• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 604
  • 210
  • 136
  • 133
  • 133
  • 133
  • 133
  • 133
  • 130
  • 41
  • 26
  • 13
  • 9
  • 7
  • 5
  • Tagged with
  • 1385
  • 511
  • 496
  • 467
  • 386
  • 262
  • 224
  • 221
  • 201
  • 191
  • 190
  • 187
  • 186
  • 156
  • 123
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Retrospective study at a single tertiary hospital in South Africa (Groote Schuur) on the treatment outcome in patients who underwent TransArterial Chemo-Embolization (TACE) for hepatocellular carcinoma

Sihlahla, Irvine 26 April 2023 (has links) (PDF)
Background: Hepatocellular carcinoma is amongst the common causes of cancer deaths and has few curative treatment options. Transarterial chemoembolisation (TACE) is an option widely reported and used for palliative care and as a bridge to liver transplantation. Limited South African studies have examined the outcome of this type of therapy, with one comparing survival benefit and hospital stays in TACE using Adriamycin with lipiodol, with no benefit demonstrated. The current study aims to compare the imaging and alpha fetoprotein (AFP) responses with previous international studies on treatment response. Objectives:. To elucidate imaging and AFP outcomes after TACE in patients with hepatocellular carcinoma by measuring these in comparison with previous studies. Methods: 24 patients with hepatocellular carcinoma treated with TACE in the radiology department at Groote Schuur Hospital over a 4-year period were retrospectively reviewed by using an structured protocol. Baseline and post-TACE radiological features were assessed including tumour size and necrosis in conjunction with AFP levels were evaluated to determine tumour response. Results: During the study period 24 patients (17 males [70.8%] and 7 females[29.2%], with a mean age of 52.9 years) underwent TACE for HCC. 15 patients (62.5%) had documented cirrhosis, 14 patients (54 % ) had concomitant hepatitis, with hepatitis B being the commonest in 11 patients (45.8%). The majority of patients were Child Purgh A 21 patients (87.5% ) while 3 (12.5%) were Child Pugh B, 20 patients (83.3%) were TACE naïve, while 4 patient's (16.7%) had prior TACE treatment. 4 patient's (16.7%) of the study population had histologically confirmed hepatocellular carcinoma, 5 patients (20%) had HCC metastasis at baseline, 11 patients (45.8%) had AFP levels below 200ug/L and 13 patient's (54.2%) had levels above 200ug/L at baseline. 13 patients had large > 100 mm tumours at baseline, with median tumour size of 115 mm ( range 55,50-173 mm). 20 patients (83.3%) had imaging by 6 months (mean of 84 days, range 34- 126 days) post-TACE with a median tumour size of 91.00 mm [range 36.50-168.50 mm]. By both mRECIST criteria and EASL criteria, 10% of the study population had complete responses, 10% demonstrated partial responses by mRECIST criteria alone and none by EASL criteria. 20% had progressive disease by both mRECIST and EASL criteria. Stable disease was evident in 60% by mRECIST and 70% by EASL criteria.15 patients (62.5%) of the study population had AFP results post treatment, with a median of 624.00 micrograms/L (range 5.00 – 11548.00 micrograms/L). No patients demonstrated more than 90% reduction or normalisation of alpha-fetoprotein levels. 7 patients (46,67%) had greater than 50% but less than 90% reductions while 8 patients (53.3 %) had increased levels. The study demonstrated a weak correlation between alpha fetoprotein reduction and radiological response post-TACE (r = 0.085). Conclusion: Our study revealed 60% stable disease following TACE similar to 77% in the previous study by Lewandowski RJ et al ,with our 10% partial response compared to the 35% obtained by Llovet JM et al. The AFP had a 46% response compared to the one shown by Sherman et al which had 65%. TACE in patients with hepatocellular carcinoma has a modest radiological and biochemical response, with the majority of patients having stable disease.
12

Diffusion Tensor Imaging: Application to Cardiovascular Magnetic Resonance Imaging

Edalati Ahmadsaraei, Masoud 10 October 2016 (has links)
No description available.
13

An analysis of the CT and CT angiogram findings of methamphetamine induced stroke in young adults (≤45 years) presenting to GSH Emergency department

