No description available.

A research report submitted to the Faculty of the Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine in the branch of Nuclear Medicine. Johannesburg 2011 / Paediatric Nuclear Medicine is associated with a high preponderance of nephro-urological investigations. This preponderance has been attributed to the relatively higher occurrence of urinary tract infections and their sequelae in children, as well as to improved antenatal detection of anomalies of the genitor-urinary tract. Nuclear Medicine is involved in the management of these children to assist with diagnosis, clinical decision-making and follow-up of global and relative renal function. As such, these scans need to be carried out as efficiently as possible. International protocols established by the European and American societies of Nuclear Medicine have been formulated to aid the Nuclear Medicine technologist and physician in performing these procedures and interpreting them correctly. Audits of Nuclear Medicine practice are performed in order to assess compliance with these guidelines. A clinical audit has been defined as “a systematic and critical analysis of the quality of medical care, including procedures for diagnosis and treatment.” An audit of the renal paediatric procedures carried out in the Division of Nuclear Medicine at the Charlotte Maxeke Johannesburg Academic Hospital was performed retrospectively on studies carried out from January 2006 - December 2009, as well as a prospective study of procedures from February – July 2010. Results showed overall conformity to most of the recommended practices of the EANM guidelines. As occurs in most institutions, each institution may adapt guidelines to comply with local circumstances.

No description available.

From an engineering background, it is often believed that the human anatomy has already been fully described. Radiology has greatly contributed to understand the inside of the human body without surgical intervention. Despite great advances in clinical CT scanning, image quality is still related to a limited amount X-ray exposure for the patient safety. This limitation prevents fine anatomical structures to be visible and, more importantly, to be detected. Where such modality is of great advantage for screening patients, extracting parameters like surface area and volume implies the bone structure to be large enough in relation to the scan resolution. The mastoid, located in the temporal bone, houses an air cell system whose cells have a variation in size that can go far below current conventional clinical CT scanner resolution. Therefore, the mastoid air cell system is only partially represented on a CT scan. Any statistical analysis will be biased towards air cells of smaller size. To allow a complete representation of the mastoid air cell system, a micro-CT scanner is more adequate. Micro-CT scanning uses approximately the same amount of X-rays but for a much longer exposure time compared to what is normally allowed for patients. Human temporal bone specimens are therefore necessary when using such scanning method. Where the conventional clinical CT scanner lacks level of minutes details, micro-CT scanning provides an overwhelming amount of fine details. Prior to any image analysis of medical data, visualization of the data is often needed to learn how to extract the structures of interest for further processing. Visualization of micro-CT scans is of no exception. Due to the high resolution nature of the data, visualization of such data not only requires modern and powerful computers, but also necessitates a tremendous amount of time to adjust the hiding of irrelevant structures, to find the correct orientation, while emphasising the structure of interest. Once the quality of the data has been assessed, and a strategy for the image processing has been decided, the image processing can start, to in turn extract metrics such as the surface area or volume and draw statistics from it. The temporal bone being one of the most complex in the human body, visualization of micro-CT scanning of this bone awakens the curiosity of the experimenter, especially with the correct visualization settings. This thesis first presents a statistical analysis determining the surface area to volume ratio of the mastoid air cell system of human temporal bone, from micro-CT scanning using methods previously applied for conventional clinical CT scannings. The study compared current resul s with previous studies, with successive downsampling the data down to a resolution found in conventional clinical CT scanning. The results from the statistical analysis showed that all the small mastoid air cells, that cannot be detected in conventional clinical CT scans, do heavily contribute to the estimation of the surface area, and in consequence to the estimation of the surface area to volume ratio by a factor of about 2.6. Such a result further strengthens the idea of the mastoid to play an active role in pressure regulation and gas exchange. Discovery of micro-channels through specific use of a non-traditional transfer function was then reported, where a qualitative and a quantitative preanalysis was performed are described. To gain more knowledge about these micro-channels, a local structure tensor analysis was applied where structures are described in terms of planar, tubular, or isotropic structures. The results from this structural tensor analysis, also reported in this thesis, suggest these micro-channels to potentially be part of a more complex framework, which hypothetically would provide a separate blood supply for the mucosa lining the mastoid air cell system.

