Browsing by Department "Division of Nuclear Medicine"
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- ItemOpen AccessAppropriate indications for positron emission tomography/computed tomography, 2015(2015) Vorster, Mariza; Doruyter, Alexia; Brink, Anita; Mkhize, Sonto; Holness, Jen; Malan, Nico; Nyakale, Nozipho; Warwick, James M; Sathekge, MikeThese recommendations are intended to serve an important and relevant role in advising referring physicians on the appropriate use of 18F-fluorodeoxyglucose (18F-FDG) and non-18F-FDG positron emission tomography/computed tomography (PET/CT), which can be a powerful tool in patient management in oncology, cardiology, neurology and infection/inflammation. PET is a non-invasive molecular imaging tool that provides tomographic images and quantitative parameters of perfusion, cell viability, proliferation and/or metabolic activity of tissues. These images result from the use of different substances of biological interest (sugars, amino acids, metabolic precursors, hormones) labelled with positron-emitting radionuclides (PET radiopharmaceuticals). Fusion of the aforementioned important functional information with the morphological detail provided by CT as PET/CT provides clinicians with a sensitive and accurate one-step whole-body diagnostic and prognostic tool, which directs and changes patient management. Hence PET/CT is currently the most widely used molecular imaging technology for a patient-tailored treatment approach. In these recommendations we outline which oncological and non-oncological indications are appropriate for PET/CT. Once each combination of pathology and clinical indication is defined, a recommendation is given as: 1. Recommended; 2. Recommended in select cases; 3. May be considered; or 4. Not recommended.
- ItemOpen AccessAssessment of the impact of the application single photon emission computerized tomography and SPECT-CT on lesion catergorization(2015) Yunusa, Garba Haruna; Brink, Anita; Mann, Michael DObjectives: To assess initial experience with the use of a new SPECT-CT in the evaluation of lesions. Methods: The folder number, radiopharmaceutical used and type of scan of patients examined with a new Siemens T6 SPECT-CT between 2 April and 31 December 2013 were retrieved. The number of 99m Tc -MDP bone scans was sufficient for a detailed analysis. The scans were re-processed and reported by the observer before he was given any clinical information. Whole body planar, whole body planar plus SPECT and whole body planar plus SPECT-CT images were assessed successively in three separate sessions at least two weeks apart. At each session, the certainties of detection, localisation, and categorisation of each lesion were recorded. Results: A total of 539 lesions were seen on the whole body, SPECT and CT images in 133 patients. The whole body images showed no lesions in three patients and 378 lesions in 130 patients, 117(31%) lesions in areas not covered by the SPECT. SPECT detected 122 additional lesions in 79 patients. Thirty-nine (12.2%) lesions were seen only on CT in 32 (24.1%) patients. F or the 261 lesions seen on the planar images in the SPECT FOV, lesion detection was definite in 233 (89.3%), localisation definite in 151(57.9%) and categorisation definite in 123 (47.1%) lesions. On the SPECT, definite lesion detection, localisation and categorisation were recorded respectively for 259 (99.2%), 228 (87.4%) and 176 (67.4%) of the 261 lesions. Lesion detection, localisation and categorisation certainties were definite for 100%, 99.1% and 94.7% of the SPECT-CT lesions respectively. Conclusion: Whole body planar scintigraphy is essential in lesion detection. SPECT markedly improves lesion detection and localisation and CT enhances lesion categorisation.
- ItemOpen AccessCarcinoid heart disease: Two clinical cases and a review(2011) Weinreich, C; Ross, I L; Kotze, T; Levitt, N; Steyn, R EWe present two cases of metastatic carcinoid tumours, complicated by carcinoid syndrome and by cardiac valve involvement, a well-known, but infrequent, complication. Carcinoid tumours are generally more indolent than other cancers and may have a long asymptomatic phase. The symptoms of carcinoid syndrome generally manifest only once metastases to the liver have occurred. Cardiac involvement occurs in up to 50% of patients, and heralds a poor prognosis. However, a multidisciplinary team approach has improved the prognosis and quality of life for patients with carcinoid heart disease. Therapy includes somatostatin analogues and treatment for heart failure, removal of primary or metastatic tumour deposits, valve replacement in the presence of valvular involvement, and radioisotopes therapy.