Ngamolane, Aaron 19 July 2023 (has links) (PDF)
MMED Title: An analysis of the CT and CT angiogram findings of methamphetamine induced stroke in young adults (≤ 45 years) presenting to GSH emergency department. The recreational use of methamphetamine in the Republic of South Africa is on the rise accounting for 30% of patients admitted to addiction rehabilitation centres countrywide1 . In the Western Cape province alone methamphetamine is the commonly abused drug, detected in 44% of patients admitted for addiction rehabilitation2 . Methamphetamine is a risk factor for stroke especially in young adults, it is therefore important to determine key radiological features of methamphetamine related stroke for prompt and accurate differentiation from other stroke aetiologies. Study of stroke in this group of participants is of paramount importance as stroke is the second most common cause of death worldwide, responsible for 11.8% of all deaths after ischaemic heart disease (14.8%)3 . Stroke is also responsible for 4.5% of disability adjusted life years (DALYs)3 . The aim of the study was to determine whether stroke in young adults (≤ 45 years) exposed to methamphetamine can be differentiated from other stroke aetiologies on brain CT and CT angiogram. A cross-sectional retrospective study was performed in the department of radiology in Groote Schuur Hospital on brain CT and CT angiograms and their final reports from October 2012 to October 2020. All patients aged 45 years old or younger with clinical features of stroke and a history of methamphetamine or polysubstance abuse were included. Data collection tools were designed to suit inclusion criteriums and used as search keywords in the PACS for GSH. A re-read was done by the principal investigator as a second-year radiology registrar with limited neuroradiology experience guided by the study parameters outlined in the data collection tool. The obtained data was correlated with the finalized reports from each study. Our study has shown that in a group of young patients who admitted to using tik and who presented to the emergency room with clinical features of cerebral stroke, ischaemic infarct was found significantly more often than intracerebral haemorrhage. This study demonstrated that MCA territories were most frequently involved with occlusion of the M1 segments bilaterally. Radiologically loss of grey-white matter interface and a wedge-shaped appearance are the predominant patterns of radiographic presentation. This study has demonstrated that CT appearance of methamphetamine induced stroke does not differ from stroke patterns seen with traditional risk factors.
14

Assessing Doppler-Derived Pressure Gradients and Liver Echogenicity to Predict Liver Disease

Guthrie, Joy D. 01 January 2011 (has links)
Liver disease causes an estimated 36,000 deaths in the United States each year. Currently, to detect liver disease, an invasive biopsy is required. Other, less invasive diagnostic alternatives are needed. The purpose of this study was to assess the efficacy of a modified form of sonographic screening, including portal, hepatic, and splenic venous pressure, hepatic venous waveform analysis, portal vein diameter, and echogenicity of liver parenchyma in predicting liver disease. The study was based on conversion of a velocity measurement to a pressure gradient, allowing a fluid comparison between known catheterization venous pressures and sonographic Doppler-derived pressure gradients. This study was a secondary data analysis of a data set from 546 patients who received abdominal sonograms at a medical facility in the western United States between March 2010 and December 2010. The dependent variable was liver disease and the independent variables were ECHOGRADE, hepatic venous waveform (HVW), splenic vein pressure gradient (SVPG), modified portal vein pressure gradient (MPVPG), and hepatic vein pressure gradient (HVPG). Logistic regression was used to analyze the data. ECHOGRADE, HVW, and MPVPG in males were found to be statistically significant in detecting liver disease, supporting the theoretical framework and thus documenting a novel use of Doppler for the detection of liver disease. The social change significance of these results is to provide clinicians with an alternative, noninvasive method of diagnosing early liver disease before it progresses into chronic liver disease. With earlier detection, severe adverse health outcomes leading to irreversible liver cirrhosis may be avoided.
15

Determination of parameters related to the output of diagnostic X-ray sets by calculations based on the results of direct measurement of the spectral output

Alexander, George W. A. January 1993 (has links)
No description available.
16

Functional Magnetic Resonance Imaging for Clinical Diagnosis : Exploring and Improving the Examination Chain