In current practice, it is common in medical diagnosis or treatment monitoring for a patient to require multiple examinations using different imaging techniques. Magnetic resonance (MR) imaging and computed tomography (CT) are good at providing anatomical information. Three-dimensional functional information about tissues and organs is often obtained with radionuclide imaging modalities: positron emission tomography (PET) and single photon emission tomography (SPET). In nuclear medicine, such techniques must contend with poor spatial resolution, poor counting statistics of functional images and the lack of correspondence between the distribution of the radioactive tracer and anatomical boundaries. Information gained from anatomical and functional images is usually of a complementary nature. Since the patient cannot be relied on to assume exactly the same pose at different times and possibly in different scanners, spatial alignment of images is needed. In this thesis, a general framework for image registration is presented, in which the optimum alignment corresponds to a maximum of a similarity measure. Particular attention is drawn to entropy-based measures, and variance-based measures. These similarity measures include mutual information, normalized mutual information and correlation ratio which are the ones being considered in this study. In multimodality image registration between functional and anatomical images, these measures manifest superior performance compared to feature-based measures. A common characteristic of these measures is the use of the joint-intensity histogram, which is needed to estimate the joint probability and the marginal probability of the images. A novel similarity measure is proposed, the symmetric correlation ratio (SCR), which is a simple extension of the correlation ratio measure. Experiments were performed to study questions pertaining to the optimization of the registration process. For example, do these measures produce similar registration accuracy in the non-brain region as in the brain? Does the performance of SPET-CT registration depend on the choice of the reconstruction method (FBP or OSEM)? The joint-intensity based similarity measures were examined and compared using clinical data with real distortions and digital phantoms with synthetic distortions. In automatic SPET-MR rigid-body registration applied to clinical brain data, a global mean accuracy of 3.9 mm was measured using external fiducial markers. SCR performed better than mutual information when sparse sampling was used to speed up the registration process. Using the Zubal phantom of the thoracic-abdominal region, SPET projections for Methylenediphosponate (MDP) and Gallium-67 (67Ga) studies were simulated for 360 degree data, accounting for noise, attenuation and depth-dependent resolution. Projection data were reconstructed using conventional filtered back projection (FBP) and accelerated maximum likelihood reconstruction based on the use of ordered subsets (OSEM). The results of SPET-CT rigid-body registration of the thoracic-abdominal region revealed that registration accuracy was insensitive to image noise, irrespective of which reconstruction method was used. The registration accuracy, to some extent, depended on which algorithm (OSEM or FBP) was used for SPET reconstruction. It was found that, for roughly noise-equivalent images, OSEM-reconstructed SPET produced better registration than FBP-reconstructed SPET when attenuation compensation (AC) was included but this was less obvious for SPET without AC. The results suggest that OSEM is the preferable SPET reconstruction algorithm, producing more accurate rigidbody image registration when AC is used to remove artifacts due to non-uniform attenuation in the thoracic region. Registration performance deteriorated with decreasing planar projection count. The presence of the body boundary in the SPET image and matching fields of view were shown not to affect the registration performance substantially but pre-processing steps such as CT intensity windowing did improve registration accuracy. Non-rigid registration based on SCR was also investigated. The proposed algorithm for non-rigid registration is based on overlapping image blocks defined on a 3D grid pattern and a multi-level strategy. The transformation vector field, representing image deformation is found by translating each block so as to maximize the local similarity measure. The resulting sparsely sampled vector field is interpolated using a Gaussian function to ensure a locally smooth transformation. Comparisons were performed to test the effectiveness of SCR, MI and NMI in 3D intra- and inter-modality registration. The accuracy of the technique was evaluated on digital phantoms and on patient data. SCR demonstrated a better non-rigid registration than MI when sparse sampling was used for image block matching. For the high-resolution MR-MR image of brain region, the proposed algorithm was successful, placing 92% of image voxels within less than or equal to 2 voxels of the true position. Where one of the images had low resolution (e.g. in CT-SPET, MR-SPET registration), the accuracy and robustness deteriorated profoundly. In the current implementation, a 3D registration process takes about 10 minutes to complete on a stand alone Pentium IV PC with 1.7 GHz CPU and 256 Mbytes random access memory on board.

