Browsing by Department "Department of Radiation Medicine"

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    Open Access
    Comparison of 18F-Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (18F-FDG PET/CT) and conventional imaging (CI) for locally advanced breast cancer staging: a prospective study from a tertiary hospital cancer centre in Western Cape
    (2019) Chilwesa, Paul Mambwe; Parkes, Jeannette
    Background: Breast cancer is the second most common cancer in adults and the most frequent cancer diagnosed in women. In South Africa, breast cancer accounts for 38.5% of cancers diagnosed in women. Since the presence, extent and location of distant metastases is one important prognostic factor in locally advanced breast cancer (LABC), accurate staging at diagnosis is crucial to ensure patients receive the appropriate treatment. Increasing evidence shows that the use of 18F-FDG PET/CT for disease staging of LABC may improve diagnostic sensitivity. Aim: To prospectively assess the difference in diagnostic accuracy between whole-body PET/PET-CT and conventional imagine (CI) for staging LABC. Methods: A total of 42 participants with clinical stage III and a select few stage II breast cancer underwent both 18F-FDG PET/CT and CI. Results: 18F-FDG PET/CT found significantly more (p=0.0077) distant metastatic sites than CI (36% vs. 21%). 18F-FDG PET/CT upstaged 9 (21.4%) of patients from clinical stage IIIa to stage IIIc, and changed management of 54% of patients. Thirty-eight percent (38%) of the patients had their clinical stage unchanged. One of 5 suspected metastatic sites 18F FDG PET/CT was positive for malignancy on biopsy. Conclusion: The 18F-FDG PET/CT is useful for staging locally advanced non-inflammatory infiltrating ductal carcinoma of the breast. Use of 18F-FDG PET/CT was superior to conventional imaging in assessing metastatic mediastinal lymphadenopathy, but with a poor specificity. The use of 18F-FDG PET/CT in LABC is useful, with the biopsy of isolated suspicious lesions for metastasis increasing its accuracy.
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    Open Access
    CT angiogram findings in patients presenting with mechanical strangulation and near hanging injuries
    (2019) September-Jaffer, Zorina; Candy, Sally
    Background: Blunt cerebrovascular injury (BCVI) is relatively uncommon in near-hanging and strangulation injuries but may have devastating neurological outcome. In developed countries, CT angiography (CTA) of the head and neck is performed as a screening tool in the acute clinical setting. This study was undertaken to assess the prevalence of vascular injury in patients presenting acutely to GSH trauma unit with these injuries and to recommend guidelines to ensure rational use of CTA in our resource restricted environment. Aim: 1. To assess the prevalence and nature of vascular injury in patients referred for CTA imaging following strangulation or hanging injury at our institution. 2. To determine if international criteria (modified Denver Criteria) for CTA referral for suspected BCVI due to strangulation or hanging injuries are followed at our institution. 3. To determine if international criteria for CTA imaging following suspected BCVI are appropriate following strangulation or hanging in a resource-restricted environment, and to identify aspects of existing protocols that may require future discussion. Method: This is a retrospective, quantitative, cross-sectional review of patients who had CTA studies after presenting with either strangulation or hanging to an urban Level 3 Trauma Unit. Radiological reports for the 45-month period ranging from January 2013 until September 2016 were reviewed and the frequency of positive findings was recorded. Results: 45 patients met the inclusion criteria after presenting with a history of strangulation (n=8) or hanging (n=37). The average age was 31 years, 73% were male, 18% presented with strangulation injuries and 82% presented after hanging. 82% received a non-enhanced CT head scan and all patients had CTA scans of the neck and head. Six (13%) vascular injuries were reported on CTA (2 arterial and 4 venous). Both arterial injuries were reported in the strangulation group and none after hanging (p < 0.05). Two venous injuries were reported in each group). No base of skull, cervical spine or Le Fort facial fractures were demonstrated and there was no correlation between nadir of GCS and the presence of vascular injury on CTA. Conclusions: In this study comparing BCVI in strangulation and hanging, arterial injury was reported only in patients presenting after strangulation. Although such injury may be partially attributable to other co-existing mechanisms of trauma we support the continued use of CTA screening in the setting of strangulation injury in a resource restricted environment. The absence of arterial injury in the setting of near-hanging, however, argues against routine screening CTA screening even in patients with depressed level of consciousness.
