Respiratory gating in lung PET imaging to compensate for respiratory motion artifacts is a current research issue with broad potential impact on quantitation, diagnosis and clinical management of lung tumors. However, PET images collected at discrete bins can be significantly affected by noise as there are lower activity counts in each gated bin unless the total PET acquisition time is prolonged, so that gating methods should be combined with imaging-based motion correction and registration methods. The aim of this study was to develop and validate a fast and practical solution to the problem of respiratory motion for the detection and accurate quantitation of lung tumors in PET images. This included: (1) developing a computer-assisted algorithm for PET/CT images that automatically segments lung regions in CT images, identifies and localizes lung tumors of PET images; (2) developing and comparing different registration algorithms which processes all the information within the entire respiratory cycle and integrate all the tumor in different gated bins into a single reference bin. Four registration/integration algorithms: Centroid Based, Intensity Based, Rigid Body and Optical Flow registration were compared as well as two registration schemes: Direct Scheme and Successive Scheme. Validation was demonstrated by conducting experiments with the computerized 4D NCAT phantom and with a dynamic lung-chest phantom imaged using a GE PET/CT System. Iterations were conducted on different size simulated tumors and different noise levels. Static tumors without respiratory motion were used as gold standard; quantitative results were compared with respect to tumor activity concentration, cross-correlation coefficient, relative noise level and computation time. Comparing the results of the tumors before and after correction, the tumor activity values and tumor volumes were closer to the static tumors (gold standard). Higher correlation values and lower noise were also achieved after applying the correction algorithms. With this method the compromise between short PET scan time and reduced image noise can be achieved, while quantification and clinical analysis become fast and precise.

Na rotina clínica de felinos domésticos, algumas modalidades de diagnóstico por imagem, como a ultra-sonografia, radiografia simples e urografia excretora, já são amplamente utilizadas. A cintilografia é uma técnica não invasiva, capaz de oferecer informações funcionais de rins individualmente, porém é considerada uma modalidade menos usual. O objetivo deste estudo foi determinar o tempo de excreção renal de felinos domésticos através da cintilografia, em animais com parâmetros ultra-sonográficos e radiográficos dentro dos limites da normalidade. Foram utilizados 15 animais, 9 machos e 6 fêmeas, e estes foram divididos em grupos de animais não submetidos à anestesia e anestesiados. Foi estabelecido o tempo para o radiofármaco obter acúmulo máximo em cada um dos rins e o tempo para este acúmulo máximo ser reduzido pela metade. Não houve diferença estatística entre os valores dos animais não-anestesiados e anestesiados, nem entre machos e fêmeas, tampouco entre os rins esquerdo e direito. / In internal medicine of domestic cats, imaging modalities, such as ultrasonography, radiography and intravenous pylogram are widely used. Scintigraphy is a non-invasive technique, which provides functional information of each individual kidney; however, it is not widely available or utilized currently in veterinary medicine. The aim of this study was to determine the time of excretion of each kidney in normal domestic cats using nuclear scintigraphy. Fifteen cats (9 males and 6 females) determined to be within normal limits for radiographic and ultrasonographic renal parameters, were divided into two experimental groups (awake and anesthetized cats). Time to maximum radiopharmaceutical activity (T max) and time to decline to half maximum radiopharmaceutical activity (half-time) were determined in each kidney for each cat. No statistical difference was found between groups (awake vs. anesthetized) or sex (males vs. females), or between left and right kidneys.