Thesis (Ph. D.)--University of Chicago, Dept. of Radiology, June 1997. / Includes bibliographical references. Also available on the Internet.

The rise in demand for specialized medical services in the U.S has been recognized as one of the contributors to increased health care costs. Nuclear medicine is a specialized service that uses relatively new technologies and radiopharmaceuticals with a short half-life for diagnosis and treatment of patients. Nuclear medicine procedures are multi-step and have to be performed under restrictive time constraints. Consequently, managing patients in nuclear medicine clinics is a challenging problem with little research attention. In this work we present simulation and optimization models for improving patient and resource scheduling in health care specialty clinics such as nuclear medicine departments. We rst derive a discrete event system speci cation (DEVS) simulation model for nuclear medicine patient service management that considers both patient and management perspectives. DEVS is a formal modeling and simulation framework based on dynamical systems theory and provides well de ned concepts for coupling components, hierarchical and modular model construction, and an object-oriented substrate supporting repository reuse. Secondly, we derive algorithms for scheduling nuclear medicine patients and resources and validate our algorithms using the simulation model. We obtain computational results that provide useful insights into patient service management in nuclear medicine. For example, the number of patients seen at the clinic during a year increases when a group of stations are reserved to serve procedures with higher demand. Finally, we derive a stochastic online scheduling (SOS) algorithm for patient and resource management in nuclear medicine clinics. The algorithm performs scheduling decisions by taking into account stochastic information about patient future arrivals. We compare the results obtained using the SOS algorithm with the algorithms that do not take into consideration stochastic information. The SOS algorithm provides a balanced utilization of resources and a 10% improvement in the number of patients served.

Along with the enormous impacts resulted from the change of National health insurance policy, there has been a great influence on health-care seeking behaviors of people, thus leading to a extensively vigorous competition and challenge for management spreading among health-care industries. Therefore updated management concept, assuring health-care quality, rising standard of health-care and realization of ideals of perpetual service-providing are desperately required for all hospitals. Also for hospital marketing, to ascertain the customers need, to establish relationships with customers, to set an effective marketing-strategy to satisfy customers need and to match the assessment of customers response with improvements are necessary. Marketing is not only for external customers but also for internal ones (intra-hospital customers). In this study we aim to promote nuclear medicine through understanding colleagues need, providing decent service and to lead intra-department health-care marketing activities to hospital-wide ones by way of education and elevating service quality. Conclusively, despite an insignificant achievement quantitatively, the qualitative analysis reveals we could facilitate our colleagues understanding nuclear medicine practice by utilization of E-trsnsmission, detailed flowchart, and mobile educational service.

