Department of Physics

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    EFFECTIVENESS OF THE SHIELDING MECHANISM IN ROOMS HOUSING X-RAY DIAGNOSTIC EQUIPMENTS :A CASE STUDY OF MULAGO HOSPITAL, UGANDA
    (International Journal of Innovative Research in Advanced Engineering (IJIRAE), 2018-02-02) Festo Kiragga; Kisolo Akisophel; Nakatudde Rebecca
    The effectiveness of the shielding against ionizing radiation in controlled and supervised areas of four (4) selected imaging rooms of Mulago hospital was determined. Scattered radiation transmitted to the operator’s console, leakage through the walls and doors to the patient waiting areas was also determined. The effective doses to occupational workers were also determined. The availability and effectiveness of the lead aprons and other protective gears was also investigated. Thermoluminiscent Dosimeters (TLDs) were installed at selected points for a period of four (4) weeks. Radiation leakages to the members of the public were measured using a survey meter, scattered X-ray radiation to staff was measured using TLD badges. The mean scattered radiation in the imaging rooms varied from 1.19 mSv/month in the Computed Tomography (CT) room to 0.38 mSv/month from the Casualty Center (CC). The effective doses to occupational staff were highest in Room 4 (R4) (plain radiography) of 6.8 mSv/yr and lowest in CC at 1.4 mSv/yr. Radiation leakages through selected doors were found to be 18.1 mSv/hr at the Uganda Cancer Institute (UCI). Though there was some leakage, the available shielding was found to be generally effective.
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    Establishment of Computed Tomography Diagnostic Reference Levels on Paediatric Patients in Uganda
    (Journal of Radiation and Nuclear Applications, 2021-08-01) Ayugi. G,; Oruru. B,; Kiragga. F,; Kisembo. H; Kyagulanyi. H
    Paediatric dosimetry in radiation protection when compared with adults is based on radiation sensitivity of children to radiation. Children are known to be at a higher risk of developing radiation-induced cancer. The aim of this study was to determine the radiation doses to paediatric patients during computed tomography procedures (CT) so that a diagnostic reference levels (DRLs) could be proposed. DRLs are useful in high dose examinations such as CT to achieve collective dose reduction. Information about patients, protocol and CT system for 684 patients were recorded during 2019 and 2020 from five CT scanners. The dose was determined in four age groups: 0-1 year, 1-5 years, 5-10 years, and 10-15 years for the head, chest and abdomen protocols. The 75th percentile of CTDIvol and DLP were considered as DRLs and compared with IAEC and Japan DRLs. CT dosimetry software Impact CT patient dosimetry calculator, version 1.0.4 with National Radiation Protection Board SR250 data set, was used to validate and compare scanner generated dose values. DRLs are proposed using CTDIvol (mGy) and DLP (mGy cm). The mean DRL of 43.6 and 922 for the head, 3.0 and 258 for the Chest and 3.1 and 292.5 for the abdomen were established during the study. There was high deviation in head CT doses compared to the reported DRLs in IAEC and Japan. The established DRLs for head were higher than those available in other countries. This study showed the need for harmonization of radiation dose optimization of this protocol.
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    Establishment of Computed Tomography Diagnostic Reference Levels on Paediatric Patients in Uganda
    (NSP: Natural Sciences Publishing Cor., 2021-09-01) Ayugi G 1,*, B. Oruru 1, F. Kiragga 2, H. Kisembo 3 and H. Kyagulanyi 1.
    Paediatric dosimetry in radiation protection when compared with adults is based on radiation sensitivity of children to radiation. Children are known to be at a higher risk of developing radiation-induced cancer. The aim of this study was to determine the radiation doses to paediatric patients during computed tomography procedures (CT) so that a diagnostic reference levels (DRLs) could be proposed. DRLs are useful in high dose examinations such as CT to achieve collective dose reduction. Information about patients, protocol and CT system for 684 patients were recorded during 2019 and 2020 from five CT scanners. The dose was determined in four age groups: 0-1 year, 1-5 years, 5-10 years, and 10-15 years for the head, chest and abdomen protocols. The 75th percentile of CTDIvol and DLP were considered as DRLs and compared with IAEC and Japan DRLs. CT dosimetry software Impact CT patient dosimetry calculator, version 1.0.4 with National Radiation Protection Board SR250 data set, was used to validate and compare scanner generated dose values. DRLs are proposed using CTDIvol (mGy) and DLP (mGy cm). The mean DRL of 43.6 and 922 for the head, 3.0 and 258 for the Chest and 3.1 and 292.5 for the abdomen were established during the study. There was high deviation in head CT doses compared to the reported DRLs in IAEC and Japan. The established DRLs for head were higher than those available in other countries. This study showed the need for harmonization of radiation dose optimization of this protocol.