SAMMANFATTNING Bakgrund Antalet personer som drabbas av kolorektalcancer ökar varje år och är den tredje vanligaste cancersjukdomen i Sverige. Det gör att efterfrågan av undersökningsmetoderna blir större för att man ska kunna ställa en korrekt diagnos och påbörja behandling. DT-kolon är en av undersökningsmetoderna och används ofta som en andrahandsmetod. Syfte Syftet med studien är att undersöka vad DT-kolon har för betydelse vid utredningen av kolorektalcancer. Metod Studien är en systematisk litteraturstudie. Insamling av data har gjorts via databaserna PubMed och CINAHL där vetenskapliga artiklar som uppfyllt inklusionskriterierna och besvarat frågeställningen har kvalitetsgranskats och analyserats. Resultat DT-kolon kan påvisa både koloniska- och extrakoloniska fynd och är en särskilt fördelaktig metod vid lokalisering av extrakoloniska fynd. Vid den preoperativa bedömningen anses DT-kolon vara en betydelsefull metod vid exakt lokalisering av patologier i kolon och rektum och är ett bra komplement till koloskopiundersökningar. DT-kolon ses som en tillförlitlig metod och har en sensitivitet på 94–99.9 %. När CAD används som granskningsmetod vid DT-kolon så ökar sensitiviteten, speciellt vid detektion av patologier som är mindre än 10 mm. Slutsats DT-kolon är en betydelsefull undersökningsmetod vid utredning av kolorektalcancer och av andra patologier i buken, kolon och rektum. Undersökningsmetoden är tillförlitlig med hög sensitivitet och med CAD som granskningsmetod ökar sensitiviteten. En stark fördel är att man får med hela bukområdet vid bildtagning och kan därmed även lokalisera extrakoloniska fynd så som exempelvis metastaser. Man kan även se tarmväggens tjocklek och utvändig kontur av kolon och rektum. Nyckelord Kolorektalcancer, Datortomografi, Kolografi / ABSTRACT Background The number of people suffering from colorectal cancer increases every year and is the third most common cancer disease in Sweden. Therefore the demand increases for the examination methods in order to be able to make a correct diagnosis and start treatment. CT Colonography is one of the methods often used as a secondary method. Aim The purpose of this study is to examine what significance CT Colonography has in the investigation of colorectal cancer. Method This study is a systematic review. The collection of data were made from the databases PubMed and CINAHL. Studies which fulfil the inclusive criteria and answered the aim of this study were quality reviewed and analyized. Result CT Colonography can show colonic findings and is particularly useful to locate extracolonic findings. The method is important in the preoperative evaluation because of its exact localisation rate and is a good compliment to colonoscopy. CT Colonography is a reliable method with a sensitivity at 94–99.9 % which increases when CAD is used as a reading method, especially in the detection of pathology >10 mm. Conclusion CT Colonography is a valuable method in the investigation of colorectal cancer and other pathologies in the abdomen, colon and rectum. It’s a reliable method with a high sensitivity which increases with CAD as a reading method. A strong advantage of this method is that the whole abdomen is visible in the images so the localisation of extracolonic findings can be detected. Keywords Colorectal neoplasms, Computed Tomography, Colonograph

Cancer is a widespread type of diseases that each year affects millions of people. It is mainly treated by chemotherapy, surgery or radiation therapy, or a combination of them. One modality of radiation therapy is high dose-rate brachytherapy, used in treatment of for example prostate cancer and gynecologic cancer. Brachytherapy is an invasive treatment in which catheters (hollow needles) or applicators are used to place the highly active radiation source close to or within a tumour. The treatment planning problem, which can be modelled as a mathematical optimization problem, is the topic of this thesis. The treatment planning includes decisions on how many catheters to use and where to place them as well as the dwell times for the radiation source. There are multiple aims with the treatment and these are primarily to give the tumour a radiation dose that is sufficiently high and to give the surrounding healthy tissue and organs (organs at risk) a dose that is sufficiently low. Because these aims are in conflict, modelling the treatment planning gives optimization problems which essentially are multiobjective. To evaluate treatment plans, a concept called dosimetric indices is commonly used and they constitute an essential part of the clinical treatment guidelines. For the tumour, the portion of the volume that receives at least a specified dose is of interest while for an organ at risk it is rather the portion of the volume that receives at most a specified dose. The dosimetric indices are derived from the dose-volume histogram, which for each dose level shows the corresponding dosimetric index. Dose-volume histograms are commonly used to visualise the three-dimensional dose distribution. The research focus of this thesis is mathematical modelling of the treatment planning and properties of optimization models explicitly including dosimetric indices, which the clinical treatment guidelines are based on. Modelling dosimetric indices explicitly yields mixedinteger programs which are computationally demanding to solve. The computing time of the treatment planning is of clinical relevance as the planning is typically conducted while the patient is under anaesthesia. Research topics in this thesis include both studying properties of models, extending and improving models, and developing new optimization models to be able to take more aspects into account in the treatment planning. There are several advantages of using mathematical optimization for treatment planning in comparison to manual planning. First, the treatment planning phase can be shortened compared to the time consuming manual planning. Secondly, also the quality of treatment plans can be improved by using optimization models and algorithms, for example by considering more of the clinically relevant aspects. Finally, with the use of optimization algorithms the requirements of experience and skill level for the planners are lower. This thesis summary contains a literature review over optimization models for treatment planning, including the catheter placement problem. How optimization models consider the multiobjective nature of the treatment planning problem is also discussed.