Ragnehed, Mattias January 2009 (has links)
Functional Magnetic Resonance Imaging (fMRI) is a relatively new imaging technique, first reported in 1992, which enables mapping of brain functions with high spatial resolution. Functionally active areas are distinguished by a small signal increase mediated by changes in local blood oxygenation in response to neural activity. The ability to non-invasively map brain function and the large number of MRI scanners quickly made the method very popular, and fMRI have had a huge impact on the study of brain function, both in healthy and diseased subjects. The most common clinical application of fMRI is pre-surgical mapping of brain functions in order to optimise surgical interventions. The clinical fMRI examination procedure can be divided into four integrated parts: (1) patient preparation, (2) image acquisition, (3) image analysis and (4) clinical decision. In this thesis, important aspects of all parts of the fMRI examination procedure are explored with the aim to provide recommendations and methods for prosperous clinical usage of the technique. The most important results of the thesis were: (I) administration of low doses of diazepam to reduce anxiety did not invalidate fMRI mapping results of primary motor and language areas, (II) the choice of visual stimuli equipment can have severe impact on the mapping of visual areas, (III) three-dimensional fMRI imaging sequences did not perform better than two-dimensional imaging sequences, (IV) adaptive spatial filtering can improve the fMRI data analysis, (V) clinical decisions should not be based on activation results from a single statistical threshold.
17

