Humans are constantly exposed to different types of radiations. It has been suggested that low dose and low dose rate of γ-radiation as well as ultra violet A (UVA) induce oxidative stress in cells that may promote mutations. The mechanisms behind radiation-induced oxidative stress and its relation to genotoxicity and cancer induction are not well understood. In the majority of investigations, the DNA molecule has been studied as the target for mutations, however the results obtained in our group point out that DNA bases in the cytoplasm could also be a significant target. MTH1 and MYH are two of the key proteins of the repair pathway that prevent mutations arising from oxidized DNA bases. In this thesis, we studied the role of MTH1 and MYH in genotoxicity of UVA and γ-radiation. The adaptive response to low dose rates of γ-radiation was also investigated. MTH1 and/or MYH were knockdown in human lymphoblastoid TK6 cells. The clonogenic survival, mutant frequency and chromosomal aberration assays were performed following UVA or γ-radiation exposure. Our results indicated that acute exposure to UVA or γ-radiation affects cell survival and also increases the mutant frequency above the background. The mutant frequency in MTH1 deficient cells was higher than that in wild types after UVA exposure. Following γ-radiation exposure, a higher mutant frequency was observed in the MYH and MTH1 deficient cells, in comparison to either MYH or MTH1 deficient or wild type cells. No dose rate effect of γ-radiation for mutations was observed. An adaptive response to γ-radiation was observed at the mutation level in MCF-10A cells but not at the survival level. In summary, our results suggest that; a) MYH and MTH1 cooperatively protect cells against genotoxic effects of γ-radiation; b) MTH1 protects cells from UVA-induced mutations; c) low dose rates of γ-radiation may induce an adaptive response at the mutation level; d) there is no dose rate effect for γ-radiation at the mutation level. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript.</p>

A novel optical calorimetry approach is proposed for the dosimetry of therapeutic radiation, based on the optical technique of Digital Holographic Interferometry (DHI). This detector determines the radiation absorbed dose to water by measurement of the refractive index variations arising from radiation induced temperature increases. The output consists of a time series of high resolution, two dimensional images of the spatial distribution of the projected dose map across the water sample. This absorbed dose to water is measured directly, independently of radiation type, dose rate and energy, and without perturbation of the beam. These are key features which make DHI a promising technique for radiation dosimetry. A prototype DHI detector was developed, with the aim of providing proof-of-principle of the approach. The detector consists of an optical laser interferometer based on a lensless Fourier transform digital holography (LFTDH) system, and the associated mathematical reconstruction of the absorbed dose. The conceptual basis was introduced, and a full framework was established for the measurement and analysis of the results. Methods were developed for mathematical correction of the distortions introduced by heat di usion within the system. Pilot studies of the dosimetry of a high dose rate Ir-192 brachytherapy source and a small eld proton beam were conducted in order to investigate the dosimetric potential of the technique. Results were validated against independent models of the expected radiation dose distributions. Initial measurements of absorbed dose demonstrated the ability of the DHI detector to resolve the minuscule temperature changes produced by radiation in water to within experimental uncertainty. Spatial resolution of approximately 0.03 mm/pixel was achieved, and the dose distribution around the brachytherapy source was accurately measured for short irradiation times, to within the experimental uncertainty. The experimental noise for the prototype detector was relatively large and combined with the occurrence of heat di usion, means that the method is predominantly suitable for high dose rate applications. The initial proof-of-principle results con rm that DHI dosimetry is a promising technique, with a range of potential bene ts. Further development of the technique is warranted, to improve on the limitations of the current prototype. A comprehensive analysis of the system was conducted to determine key requirements for future development of the DHI detector to be a useful contribution to the dosimetric toolbox of a range of current and emerging applications. The sources of measurement uncertainty are considered, and methods suggested to mitigate these. Improvement of the signal-to-noise ratio, and further development of the heat transport corrections for high dose gradient regions are key areas of focus highlighted for future development.