This project represents one of the foundation steps to a collaboration between the Department of Human Physiology, University of Pretoria and the Nuclear Medicine Department at Steve Biko Academic hospital. Following the initial discovery of the surprising effect zolpidem has on patients in persistent vegetative states in 1999 by Dr H.W. Nel - namely that zolpidem administration results in a significant qualitative increase in brain function, to the extent that patients were able to once again communicate and respond appropriately to their surroundings - much data has been collected by both Dr Nel as well as the Nuclear Medicine Department of Steve Biko Hospital. Over the course of twelve years SPECT scans have been carried out on patients of various pathologies both before and after a course of zolpidem. To this day, both assessment and follow up of these and new patients is still being done by the Nuclear Medicine Department and Dr Nel. As this vast collection of data grows it has become increasingly daunting for a single research team to consolidate all this information into a usable form and an outside team has been deemed necessary to facilitate this process. The primary goal of this study was to quantify the neurological perfusion changes following zolpidem administration within responder patients. This was achieved through reprocessing and semi-quantification of the existing SPECT scan records held by the Pretoria Academic Hospital. Within the group of responder patients (n = 29), 22 patients (~76%) presented a significant increase in perfusion within at least one lesion with a range of 4.5 - 46.1% (mean = 11.9%). In opposition to this finding non-responsive lesion perfusion decreased with a significant mean change of -14.5%. For both sets the p-value was determined to be <0.01. Of all lesions measured (n = 85) 32% displayed increased perfusion after zolpidem administration, whereas 30.6% presented with a perfusion decrease. It was determined that only one lesion is required to respond to zolpidem in a positive manner to facilitate positive functional improvements with a given patient. In a small minority of patients post-zolpidem functional improvements seems to be connected to wide-spread cortical changes as opposed to singular lesional improvements. This study provides further evidence of zolpidem’s paradoxical action in a subset of brain damaged individuals. Unique quantification of results allows for additional insight and provides further understanding the physiological changes associated with zolpidem administration. / Dissertation (MSc)--University of Pretoria, 2014. / tm2015 / Physiology / MSc / Unrestricted

Molecular breast imaging (MBI) is a relatively new clinical breast imaging modality, which has the potential to have a significant impact in breast cancer screening and perioperative breast imaging for women with high risk factors for developing breast cancer. Two objectives were proposed in this thesis to increase the use of MBI. First, a magnetic resonance (MR)-compatible gamma camera was developed for combined molecular/MR breast imaging. MBI is a functional imaging technique with high specificity and sensitivity but could benefit from the addition of anatomical information from breast MRI for lesion localization, cancer staging, treatment planning and monitoring. A small area (8cm x 8cm) cadmium zinc telluride (CZT) based gamma camera was developed and tested for MR compatibility in both sequential and simultaneous imaging conditions. Results indicated that the gamma camera was minimally affected during both sequential and simultaneous imaging with a gradient echo (GRE) and spoiled gradient echo (GRE) sequence. Signal to noise ratio (SNR) degradation was observed in the MR images but no geometric distortions were observed. Simultaneous imaging is feasible, but a reassessment of the RF shielding would be required to minimize the noise contribution degrading image quality. Second, backscatter photons were investigated as a potential dose reduction technique for MBI. While the effective dose from MBI is relatively low in comparison to other nuclear medicine procedures, the dose is considered high in relation to mammography and in order to increase acceptance as an alternative breast imaging method, dose reduction is an important objective. Backscatter photons have the same spatial information as primary photons but are typically discarded along with other scattered photons. A scatter compensation method called the triple energy window (TEW) was used to extract backscatter photons from the Compton scattering spectrum and added to the primary photons, increasing count sensitivity by 6%. The noise level matched the increase in contrast leading to negligible change in lesion contrast to noise ratio (CNR). Dose reduction is not justified with this particular technique because of the elevated noise level, but the use of backcsatter photons show potential with improved contrast. / Dissertation / Doctor of Philosophy (PhD)

Yes / Research is critical to evidence‐based practice, and the rapid developments in technology provide opportunities to innovate and improve practice. Little is known about the research profile of the medical radiation science (MRS) profession in Australia and New Zealand (NZ). This study provides a baseline of their doctoral activity. A cross‐sectional survey of MRS professionals in Australia and NZ holding a doctorate or undertaking doctoral studies, was performed using an online tool (Bristol Online Survey®, Bristol, UK). A chain‐referral sampling technique was adopted for data collection. An email invitation with a link to the survey was generated and distributed through email and social media. The survey contained questions related to participant demographics, doctoral status, qualification route, funding and employment. There were 63 responses to the survey comprising 50.8% diagnostic radiographers (DRs; n = 32), 23.8% radiation therapists (RTs; n = 15), with the remaining 25.4% (n = 16) equally split between sonographers and nuclear medicine technologists (NMTs). A total of 40 (63.5%) of respondents had completed their doctoral qualification. In NZ, only DRs held a doctoral award constituting 0.3% of DRs and 0.2% of the total registered MRS population. In Australia, there was a greater proportion of doctoral NMTs (n = 8/1098; 0.7%) than RTs (n = 15/2394; 0.6%) and DRs (n = 27/12,001; 0.2%). Similar to other countries, findings show a very small percentage of doctoral MRS professionals in Australia and NZ. Strategies to engage and support individuals in research, up to and beyond doctoral study, need to be embedded in practice.