- ItemOpen AccessColonic transit in subjects with spinal cord injuries(2001) Freedman, Patricia Noel; Mann, Michael DThe rehabilitation of patients with spinal cord injuries (SCI) is long and difficult. Not only do they lose mobility but they also have changes in bowel continence caused by loss of voluntary motor and sensory function and damage to the visceral nerve supply. The maintenance and management of bowel function causes major morbidity for subjects with SCI. The effect of SCI on colonic function is poorly understood and little studied. Aim: This study sought to establish a method of studying regional colonic transit and to investigate whether the level of SCI influences colonic transit. Patients and Methods Sixteen subjects (8 paraplegics and 8 tetraplegics) with spinal cord injury, at least one year previously were recruited. The tetraplegics group had spinal cord injuries above T1 and the paraplegic group had injuries below T1 . They were given a pancake labelled with 10-18 Mbq of ln-111 Amberlite resin to eat. Anterior and posterior images were acquired for 400 seconds each, using a 40 cm field of view gamma camera, once on the first day and then 3 times a day for the next 4 days. The subjects were asked to report every time they had a bowel evacuation. No laxatives or enemas were permitted during the study. Subjects were permitted to eat and drink normally after the first images (3 hours) were acquired. Seven regions of interest (ROI) outlining, 1) ascending colon, 2) hepatic flexure, 3) transverse colon, 4) splenic flexure, 5) descending colon, 6) rectosigmoid and 7) total abdominal activity, were drawn on each set of anterior and posterior images. The counts were decay corrected. The decay corrected counts were used to calculate the geometric mean (GM), for each region, at each time point. The GM was used to calculate the percentage of the total abdominal activity in each region, at each time point. Colonic transit was assessed in 4 ways. Firstly, 3 independent Nuclear Medicine Physicians visually assessed transit on hard copies of the images and classified subjects into 5 categories of colonic transit (rapid transit, intermediate transit, generalised delay, right-sided delay or left-sided delay). Secondly, parametric images were constructed from the percentage activity in each region at each time point. Thirdly, the arrival and clearance times of the activity in the right and left colon were plotted as time-activity curves. Finally, the geometric centre of the distribution of the activity was calculated and plotted on a graph versus time. The parametric images, time activity curves of the right and left sides of the colon and the geometric centre for each subject were classified into the same categories as the visual assessment. All statistics were assumed to be non-parametric. Results: The results of the four methods of assessing colonic transit were compared and the majority categorisation was accepted as the final diagnosis. The best agreement occurred between the parametric images and the arrival and clearance times of the activity in the right and left colons. No single method was consistently correct. Amongst the paraplegic subjects, two had generalised delay, four had rightsided delay, and two left-sided delay. In the tetraplegic subjects, two had intermediate transit, 1 generalised delay, and 5 left-sided delay. Conclusion A combination of at least two methods of determining colonic is necessary. The level of spinal cord injury effects colonic transit. Injuries below T7 /T8 result in right-sided delay. Injuries above this most commonly result in left-sided delay. Occasionally injuries above T7/8 can result in intermediate transit or generalised delay. Paraplegics are more likely to have right-sided delay (p =0.04), whereas tetraplegics are more likely to have left-sided delay.
