Radiology Commons^™

Using Thermoluminescent Dosimeters To Measure The Dose From High And Low Energy X-Ray Sources, Wesley Leon Boyd

UNLV Theses, Dissertations, Professional Papers, and Capstones

This work focused on using thermoluminescent dosimeters (TLDs) to measure the doses from two x-ray sources, a CT scanner and a linear accelerator (linac). In addition ion chambers were used to determine the isodose contours from the operation of the linac. 1mm x 1mm x 1mm TLD-100 microcubes were placed in a Lawrence Livermore National Laboratory (LLNL) torso phantom and irradiated using a Toshiba Aquilion One 320-Slice CT Scanner. Different thicknesses of shielding composed of antimony and bismuth powder suspended in an ethylene copolymer were used to shield the phantom and the dose reduction was measured. The dose reduction ranged …

Buccal Bone Changes Following Rapid Maxillary Expansion (Rmf), Long-Term Results, Elena S. Iacob

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to use Cone Beam Computed Tomography (CBCT) images to quantitatively evaluate buccal bone changes of maxillary first premolar (P1), second premolar (P2) and first molar (M1) shortly after Rapid Maxillary Expansion (RME) and at the end of orthodontic treatment, as well as to evaluate the variables that may be associated with the short-term and long-term changes. Forty-seven consecutive patients (25 males and 22 females) with a mean age of 14.5years and who required RME as part of their orthodontic treatment and had pre-RME (T1) and post-RME (T2) CBCT images available were used for the …

Management Of Pediatric Acute Appendicitis In The Computed Tomographic Era., Kuojen Tsao, Shawn D. St Peter, Patricia A. Valusek, Troy L. Spilde, Scott J. Keckler, Abhilash Nair, Daniel J. Ostlie, G W. Holcomb Iii

Manuscripts, Articles, Book Chapters and Other Papers

BACKGROUND/PURPOSE: The treatment options for complicated appendicitis in children continue to evolve. Optimal management of complicated appendicitis relies on an accurate preoperative diagnosis. We examined the accuracy of our preoperative diagnosis including computed tomography (CT) and the influence on the management of children with perforated and nonperforated appendicitis.

METHODS: Following IRB approval, a 6-year review of all patients that underwent an appendectomy for suspected appendicitis was performed. Treatments included immediate operations and initial nonoperative management (antibiotic therapy +/- percutaneous drainage of abscess). Appendicitis was confirmed by histological examination.

RESULTS: One thousand seventy-eight patients underwent appendectomy for suspected appendicitis. Preoperative CT …

Immediate Provionalization Of Single Threaded Oxidized Implants On Maxillary Premolars Healed Sites: One-Year Study, Kiyotaka Umezu

Loma Linda University Electronic Theses, Dissertations & Projects

Osseointegrated endosseous implants have been widely used and become a predictable treatment option for completely and partially edentulous patients. The viability and predictability of this treatment modality have been supported with the high success rates in numerous studies. Clinical guideline requires a healing period of 3 to 6 months without functional loading to achieve osseointegration with machine surface implants. Therefore, numerous studies on immediately loaded implants have been conducted in an attempt to minimize or eliminate this healing period. The purpose of this study was to evaluate the success rate of the immediately provisionalized oxidized-surface implants in healed sites supporting …

Predicting Long-Term Memory In Adult Brain Injury Patients Using Mr Spectroscopy, Herminia De La Rosa-Trujillo

Loma Linda University Electronic Theses, Dissertations & Projects

Accurate outcome prediction has proven to be somewhat elusive for patients with traumatic brain injury (TBI). The difficulty is due to the sometimes inaccurate methods of prediction currently available. Despite the advances seen in radiological technology, the traditional methods of x-rays, CT scans and MRIs are not always accurately able to predict patient functional outcome. These radiological methods are adequate in determining gross structural anatomical disturbances, however, they unable to detect more diffuse cellular damage believed to be responsible for the functional impairments evidenced in patients sustaining TBI. Magnetic Resonance Spectroscopy (MRS) is an imaging technique which measures brain metabolites …

Detection Of Simulated Apical Root Resorption Using Three Cone Beam Ct Machines, Marcus Paulson