The World Health Organization published in 2004 a bulletin addressing the gap between research, technology, and its implementation in the health systems of different countries (Haines, Kuruvilla, & Borchert, 2004). Among the barriers described for the implementation of new knowledge in the medical practice is the lack of connection between research results and policy makers. This happens in different subfields within the medical field. The focus of this project is to analyze the differences in implementation of radionuclide therapy technology between the EU and the US. The hypothesis is that this technology has been implemented in the EU earlier and more often than in the US, and that this variation can be connected to the differences in the policies relevant to nuclear medicine. Nuclear medicine is a unique field because of the way radioactive material is used to create diagnostic images and treat illnesses (mostly cancer). Although radiation is used every day in radiotherapy and radiology, the main difference between these two fields and nuclear medicine is the type of radiation used. Radiotherapy and radiology use closed sources of radiation, or particle accelerators that produce radiation, while nuclear medicine uses open sources of radiation that are injected into the patient’s body. This is an important difference because the accelerators used in radiotherapy and radiology can be turned on and off unlike the open sources of radiation used for nuclear medicine. If not handled properly, open sources of radiation may cause radiation contamination. Additionally, the radioactive material must be supplied on a daily basis. With nuclear medicine is possible to create diagnostic images of the body, and to record bodily functions all the way down to the molecular level. It is also possible to treat certain illnesses, such as some types of cancer, in a targeted manner. This is possible because the radioactive material is “connected” with a chemical compound (or drug) that carries the radioactive atoms to a desired location in the body; this is called targeted therapy. It is also possible to inject the radioactive material directly into the organ or region of interest. The targeted therapy and injected techniques are two processes that are part of radionuclide therapy technology. In order to check the status of the implementation of radionuclide therapy I used the practice guidelines published on the websites of the European Association of Nuclear Medicine (EANM) and the Society of Nuclear Medicine (SNM) in the US. Assuming that the practice guidelines are evidence of well-established and implemented techniques in the regions, these documents were evaluated according to their content and publication date. The content analysis was focused on the type of practices described: diagnostic, general, or therapy, as well as the type of radioactive material (or radioactive isotopes) used in such practices. The practice guidelines evaluation was done in Nvivo, a text analysis software. In addition to the analysis of practice guidelines, a bibliometric analysis of four databases (Pubmed, Medline, Biosis, and ISI Web of Science) was conducted in four databases. The keywords used for the search were (“radionuclide therapy” AND case AND report) OR (radioinmunotherapy AND case AND report). Case reports are publications that expose the day-to-day practice of physicians, and allow medical personnel to take a detail look into a specific case. The records from these sources were analyzed in Vantage Point, a bibliometric analysis software. From the policy landscape, three main types of policies were studied in relation to the practice of nuclear medicine: first, the education standards for the different professionals involved; second, the policies related to the approval of radiopharmaceuticals in the different drug administration entities; and finally, the policies concerning the production of radionuclide therapies in the two regions. The main finding of this project is that Europe and US have different policy approaches that affect, directly or indirectly, the nuclear medicine field. The main differences are in the standards of education for nuclear medicine specialist that is divided between radiologist and nuclear medicine specialists in the US; the production of radioactive material, which is commercially supplied by a very few reactors in the world, none of them in the US; and the drug administration institutions, which have very different approaches approving new drugs. Aditionally, Europe has implemented more radionuclide therapy technologies than US. From the practice guidelines analysis, it was evident that the US started publishing guidelines for nuclear medicine several years before Europe. The US published its first guideline in 1994, while the EU’s first guideline was published in 2000. However, as of July 2013, the European association had published more guidelines with 54 unique ones versus 49 from the US. EU also leads in the number of guidelines in regards to therapy, with 13 versus 2 from the US. Additionally, there is more variety in the radioisotopes used in therapy than the ones in diagnostics, and all the radioisotopes are mentioned in the European guidelines, while the US doesn’t have guidelines that mention Lu-177, Re-186, and Y-90 isotopes. From the bilbiometric analysis it was evident that Europe had published case reports for more time and more frequently than the US regarding radionuclide therapy. The first case report record from Europe was published in 1988, almost a decade before the first case report in the US. Additionally, the US has only 10 publications that match the keywords while the EU has 37. In conclusion, the EU has more practice guidelines on radionuclide therapies regarding more types of illnesses and more radioisotopes, and Europeans have published more case reports on these therapies, which indicates that the EU has implemented radionuclide therapy technology more fully than has the US. The differences in the policies and standards in education for Nuclear Medicine may influence this difference, because EU has a more standardized education and a more unified professional field than US. While the EU has a proposed syllabus for nuclear medicine practitioners, medical physicists, and radiopharmacists, in the US the education is neither standardized nor unified. Two different boards can certify physicians specializing in nuclear medicine: the American Board of Radiology and The American Board of Nuclear Medicine. The first one does a Nuclear Radiology certification for which the physicians are not required or allowed to conduct radionuclide therapies, while the American Board of Nuclear Medicine requires more nuclear medicine training and involves diagnostics and therapy. These differences are important in the implementation of radionuclide therapy techniques, because not all the nuclear medicine physicians in the US are trained on this aspect or allowed to practice it. For that reason a fraction of the professionals may not be interested or informed about these techniques, leaving the field of nuclear medicine in the US behind its EU counterpart. The policies that involve the production of radioisotopes and the market for this good deeply affects the status of the field in both regions. Since most of the radionuclide materials for therapies are produced in nuclear reactors, this is a very complex topic. Nuclear reactors are recognized for their capability to produce nuclear energy and not frequently associated with medicine. The precautionary approach that some regions apply to this topic may affect the availability of the radioisotopes in local markets. The EU has more nuclear reactors capable of the production of materials for radionuclide therapies, while the production of radioisotopes in the US is less and it focused on research. Therefore, the EU has a more stable and reliable supply of radioisotopes, which allows them to use the technology in everyday practice. Finally, the drug administration entities seem to differ in the clarity of their procedures for the approval of radiopharmaceuticals. The EU tools for approval are clear and easy to find, which may encourage European researchers to work on new radiopharmaceuticals and to carry their findings to the application level. The European Medicines Agency has a Radiopharmaceutical Drafting Group that supports the creation and approval of radiopharmaceuticals. In addition, one of the practice guidelines from the European Association of Nuclear Medicine (EANM) is about the approval of new drugs. This is not replicated in the US; although the Food and Drug Administration (FDA) has a special group that works with radiation therapies and devices, there are no references to a group that relates to radiopharmaceuticals, or the information is not as easy to find. It also looks like the Society of Nuclear Medicine (SNM) is focusing more on research and approval of Positron Emission Tomography (PET) radiopharmaceuticals than on therapy based ones. This is understandable since the radioactive material for PET images is produced in cyclotrons available at many clinics and hospitals around the world. In conclusion, nuclear medicine is a very diverse field that is capable of important contributions to medicine. However, the radioactive nature of the material needed for the development of new radionuclide therapies presents a barrier to the development of new drugs. The availability of the drug and the personnel trained in these matters are the most important factors for the successful use of this technology. Although the US and the EU have been collaborating more and more in the creation of standardized procedures for nuclear medicine, it is evident that the EU has more experience in the day to day application of the technology, and the technology is also more accessible in the EU by the physicians interested in it. A trained and informed group of professionals can raise awareness in the public and influence the policy making by monitoring agencies to create clearer paths for drug approvals, and pushing for laws that approve the research and production of alternatives for radioisotopes production such as Low Enriched Uranium reactors.