In-vivo dosimetry with diode detectors is used in radiation therapy as a quality assurance tool. The diode sensitivity under radiation depends upon temperature, dose rate and SDD (source-to-detector distance), field size, beam angle, and energy. This dissertation presents the first systematic and quantitative study of dosimetric characteristics for most of the commercial radiation diodes (n-type and p-type) under different radiation beams.In the temperature dependence study, the systematic study on the dose rate dependence of svwt (sensitivity variation with temperature) was performed. It was concluded that sufficient preirradiation can eliminate dose rate dependence of svwt. However, preirradiation cannot eliminate dose rate dependence of the diode sensitivity, S, itself. In the dose rate and SDD dependence study, it was shown that the p-type diodes do not always show less dose rate dependence than the n-type diodes. Preirradiation does not always reduce diode dose rate dependence. SDD dependence of diode sensitivity can be explained by the instantaneous dose rate dependence if sufficient buildup is provided to eliminate electron contamination. An empirical formula was proposed to fit the dose rate dependence of diode sensitivity. In the energy dependence study, the energy dependence diode detectors are quantified. The empirical theory to quantify this effect was developed. Monte Carlo simulation and the cavity theory are used to predict the energy dependence. It was concluded that the energy dependence does not depend on whether the diode is n- or p- type but rather depends mainly on the material around the die (buildup and its geometry). A systematic study of the correction factors for accurate diode dosimetry is presented in this dissertation.This dissertation has established a theoretical foundation for the modeling of the transient electric and radiation properties of the diode detectors, separately. We believe that the Monte Carlo simulations code for radiation transport should be coupled with the continuity equations to describe the charge transport in the diode detector, and thus provides a complete quantitative description of dosimetric characteristics of the diode detectors. The ultimate goal is to use the diode detector as an absolute dosimeter, rather than as a relative dosimeter.

Les faisceaux de photons produits par les accélérateurs d'électrons linéaires médicaux sont plats, grâce à un cône égalisateur. Les technologies ont évolué et la présence d'un cône n'est plus indispensable. On parle alors de faisceaux FFF (flattening filter free). Les faisceaux FFF présentent des débits de dose plus élevés, des profils de dose hétérogènes, des spectres énergétiques différents et une diminution de la dose hors-champ. Cette thèse a eu pour but d'étudier les caractéristiques des faisceaux FFF, ainsi que l'impact de leur utilisation thérapeutique. Plusieurs thématiques ont été. Des expériences d'irradiation in vitro ont tout d'abord permis de s'assurer que les débits de dose FFF n'ont pas d'impact radiobiologique sur la réponse des cellules irradiées. Une large revue de la littérature a permis de corroborer ces résultats. Afin de maitriser les caractéristiques physiques des faisceaux FFF, des mesures ont été faites avec différents détecteurs. Les effets du spectre et du débit de dose sur la calibration en dose ont aussi été étudiés. Les faisceaux FFF ont été modélisés dans deux TPS. Les modèles ont été comparés entre les deux types de faisceaux et entre les deux TPS. La mise en place des traitements stéréotaxiques a aussi été l'occasion d'appréhender la dosimétrie des petits faisceaux. Nous avons étudié des cas VMAT de cancer de la prostate et des cas de stéréotaxies 3D de tumeurs pulmonaires. La comparaison donne un avantage aux faisceaux FFF. La maitrise de la physique et de la biologie des haut débits a permis de débuter les traitements FFF à l'IPC. Des études comparatives nous permettent aujourd'hui d'adapter leur utilisation au cas par cas. / In medical linear electron accelerators, photon beams profiles are homogenised using flattening filters. Technologies have evolved and the presence of this filter is no longer necessary. Flattening filter free (FFF) beams exhibit higher dose rates, heterogeneous dose profiles, modified energy spectra and lower out-of-field dose. This PhD aimed at studying the characteristics of unflattened beams, as well as their impact in clinical utilization. Several subjects were thoroughly investigated: radiobiology, dosimetry, quality controls, modelling and treatment planning. In vitro experiments ensured that the high dose-rate of FFF beams had not a radiobiological impact. A wide review of the literature was conducted to corroborate these results. In order to understand thoroughly the characteristics of FFF beams, measurements were conducted using several detectors. The effect of the spectra and dose rates of unflattened beams on dose calibration were also studied. FFF beams were modeled in two TPSs. The methods, results and model parameters have been compared between the available beam qualities as well as between both TPSs. Furthermore, the implementation of stereotactic treatments technique was the occasion to investigate small beam dosimetry. Prostate cancer cases treated with VMAT and pulmonary tumors treated with stereotactic 3D beams were also studied. The comparison of dose distributions and treatment metrics give advantage to FFF beams. Mastering physical and biological aspects of flattening filter free beams allowed the IPC to start FFF treatments. Comparative studies have since resulted in a deeper understanding on the pertinent use of these beams.