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine orthodontists' ability to discriminate small differences of simulated apical root resorption (SARR) on extracted teeth, using the output from three cone beam computed tomography (CBCT) machines. Twenty-four unrestored maxillary anterior teeth exhibiting normal morphology, were collected. The teeth were scanned by three CBCT machines: 1) the NewTom 3G (AFP imaging, USA), 2) the iCAT (Imaging Sciences, USA) 3) and the MicroCAT II (Siemens Medical, USA). Using a sandblaster the apical portion of each tooth was reduced in 0.5 mm increments up to a total reduction of 1.5 mm. Each root modification was …

Reproducibility Of Two Non-Consecutive Scans Using A Newtom 3g; In Vitro Model, Hyoung Jin Park

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: The aim of this study was to evaluate the reproducibility of mineral density measurement expressed in Hounsfield Units (HU) using a phantom device with known mineral densities and the NewTom 3G Cone Beam Computerized Tomography (CBCT).

Materials and Methods: A phantom device made of 21 HA cylindrical disks with known densities was fabricated. The phantom was scanned in 6, 9, and 12 inch fields of view using a NewTom 3G CBCT. The scans were repeated at non-consecutive sessions. Volumetric data in each of the scans were formatted to DICOM images. HU values of the regions of interest were retrieved …

Variability In Selecting Lateral Cephalometric Landmarks In Two Cbct Image Modes, Dana Nguyen

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: The purpose of this study was to determine the variability of lateral cephalometric landmark selection in two cone beam computed tomography (CBCT) lateral cephalometric simulations: 1) a mean projection image (MPI) and 2) a serial sagittal slice image (SSSI).

Methods: A MPI is a two-dimensional (2D) image obtained from the NewTom 3G^TM CBCT that resembles the conventional lateral cephalogram. A SSSI is a 2D image also obtained from CBCT data, but is created by superimposing a series of selected thin sagittal slices containing the required cephalometric landmarks. This study compared the Ricketts and Steiner analysis of the MPI …

Automatic Colonic Polyp Detection Using Multiobjective Evolutionary Techniques, Jiang Li, Adam Huang, Jianhua Yao, Ingmar Bitter, Nicholas Petrick, Ronald M. Summers, Perry J. Pickhardt, J. Richard Choi

Electrical & Computer Engineering Faculty Publications

Colonie polyps appear like elliptical protrusions on the inner wall of the colon. Curvature based features for colonie polyp detection have proved to be successful in several computer-aided diagnostic CT colonography (CTC) systems. Some simple thresholds are set for those features for creating initial polyp candidates, sophisticated classification scheme are then applied on these polyp candidates to reduce false positives. There are two objective functions, the number of missed polyps and false positive rate, that need to be minimized when setting those thresholds. These two objectives conflict and it is usually difficult to optimize them both by a gradient search. …

Accuracy Of The Newtom 3g™ In Measuring The Angle Of The Articular Eminence, Rehana Khan

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine the accuracy of the Newtom 3G™ in determining the angulation of the articular eminence. The benefits of conducting this study were to provide additional uses for the standard records that are taken for the purposes of orthodontic treatment, as well as evaluate the Newtom 3G™ for accuracy in measuring the anatomy of the glenoid fossa. This study required 20 participants that volunteered to allow their records to be used. Records evaluated were the Newtom 3G™, impressions, and wax check bite registrations. The wax record was taken using the 'forced bite' technique to …

Near-Infrared Characterization Of Breast Tumors In Vivo Using Spectrally-Constrained Reconstruction, Subhadra Srinivasan, Brian W. Pogue, Ben Brooksby, Shudong Jiang, Hamid Dehghani, Christine Kogel, Wendy A. Wells, Steven P. Poplack, Keith D. Paulsen

Dartmouth Scholarship

Multi-wavelength Near-Infrared (NIR) Tomography was utilized in this study to non-invasively quantify physiological parameters of breast tumors using direct spectral reconstruction. Frequency domain NIR measurements were incorporated with a new spectrally constrained direct chromophore and scattering image reconstruction algorithm, which was validated in simulations and experimental phantoms. Images of total hemoglobin, oxygen saturation, water, and scatter parameters were obtained with higher accuracy than previously reported. Using this spectral approach, in vivo NIR images are presented and interpreted through a series of case studies (n=6 subjects) having differing abnormalities. The corresponding mammograms and ultrasound images are also evaluated. Three of six …

Magnification In Images Produced By Five Popular Digital Lateral Cephalometric Machines, Gretchen Marie Schnepper