- ItemOpen AccessComparison of estimates of left ventricular ejection fraction using gated blood imagining(2013) Steyn,Rachelle; acquisition; cameras; comparison; gated blood pool studiesSerial measurement of left ventricular ejection fraction (L VEF) using GBP imaging is an established technique for monitoring L VEF in patients undergoing chemotherapy with cardio-toxic medication and in patients after heart transplants. Oncologists at our institution decide that cardio-toxic chemotherapy should be discontinued if the L VEF decreases by 10%, or if a value of 50% is reached. In patients with baseline L VEFs of less than 50% but greater than 30% therapy will be discontinued if the L VEF decreases by 10% or if a value of less than 30% is reached. This is in accordance with the guidelines set out by the Oxford Textbook ofOncology.3 In patients who have had heart transplants, GBP studies are used to monitor L VEF. If there is a decrease in L VEF, cardiologists may decide to start glucocoricosteroids for rejection. It is therefore imperative that serial studies on an individual patient are comparable. There are two software systems used in our nuclear medicine department; the Siemens system and the Hermes system. In a pilot study we found large differences between the L VEFs calculated by the two systems. This is consistent with the consensus in the literature that different software programs for processing GBP studies cannot be used interchangeably.
- ItemOpen AccessThe diagnostic accuracy to Technetium 99m labelled erythrocyte scintigraphy in the investigation of hepatic mass lesions : special reference to hepatic cavernous haemangioma and hepatocellular carcinoma(1995) Lourens, Steven; Mann, Michael DThe distinction between cavernous haemangiomas of the liver (which are the second most common hepatic mass lesions) from malignant lesions, is often difficult. An incorrect diagnosis of cavernous haemangioma, in a patient with malignancy, may adversely influence the outcome of subsequent treatment in these patients, due to delay in therapy. Although previous studies have suggested that ⁹⁹ᵐTc erythrocyte blood pool scintigraphy is both highly sensitive and specific for haemangiomas, a basic flaw in all previous studies has been the small number of control patients studied. Bayesian analysis clearly shows that specificity for a test is dependant on the pre-test probability of the lesion being present. Thus all the studies done to date, may reflect an inappropriately high specificity for ⁹⁹ᵐTc scintigraphy, in diagnosing cavernous haemangiomas, because they have mainly studied patients with haemangiomas and relatively few patients with other lesions. This study was thus undertaken to clarify the true accuracy of this technique, in distinguishing haemangiomas from other hepatic mass lesions, by studying a large number of patients with haemangiomas and other hepatic mass lesions.
- ItemOpen AccessThe differentiation of extrahepatic biliary atresia from the neonatal hepatitis syndrome(1989) Daubenton, John David; Mann, Michael DThe differentiation, in an infant with cholestasis, between extrahepatic biliary atresia (EHBA) and the neonatal hepatitis syndrome (NHS) is important in that laparotomy is always indicated in EHBA but is undesirable in NHS. This differentiation is particularly difficult in those infants with complete cholestasis. Hepatobiliary scintigraphy is a commonly used investigation in infants with obstructive jaundice. The scintigraphic demonstration of excretion into the gut excludes extrahepatic obstruction, however, absence of excretion may be due to EHBA, severe cholestasis with patent extrahepatic bile ducts or poor uptake of the agent, and is therefore not diagnostic. This study has examined the quantitative measurement of the hepatic uptake of p-butyl IDA and Sn colloid, and an estimation of liver shape, in a group of patients with complete cholestasis in whom conventional scan interpretation, based on excretion into the-gut, would not be useful. The scans were recorded as dynamic studies and the resultant time-activity curves were subjected to curve fitting to calculate a rate constant for uptake of radiopharmaceutical. Liver shape was determined from the anterior static image of the colloid scan. The results show a significant difference between the EHBA and the NHS patients in the rate of uptake of p-butyl IDA, in the ratio of the rate of uptake of p-butyl IDA/the rate of uptake of colloid and in the measurements used to express liver shape. Using this method of scan interpretation, a diagnostic accuracy of 85% was achieved in this study of patients who clinically, and on scan, had no evidence of bile flow. Hepatic scintigraphy is therefore a useful investigation in the diagnostic work-up of infants presenting with obstructive jaundice even when bile flow is completely absent.
