ABSTRACT The main objective of this study was to compare the similarities and differences in MRbased and pseudo CT µ-map generation in PET/MR and radiotherapy respectively. The study sought to look at ways attenuation correction could be done on PET hybrid imaging systems and compare them in various ways so as to improve treatment and patient care. The methodology involved patient selection, image processing and generation of both µmaps for PET-attenuation correction and pseudo CT for radio...
ABSTRACT In this study, the effective dose and its associated cancer risk were estimated for adult patients undergoing the five most common types of CT examinations (head, neck, chest, abdomen and pelvis) at Sweden Ghana Medical Centre (SGMC) in the Greater Accra Region of Ghana. Two main methods were employed in the study: patients’ data collection and phantom measurement to verify the patient data. The effective doses were estimated using the dose length product (DLP) from the control con...
ABSTRACT Low doses of ionizing radiation are delivered to the area of clinical interest in projection radiography. However, the application of digital radiography systems (DRS) is characterized by higher doses than film-screen radiography. Radiation exposure of the pelvis is of primary concern because of the radio sensitive reproductive organs in the pelvic region. For the radiation protection of patients, dose monitoring is essential in pelvic radiography and whenever possible, dose and ima...
ABSTRACT The aim of this study is to estimate the effective dose and assess the lifetime attributable risk of cancer incidence of patients undergoing computed tomography scan at the KorleBu Teaching Hospital. Data on Volume CT Dose Index ( ) and Dose Length Product ( ) displayed on the scanner control console was recorded after confirmation of the results by performing independent checks on a phantom. The effective doses were estimated using the displayed and the anatomic region specific co...
ABSTRACT Quality assurance (QA) in all aspects of radiotherapy reduces the number of instances of accidental dose misadministration. Reduction of such errors and uncertainties plays an important role in the outcome of radiotherapy. As part of the audit supported by the IAEA in Ghana this study was designed to review the whole chain of activities in 3D conformal radiotherapy (3D-CRT) workflow, from patient data acquisition to treatment planning and dose delivery.The study focused on dosimetry...
ABSTRACT The objective of this research is to ascertain if it is feasible to replicate tomotherapy treatment with telecobalt machine based on phantom studies. To replicate gantry motion around a patient during tomotherapy treatment, the phantom was placed on a fabricated turn-table capable of translational and rotational motions while the gantry of the telecobalt machine was kept constant. The treatment simulations were performed with Cirus cobalt 60 teletherapy machine at the Komfo Anokye T...
ABSTRACT The use of beam modifiers in today’s radiotherapy is very important as it attenuates the beam and reduces the dose to the patient; therefore the need to know the amount of attenuation (in terms of a transmission factor) they provide during treatment. The purpose of this research work is to evaluate the variation (or dependence) of the transmission factors (TFs) of block tray and physical wedges (of different angles) as a function of treatment depth and field size using both iso-cen...
ABSTRACT Set-up errors are the inherent features of the radiation treatment process. Coverage of target volume is a direct function of set-up margins, which should be optimized to prevent unintended irradiation of adjacent normal tissues. The aim of this study was to evaluate three dimensional set-up errors and propose optimum margins for target volume coverage in prostate cancer radiotherapy. 1620 Portal images were obtained for an average of 30 fractions per patient for 54 prostate cancer p...
ABSTRACT The main objective of radiotherapy is to increase therapeutic ratio (ratio of tumor control probability to the normal tissue complication probability) with minimal exposure to the personnel. In order to achieve this, the performance of the LINAC must be optimized toobtain the desired treatment result. The data collected on the equipment must be investigated retrospectively and extensively to assess the actual performance to check if it is functioning within the required standard....
ABSTRACT Dose calibrators are used for accurate measurement of radionuclide activity which is required to achieve the desired efficacy for the best clinical outcome. Observations from assayed activity with Capintec and Comecer dose calibrators at the nuclear medicine department of the Korle-Bu Teaching Hospital have indicated that the two systems report significantly different (>10%) readings for the same activity source. Also unusually high background readings (>20% of the mean) have been no...
ABSTRACT The dose to the contralateral breast for tangential breast irradiation has been estimated using Gafchromic films EBT2. The data collected consisted of measurements taken with anthropomorphic female Rando phantom. The EBT2 films were scanned and read using ScanMaker 9800XL plus and ImageJ software. A calibration curve was constructed using fourth – order polynomial fit to the data and a calibration equation was obtained from the graph which was used to convert the grey values into d...
ABSTRACT This study was to examine procedures used to estimate radiation dose delivered to adult and paediatric patients undergoing computed tomography (CT) examination and propose alternative and more efficient ways to establish body CT protocols for optimum protection of patient for clinical use. Automatic exposure control (AEC) and fixed tube current (FTC) techniques were used for Polymethylmethacrylate (PMMA) dosimetry phantoms in a Siemens emotion 16-slice multidetector computed tomograp...
ABSTRACT The aim of this study is to estimate computed tomography (CT) dose levels for common CT examinations in North-Central Nigeria. Dose parameters and scan parameters for the most commonly performed CT examinations (head, chest and abdominal CT scans) were surveyed during a four month period in 4 CT centres with Multislice scanning capabilities (4- 64 slices). Data on CT volume index (CTDIvol) and dose length product (DLP) displayed on scanner console was recorded for a minimum of 10 ave...
ABSTRACT Iodine-125 brachytherapy (BT) sources have gained a wide application in the treatment of prostate and intraocular cancers. Determination of the source strength of I-125 seeds is, therefore, mandatory to ensure accurate and optimal dose delivery to a patient undergoing BT treatment. There is the need to verify source strength stated or provided by a manufacturer of any BT source prior to clinical use of the source in fulfillment of American Association of Physicists in Medicine and Eu...
ABSTRACT The aim of this study was in two to investigate; firstly, (i) location of radiosensitive organs in the interior of four (4) paediatric anthropomorphic phantoms, and, secondly, (ii) effectiveness of single and double bismuth thyroid shields, distance between shield and phantom surface, during paediatric multi-detector computed tomography (MDCT) using fixed tube current (FTC) and automatic exposure control (AEC) on dose reduction and image quality. Four (4) paediatric anthropomorphic p...