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    Open Access
    Dual energy window imaging for optimisation of P/V ratios in VP SPECT
    (2021-10-16) Doruyter, A G G; Holness, J L
    Purpose Ventilation–perfusion single-photon emission computed tomography (VP SPECT) plays an important role in pulmonary embolism diagnosis. Rapid results may be obtained using same-day ventilation followed by perfusion imaging, but generally requires careful attention to achieving an optimal count rate ratio (P/V ratio) of ≥ 3:1. This study investigated whether the ratio of counts simultaneously acquired in adjacent primary and Compton scatter energy windows (Eratio) on V SPECT was predictive of final normalised perfusion count rate (PCRnorm) on P SPECT using [99mTc]Tc-macroaggregated albumin (MAA), thus allowing for optimisation of P/V ratios. Methods Same-day VP SPECT studies acquired using standard protocols in adult patients during a 2-year period (training dataset) were assessed. Studies were included provided they were acquired with correct imaging parameters, and injection site imaging and laboratory records were available for quality control and normalised count rate corrections. Extraction of DICOM information, and linear regression were performed using custom Python and R scripts. A predictive tool was developed in Microsoft Excel. This tool was then validated using a second (validation) dataset of same-day studies acquired over a subsequent 7-month period. Accuracy of the prediction tool was assessed by calculating the mean absolute percentage error (MAPE). Results Of 643 studies performed, the scans of 342 participants (median age 30.4 years, 318 female) were included in the training dataset, the analysis of which yielded a significant regression equation (F(1,340) = 1057.3, p < 0.0001), with an adjusted R2 of 0.756 and MSE of 0.001089. A prediction tool designed for routine clinical use was developed for predicting final P/V ratio. Of an additional 285 studies, 198 were included in the second (validation) dataset (median age 29.7 years, 188 female). The Excel-based tool was shown to be 91% accurate (MAPE: 9%) in predicting P/V ratio. Conclusion The relationship between the ratio of simultaneously acquired counts in adjacent energy windows on V SPECT and perfusion count rate after administration of a known activity of [99mTc]Tc-MAA can be linearly approximated. A predictive tool based on this work may assist in optimising the dose and timing of [99mTc]Tc-MAA administration in same-day studies to the benefit of patients and workflows.
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    Open Access
    Efficacy of single fixed dose of radioiodine (I-131) therapy in patients with hyperthyroidism at Groote Schuur Hospital
    (2019) Isah, Ahmed Rufai; Kotze, Tessa
    Aim: The aims of this audit were: To determine the proportion of hyperthyroid patients receiving I-131 therapy in whom treatment with a single fixed dose was successful, as defined by the achievement of euthyroidism or hypothyroidism 6-months after the therapy; To identify patients in whom treatment was not successful and a second dose needed; And, if possible, to establish the factors associated with treatment failure. Methods: A single observer reviewed the records of all patients who received I-131 therapy for hyperthyroidism between 23rd April 2010 and 23rd November 2017 in conjunction with their pre and post treatment thyroid function tests. Results of their thyroid ultrasound were retrieved and documented. The images of their Tc-99m sodium pertechnetate thyroid scans were also retrieved and reprocessed. Results: The records of 409 patients treated between April 2010 and November 2017 were retrieved. 223 (63%) patients were referred by the endocrine clinic at Groote Schuur hospital (GSH. Of the 409 patients, 56 (14%) patients that were excluded because their post therapy records were not available for analysis. Majority of our patients were females 310 (88%). Patients between the ages of 15 and 45 years are more likely to present with Grave’s disease while those aged more than 45 years presented with toxic multinodular gland (p=0.000). Patients that presented between the ages of 15 and 45 years are more likely to have moderately increased pretreatment FT4 (12-51 mmol/L) (p=0.002). We administered a radioiodine therapy dose of 456.6±54.8 MBq (Mean ± SD) to these 409 patients. Among the 353 patients, with complete records, 314(89%) achieved