crack. It has also been reported that Acoustic Emission (AE) is generated due to microcrack formation and crack growth, prior to, and during final fracture in …

Sequential Labelling And Acoustic Emission Analysis Of Damage Occurring In Cortical Bone During Indentation Cutting, Ger Reilly, Ashkan Safari, David Taylor, Brendan Mccormack

Conference Papers

When a surgeon uses a wedge shaped blade or an osteotome to cut cortical bone during an operative procedure the bone will fail by a process of microcracking and primary crack propagation. It has previously been observed that crack propagation is dependent on the direction of cutting relative to the main axis of the bone. It has also been observed that microcracks occurring during fracture release acoustic signals that facilitate real-time monitoring of a cutting process. In these novel studies, we labelled damage accumulation during cutting of cortical bone using sequential chelating dyes and we correlated recorded AE signals during …

Organization And Signal Processing Of The Descending Tracts In The Cervical Spinal Cord, Yanmei Tie

Doctoral Dissertations

This dissertation addresses the research for the development of spinal cord-computer interface (SCCI). The main objective of SCCI is to generate voluntary motor control signals for individuals with spinal cord injury (SCI).

In the neuroscience aspect, organization of the fibers in the descending tracts of the dorsolateral funiculus of the cervical spinal cord was investigated in cats. The spinal cord was penetrated with silicon substrate microelectrodes at 400 μm intervals in the medio-lateral direction at the C5/C6 and C6/C7 segmental borders. The stimulus consisted of a 20 ms train of charge-balanced biphasic pulses at 330 Hz. The evoked activities from …

An Investigation Of The Heat Affected Zone In Cortical Bone Sawing, Hamid Khalili Parsa, Ger Reilly, Brendan Mccormack, Andrew Macey

Conference Papers

Surgical procedures such as osteotomy and hip replacement involve the cutting of bone with the aid of various manual and powered cutting instruments including manual and powered bone saws. Frictional rubbing between the blade of the saw and the bone results in the generation of localised heating of the cut bone and increased cutting forces (Ark et al, 1997). Overheating in localised areas can cause bone necrosis and have an impact on the rate of healing of the bone post operation and overheating also affects the sharpness life of the blade. A review of the literature indicates that work has …

Robot Assisted Ultrasound Imaged Guided Interstitial Lung Brachytherapy In A Porcine Model, Richard A. Malthaner, Edward Yu, Jerry J. Battista, Chris Blake, Donal Downey, Aaron Fenster

Oncology Presentations

We set out to see if permanent interstitial brachytherapy seeds could be safely and reproducibly inserted thoracoscopicaly with the ZEUS Robotic system and intraoperative ultrasound into in-vivo porcine lungs.

Interpreting Hemoglobin And Water Concentration, Oxygen Saturation, And Scattering Measured In Vivo By Near-Infrared Breast Tomography, Subhadra Srinivasan, Brian W. Pogue, Shudong Jiang, Hamid Dehghani, Christine Kogel, Sandra Soho, Jennifer J. Gibson, Tor D. Tosteson, Steven P. Poplack, Keith D. Paulsen

Dartmouth Scholarship

Near-infrared spectroscopic tomography was used to measure the properties of 24 mammographically normal breasts to quantify whole-breast absorption and scattering spectra and to evaluate which tissue composition characteristics can be determined from these spectra. The absorption spectrum of breast tissue allows quantification of (i) total hemoglobin concentration, (ii) hemoglobin oxygen saturation, and (iii) water concentration, whereas the scattering spectrum provides information about the size and number density of cellular components and structural matrix elements. These property data were tested for correlation to demographic information, including subject age, body mass index, breast size, and radiographic …

Evaluation Of Intra-And Inter-Fraction Motion In Breast Radiotherapy Using Electronic Portal Imaging Cine Loops, Chrison Lee, Edward Yu, Tomas Kron

Oncology Presentations

Parallel tangent breast irradiation is commonly used postbreast conservation surgery for early breast cancer patient without lymph node involvement to improve local disease control. Intra-fractional and inter-fractional variabilities are often presented in daily treatment setup. The present pilot study used Electronic Portal Imaging (EPI) to evaluate intra-and inter-fraction motion in patients undergoing simple breast tangent radiotherapy.

Implementation Of Gy-Eq For Deterministic Effects Limitation In Shield Design, John W. Wilson, Myung-Hee Y. Kim, Giovanni De Angelis, Francis A. Cucinotta, Nobuaki Yoshizawa, Francis F. Badavi

Mathematics & Statistics Faculty Publications

The NCRP has recently defined RBE values and a new quantity (Gy-Eq) for use in estimation of deterministic effects in space shielding and operations. The NCRP's RBE for neutrons is left ambiguous and not fully defined. In the present report we will suggest a complete definition of neutron RBE consistent with the NCRP recommendations and evaluate attenuation properties of deterministic effects (Gy-Eq) in comparison with other dosimetric quantities.