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    Sales Promotion Strategies, Relationship Management and Channel loyalty: the case of coca-cola Uganda, Gulu Distribution area
    (2022-04) OKWERA DENIS
    This study investigated the association of sales promotion strategies, channel relationship management and channel loyalty with switching cost and trust as intervening variables. The objectives of this study were to; assess the influence of promotion strategies on channel loyalty; to assess the influence of channel relationship management on channel loyalty and finally, to examine the extent to which switching costs and trust affect channel loyalty. Data were collected from Coca-Cola‘s distribution in Gulu city using a descriptive survey design method with closed ended questionnaires. The results show that channel loyalty is not influenced by channel member‘s business interest and the period the member has been in business. The study findings indicated that; sales promotion strategies, channel relationship management, and trusts all have positive and significant effect on channel loyalty though at varying levels except for switching cost, which had no significant impact on channel loyalty. The study therefore recommends the following; to win channel loyalty, manufacturers should strive for lower price products with similar content, better quality, and bigger quantity per unit, but with greater profit margins to the channel members. Due to the rapid decline in the role of switching cost on channel loyalty today, manufacturers should focus on relationship marketing and develop capabilities to implement pull promotion strategy more effectively. To popularize coke studio Africa in Uganda, the management of Coca-Cola Uganda should start a similar program and brand it ‘coke studio Uganda’. This will help them build a nationwide popularity of that program by encouraging local artists from all over Uganda to participate in it then advance to coke studio Africa.
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    Calibration of Various Detectors for Commissioning of Total Body Irradiation for a New Installation in Maggiore Hospital, Trieste-Italy
    (African Journal of Medical Physics, 2023-07-30) Kiragga , Festo; Vidimari , Rosella
    Calibration of detectors: Gafchromic EBT3(GAF) and Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) was done under reference conditions for use in Total Body Irradiation (TBI) conditions. Three Source Axis Distances (SAD) were chosen: 5m, 4.5 m, and 4m with minimal or no backscatter from the wall. Lateral-Lateral (LL), gantry angle 90o, collimator angle 0o, and 6 MV energy were chosen with respect to the nature of the bunker. Percentage Depth Doses (PDDs) were evaluated, first with a big water phantom using calibrated dosimetry diode, P and then also with RW3 slab phantom (30 x 30 x 30 cm3) at the three positions using GAF. Afterwards, the PDDs were then compared allowing the beam to be characterized in different setups. MOSFETs calibration factors corresponding to each channel were also obtained by first measuring the average dose with a Farmer chamber under reference conditions in the same position. Then the MOSFETs were cross-calibrated against the Farmer chamber. A length of 140 cm (pediatric) was found to be in the flatness region with a dose variation of 3%. GAF, and MOSFETs were calibrated and a calibration curve was plotted for GAF while a table of calibration factors was made for the MOSFETs to be used in TBI conditions. A dose variation of less than 2% was achieved between the Farmer chamber and GAF readings at similar points in the RW3 phantom. The beam characteristics were important parameters to understand the behavior of the beam in non-reference conditions (TBI conditions). These were within the tolerance range as dose variations of up to ± 10% are allowed in TBI conditions. The doses measured with the calibrated Farmer chamber and GAF were compared with less than 2% difference and this meant that the GAF can be used in any TBI setup. Therefore, the bunker was found fit for carrying out the TBI technique, particularly for pediatrics.