Dose optimization in diagnostic radiology

Nyathi, Thulani 02 May 2013 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree for the Doctor of Philosophy. Johannesburg 2012 / Medical X-ray imaging is nowadays ubiquitous in healthcare. International studies have shown that patient doses during both diagnostic X-ray examinations and fluoroscopically guided procedures from one clinic to another can vary by a factor of up to 100. Such a variation in patient doses offers an opportunity for dose – image quality optimization. Given this background, every radiology clinic which wants to use X-ray imaging ethically and efficiently should have in place ways of optimizing the patient dose – image quality relationship. One generally accepted tool in the optimization process is diagnostic reference levels (DRLs). Currently in South Africa there are no established DRLs and there is no systematic patient dose data collection by the either the national regulator or any competent authority. The main purpose of this thesis was to quantify patient doses for patients undergoing diagnostic examinations and fluoroscopically guided procedures, educate radiation workers on typical patient doses, develop effective methods in quality control of radiographic and fluoroscopic equipment and evaluate radiographer familiarity with digital radiography technology within the context of a typical university teaching South African hospital. The present thesis comprises of seven studies, all carried out at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH), formerly Johannesburg Hospital: Study I: In this investigation the luminance level of X-ray viewing boxes and ambient lighting levels in reporting rooms were measured as a quality assurance procedure and compared with the recommended values by the Directorate of Radiation Control (DRC) of South Africa, European Commission (EC) and Nordic Radiation Protection Co-operation (NORDIC). Results from this investigation showed that the mean average luminance was 1027 cd m-2 and 3284 cd m-2 at the Division of Radiology and Division of Radiation Oncology respectively. The Division of Radiation Oncology had an average viewing box uniformity 7.14% compared to 27.32% at the Division of Radiology. The average ambient lighting was found to be 66 lux for both Divisions. The radiograph viewing conditions variably comply with guidelines. The radiographic imaging chain can only be as strong as its weakest link, thus this study underscores the need of implementing quality control and quality assurance standards in radiographic image viewing. Based on the practical experience of this investigation it is recommended that the DRC test criteria be adopted, in light of the varied recommendations worldwide. Study II: This study aimed to develop, implement and evaluate a software program which can be used in a radiology quality control program. A Microsoft Excel™ based software program was developed for use in quality control: tests data collection, analysis and archiving of the tests done on general radiography equipment, fluoroscopy equipment and film processors. Validation of the software application in terms of usability, user-friendliness was done by an experienced radiographer. This software provides an easier and efficient way of recording quality control data, analysis and archiving. Study III: This study retrospectively analyzed the radiation doses delivered to patients undergoing fluoroscopy guided procedures in terms of the skin dose1 and the kerma-area product readings. A total of three hundred and thirty one fluoroscopically guided procedures were analyzed. In agreement with other published studies, a weak correlation was shown between skin dose and screening time, while a poor correlation was shown between KAP reading and screening time. There was a wide spread in the radiation doses registered for any one given type of examination, which shows that there is room for dose optimization. From the lessons drawn from this study it is practically feasible to record the KAP, fluoroscopy time and number of images routinely. The usefulness and potential use of KAP meters with regards to dose optimization in radiology was confirmed. Study IV: This investigation aimed to assess the feasibility of fabricating in-house the clinical dosimetry radiology phantoms. A total of six patient dose assessment phantoms were fabricated of which four phantoms were as per American National Standards Institute (ANSI) specifications and the other two as per Centre for Devices and Radiological Health (CDRH) specifications. This study proved that the phantoms can be fabricated cost-effectively in-house in a hospital with a mechanical engineering workshop using materials which are locally available. In addition, this study determined radiation doses received by patients undergoing six general radiography examinations. The feasibility of both direct and indirect methods of patient dosimetry was studied. Patient dosimetry based on indirect measurements was the method of choice. Patient data and technical parameters related to the X-ray examinations were collected. The study involved the following examinations: chest posterior-anterior (PA), chest lateral (LAT), pelvis anterior-posterior (AP), abdomen AP, lumbar spine AP and thoracic spine AP. Entrance surface air kerma was calculated based on the X-ray tube 1 See Section 8.3 on the use of the term skin dose output of the unit used and the exposure parameters used for the actual examination. Based on the mean entrance surface air kerma (ESAK) values from the individual rooms, the following DRLs were established: 0.10 mGy for chest PA, 0.22 mGy for chest LAT, 2.98 mGy for pelvis AP, 4.19 mGy for abdomen AP, 5.30 mGy for lumbar spine AP and 3.28 mGy for thoracic spine AP. The calculated mean ESAK values were compared with previously published mean values from other countries. For the first time, a baseline for potential dose reference levels (DRLs) in South Africa was established for the selected examinations. The results of this snapshot audit serve as a benchmark for future dose optimization attempts in South Africa. Feasible and practical dose saving measures are presented and discussed based on the experience of the present patient dose audit carried out. Study V: A replica of the CDRAD phantom was successfully fabricated in-house for use as an image quality test object. It has been shown that the phantom when fabricated in-house is inexpensive and can be made from materials that are readily available locally. Furthermore the utility of the replica phantom as both an acceptance testing and routine quality control tool has been demonstrated. The replica phantom proved effective for purpose and user-friendly. Study VI: The purpose of this study was to assess radiographer familiarity and preferences with digital radiography and thereafter make recommendations in line with the migration from screen film to digital radiography in South Africa. A questionnaire was designed to collect data from either qualified or student radiographers from four teaching hospitals. From the four teaching hospitals there were a total of 205 potential respondents. Among other things, responses regarding experiences and preferences with digital radiography, quality control procedures, patient dose, advantages and disadvantages of digital radiography were sought. The information collected was based on self-reporting by the participants. Sixty-three out of 205 (31 %) radiographers from all the four radiology centres responded to the circulated questionnaire. The participants of this survey showed familiarity with digital radiography and have embraced this relatively new technology as shown by the fact that they can identify both its advantages and disadvantages as applied to clinical practice. However, there are minimal quality control procedures specific to digital radiography being undertaken and there is need for formal education, continuing education and manufacturer training with respect to quality control as institutions make the transition from conventional screen film radiology to digital radiology. Study VII: An investigation into the amount of scattered radiation from the couch during under-couch procedures was carried out. Of dosimetric concern are the forward scattered photons from the couch which contribute in principle to patient dose. Measurement of the amount of scattered radiation off the patient couch was accomplished by using an ionization chamber. The results of the investigation showed that for field size of dimensions, 10 cm * 10 cm, the scatter contribution is approximately 12 % of the total radiation reaching the patient surface. In addition the scatter contribution varies by ±2% across field sizes ranging from 8 cm * 8 cm to 20 cm * 20 cm, with the 10 cm * 10 cm field size taken as a reference field. This study underscores the need to account for the forward scattered radiation so as to improve the accuracy of clinical patient dosimetry. Programs of continuing education and training of radiological personnel in appropriate radiological technique need be actively implemented in order to maintain a high level of awareness of the factors that determine the diagnostic quality and dose to the patients. In line with efforts to optimize dose from diagnostic radiography examinations it is recommended that national DRLs be established in South Africa for the most frequent examinations in general radiography and fluoroscopy. It is recommended that the South African national regulator endeavour to implement or facilitate implementation of a national patient dose database. In summary, this thesis indicates the possibility of dose reduction in diagnostic radiology through optimization of radiographic process.
18

Alguns métodos de calibração e dosimetria da radiação beta / Methods Calibration Dosimetry Beta Radiation