Loma Linda University Electronic Theses, Dissertations & Projects

Modern digital lateral cephalometric images are produced by machines that vary in a number of critical features such as: 1) machine geometry, 2) movement (or lack of movement) of the x-ray source, 3) movement (or lack of movement) or x-ray detectors, 4) cephalostat geometry and 5) digital data manipulations by proprietary software. The purpose of this study was to evaluate the magnification characteristics of images produced by five commercial digital lateral cephalometric machines. These digital image magnification characteristics were then compared with images produced by an analog cephalometric machine. The two goals of this study were to: 1) measure the …

Resonance Frequency Analysis As A Determinant Of Implant Initial Stability, Negar Tabandeh

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: The clinicians' decision regarding immediate loading is largely determined by the assessment of initial stability of the dental implant. Computed tomographic assessment of recipient site bone quality, insertion resistance torque and post-insertion resonance frequency are currently the only objective methods of measurement establishing initial stability.

Purpose: A study was designed to measure resonance frequency of root form dental implants placed in cadaver jaws. The resonance frequency values were compared to previous subjective and objective data reported in prior studies in the series.

Materials and Methods: Resonance frequency measurements were secured using the Osstell ™ mentor unit on 4.0 X …

Comparison Of Different Methods Of Assessing Ridge Width Prior To Implant Placement, Lung-Cheng Chen

Loma Linda University Electronic Theses, Dissertations & Projects

The aim of this study was to compare the following 3 methods of assessing alveolar ridge dimensions prior to placement of dental implants: 1) ridge mapping measurement before surgical flap reflection using a caliper; 2) direct caliper measurement following surgical exposure of the bone, and 3) measurement using images from cone beam computerized tomography.

Sixteen subjects having 25 sites for planned implant placement or ridge augmentation were recruited. An acrylic stent was fabricated for each patient. The stent provided 3 buccal/lingual pairs of consistent measurement points for each implant site, located 4, 7 and 10 mm from the summit of …

Cbct Panoramic Images Vs. Traditional Panoramic Radiographs, Sunny Young Hutchinson

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this research was to compare the accuracy of angular measurements of the panoramic image of the Newtom 9000™ Cone Beam Computed Tomography (CBCT) with the Sirona™ Orthophos panoramic unit. The study was separated into three parts: phantom study, patient study, and archform study. The phantom study used fabricated phantom typodonts to compare angular measurements between the Newtom 9000™ panoramic image and the Sirona™ panoramic radiograph. Accuracies of the measurements were then determined by comparing the values to the actual phantom typodont. No marked differences in angular measurements were recorded for the phantom typodont using either of the …

Prevalence Of Degenerative Joint Disease In A Pre-Orthodontic Adolescent Sample, Marie Mansour

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this research was to determine a prevalence of degenerative joint disease in our pre-orthodontic adolescent patients age ten through seventeen. The prevalence was assessed according to gender. Severity of DJD was established for each patient and a "red flag" for diagnosis was identified. The purpose was also to establish norms for joint space for patients with and without degenerative joint disease. Correlations to distal condyle position and angle classification were described. 123 consecutive patients, 77 female and 46 male T1 NewTom records were reviewed. Severity of DJD was classified according to none, mild, moderate, and severe. Sagittal …

Cone Beam Ct And Digital Radiography. A Comparative Study Of P/A Cephalometrics., Michael John Erickson

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine if Rickett's posterio-anterior (P/A) cephalogram measurements could be obtained from Cone Beam Computerized Tomographic (CBCT) images taken on the NewTom QR-DVT 9000™.

Fifteen frontal cephalometric radiographs were chosen for good image quality, with no regard for patient age or gender. Each cephalogram was traced three times by the same operator using ZeroBase™ software. Landmarks were located and measured according to the Rickett's frontal analysis technique. Methods were devised for obtaining analogous measurements using CBCT images on the same group of patients.