Modular Machine Learning Methods For Computer-Aided Diagnosis Of Breast Cancer, Mia Kathleen Markey '94

Doctoral Dissertations

The purpose of this study was to improve breast cancer diagnosis by reducing the number of benign biopsies performed. To this end, we investigated modular and ensemble systems of machine learning methods for computer-aided diagnosis (CAD) of breast cancer. A modular system partitions the input space into smaller domains, each of which is handled by a local model. An ensemble system uses multiple models for the same cases and combines the models' predictions.

Five supervised machine learning techniques (LDA, SVM, BP-ANN, CBR, CART) were trained to predict the biopsy outcome from mammographic findings (BIRADS™) and patient age based on a …

Is Extended Volume Of External Beam Irradiation Beneficial In Post-Esophagectomy High Risk Patients Receiving Combined Chemoradiation Therapy?, E. Yu, A. R. Dar, R. Ash, G. Videtic, P. Truong, L. Stitt, A. Tomiak, M. Vincent, R. Malthaner, I. Craig, E. Brecevic, W. Kocha, R. Inculet, M. Lefcoe

Oncology Presentations

OBJECTIVE: To assess the value of extended volume irradiation with anastomotic coverage in high risk resected esophageal cancer patients.

METHOD: A retrospective study was undertaken at LRCC from 1989-1999 for high risk resected esophageal cancer patients. Adjuvant treatments consisted of 4 cycles of chemotherapy (epirubicin/fluorouracil/cisplatin or cisplatin/fluorouracil), and local regional irradiation with or without coverage of the anastomotic site. Radiation dose ranged from 45-60Gy at 1.8-2.0 Gy/fraction given with initial anterior-posterior/posterior-anterior arrangement with either extended (with anastomotic coverage) or small (without anastomotic coverage) field followed by oblique fields for boost.

RESULT: One hundred eighty-eight charts were reviewed. Seventy-two patients were …

Time Course Of Recruitment, Pit Formation And Apoptosis Of Osteoclast Populations On Dentin In Vitro, Jihyun Kang, Rigoberto Cornejo, Kevin J. Hirokawa, Susan M. Digiorgio, Darlene F. Howard, Susan F. Silverton

Cells and Materials

The resorptive capacity of osteoclasts in vitro has been used as an indicator of bone resorption. However, the kinetics of osteoclast development and senescence is not well understood. It has been noted that mononuclear precursors migrate to calcified substrate and after multi-nucleation become competent bone resorbing cells. Osteoclasts, once finished a wave of resorption, become senescent. In order to determine the survival characteristics of osteoclast populations involved in calcified tissue destruction, we have investigated the time course of the recruitment to dentin and apoptosis of osteoclasts. We have established the linkage between these measurements and the time course of the …

Biofilm Mediated Calculus Formation In The Urinary Tract, Robert J. C. Mclean, David J. Stickler, J. Curtis Nickel

Cells and Materials

Mineralization and subsequent calculus formation is a common complication of biofilm infections. In the urinary tract, these infected calculi often arise from infections by urease-producing bacteria. Ammonia, liberated by bacterial urease activity, increases urine pH, resulting in the precipitation of Ca and Mg as carbonateapatite {Ca₁₀(PO₄,CO₃)₆(OH,CO₃)₂} and struvite (NH₄MgP0₄·6H₂O). These minerals become entrapped in the organic matrix which surrounds the infecting organisms and ultimately grow into mature calculi. When the causative organisms grow on urinary catheters and stents, the resulting mineralization can …

Perturbations Of Periosteel Bone During Healing: Effect Of Non-Weight Bearing, Helen E. Gruber, Mary E. Kirchen, John R. Sweeney, William E. Anderson, G. June Marshall

Cells and Materials

Weight bearing (WB) is an important factor influencing bone remodelling. The present study evaluates the effects of weight bearing and non-weight bearing (S) (achieved by tail suspension and hindlimb elevation) on the healing of a fibular osteotomy in adult male rats. After 9, 18 or 36 days under WB or S conditions, periosteum near the callus formed at the osteotomy site was compared to periosteum of the contralateral fibula (which did not receive an osteotomy) or to periosteum of fibula of control animals which did not receive an osteotomy. Data show that periosteal bone healing is sensitive to alterations in …

Validation Of Energy Dispersive X-Ray Spectrometry As A Method To Standardize Backscattered Electron Images Of Bone, E. G. Vajda, R. D. Bloebaum, J. G. Skedros

Cells and Materials

The use of backscattered electron (BSE) imaging as a tool for the qualitative measurement of mineral content in bone has been well documented. The challenge still remains to develop BSE imaging as a tool for quantitative mineral content analysis in bone. The limiting factor has been the ability to standardize the BSE signal within and between laboratories. Energy dispersive x-ray spectrometry (EDX) has been proposed as a method to standardize the BSE operating environment. The goal of this study is to investigate the relationship between EDX-determined wt.% Ca measurements and BSE graylevels. A comparison with traditional ash content measurements will …

