OAR@UM Collection:

The use of transcutaneous electrical stimulation of the calf undergoing infra-inguinal bypass surgery.

2020-11-10T06:57:28Z

Title: The use of transcutaneous electrical stimulation of the calf undergoing infra-inguinal bypass surgery. Abstract: 1.1. Objective Infrainguinal bypass surgery is frequently associated with significant post reperfusion oedema of the limb. This may lead to surgical wound complications as well as limit the patient's early postoperative mobility. We conducted a prospective randomised controlled trial to evaluate whether the application of electrical calf muscle stimulation in the first postoperative week after infrainguinal bypass surgery reduces lower limb swelling of reperfusion oedema and improves venous and arterial flows at one and six weeks post-operatively. 1.2. Methods Forty consecutive patients over a one-year period who were due to undergo infrainguinal bypass for critical lower limb ischaemia were recruited and randomly divided into the control, who received the current standard of care, and study group, who received electrical calf muscle stimulation for a one-hour session twice daily for the first post-operative week via the use of a standard CE marked device. Pre-operatively, at one-week post-operatively and again at six weeks post-operatively, the limb was measured using a tape measure at three predetermined sites and an arterial and venous ultrasound scan performed with measurement of peak systolic velocities and flow volumes measured. 1.3. Results The control and study groups were well matched for age, side and type of surgery, and all tested risk factors and relevant treatment (all P > .05). The mean age was 72.75 years and 70.95 years in the control and study group respectively. In both groups, the predominant surgical procedure was a femoral to below knee popliteal bypass using ipsilateral long saphenous vein. At one week, the below-knee girth and calf girth were significantly less in the study group (P = .025 and P = .043 respectively). Venous flow volume at rest and venous flow volume on stimulation were significantly more in the study group (P = .01 and P = .029 respectively). At six weeks, the below knee girth remained significantly less in the study group (P = .011). Description: M.SC.by Research

Ultrasound technology for controlling the food safety and quality of fresh produce

2017-10-10T10:09:51Z

Title: Ultrasound technology for controlling the food safety and quality of fresh produce Abstract: Fresh produce contain bioactive compounds with diverse beneficial health effects. Due to the consumers’ awareness about these health benefits, consumption of fresh produce has increased. However, this has been accompanied by an increase in food-borne illnesses since fresh produce, apart from having a relatively short shelf-life; it also favours the growth of pathogenic food-borne microorganisms. Thus, the demand for novel technologies that enhance food safety of fresh produce has increased with time. Furthermore, consumers also demand the use of methods that avoid the use of chemicals and have a lower impact on the nutritional content and quality of food. The objective of this research was to assess the effect of ultrasound as an alternative decontamination technology on selective chemical (peroxidase, POD and pectin methylesterase, PME enzymes) and nutritional (polyphenols and vitamin C) properties of Romaine lettuce and yellow bell pepper. For this purpose a number of different experimental protocols were assessed and further improved to achieve reproducible and accurate measurements of these chemical and nutritional indices following the application of ultrasound. This was implemented so as to decide on the optimal ultrasound treatment parameters whereby the quality of the fresh produce was not affected if it had to be used as an alternative decontamination technology. PME and POD were present at a low concentration in yellow bell peppers. In lettuce, the most effective treatment to reduce PME activity was US 5 min continuous while in the case of POD, none of the applied ultrasound treatments significantly reduced POD activity. All ultrasound treatments reduced the total polyphenol content in lettuce, therefore, it can be concluded that the investigated ultrasound processes are not suitable to treat lettuce in terms of their effect on total polyphenol concentration. In bell peppers, the ultrasound process which caused the least reduction was ultrasound applied for 5 min continuous. Vitamin C in lettuce appeared to be present in insignificant levels. In bell peppers, the ultrasound process which caused the least degradation of vitamin C was ultrasound applied for 5 min continuous. When considering all the four analysed food quality indices, in the case of bell peppers, ultrasound applied for 5 min continuous was the best process since it caused the least reduction in both polyphenol content and vitamin C. However, in the case of lettuce, further research is required related to the application of ultrasound treatment since, only in the case of PME, conclusive results were obtained in favour of ultrasound application. It can be concluded that ultrasound is a decontamination technology that has the potential to be implemented in the fresh produce industry and needs to be further investigated with respect to different food products and a number of critical quality indices. Description: M.SC.FOOD STUD.&ENV.HEALTH

Adapting planning strategies for cervix brachytherapy to reduce the dose to the vagina