cure at some stage after receiving one dose of RAI; 239(76%) achieving cure ≤ 6 months of therapy and 75(24%) patients after 6 months. In our audit the patients who failed to achieve cure following the first RAI therapy appeared to be younger (median(interquartile range) age 39(16), p= 0.03), have severe hyperthyroidism as demonstrated by higher pre-treatment FT4 (median(interquartile range) 27 pmol/L(30.6), p= 0.05) and high pertechnetate uptake (median(interquartile range) uptake 9.9%(14), p= 0.002) on thyroid scintigraphy. CONCLUSION Our audit showed RAI therapy was found to be successful in 68% of patients at 6 month and 89% at a year. A second therapy with radioactive iodine would be indicated in 32% of patients, as these patients have not achieved cure at 6 months. Patients presenting with severe thyrotoxicity are likely to require more than one RAI therapy. Due to major deficiencies in referral, record keeping and follow up, other factors responsible for treatment were not be able to be evaluated. Based on these findings, suggested areas for further research are: should patients with severe hyperthyroidism be considered for pretreatment with antithyroid medication prior to RAI; would a one year follow up after radioiodine therapy be considered before second RAI. Now that the deficiencies in our current practice have been identified and suggestions put forward to address these deficiencies, a follow up audit would be needed.
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    Open Access
    Emergency room arteriography: An updated digital technology
    (2007) Ball, C G; Moodley, S; Beningfield, S J; Navsaria, P H; Nicol, A
    Background: Emergency room arteriography (ERA) is a safe, accurate, simple and costeffective method of defining arterial injuries. Limitations include the difficulty of evaluating limb vasculature distal to the suspected site of injury. Statscan is a novel, low-dose digital X-ray machine that can rapidly obtain a whole body image inasingle scan. Our goal was to evaluate the role of Statscan technology in ERA. Methods: A 24 month retrospective review of all patients who underwent a Statscan assisted ERA at the Groote Schuur Hospital Trauma Unit was completed. Indications for ERA included a hemodynamically stable patient with hard signs of a vascular injury in conjunction with the clinical assessment of a threatened limb. Contraindications encompassed instability, massive bleeding or a rapidly expanding hematoma. Results: Ten patients underwent Statscan assisted ERA of their lower limbs. Eight had cold, pulseless limbs with impaired neurological examinations. Common femoral, superficial femoral and popliteal artery lacerations were displayed. Three patients had no identifiable injury and were observed. Seven patients underwent operative management for threatened limbs. Two had Statscan evidence of arterial emboli distal to the site of injury leading to further exploration and distal embolectomy. Conclusions: Statscan ERA is safe, rapid, simple and accurate. It has the advantage of providing arteriography distal to the site of injury. This directly altered patient care in 20% of cases, primarily by detecting distal arterial emboli. Thirty percent of patients with normal ERA also avoided an unnecessary operation. This study demonstrates a new role for Statscan technology.
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    Endovascular treatment of post-traumatic carotid-cavernous fistulae using latex detachable balloons
    (2005) Szkup, P; Beningfield, S
    Objective. To determine the efficiency of latex detachable balloons in the treatment of post-traumatic carotid-cavernous fistulae (CCF). Methods. Management and outcome were reviewed for 34 consecutive patients with post-traumatic CCF personally treated by one of the authors (PS) using latex detachable balloons during the 4-year period 1996 - 2000. Results. Endovascular embolisation of 34 CCFs was attempted in 33 patients. In 1 patient where the fistula was a result of rupture of an intracavernous aneurysm, the fistula thrombosed spontaneously before embolisation was attempted. In the 33 treated patients, the fistula was occluded in 30 cases (91%). Patency of the internal carotid artery was preserved in 16 cases (53%). Conclusion. A high percentage (91%) of direct CCFs were successfully occluded with latex detachable balloons. There were no permanent neurological complications in any of the patients treated.