Caldas, Linda Viola Ehlin 04 June 1980 (has links)
A calibração da radiação beta foi estudada do ponto de vista de padronização tanto primária como secundária, usando-se câmaras de extrapolação e examinando-se diversos efeitos. As propriedades de uma câmara de ionização, comercial, foram investigadas, demonstrando-se a possibilidade do seu uso na calibração e dosimetria da radiação beta de 90 ANTPOT Sr-90 ANTPOT Y. Foi desenvolvido um método e montado um sistema de calibração padrão secundária, cujos resultados foram sempre que possível direta ou indiretamente comparados com os obtidos com o sistema primário. A câmara usada neste caso apresentou resposta praticamente independente com a energia média da radiação beta no intervalo de 60 keV a 0,8 MeV. Duas técnicas de estado sólido, termoluminescência (TL) e emissão exoeletrônica termicamente estimulada (TSEE), foram também usadas para a dosimetria beta. Foram estudadas várias características como reprodutibilidade, resposta com a dose, dependência com a energia, etc., dos materiais : LiF, Ca F IND 2, CaS 0 IND 4, Li IND 2B IND4O IND 7, BeO e AI IND 2O IND 3. Os detectores TL de espessura 0,9 mm mostraram uma subestimativa na determinação de dose. As amostras de CaS0 IND 4: Tm, de espessura 60 µm, em suporte fino de alumínio, apresentaram resposta independente com a energia da radiação da radiação incidente, atrás de camadas de tecido de densidade superficial de 7 mg/cm2. Este dosímetro foi também usado para analisar campos mistos de radiação X, gama e beta. As amostras de BeO em base de quartzo e de -Al IND 2O IND 0 3 em base de grafite apresentaram-se como muito bons detectores de radiação beta, usando-se a técnica de TSEE. Os dosímetros TL de CaS 0 IND 4:Tm, independentes com a energia, foram utilizados numa comparação internacional de medidas de dose; os resultados obtidos exibiram uma boa concordância com os valores reais das doses (cerca de apenas 10% de diferença). Estes detectores TL, foram também usados para medidas de taxas de dose de azulejos esmaltados, coloridos, usados em indústria de construção, e de uma fonte de ANTPOT 85 Kr empregada em indústrias têxteis e de metais. Os resultados no último caso foram comparados com os obtidos usando-se o sistema de padronização secundária. / The calibration of beta radiation was studied from the point of view of primary and secondary standardization, using extrapolation chambers and examining several effects. The properties of a commercial ionization chamber were investigated, and the possibility of its use in calibration and dosimetry of 90Sr- 90Y beta radiation was demonstrated. A secondary standard calibration facility was developed and the results obtained with this facility were compared with those obtained from a primary system directly or indirectly. Nearly energy independent response was obtained in the range 60 keV to 0,8 MeV with this secondary standard. Two solid state techniques namely thermoluminescence (TL) and thermally stimulated exoelectron emission (TSEE) were also used for beta dosimetry. Various characteristics like reproductibility, response with dose energy dependence, etc. were studied for the materials: LiF, CaF2,Li2 B4 O7, BeO, CaS04 and AL2O3 . TL detectors of thickness 0,9 mm underestimate the dose. 60 µm thick CaS04:Tm embedded on a thin aluminium plate gave energy independent response behind skin layers of 7 mg/cm2. Mixed field of beta, X and gamma radiation was analysed using this detector. Quartz based BeO and graphite based -Al2O3 were found to be good beta radiation detectors when the TSEE tecnique is used. Energy independent CaS04:Tm TL dosimeters were used in international comparison for dose measurements and the results obtained were in agreement with the actual given doses within 10%. The TL detectors were also used for dose rate measurements from glazed painted tiles construction industry and a 85Kr source used used in in textile and metal industries. Results obtained in the later case were compared with those using the secondary standard facility.
19

Alguns métodos de calibração e dosimetria da radiação beta / Methods Calibration Dosimetry Beta Radiation