Thesis (MSc (Medical Imaging and Clinical Oncology. Nuclear Medicine))--University of Stellenbosch, 2010. / ENGLISH SUMMARY: Introduction: Bone scintigraphy is used extensively in evaluating metastatic disease. There are currently no clear recommendations for the use of SPECT/CT in metastatic bone disease. Existing procedural guidelines from the Society of Nuclear Medicine (SNM) for SPECT/CT do not provide specific indications for use of SPECT/CT in bone scintigraphy, and there are currently no other guidelines for the use of SPECT/CT in bone scintigraphy that the author is aware of. The aim of this study was to investigate the additional value of SPECT/CT, and to identify the clinical indications for which SPECT/CT is most useful in patients with suspected bone metastases. Subjects and Methods: Forty-two patients with equivocal lesions on planar scintigraphy were prospectively recruited and planar imaging, SPECT, and SPECT/CT done on all patients. On reading of SPECT and then SPECT/CT, patients and individual lesions were classified as malignant, benign or equivocal. Radiological studies and available clinical information were also used during reading of scans. Review of clinical information, radiological studies and/or follow-up bone scans were used as gold standard. The results of the SPECT and SPECT/CT were compared in terms of proportion of equivocal findings and accuracy. Results: Forty-two patients with 189 skeletal lesions were examined. There was a diverse variety of primary tumours, although the majority had breast (n=22) or prostate cancer (n=8). Overall, SPECT/CT resulted in a significant reduction in the proportion of equivocal findings on both a patient-wise (p=0.0015) and lesion-wise basis (p<0.0001). The overall accuracy of SPECT/CT was significantly higher than that of SPECT on both a patient-wise (p=0.0026) and lesion-wise basis (p<0.0001). Generally SPECT/CT decreased the proportion of equivocal findings and increased the accuracy independent of the presence of bone pain, type of primary tumour, or skeletal region involved. SPECT/CT did not significantly improve the diagnostic confidence of readers in equivocal lumbar lesions although accuracy was significantly improved in this region. Conclusion: SPECT/CT performs significantly better than SPECT alone for the interpretation of equivocal planar lesions. There is no evidence that the benefit of SPECT/CT is dependent on the type of primary tumour or the presence of bone pain. Where resources are limited, SPECT/CT is indicated only in those patients in whom correct classification of the lesions in question is expected to alter the patient’s management. SPECT/CT images should be interpreted with the aid of a diagnostic radiologist or nuclear medicine physicians should acquire sufficient experience in Computed Tomographic image interpretation in order to optimise diagnostic benefit from SPECT/CT. / AFRIKAANSE OPSOMMING: Inleiding: Beenflikkergrafie word wyd vir die