- ItemOpen AccessLiver spleen scintigraphy in the assessment of blunt abdominal trauma in adults(1994) Naidoo, Vahini Vishnu; Professor J Knottenbelt and Dr AB FataarDUPLICATE
- ItemOpen AccessNormal reference values for thyroid uptake of technetium-99m pertechnetate for the Namibian population(2013) Hamunyela, R H; Kotze, T; Philotheou, G MObjective: Historically, changes in normal thyroid uptake values for iodine have been reported in different geographical areas. These changes have been linked to geographical and chronological fluctuations in dietary iodine intake in different populations. Namibia is a country with mixed ethnicity, with access to dietary iodine in table salt. Despite historical reports on deviating normal thyroid uptake values (emphasising the importance of establishing local normal reference values), the relevant Namibian authorities have never revised these reference values, nor have local reference values been established. The aim of this study was to establish the normal reference values for thyroid uptake of technetium-99m pertechnetate in the Namibian population. Design: Participants who were considered to be euthyroid completed a questionnaire designed to exclude individuals with thyroid pathologies, as well as those with renal or heart disease. Settings and subjects: The study cohort consisted of 76 participants (58 women and 18 men), ranging in age from 39-81 years. The participants were of mixed ethnicity, consisting of Hereros, Ovambos, Damaras, Namas, Coloureds, Caucasians and other (non-Namibian immigrants), and were from Windhoek, Namibia. Studies were performed at the Windhoek Central Hospital. Outcome measures: Blood was drawn for thyroid hormone assessment. Participants were then given 100 MBq of technetium-99m pertechnetate intravenously, and their percentage thyroid uptake recorded after 20 minutes. Results: In this study, thyroid-stimulating hormone, triiodothyronine, and thyroxine levels were found to be 1.7 μIU/ml, 4.9 pmol/ml and 10.3 pmol/ml, respectively. Analysis of the empirical data showed that the normal reference uptake value for technetium-99m pertechnetate in the studied population ranged between 0.04% and 2.40%. The fifth and 95th percentiles for pertechnetate uptake were 0.15% and 1.69%, respectively. Conclusion: These results provide new evidence which supports the importance of periodical evaluation of normal thyroid uptake reference values for technetium-99m pertechnetate.
- ItemOpen AccessParathyroid scintigraphy(1990) Jennings, P AThe purpose of this study is not only to describe scintigraphy in parathyroid imaging and the results obtained but also to discuss the merits and limitations of the technique so that its role in today's climate of cost containment, may better be defined.
- ItemOpen AccessRelationship between ¹²³l-metaiodobenzylguanidine (¹²³l-MIBG) imaging findings and outcome in patients with neuroblastoma at the Red Cross War Memorial Children's Hospital(2017) Amoako, Yaw Ampem; Brink, Anita; Mann, Michael DBackground: In neuroblastoma, the presence of distant metastases is associated with a poor prognosis. Aim: To assess the relationship between the findings on ¹²³I-MIBG scan and outcome in patients with neuroblastoma at the Red Cross War Memorial Children's Hospital (RCWMCH). Methods: A single observer reviewed the ¹²³I-MIBG scans and clinical data of patients who had a histologically confirmed diagnosis of neuroblastoma and a baseline ¹²³I-MIBG scan and at least one follow up scan after chemotherapy cycles 4 or 7 between January 2001 and May 2015. Follow up extended to June 2016. Disease burden was assessed using the Curie scoring (CS) method. Results: Thirty four stage 4 patients were included in the analysis. Twenty nine (85%) were older than 12 months, with a median age at diagnosis of 32.5 months (range 6 - 93 months). 62% of primary tumours were located in the adrenal gland and half were NMYC amplified. Twenty (59%) patients died, 90% of deaths occurring in patients older than 12 months. No deaths were recorded in the 13 months after recruitment ended. The baseline CS did not predict outcome (alive or dead) or duration of survival. Patients with CS >2 (n = 5) on the cycle 4 scan had a median survival of 19.5 months compared with 29 months for those with a score ≤ 2 (n = 17, p = 0.88). Patients with a CS > 2 on the cycle 7 scan (n = 7) had a median survival of 28 months compared with 35 months for those with CS ≤ 2 (n = 14, p = 0.93). There was no relationship between the magnitude of the decrease in CS between the baseline and post cycle 4 or 7 scans and outcome. Conclusion: In these 34 high risk patients, the baseline CS and CS at cycle 4 or cycle 7 were not significantly indicative of survival. This is similar to other studies that did not find the pre-treatment score or the post treatment MIBG scan to be a predictor of outcome.
