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Item Exploiting the unique interaction characteristics of Neutrons for improved Cancer Therapy: A radiobiological Perspective(Elsevier, 2024-01-01) Kiragga, FestoFast 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 therapyItem 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.Item 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 , RosellaCalibration 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.Item 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. HPaediatric 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.