Coded-aperture imaging without detector motion can be used to reconstruct three-dimensional radionuclide distributions in the context of nuclear medicine. This approach offers several advantages over the rotating gamma-ray camera systems presently employed in the clinic. These advantages include improved sensitivity, potentially better spatial resolution, and the capability of doing dynamic studies. There are two problems associated with the coded-aperture approach, however. First, the data is "multiplexed", which refers to the fact that many line integrals of the source distribution are combined together and not measured individually, so that information is lost. Second, the number of resolvable detector elements is typically an order of magnitude less than the number of object elements to be reconstructed, so that the reconstruction problem is underdetermined. Consequently, the reconstruction is not unique. By using various types of a priori information in forming the reconstruction, however, it is possible to augment the incomplete data set. Two algorithms are presented to reconstruct objects from their coded-image projections and various types of a priori information. The first, a Monte Carlo algorithm, is a flexible and computationally efficient approach using the a priori knowledge of positivity and nearest-neighbor correlation. This algorithm is used to qualitatively explore the effect of the data-taking geometry on reconstruction performance. The second algorithm is a linear estimator incorporating as a priori knowledge completely general first- and second-order statistical information about the object class to be reconstructed. The linear-estimator formalism also provides a minimum-variance expression for system optimization. This linear algorithm is used to explore the effects of correct and incorrect a priori information on reconstruction performance, and to quantitatively investigate reconstruction quality with respect to data-taking geometry.