Three Dimensional Localization Of Lesions From Digitized Mammograms, Amy L. Magnus

Theses and Dissertations

This thesis describes new algorithms to localize regions-of-interests (ROIs) three dimensionally from a pair of digitized mammograms. This work is intended to add a layer of sophistication to computer aided diagnosis by putting to use the fixed and measurable parameters of mammographic imaging. The fixed parameters are the source to film orientation and the podium-image distance. Measurable parameters are the rotation angle of the x-ray tube from the horizontal and the compression depth (the distance from compression paddle to contact podium distance) at the time of imaging. As an additional benefit, three dimensional localization algorithms alleviate the confusion radiologists may …

Optical Bone Chambers As Tools For Studying The Bone-Implant Interface: A Review, Howard Winet

Cells and Materials

Bone chamber intravital microscopy combines the control volume of in vitro models and the chemical complexity of in vivo models to optimize the study of bone physiology in situ. As an optical tool it provides a window to dynamic events at the tissue level of magnification. In particular, it allows measures of microvascular events: (1) in space by magnifying local perfused vasculature and microcirculation at any instant, and (2) in time by providing the same volume of tissue for weekly viewing of an evolving process such as bone healing. This quartz-bearing titanium screw has revealed a consistent order for …

Bone Absorptiometry In Metabolic Bone Disease: Baseline Values And Long-Term Treatment With Calcitriol (Post-Menopausal Osteoporosis Versus Osteomalacia), A. Caniggia, B. Frediani

Cells and Materials

Total body bone absorptiometry reveals low mineral density in both postmenopausal osteoporosis and osteomalacia patients. The method was used to investigate the effect of calcitriol administration on patients suffering from one of these conditions. In osteomalacia, the administration of calcitriol resulted in a dramatic improvement in bone mineral density (sometimes up to 50% in 12 months), indicating the rapid mineralization of previously uncalcified bone tissue as a result of the normalization of the Ca x P product. In osteoporosis a similar treatment was seen to halt the progressive decrease in bone mineral levels and sometimes resulted in minor increases in …

Some Observations On The Structure Of Encrusting Biofilms Of Proteus Mirabilis On Urethral Catheters, C. Winters, D. J. Stickler, N. S. Howe, T. J. Williams, N. Wilkinson, C. J. Buckley

Cells and Materials

A physical model of the bladder has been used to study the process of urinary catheter encrustation. Techniques have been devised for the preparation of sections through these encrustations in situ on the luminal surfaces of catheters and for mapping the distribution of calcium and magnesium in the biofilms. Transmission electron microscopy on these sections showed struvite-like crystals lying in the matrix and in direct contact with the catheter surface. Calcium phosphate ("bioapatite") was distributed throughout the film and many of these amorphous particles appear to have cells at their cores. Freeze-substituted sections of biofilms also showed electron dense materials …

Development Of A Mammographic Image Processing Environment Using Matlab, John L. Kelley

Theses and Dissertations

Breast cancer is a disease that accounts for a disturbingly large number of deaths in females each year. Its prevalence is a topic of concern to all of us since it can affect our families, friends, and coworkers. Although mammographic screening is the most effective method currently available for the early detection of breast cancer, it is far from being an infallible procedure. Mammographic reading is error prone, partly because of the complexity of the task and partly because of the variability in human performance. Computers offer high reproducibility, and when used as an adjunct by the radiologist, may improve …

Instrumentation And Control For A Microprocessor-Based Coronary Perfusion System, Daniel L. Priester

Master's Theses (1922-2009) Access restricted to Marquette Campus

No abstract provided.

A Comparative Analysis Of Intrusion Of Incisor Teeth Achieved In Adults And Children According To Facial Type, Ronald L. Otto

Loma Linda University Electronic Theses, Dissertations & Projects

A comparison of incisor intrusion achieved in deep bite adults and children was made. Facial type was also examined for affect upon intrusion achieved. Fifty-five cases treated with Bioprogressive mechanics were studied cephalometrically, including twenty-four adults and thirty-one children. Neither age nor facial type was found to be statistically related to the amount of incisor intrusion achieved in this sample. A method of measuring intrusion at the root apices was devised which was felt to give a more accurate indication of actual bodily intrusion. More external root changes during treatment were observed for adults than for growing children. Wide latitude …

A Method Of Analyzing Mandibular Movement, Richard B. Mccoy

Loma Linda University Electronic Theses, Dissertations & Projects

Mandibular movement is considered to be a fundamental factor in the study, analysis, and treatment of occlusion. For many years, dentists have realized that dental health depends upon the compatibility of mandibular movements and occlusion. This realization has led to the development of new methods and techniques for recording accurately and scientifically the movements of the mandible. In order for this data to be of scientific value, it must be stored in a usable form which is easily available for analysis.

The purpose of this research project was to develop a procedure for storing and recalling mandibular-movement information. Before such …