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    Mitochondrial dynamics in the radiation response of cancer cells
    (2017) Parker, Michelle; Hunter, Alistair
    Mitochondria are involved in the regulation of key cellular processes that determine the response of cells to damage. Mitochondrial fission and fusion are associated with cell cycle regulation, apoptosis, cellular bioenergetics and redox status, which contribute to cellular homeostasis and damage response. The study aimed to describe and correlate cancer cell mitochondrial features and inherent radiosensitivity, and to determine the effect of modulation of mitochondrial dynamics on radiation response using a fission inhibitor, Mdivi-1. Methods: Mitochondrial status in a number of cancer cell lines was characterised by assessment of mitochondrial morphology, respiration and membrane potential using MitoTracker® Red staining, respirometry and JC-1 ratiometric staining, respectively. Correlations with radiation sensitivity were performed. Radiation- and Mdivi-1-induced changes in mitochondrial morphology were also examined. Responses to various schedules of radiation and Mdivi-1 treatment were assessed using clonogenic survival. Microscopy was used to quantify apoptosis, micronuclei and mitotic features, while cell cycle dynamics were analysed using flow cytometry. Results: Notably, modulation of mitochondrial fission using Mdivi-1 significantly increased radiation response in A549 cancer cells. Mdivi-1 reduced fragmentation, increased membrane potential and induced cytotoxicity, cytogenetic damage, apoptosis and G2/M cell cycle arrest. However, with the exception of survival, sub-additive responses were consistently observed when Mdivi-1 was combined with radiation. Sub-lethal damage repair was unaffected by Mdivi-1. Characterisation of cancer cell lines revealed inherent diversity in radiation response and mitochondrial morphology, membrane potential and respiration, and several correlations were identified. Discussion and conclusions: Inhibition of mitochondrial fission was shown for the first time to enhance radiosensitivity in cancer cells, and to induce cytotoxicity. Mitochondrial modulators may therefore have therapeutic application. However, the sub-additive responses observed with Mdivi-1-radiation interactions suggest that optimisation of treatment scheduling may be important. The Mdivi-1-induced mitotic arrest may, in part, be responsible for the observed radiosensitisation, as cells accumulate in a radiosensitive cell cycle phase. In addition, the finding that Mdivi-1 treatment induced micronuclei suggested that the radiosensitisation may result from the interaction of cytogenetic damage induced by each agent. Overall, mitochondrial dynamics appears to significantly influence radiation response.
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    The conclusions drawn from ventilation/perfusion single photon emission computed tomography (SPECT) compared to lung perfusion SPECT and a chest x-ray (CXR) in patients with suspected pulmonary pulmonary thromboembolism
    (2018) Abubakar, Sofiullah; Kotze, Tessa; Mann, Mike D
    Purpose: There are conflicting results from studies on whether the ventilation (V) scintigraphy can be safely omitted or replaced by a chest x-ray. These studies were based on planar ventilation perfusion (V/Q) scintigraphy. We evaluated the value of the V single photon emission computed tomography (SPECT) on the final conclusion drawn from a V/Q SPECT and the possible role of the chest x-ray as a surrogate for the V SPECT. Methods Raw data of V/Q SPECT images and chest x-ray acquired within 48 hours over 18 months period were retrieved, reprocessed and reviewed in batches. The V SPECT, Q SPECT and chest x-ray were reviewed separately and in combination. Data on the presence and character of defects and chest x-ray abnormalities were recorded. The V/Q SPECT images were interpreted using the criteria in the EANM guideline and the Q SPECT and chest x-ray images were interpreted using the PISAPED criteria. Agreement between the diagnosis on the V/Q SPECT review and the Q SPECT and chest x-ray review was analysed. Results 21.1% of the patients were classified as 'PE present’ on the V/Q SPECT review whereas 48.9% were classified as 'PE present’ on the Q SPECT and chest x-ray review. Only 5.4% of defects seen on V SPECT had matched chest x-ray lung field opacity. Conclusion Our study showed that the omission of a V SPECT led to a high rate of false positive diagnoses and that the ventilation scan cannot be replaced by a chest x-ray.