2017-07-18T09:56:43Z

Title: Adapting planning strategies for cervix brachytherapy to reduce the dose to the vagina Abstract: Background: The implementation of Image-guided Brachytherapy (IGBT) to treat cervical cancer has improved delineation of the target structures and Organs At Risk (OARs) to provide a more conformal and individualised treatment for patients. A European study on MRI guided brachytherapy in locally advanced cervical cancer (EMBRACE) is assessing the impact of IGBT in a multi-institutional setting. Findings of the EMBRACE study demonstrate that vaginal morbidity is common and may e ect the patients' Quality Of Life (QOL). Vaginal dose parameters still need to be de ned; only few studies have looked at this in detail. Objectives: To recommend the most appropriate planning strategy for IGBT of the cervix that conforms to all current planning aims and provides the greatest vaginal dose sparing. Research Design: Fifteen patients that were previously treated for cervical carcinoma with a Computed Tomography (CT)/Magnetic Resonance Imaging (MRI) compatible tandem-ring applicator were chosen. Five patients were randomly selected from the aforementioned sample. Di erent methods were investigated on these ve patients to model appropriately the dose to the vagina. These methods include vaginal points and volumetric dose parameters. Di erent planning strategies such as the clinically delivered plan, standard Manchester plan, conformal plan with modi ed applicator dwell time and positions and the Inverse Planning Simulated Annealing (IPSA) algorithm were applied on the ve patients and the best treatment plan in reducing the dose to the vaginal wall was applied to the rest of patients. The best vaginal dose reporting method and planning strategy were implemented for the rest of the patients and the resulting dose parameters were compared to the ones resulting from the clinically delivered plan. Finally, an investigation was done to determine whether vaginal morbidity including mucositis, stenosis, dryness and bleeding can be correlated with vaginal dose. Results and Conclusions: From this study it was concluded that the vaginal Dose Volume Histogram (DVH) parameters for the vaginal wall are inaccurate due to contouring uncertainties. On the other hand the vaginal dose points presented in this study provide a good dose representation throughout the vagina and can easily be used clinically in the near future. The best planning strategy in reducing the vaginal dose whilst maintaining the current planning aims was found to be the manual conformal plan. It kept the target coverage and dose to the bladder, rectum sigmoid and small bowel within dose constraints while it reduced vaginal dose by 42.34 %, 30.28 %, 33.71 %, 28.00 % and 24.21 % at the vaginal ring surface, the transition zone between middle and upper vagina, the anatomical mid-vagina, the transition zone from the lower and middle part of vagina and the vaginal introitus respectively. No correlation could be demonstrated between brachytherapy vaginal dose and vaginal morbidity in this small sample of patients used in this study. Description: M.SC.MEDICAL PHYSICS

A comparison of SNR of two generations of Siemens 1.5T MRI scanners and their associated RF phased array coils

2017-07-24T08:43:00Z

Title: A comparison of SNR of two generations of Siemens 1.5T MRI scanners and their associated RF phased array coils Abstract: Background: The hospital where this study was carried out is in possession of two whole-body MRI Siemens scanners (Siemens Magnetom Aera (2012) and Siemens Magnetom Avanto (2007), Erlangen, Germany). Both machines have field strength of 1.5T but have significant differences between them, namely: the bore size, field of view restrictions and radio frequency receive coils. Despite these differences, the two machines are currently being operated using the same protocol which indicates that the latter may not be optimised for both scanners. Objectives: The primary purpose of this study was to measure and compare Signal to noise ratio (SNR) and SNR uniformity of the two systems. A second objective was to evaluate the different methods of SNR measurement found in MRI literature. Research Design: SNR measurements were carried on spin echo (SE) images using the head coils and combination of body-spine coils. SNR evaluation was carried out on region-of-interests (ROIs) on both phantom and anonymised patient images. The American College of Radiology (ACR) phantom and five cylindrical fluid filled phantoms provided by the manufacturer were used to obtain phantom images. For patient images, neurological and prostate images were used for evaluation of SNR. Different approaches of SNR measurement were compared in phantom measurements with the gold standard multiple-acquisition method (MAM). In patient images only single-image methods could be applied. Results: Deviations from the gold standard were noted. For the head phantom measurements, the Aera produced higher SNR than the Avanto with the highest being 166% and lowest 131%. For the body phantom, SNR values from the Aera were again higher, the highest being 132% and lowest 103%. In general, t-testing indicated that the Aera produces significantly (P<0.05) higher SNR than the Avanto for various ROIs on patient images. Conclusions and recommendations: The Aera scanner produced higher SNR than the Avanto for both phantom and patient images. Based on the assumption that the Avanto SNR is adequate, it is recommended that the increased SNR of the Aera should be used to optimise scanning protocols allowing shorter scan times or improvements in resolution. Description: M.SC.MEDICAL PHYSICS