- ItemOpen AccessRenogram Image Characteristics and the Reproducibility of Differential Renal Function Measurement(2019) Brink, Anita; Levin, Mike; Mann, MichaelAim The reproducibility of differential renal function (DRF) estimates on 99mTc-mercaptoacetyltriglycine (99m Tc-MAG3) is good in the majority of children. There is however a small but important group with poor reproducibility which, if not recognized, could affect clinical decision making. Some factors, such as age and glomerular filtration rate (GFR), have been implicated as causes for poor reproducibility. The aim of this study is to formally investigate image characteristics associated with the reproducibility of DRF measurements. Patients and methods The image characteristics and reproducibility of the DRF estimates of the 127 patients in cohort 1 was used to identify the characteristics associated with reproducibility. The associations between these image characteristics and reproducibility were then tested in a second cohort of 227 patients. The DRF measurements were calculated using two internationally accepted methods for calculating DRF, the HERMES area under the curve (HAUC) method and the HERMES Rutland Patlak (HRP) method. The images were visually inspected to categorise the categorical variables and processed to obtain the values of the continuous variables. The variables investigated included two nonimaging variables, age (in months) and GFR which included measured or estimated GFR values. The association between each variable and the reproducibility of DRF measurement for both the HAUC and the HRP methods was tested with univariate linear regression. The results of the univariate linear regression were used to plan the multiple linear regression combinations. All possible combinations were tested with multiple linear regression. Results The goodness-to-fit for the multiple regression models were much higher for all the combinations analysed in cohort 1 than in cohort 2. In cohort 1 the R2 -values ranged from 0.3510 to 0.4906 for log MAXMINHAUC and 0.3284 to 0.4500 for log MAXMINHRP. In cohort 2, they ranged from 0.1675 to 0.2163 for log MAXMINHAUC, and 0.1706 to 0.2191 for log MAXMINHRP. The combinations with the highest R2 -value for multiple linear regression analyses were similar in cohort 1 and 2. The only individual variable which was significant in all the multiple linear regression combinations for cohort 1 and 2 for both log MAXMINHAUC and log MAXMINHRP was LEFT KIDNEY TO BACKGROUND RATIO. RIGHT KIDNEY TO BACKGROUND RATIO, RIGHT RENAL MARGINS WELL DEFINED, RIGHT RENAL MARGINS POORLY VISUALISED and TIME VISUALISATION RIGHT CALYCES were significant in most of the combinations analysed. A high kidney to background ratio, RIGHT RENAL MARGINS WELL DEFINED and higher AGE predicted a good reproducibility. A low kidney to background ratio and later TIME VISUALISATION RIGHT CALYCES predicted poor reproducibility. The variables LEFT RENAL AREA, LEFT BACKGROUND AREA, BOTH RENAL MARGINS SMOOTH and RIGHT RENAL MARGINS IRREGULAR were not-significant in any combinations analysed cohort 1 and 2 for both log MAXMINHAUC and log MAXMINHRP. The remaining variables inconsistently predicted reproducibility in log MAXMINHAUC and log MAXMINHRP for both cohort 1 and 2. Conclusion: The only variables which consistently predicted good and poor reproducibility for the measurement of DRF on 99mTc-MAG3 renograms performed according to the EANM guidelines for both log MAXMINHAUC and log MAXMINHRP were AGE, LEFT KIDNEY TO BACKGROUND RATIO, RIGHT KIDNEY TO BACKGROUND RATIO, RIGHT RENAL MARGINS WELL DEFINED and TIME VISUALISATION RIGHT CALYCES. Consideration should be given to incorporating the kidney to background ratio into the renal processing screen display as a valuable quality control step. The DRF values should be interpreted with caution if the kidney to background ratio is < 2.0.