Measurements obtained using CBCT correlated well with those obtained using the …

Measured Effects Of Rapid Palatal Expansion On Nasal Cavity Volume Utilizing Cbct, Jon Neal Robinson

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to evaluate and predict the expected changes that occur in the nasal cavity volume following rapid palatal expansion. Eighteen subjects (11 female, 7 male), ages 9 to 18, requiring rapid palatal expansion in conjunction with comprehensive orthodontic treatment, were selected for the study. Rapid palatal expansion was accomplished using the standard, banded hyrax appliance. Three-dimensional cone beam computed tomograms using the NewTom 9000™ were acquired before and after expansion. Serial coronal slices of the nasal cavity were made using the QV9000™ software program. The resultant serial images were imported into 3-D Doctor™ for analysis …

The Radiopacity Of 29 Resin Restorative Materials Compared To Enamel, Peter Lubisich Iv

Loma Linda University Electronic Theses, Dissertations & Projects

The radiodensity of a composite resin can greatly influence a clinician's ability to analyze a restoration for failure. The purpose of this study was to determine the relative radiopacities of 29 resin restorative materials compared to enamel, and to verify the comparable radiopacity between shades of 23 of the restorative composite resin materials. Composite resin discs measuring >5mm in diameter and 2 mm in thickness were made and polymerized. Radiographs were taken of the composite resin discs, which included an aluminum step wedge for calibration and a densitometer was used to measure the radiodensity of the composite resin samples. The …

Linder-Aronson S Analysis Using Rhinomanometry And Newtom, Noel Moser

Loma Linda University Electronic Theses, Dissertations & Projects

Investigations into the effects of airway patency on craniofacial development are essential to ensure that interceptive orthodontic treatment provides the maximum benefit to the patient. The aims of this study were to (1) compare the size of the nasopharyngeal airway space on lateral cephalometric and 3D volumetric radiographs to determine if volumetric scans can be of greater diagnostic value than a lateral cephalometric film in determining the degree of airway blockage or patency and (2) to examine the correlation between functional airway resistance, as evaluated by rhinomanometry, and radiographic constriction due to nasal turbinate and adenoid size.

Twenty-eight subjects from …

Comparative Methods Of Measurement To Evaluate Onplant Assisted Anchorage, Marc Reid Larson

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to compare the two-dimensional cephalometric and the three-dimensional tomographic radiographic methods in their ability to assess anatomic measurements while using the Onplant anchoring device in anterior retraction cases.

The Onplant was surgically placed beneath the periosteum of the hard palate. After osseointegration the Onplant was then uncovered and attached to the first molars by means of a transpalatal bar. Conventional orthodontic treatment was then used to retract the anterior teeth after 1^st premolars were extracted.

To evaluate the movement of the Onplant, a three-dimensional measuring tool was needed. Seven different measurements were made …

Establishing Norms For A Mexican Group Using Ricketts, Steiner And Arnett Analyses, Mauricio Gonzalez Balut

Loma Linda University Electronic Theses, Dissertations & Projects

Most existing cephalometric analyses are based on norms for the Caucasian population. Therefore, they cannot be properly applied for Mexican or Hispanic patients. Ethnic variations in the normal positions of the maxilla and mandible influence and alter the diagnosis and treatment plan for each of the different type of malocclusions. Previous studies have addressed the difference between the Caucasian norms and the Hispanic norms, this indicates the variety of their skeletal, dental and facial features.

It is the purpose of this study to establish specific cephalometric standards for the native Mexican group, using the Steiner and Ricketts analyses along with …

A Cephalometric Study Of The Class Ii Correction Effects Of The Eureka Spring, Ernest L. Stromeyer

Loma Linda University Electronic Theses, Dissertations & Projects

The effect of the Eureka Spring appliance, was investigated on 37 consecutively treated, non compliant, bilateral Class II malocclusions, requiring at least 3 mm or more of additional molar correction. The mean pretreatment age of this sample was 13.9 years. All patients were treated by a single clinician utilizing the Eureka Spring. Lateral cephalographs were taken at start of orthodontic treatment (T1), at insertion of Eureka Springs (T2), and at removal of the Eureka Springs (T3). The average treatment interval between T2 and T3 was 4 months. Class II correction occurred almost entirely by dentoalveolar movement, 33% in the maxilla …

A Pilot Study On The Short Term Effects Of The Herbst Appliance On The Glenoid Fossa, David A. Bennion

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this pilot study was to evaluate the initial effects of the Herbst appliance and determine through the use of common cephalometric radiographs that were optically enhanced and then digitally reproduced, if fossa migration is taking place. Fourteen, (6 male, 8 female), growing patients were treated by the same clinician for the correction of a Class II malocclusion using a modified Herbst appliance. Pretreatment (T₁) standard lateral cephalometric radiographs and post Herbst treatment (T_H) optically enhanced lateral cephalometric radiographs were taken. All radiographs were digitally captured and reproduced so 6 linear and 1 area …