evaluering van metastatiese siekte gebruik. Daar bestaan tans geen duidelike aanbevelings vir die gebruik van Enkelfotonemissie rekenaartomografie gekombineer met rekenaartomografie (EFERT/RT, Engels SPECT/CT) in metastatiese beensiekte nie. Bestaande riglyne van die Amerikaanse Society of Nuclear Medicine (SNM) vir EFERT/RT gee nie spesifieke indikasies vir die gebruik van EFERT/RT in beenflikkergrafie nie, en daar is tans geen ander riglyne waarvan die outeur bewus is nie. Die doel van hierdie studie was om die bykomende waarde van EFERT/RT te ondersoek, en om dié kliniese indikasies waar EFERT/RT in pasiënte met vermoedelike beenmetastases mees nuttig sal wees, te identifiseer. Pasiënte en Metodes: Twee en veertig pasiënte met twyfelagtige letsels op planare skeletflikkergrafie is prospektief geselekteer en planare beelding, EFERT en EFERT/RT is op alle pasiënte gedoen. Tydens beoordeling van EFERT en daarna EFERT/RT beelde is pasiënte en individuele letsels as maligne, benigne of twyfelagtig geklassifiseer. Radiologiese studies en beskikbare kliniese inligting is ook tydens interpretasie van flikkergramme gebruik. Kliniese inligting, radiologiese studies en/of opvolg beenflikkergramme is as goue standaard gebruik. Die resultate van EFERT en EFERT/RT is ten opsigte van die aantal twyfelagtige bevindings en akkuraatheid vergelyk. Resultate: Twee en veertig pasiënte met 189 skeletale letsels is ondersoek. Daar was ‘n verskeidenheid van primêre tumore, maar die meerderheid van pasiënte het borsvi (n=22) of prostaatkanker (n=8) gehad. Die gebruik van EFERT/RT het gelei tot ‘n betekenisvolle afname in die aantal twyfelagtige bevindings, beide op ‘n pasiënt- en ‘n letselbasis (p=0.0015 en p<0.0001 onderskeidelik). Die algehele akkuraatheid van EFERT/RT was betekenisvol hoër as die van EFERT alleen, beide op pasiënt- en op letselbasis (p=0.0026 en p<0.0001 onderskeidelik). Oor die algemeen het EFERT/RT die aantal twyfelagtige letsels verminder en die akkuraatheid verhoog, ongeag die teenwoordigheid van beenpyn, die tipe primêre tumor of die area van die skelet wat betrokke was. In twyfelagtige lumbale letsels het EFERT/RT nie die diagnostiese vertroue van beoordelaars van flikkergramme verhoog nie, alhoewel die akkuraatheid vir hierdie gebied wel betekenisvol toegeneem het. Gevolgtrekking: EFERT/RT vaar betekenisvol beter as EFERT in die beoordeling van twyfelagtige letsels op planare beenflikkergramme. Daar is geen bewys dat die voordeel van EFERT/RT afhanklik is van die tipe primêre tumor of die teenwoordigheid van beenpyn nie. Waar hulpbronne beperk is, is EFERT/RT slegs aangedui in dié pasiënte waar verwag word dat korrekte klassifikasie van die betrokke letsel behandeling sal beïnvloed. EFERT/RT beelde behoort met die hulp van ‘n diagnostiese radioloog beoordeel te word, of kerngeneeskundiges moet genoegsame ondervinding in die interpretasie van rekenaartomografiebeelde hê om die diagnostiese voordeel van EFERT/RT optimaal te kan benut.