Linda Viola Ehlin Caldas 04 June 1980 (has links)
A calibração da radiação beta foi estudada do ponto de vista de padronização tanto primária como secundária, usando-se câmaras de extrapolação e examinando-se diversos efeitos. As propriedades de uma câmara de ionização, comercial, foram investigadas, demonstrando-se a possibilidade do seu uso na calibração e dosimetria da radiação beta de 90 ANTPOT Sr-90 ANTPOT Y. Foi desenvolvido um método e montado um sistema de calibração padrão secundária, cujos resultados foram sempre que possível direta ou indiretamente comparados com os obtidos com o sistema primário. A câmara usada neste caso apresentou resposta praticamente independente com a energia média da radiação beta no intervalo de 60 keV a 0,8 MeV. Duas técnicas de estado sólido, termoluminescência (TL) e emissão exoeletrônica termicamente estimulada (TSEE), foram também usadas para a dosimetria beta. Foram estudadas várias características como reprodutibilidade, resposta com a dose, dependência com a energia, etc., dos materiais : LiF, Ca F IND 2, CaS 0 IND 4, Li IND 2B IND4O IND 7, BeO e AI IND 2O IND 3. Os detectores TL de espessura 0,9 mm mostraram uma subestimativa na determinação de dose. As amostras de CaS0 IND 4: Tm, de espessura 60 µm, em suporte fino de alumínio, apresentaram resposta independente com a energia da radiação da radiação incidente, atrás de camadas de tecido de densidade superficial de 7 mg/cm2. Este dosímetro foi também usado para analisar campos mistos de radiação X, gama e beta. As amostras de BeO em base de quartzo e de -Al IND 2O IND 0 3 em base de grafite apresentaram-se como muito bons detectores de radiação beta, usando-se a técnica de TSEE. Os dosímetros TL de CaS 0 IND 4:Tm, independentes com a energia, foram utilizados numa comparação internacional de medidas de dose; os resultados obtidos exibiram uma boa concordância com os valores reais das doses (cerca de apenas 10% de diferença). Estes detectores TL, foram também usados para medidas de taxas de dose de azulejos esmaltados, coloridos, usados em indústria de construção, e de uma fonte de ANTPOT 85 Kr empregada em indústrias têxteis e de metais. Os resultados no último caso foram comparados com os obtidos usando-se o sistema de padronização secundária. / The calibration of beta radiation was studied from the point of view of primary and secondary standardization, using extrapolation chambers and examining several effects. The properties of a commercial ionization chamber were investigated, and the possibility of its use in calibration and dosimetry of 90Sr- 90Y beta radiation was demonstrated. A secondary standard calibration facility was developed and the results obtained with this facility were compared with those obtained from a primary system directly or indirectly. Nearly energy independent response was obtained in the range 60 keV to 0,8 MeV with this secondary standard. Two solid state techniques namely thermoluminescence (TL) and thermally stimulated exoelectron emission (TSEE) were also used for beta dosimetry. Various characteristics like reproductibility, response with dose energy dependence, etc. were studied for the materials: LiF, CaF2,Li2 B4 O7, BeO, CaS04 and AL2O3 . TL detectors of thickness 0,9 mm underestimate the dose. 60 µm thick CaS04:Tm embedded on a thin aluminium plate gave energy independent response behind skin layers of 7 mg/cm2. Mixed field of beta, X and gamma radiation was analysed using this detector. Quartz based BeO and graphite based -Al2O3 were found to be good beta radiation detectors when the TSEE tecnique is used. Energy independent CaS04:Tm TL dosimeters were used in international comparison for dose measurements and the results obtained were in agreement with the actual given doses within 10%. The TL detectors were also used for dose rate measurements from glazed painted tiles construction industry and a 85Kr source used used in in textile and metal industries. Results obtained in the later case were compared with those using the secondary standard facility.
20

Evaluation of model-based RSA for in vivo measurement of polyethylene wear in a total knee replacement

Gascoyne, Trevor 21 September 2012 (has links)
There is a need for a repeatable method of measuring polyethylene wear in total knee re-placement (TKA). Model-based radiostereometric analysis (MBRSA) is a high accuracy diagnostic tool with the potential to meet this need; however, a number of unknowns must be examined. This research examines optimized patient positioning for MBRSA imaging as well as in vitro validation of a wear measurement technique using a loaded TKA phantom to mimic patient physiology. Imaging along the antero-posterior and medio-lateral axes of the patient achieved op-timal MBRSA accuracy of better than 0.035 mm (in-plane) and 0.12° (in-plane). The de-veloped MBRSA technique underestimated TKA wear on previously-worn polyethylene bearings; however, a number of factors can be corrected to improve this discrepancy. This research provides an overall methodology for measuring TKA wear, but additional experimentation and an improved physiological phantom are needed to obtain accurate wear measurement.

Page generated in 0.0554 seconds