Treatment Effects Of The Edgewise Bioprogressive Herbst Appliance, Bernard C. Chang

Loma Linda University Electronic Theses, Dissertations & Projects

The effect of the Edgewise Bioprogressive Herbst appliance, as described by Dr. Terry Dischinger, was investigated on 24 Class II, Division 1 malocclusions. Mean pretreatment age of this sample was 11.2 months. All patients were treated by Dischinger with a Bioprogressive Herbst appliance. Lateral cephalographs taken before, after Herbst appliance therapy, and after edgewise treatment were traced, then digitized into Quick Ceph™. Measurements were computed by the computer software. The following results were found: 1) Average treatment time was 9 months. 2) An overcorrected Class I relationship was achieved. 3) Class II malocclusion was corrected by 4.5 mm skeletal alteration …

The Accuracy Of Computer Video Imaging Prediction : Just Prior To Surgical Mandibular Advancement/Genioplasty Orthognathic Cases, Jason T. Chiakowsky

Loma Linda University Electronic Theses, Dissertations & Projects

The accuracy of the computer video imaging treatment prediction was investigated using Quick Ceph Image.™ Thirty one surgical mandibular advancement/genioplasty orthognathic cases were examined to determine if the soft tissue profile prediction was representative of the actual result. All patients were over the age of 18. Lateral cephalographs and slides were taken immediately pre-surgically, and six months post-surgically. The slides were duplicated into 4X6 photographs. The cephalographs were digitized and the photographs captured by video on the Quick Ceph Image software program. A line drawing and computer video image treatment prediction were generated using the actual surgical change that had …

Mandibular Asymmetry In Unilateral Class Ii Malocclusion : A Cephalometric Study, Raed Z. Moussa

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study is to evaluate skeletal and dental asymmetry in unilateral class II malocclusion. A study group of 25 unilateral subdivision patients was compared to 25 class I malocclusion patients serving as the control group. Submento-vertical and frontal radiographs were used for the evaluation. Symmetry was evaluated by comparing measurements between right and left sides for both groups and matching the middle points with the midsagittal axis. Statistical paired and simple t-test were used to evaluate the difference between the two sides for both groups. The measurements showed no significant skeletal and dental asymmetries except for three …

The Accuracy Of Sonographic Imaging (Dolphintm Digigraph) And Standard Lateral Cephalometric Radiographs : A Comparative Study, Michael D. Teichman

Loma Linda University Electronic Theses, Dissertations & Projects

Radiation due to x-ray exposure is a concern, and the development of the Dolphin™ DigiGraph represents an attempt to limit this exposure. The purpose of this paper was to compare measurements (using Ricketts analysis) obtained from conventional radiographic cephalometric tracings with those obtained by computerized digitizing with the DigiGraph. Forty-six patients from the Loma Linda University School of Dentistry graduate orthodontic clinic were digitized, and the results were compared to the x-ray tracings of these patients. The results showed that seven of the twenty-one variables examined exhibited a statistical similarity between the two methods (DigiGraph and x-ray tracing). An examination …

The Use Of Corrected Occlusal X-Ray For Determination Of Ald : A Comparative Study, Merlin D. Ekvall

Loma Linda University Electronic Theses, Dissertations & Projects

In this study arch length discrepancy or ALD was studied in 50 untreated patients. The measurements obtained from Hilgers' corrected occlusal x-ray using his Occlusal Paralleling Instrument or O.P.I, were compared with those derived by four conventional methods, - "Eye balling," digital caliper determination, conventional mandibular x-ray, and the Rocky Mountain Data Systems computer analysis (31 cases). When using the OPI, results give a higher negative ALD as it takes into consideration the space required to level a curve of Spee.

Measurements were made by the author and 3 faculty members using the above methods. Statistical analysis of the means …

Predictive Value Of Radiographic Analysis Of Menton, Hyoid Bone, And The Third Cervical Vertebra Angle, Kalfred G.S. Chun

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study is to determine if the hyoid bone could be used as a reliable and stable reference landmark. Previous researchers have used cranial landmarks to determine the hyoid bone position. The results of these studies have shown a large variability in hyoid position. To determine the hyoid bone position, an analysis called the hyoid triangle was used. The hyoid triangle is formed by joining the cephalometric points retrognathion (the most inferior posterior point on the mandibular symphysis), hyoidale (the most superior anterior point on the body of the hyoid bone), and C3 (the most anterior inferior …