Thesis (MScMed)--Stellenbosch University, 2004. / Copy not signed by author. / ENGLISH ABSTRACT: This study involved 33 patients, 19 men and 14 women. The age range was wide (20-90 years) and median age was 57 years. These patients had a single pulmonary nodule (SPN) defined radiologically as a well defined, round or oval intrapulmonary lung lesion not associated with atelectasis or adenopathy on chest radiography or computed tomography. Patients were investigated with Tc-99m MIBI and TI-201 (25 patients) and with Tc-99m MIBI alone (8 patients). Single photon emission computed tomography images were reconstructed using both iterative reconstruction (Ordered Subsets - Expectation Maximisation: aSEM) and filtered backprojection (FBP), on the Hermes system. Transverse, coronal and sagittal slices were displayed on the screen using a grey scale. The aSEM and FBP images for each study were co-registered semi-automatically using the multimodality programme on the Hermes. The best slice for the lesion was chosen according to the best view used to locate the SPN on chest radiograph. Regions of interest (Ral) were drawn manually outside the outer margin of the detected lesion, first on the aSEM image. This was automatically mirrored on the co-registered FBP image. For most patients, the background was automatically mirrored horizontally on the contralateral side, again, first on the OSEM then automatically on the FBP image. Automatic vertical mirroring or manual horizontal mirroring was used when background was found to be in a visually 'hot' area like the heart or vertebrae. The average counts and standard deviation of the Ral and background were generated automatically. Semi-quantitative image analysis was done by calculating the signal-to-noise ratio (SNR) and tumour-to-background (TIB) ratio using the following formulae: SNR = Mean counts ROI(lesion) - Mean counts background Standard deviation background TIB rati.o = -M---e-a-n-'--c-o--u-n-'t-s- ROI(lesion) Mean counts background Detection was found to be the same for the two reconstruction algorithms, that is, every lesion detected by using OSEM could also be detected by using FBP. However lesion detection did differ between Tl-201 and Tc-99m-MIBI. Sensitivity and specificity were calculated for different thresholds of SNR and TIB ratios. Receiver operating characteristics (ROC) curves were drawn to represent the different sensitivities and specificities at each threshold. Tuberculosis (TB) was not included in this analysis as uptake of Tl-20l was found to be significantly high and comparable to that of malignant nodules. However the effect of OSEM and FBP on the 'positive' TB nodules was assessed separately. By calculating the area under the ROC curves, TI-201 using OSEM was shown to be more accurate at differentiating malignant nodules from benign ones than FBP. Although this difference was not statistically significant (p=0.1 0), there was a clear tendency. The two reconstruction algorithms were found to be almost equally accurate, when using Tc-99m-MIBI, the difference between them being considerably insignificant. In conclusion, it was shown that there is a tendency that OSEM outperforms FBP for studies using Tl-201 but not for Tc-99m-MIBI. / AFRIKAANSE OPSOMMING: Hierdie studie sluit 33 pasiënte in, 19 mans en 14 vroue. Die ouderdomme wissel tussen 20 en 90 jaar met 'n gemiddelde ouderdom van 57 jaar. Elkeen van die pasiënte het 'n enkel longnodule (SPN) op borskas X-straal en/of rekenaar tomografie getoon, wat radiologies gedefinieer word as 'n goed omskrewe, ronde of ovaal intrapulmonale longletsel wat nie met atelektase of adenopatie geassosieer is nie. Pasiënte is met Tc-99m MIDI en TI-201 (25 pasiënte) of slegs met Tc-99m MIBI (8 pasiënte) ondersoek. Enkelfoton emissie rekenaar tomografiese (EFERT) beelde is met beide iteratiewe rekonstruksie (Ordered Subsets - Expectation Maximisation: OSEM) en gefilterde terugprojeksie (FBP) met die Hermes sisteem gerekonstrueer. Transvers, koronale en sagittale snitte is in grysskaal op die sisteem vertoon. Die OSEM en FBP beelde vir elke studie is semi-outomaties gekoregistreer met behulp van die multimodaliteitsprogram op die Hermes. Die optimale snit vir elke letsel is gekies volgens die beste aansig op die borskas X-straalom die SPN te lokaliseer. Gebiede van belang (ROl) is met die hand buite-om die buitenste rand van die letsel getrek op die OSEM beeld en daarna outomaties in die ooreenstemmende area op die gekoregistreerde FPB beeld geplaas. Vir die meeste pasiënte is die agtergrond outomaties as horisontale spieëlbeeld op die kontralaterale kant geplaas, eers op die OSEM en dan outomaties op die FBP beeld. 