- ItemOpen AccessThe role of Technetium-99m Sestamibi scintimammography to evaluate palpable breast lesions : a comparison with mammography and histological results(1999) Nizami, Mohammad Athar Farooq; Mann, Michael D; Dent, David Marshall; Adams, Bruce KThis study was conducted with the support of the Combined Breast Clinic at our institution which consists of the Departments of Surgery, Radiology and Radiation Oncology. The work was done in three parts. The literature showed somewhat lengthy imaging procedure for scintimammography which were not whole suitable to the setting of the Combined Breast Clinic. Initially a Pilot Study was conducted to determine the practicality of the imaging procedure. The results of this study were promising but the imaging procedure was time consuming. Certain modifications were subsequently done in the imaging method of the Formal Study to accommodate more number of patients into the study without jeopardizing the quality of the images. This study, however, had a shortcoming in that the way this study was structured one could not demonstrate lesion by lesion analysis of each breast lesion detected on clinical examination, mammography and scintimammography with their respective biopsy results. Our Formal Study and the literature suggested that scintimammography is of value in patients with indeterminate mammograms due to its high negative predictive value. Therefore, a separate Additional Study, with the same scintigraphic method, was conducted on patients with clinical breast lumps with indeterminate mammographic lesions. Special emphasis was placed on lesion by lesion comparison of each breast lesion detected by clinical examination or scintimammography or both with the biopsy results of that particular lesion.
- ItemOpen AccessThe use of lymphoscintigraphy to localise the sentinel lymph node(2005) Korowlay, Nisaar Ahmed; Panieri, EugeneSentinel lymph node (SLN) biopsy is being used increasingly for staging early breast carcinoma in place of complete axillary lymph node dissection. The optimal method to identify the SLN and has not been clearly elucidated in the literature. A number of techniques have been proposed for identifying SLN/s. The main debate centres on whether to use a blue dye or radiopharmaceutical method either singly or in combination.
- ItemOpen AccessThe use of scintigraphy to study gastric emptying, motility and small intestinal transit in patients who have ingested a selection of common poisons(1995) Adams, Bruce Keith; Mann, Michael DPoisoning is common and carries considerable morbidity and mortality. Two to three patients are admitted to the Emergency Unit at Groote Schuur Hospital every day with drug overdose. As absorption occurs in the small intestine the rates at which ingested poisons pass into and through the small bowel are important factors in determining the amount of poison potentially available for absorption. Although the effects of pharmacological doses of many drugs on gastric emptying and motility are known, information on the effects of higher doses is limited. I investigated patients who took overdoses of certain commonly used drugs to determine their effects on gastric emptying and motility and small intestinal transit. The study was divided into two parts. One hundred and four patients were studied in Part 1. These patients took overdoses of tricyclic antidepressants (n = 31), carbamazepine (n = 15), phenytoin (n = 12), paracetamol (n = 29) and opioid-paracetamol mixtures (n = 17). They received standard hospital management of which sorbitol was not a part. Part 2 consisted of sixty-one patients who had sorbitol added to their treatment. These patients had taken overdoses of the tricyclic antidepressants (n = 15), carbamazepine (n = 7), phenytoin (n = 8), paracetamol (n = 13) and opioid-paracetamol mixtures (n = 18). The effects of sorbitol on gastric emptying and small intestinal transit were evaluated. A third study-the paracetamol control test was done on 5 healthy volunteers. Each subject was studied twice; the first time after taking 1 G of paracetamol and the second time after no drug ingestion.