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    Calibration of Various Detectors for Commissioning of Total Body Irradiation for a New Installation in Maggiore Hospital, Trieste-Italy
    (FAMPO : Federation of African Medical Physics organizations, 2023-07-30) Festo Kiragga 1, Rosella Vidimari 2
    Calibration of detectors: Gafchromic EBT3(GAF) and Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) was done under reference conditions for use in Total Body Irradiation (TBI) conditions. Three Source Axis Distances (SAD) were chosen: 5m, 4.5 m, and 4m with minimal or no backscatter from the wall. Lateral-Lateral (LL), gantry angle 90o, collimator angle 0o, and 6 MV energy were chosen with respect to the nature of the bunker. Percentage Depth Doses (PDDs) were evaluated, first with a big water phantom using calibrated dosimetry diode, P and then also with RW3 slab phantom (30 x 30 x 30 cm3) at the three positions using GAF. Afterwards, the PDDs were then compared allowing the beam to be characterized in different setups. MOSFETs calibration factors corresponding to each channel were also obtained by first measuring the average dose with a Farmer chamber under reference conditions in the same position. Then the MOSFETs were cross-calibrated against the Farmer chamber. A length of 140 cm (pediatric) was found to be in the flatness region with a dose variation of 3%. GAF, and MOSFETs were calibrated and a calibration curve was plotted for GAF while a table of calibration factors was made for the MOSFETs to be used in TBI conditions. A dose variation of less than 2% was achieved between the Farmer chamber and GAF readings at similar points in the RW3 phantom. The beam characteristics were important parameters to understand the behavior of the beam in non-reference conditions (TBI conditions). These were within the tolerance range as dose variations of up to ± 10% are allowed in TBI conditions. The doses measured with the calibrated Farmer chamber and GAF were compared with less than 2% difference and this meant that the GAF can be used in any TBI setup. Therefore, the bunker was found fit for carrying out the TBI technique, particularly for pediatrics.
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    Exploiting the unique interaction characteristics of Neutrons for improved Cancer Therapy: A radiobiological Perspective
    (Elsevier, 2024-01-01) Kiragga, Festo
    Fast neutrons have sufficient energy to liberate recoil protons, alpha particles, and other products when they interact with the nuclei of the target material through scattering and absorption processes. Physical interactions with biological tissues occur mainly with hydrogen nuclei and as the protons interact with the hydrogen in tissues, they create dense ionization chains along their tracks thus depositing energy. Fast neutron therapy was pioneered by Robert Stone in 1938 a few years after the discovery of the neutron. Its main advantage is the limited sensitivity to hypoxia and treatment of slow-growing tumors hence better local control. This is where photon therapy has yet to have much success. Energy deposition by fast neutrons in living tissues is higher than in conventional radiotherapy using mega voltage (MV) photon beams. This higher energy deposition gives fast neutrons a higher relative biological effectiveness (RBE) in dealing with certain tumors. Fast neutrons also have a higher linear energy transfer (LET) and can reach deep-sited tumors better than photon therapy. The main challenge with Fast neutron therapy has been extreme toxicity in late-reacting tissues. Overall, fast neutron therapy holds potential for the treatment of certain tumors by leveraging the unique interaction characteristics of fast neutrons with biological tissues. This review therefore intends to bring this uniqueness to light to enhance the understanding of the radiobiological properties of fast neutrons and the advantages associated with its therapy
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    Budgetary Controls and financial performance of Manufacturing Companies in Uganda: A case study of Soroti Fruit Limited
    (Gulu University, 2024-12-22) DANIEL IKOBA
    Budgetary control plays crucial role in improving performance of an enterprise. This study investigated the effect of budgetary control on financial performance of manufacturing companies; the case of Soroti Fruits Limited. The objectives of the study were: to examine the budgetary control practices; to assess the level of financial performance; to examine the effect of budgetary controls on financial performance and to determine the moderating effect of business culture on the relationship between budgetary control and financial performance. The study used cross-sectional research design with a quantitative approach. Data was collected from 103 respondents using questionnaire and analysis was conducted using descriptive and inferential statistics with the help of SPSS Version 25.0. Study result revealed a moderate level of implementation of all the elements of budgetary control measures and average level of financial performance. The study revealed a strong significant relationship between all the dimensions of budgetary control and financial performance; cost allocation and variance analysis significantly affect financial performance. Finally, business culture has a significant moderation effect on the relationship between budgetary control and financial performance. The study concluded that: Cost allocation and variance analysis play pivotal roles in influencing Soroti Fruits Limited’s financial performance; and that business culture influences the role that budgetary control play in enhancing the financial performance. The study recommended that: measures to improve financial performance should focus cost allocation and variance analysis; Soroti Fruits Limited should cultivate a supportive and adaptive organizational culture that aligns with its budgetary control practices.