ABSTRACT In radiotherapy, a patient may present irregular surface contour at the point of beam entry and this coupled with tissue heterogeneities within the irradiated region would pose problems for dose optimization if beam modifiers are not used. Skin dose is of great concern in external beam radiotherapy with megavoltage beam as the skin is very radiosensitive, and there is the need to minimize the radiation dose received by the skin. The use of beam modifiers affects the skin dose and t...
ABSTRACT The Mean Glandular Dose (MGD) was estimated first using Polymethylmethacrylate (PMMA) slabs and secondly MGD was estimated per right craniocaudal (RCC) projection view and left craniocaudal (LCC) projection view. A number of 21 patients out of a total of 28 patients, undergoing breast examination in three (3) selected mammography facilities in the Republic of Benin were involved. Image quality was evaluated based on subjective analysis of images with Leeds Tests Objects and American ...
ABSTRACT Fusion of medical images between different cross-sectional modalities is widely used, mostly where functional images are fused with anatomical data. Ultrasound has for some time now been the standard imaging technique used for treatment planning of prostate cancer cases. While this approach is laudable and has yielded some positive results, latest developments have been the integration of images from ultrasound and other modalities such as PET-CT to compliment missing properties of u...
ABSTRACT During external beam radiotherapy treatments, high doses are delivered to the cancerous cell. Accuracy and precision of dose delivery are primary requirements for effective and efficient treatment. This leads to the consideration of treatment parameters such as percentage depth dose (PDD), tissue air ratio (TAR) and tissue phantom ratio (TPR), which show the dose distribution in the patient. Nevertheless, tissue air ratio (TAR) for treatment time calculation, calls for the need to m...
ABSTRACT This research study was aimed at performing dosimetry intercomparison on different CT scanners in the diagnostic radiology departments of Korle-Bu Teaching Hospital (KBTH), Sweden Ghana Medical Center (SGMC) and Global Medical and Imaging Center (GMIC).Using the standard body phantom and integrated ion chamber technique volume computed tomography dose index (CTDIvol) and Dose-Length Product (DLPs) within the phantom were evaluated. The ion chamber technique was applied to two 16 slic...
ABSTRACT The purpose of this research work is to evaluate the variation (or dependence) of the timer error as a function of the teletherapy treatment parameters such as treatment field size (FS) and treatment depth (d) for a SSD setup and compare the method used for others. Teletherapy timer error measurements were performed in a full scatter, large water phantom using a 0.6cc ionization chamber and an average photon energy of 1.25MeV from a cobalt-60 unit at an SSD of 100cm at various field...
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 This study investigates into the second cancer risks to the bladder and rectum during Three-Dimensional Conformal Radiotherapy Treatment (3D-CRT) of prostate cancer compared to the baseline cancer risks in literature. The risk of induced-radiation cancer related with radiation treatment for patients with prostate cancer is of great importance in clinical radiation oncology. Therefore, the dose response relationship to predict radiation-induced secondary cancers was modeled for locali...
ABSTRACT The primary aim of this work was to propose local diagnostic reference levels for fluoroscopic examinations in some selected radiological imaging facilities in Ghana. The work also aimed at investigating the distribution levels of patient radiation dose received during fluoroscopic examinations for subsequent improvement of optimization. Prior to the starting of this research a series of quality control tests were performed using the Piranha kit to assess the machine output. The pati...
ABSTRACT For external beam radiotherapy treatments, high doses are delivered to the cancerous cell. Accuracy and precision of dose delivery are primary requirements for effective and efficient cancer treatment. The dose delivered to the patient might not be uniform and therefore need to be compensated for. In treatment these inhomogeneities are taken care of by using wedge filters and incorporating wedge factors in the Treatment Planning System. Computer controlled wedges were alternatives in...
ABSTRACT This study was performed to evaluate surface doses and the effect of air gaps under bolus on surface dose during external beam radiotherapy for photon beam energies of 6 MV and 15 MV. Surface doses were measured by using calibrated GafChromic EBT3 films and the Roos chamber for various bolus-to-surface distances (including no bolus and bolus placed directly on the RW3 phantom surface) and various field sizes. Dose verification was also done for beam energies of 6 MV and 15 MV on the...
ABSTRACT Radiotherapy is a complicated procedure with several steps, and these procedures have a great influence on the treatment outcome. Exact determination of dosimetric functions that are used to calculate dose within a patient undergoing external beam radiotherapy to realize the intent of treatment is very crucial for any radiotherapy treatment technique. One of the dosimetric functions, which is of great importance, is central axis percentage depth dose, which are usually measured with ...
ABSTRACT Verification of the output of a treatment planning system (TPS) is considered to be part of quality assurance (QA) requirement for the TPS and need to be performed during commissioning and annually, but this is not given the needed priority due to non availability of appropriate phantoms to facilitate the process. Phantoms with heterogeneities that can simulate clinical situations are needed to assess the performance of TPSs. This research work sought to design and construct such a...
ABSTRACT Weighted and average dose within a scan volume of a phantom have been evaluated and validated using two different devices and techniques. The Barracuda electrometer and Ion Chamber techniques were applied on a 16 slice Siemens CT scanner and the results compared to the console displayed CTDIw and CTDIvol valuesfor accuracy and compared to each other for validation purposes. With fixed exposure parameter of 130kVp and varying tube current-time products from 140mAs to 300mAs for the ...
ABSTRACT The use of X-ray equipment in diagnostic radiography increases with demographic growth of population and Benin is not an exception. Achieving good quality image while keeping workers, public and patient exposure to ionizing radiation at an acceptable level has become a prerequisite for radiology department in their effort to comply with radiation protection principle of optimization. The present research work undertook quality control measurement of seven diagnostic radiography equip...