'n Outomatiese vertikale spieëlbeeld of manuele horisontale verskuiwing van die agtergrondsarea is gedoen indien die agtergrond oorvleuel het met 'n 'warm' area soos die hart of werwels. Die gemiddelde tellings en standaardafwyking van die ROl en agtergrond is outomaties gegenereer. Semi-kwantitatiewe beeldanalise is gedoen deur berekening van die sein-tot-agtergrond verhouding (signal-to-noise ratio - SNR) en tumor-tot-agtergrond (TIB) verhouding met behulp van die volgende formules: SNR = gemiddelde tellings ROI(letsel) - gemiddelde tellings agtergrond Standaard afwyking van agtergrond TIB rati.o = -g=em--id-d-e-l-d-e--te=ll-in-g-s__R:_O-I(-le-t-s'e-l) gemiddelde tellings agtergrond Opsporing is soortgelyk bevind vir die twee rekonstruksie algoritmes, dit wil sê elke letselopgespoor met behulp van OSEM kon ook met FBP opgespoor word. Letselwaameming het egter verskil tussen TI-201 en Tc-99m-MIBI. Sensitiwiteit en spesifisiteit is vir verskillende drempels van SNR en TIB verhoudings bereken. 'Receiver operating characteristics' (ROC) kurwes is getrek om die verskillende sensitiwiteite en spesifisiteite by elke drempel te verteenwoordig. Tuberkulose (TB) is nie in hierdie analise ingesluit nie aangesien opname van Tl-201 beduidend hoog en vergelykbaar met die van maligne nodules was. Die effek van OSEM en FBP op die 'positiewe' TB nodules is egter apart beoordeel. Deur berekening van die area onder die ROC kurwes, is getoon dat OSEM van Tl-201 tomografiese data meer akkuraat as FBP was om maligne van benigne nodules te onderskei. Alhoewel hierdie verskil nie statisties betekenisvol was nie (p=0.10), is daar wel 'n duidelike neiging gevind. Die twee rekonstruksie algoritmes was byna ewe akkuraat wanneer Tc-99m-MIBI gebruik is, met duidelik geen betekenisvolle verskil tussen die algoritmes nie. Gevo lgtrekking In hierdie studie is dit getoon dat daar 'n neiging is dat OSEM beter vaar as FBP vir studies met tallium-201 maar nie vir Tc-99m-MIBI nie.

Thesis (MMed)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Background: Hybrid imaging using single photon emission computed tomography/low dose (x-ray) computed tomography (SPECT/LDCT) is of benefit in preoperative scintigraphy of primary hyperparathyroidism. The role of SPECT/LDCT in preoperative assessment of renal hyperparathyroidism has not yet been examined. The aim of the study was to determine whether SPECT/LDCT conferred any benefit over SPECT alone in terms of detection and/or localization of hyperfunctioning parathyroid tissue in this patient group. Methods: A retrospective study of patients with renal hyperparathyroidism and positive planar and SPECT scintigraphy was undertaken. All patients underwent planar scintigraphy using 99mTc-pertechnetate immediately followed by 99mTc-sestamibi as well as SPECT/LDCT 60 min after sestamibi injection and a delayed static image to assess for differential washout at 2-3 hours. Planar subtraction images were generated. For each patient, two nuclear physicians reported on planar+ SPECT images followed by planar + SPECT/LDCT images (assisted by a radiologist). Confidence for the presence of hyperfunctioning parathyroid tissue as well as confidence of location was scored on a Likert-type scale. Interpretation of planar + SPECT was compared with interpretation of planar + SPECT/LDCT. The impact of LDCT on equivocal lesions and number of ectopic lesions detected was also assessed. Results: Twenty patients (M:13; F:7) imaged between February 2008 and June 2011 were included [mean age: 40 years (24 – 55)]. Mean creatinine was 687 μmol/l (169-1213), mean corrected calcium: 2.55 mmol/l (1.95-3.33) and median PTH 167 pmol/l (2.4 - >201). Thirty-five lesions were detected on planar and SPECT and this was unchanged after assessment of the LDCT data. Confidence for the presence of parathyroid pathology changed in 5 patients (5 lesions) with the addition of LDCT. LDCT changed the mean confidence of parathyroid pathology from 3.17 to 3.29 (p=0.16). Addition of LDCT reduced the number of equivocal lesions from 18 (14 patients) to 14 (10 patients) (p=0.13). The addition of LDCT changed localization in 4 lesions (3 patients). Confidence in localization of pathology changed in 9 lesions (7 patients) and the mean localization confidence score was improved from 4.2 to 4.46 (p=0.002) with LDCT. The number of lesions classified as ectopic increased from 5 (on planar+SPECT) to 8 (with addition of LDCT) (p=0.25). Conclusion: In renal hyperparathyroidism SPECT/LDCT altered localization of lesions detected on planar and SPECT alone and improved reader confidence of localization accuracy. SPECT/LDCT conferred no additional benefit over SPECT in terms of detection, confidence of parathyroid pathology or ability to distinguish equivocal from non-equivocal parathyroid lesions. The addition of LDCT did not detect significantly more ectopic lesions. Whereas the minor improvement in reader confidence of localization (with addition of LDCT) was of questionable clinical significance, we speculate that the changed and presumably improved localization of lesions on SPECT/LDCT had potential clinical impact in a significant proportion of patients. On this basis we recommend the use of hybrid SPECT/LDCT in imaging of renal hyperparathyroidism when surgery is considered. / AFRIKAANSE OPSOMMING: Agtergrond: Hibriedbeelding met enkelfoton emissie rekenaartomografie / lae dosis rekenaartomografie (EFERT/LDRT) is voordelig in pre-operatiewe beelding van primêre hiperparatiroïedisme. Die rol van EFERT/RT in pre-operatiewe evaluering van renale hiperparatiroïedisme is nog nie ondersoek nie. Die doel van hierdie studie was om in hierdie pasiëntgroep te bepaal of EFERT/RT 'n voordeel bo EFERT alleen verleen. Metode: 'n Retrospektiewe studie van pasiënte met renale hiperparatiroïedisme en positiewe planare en EFERT flikkergrafie is onderneem. Na die toediening van 99mTc-pertegnetaat is planare beelding op alle pasiënte gedoen, onmiddellik gevolg deur 99mTc-sestamibi sowel as EFERT/RT beelding 60 min na sestamibi inspuiting en 'n laat statiese beeld vir differensiële uitwas op 2-3 uur. Planare subtraksiebeelde is verkry. Twee kerngeneeskundiges het die planare + EFERT beelde van elke pasiënt gerapporteer, waarna die planare + EFERT/RT beelde met die hulp van 'n radioloog gerapporteer is. Sekerheid oor die teenwoordigheid van hiperfunksionerende paratiroïedweefsel sowel as die sekerheid oor die lokalisering daarvan, is op 'n Likert-tipe skaal verkry. Interpretasie van planare + EFERT is vergelyk met die interpretasie van planare + EFERT/RT. Die impak van LDRT op twyfelagtige letsels en die aantal ektopiese letsels waargeneem, is ook bepaal. Resultate: Twintig pasiënte (M:13; F:7) met beelding tussen Februarie 2008 en Junie 2011 is ingesluit [gemiddelde ouderdom: 40 jaar (24-55)] . Die gemiddelde kreatinien was 687 μmol/l (169-1213), gemiddelde gekorrigeerde kalsium 2.55 mmol/l (1.95-3.33) en mediaan PTH 167 pmol/l (2.4->201). Vyf en dertig letsels is op planare en EFERT beelde waargeneem en was onveranderd na assessering van die LDRT-data. Sekerheid oor die teenwoordigheid van paratiroïedpatologie het verander in 5 pasiënte (5 letsels) met die toevoeging van LDRT. LDRT het die gemiddelde sekerheid van paratiroïedpatologie van 3.17 tot 3.29 verander (p = 0.16). Toevoeging van LDRT het die aantal twyfelagtige letsels van 18 (14 pasiënte) tot 14 (10 pasiënte) verminder (p = 0.13). Die byvoeging van LDRT het die lokalisering in 4 letsels (3 pasiënte) verander. Sekerheid oor die lokalisering van patologie is in 9 letsels (7 pasiënte) verander en die gemiddelde lokalisering betroubaarheidswaarde is verbeter van 4.2 tot 4.46 (p = 0.002) met LDRT. Met die byvoeging van LDRT het die aantal letsels geklassifiseer as ektopies van 5 tot 8 (p = 0.25) toegeneem. Gevolgtrekking: In renale hiperparatiroïedisme het EFERT/RT die lokalisering van letsels wat op planare + EFERT beelding alleen waargeneem is, verander en die leser se vertroue om akkuraat te lokaliseer verbeter. EFERT/LDRT het geen bykomende voordeel bo EFERT in terme van die opsporing, sekerheid van paratiroïedpatologie of onderskeidingsvermoë tussen twyfelagtige teenoor nie-twyfelagtige paratiroïedletsels verleen nie. Met die byvoeging van LDRT is nie beduidend meer ektopiese letsels gevind nie. Terwyl die geringe verbetering in die sekerheid van lokalisering (met die byvoeging van LDRT) van twyfelagtige kliniese betekenis was, spekuleer ons dat die verandering en vermoedelik verbeterde lokalisering van letsels op EFERT/LDRT ʼn potensiële kliniese impak het in 'n beduidende aantal pasiënte. Die gebruik van EFERT/LDRT in die beelding van renale hiperparatiroïedisme wanneer chirurgie oorweeg word, word dus vir bogenoemde rede aanbeveel.