Avant d'approvisionner des lots de composants pour la fabrication de systèmes orbitaux, les grandes agences du spatial (CNES, ESA, NASA, JAXA…) ainsi que les industriels du spatial (EADS, Thales,…) doivent s'assurer de la fiabilité des lots proposés par les fabricants de circuits intégrés. Dans le but d'assurer la fiabilité des composants, des tests sont réalisés suivant des recommandations afin de sélectionner et trier les composants suivant leur tenue à différents modes de défaillance. Parmi tous ces tests, certains sont typiques des applications spatiales : les tests de tenue à la dose. Cette spécificité des tests de tenue à la dose de composants destinés à des applications spatiales est due au fait que l'environnement spatial est un environnement radiatif qui provoque une ionisation dans les matériaux constituant le satellite. Suite à cette ionisation des charges sont créées dans la matière et induisent des modifications au sein des matériaux qui composent les circuits intégrés, ce qui peut provoquer des dérives de leurs caractéristiques électriques. Ces dérives des paramètres électriques en environnement spatial peuvent être perçues comme un vieillissement accéléré des composants électroniques, et des tests sont donc dédiés à prédire et s'assurer du bon fonctionnement des composants même après ce vieillissement accéléré provoqué par la dose. Dans ce travail de thèse nous nous intéressons à l'applicabilité d'une technique de test accéléré des composants bipolaires développée à l'UM2: 'La technique des Débits Commutés'. Une étude de l'effet de la polarisation pendant irradiation a été mené au cours de ce travail de thèse, afin d'appréhender l'impact de la polarisation des composants bipolaires sur les estimations obtenues de façon accélérée grâce à cette technique. / Before supplying lots of components for the manufacture of orbital systems, large space agencies (CNES, ESA, NASA, JAXA ...) and the Industrial Space (EADS, Thales, ...) should ensure the reliability lots offered by manufacturers of integrated circuits. In order to ensure reliability of components, tests are performed following recommendations to select and sort the components according to their resistance to different failure modes. Of all these tests, some are typical for space applications: tests held in the dose. The specificity of the tests held at the dose of components for space applications due to the fact that the environment is a space radiation environment which causes ionization in the materials of the satellite. Following this ionization charges are created in the material and induce changes in the materials that comprise integrated circuits, which can cause drift of their electrical characteristics. These abuses of the electrical parameters in a space environment can be viewed as accelerated aging of electronic components, and tests are dedicated to predict and verify the correct operation of the components even after the accelerated aging caused by dose. In this thesis we investigate the applicability of a technique for accelerated testing of components developed in bipolar UM2: 'The technique of Switched Flows'. A study of the effect of the polarization during irradiation was conducted during this thesis, to understand the impact of the polarization of the bipolar components on the estimates obtained in an accelerated manner using this technique.

<p>²²⁶Ra is a radionuclide of much concern since it poses a high risk of radio-toxicity when ingested and is well known for its invariably long half life of 1600 years. As such ²²⁶Ra concentrations were measured in whole body tissue of fathead minnows (Pimephales promelas) in an experimental set up. Fathead minnows obtained were about two months old and fed on a Radium-226 spiked diet until 115 days. A simple and direct method to determine ²²⁶Ra ingested by fish using a homogeneous liquid scintillation counting was developed. The study consisted of three groups; a sham, Radium treatment and acid treatment. Fathead minnows were sampled 75 and 115 days after feeding, and the following end points; mass (w/w), length, specific growth rate, condition factor and radionuclide measurements obtained. Mean end point results were (0.24 ± 0.03 g), (2.78 ± 0.1 cm), (1.75 ± 0.13 % day^-1), (1.10 ± 0.06 g cm^-3) and (577.06 ± 572.13 mBq g^-1) respectively. Also mean total ²²⁶Ra level was calculated as (1911.43 ± 868.64 mBq g^-1) while the activity in sham and acid treatment resulted in levels below the Minimum Detectable Activity of 7.46 mBq g^-1. The mean rate of ²²⁶Ra accumulation, known as the concentration factor, by the fathead minnows was determined as 0.35 ± 0.19. Assuming that the ²²⁶Ra Isotope is evenly distributed in the fish whole body, the derived dose rate was found to be 5.26 μGy h^-1.</p> / Master of Science (MSc)

Water is a major component of living organisms, which can be 70-85% of the weight of cells. For this reason, water is a main target of ionizing radiations and plays a central role in radiobiology. Heavy ions, electrons and photons interact with water molecules; mainly by ionization and excitation. Neutrons interact with water molecules by elastic interactions, which generate recoil ions that will create ionizations and excitations in water molecules. These fast events (~10[superscript -12] s) lead to the formation of Reactive Oxygen Species (ROS). The ROS, in particular the hydroxyl radical (¨OH), interact with neighbour molecules such as proteins, lipids and nucleic acids by chemical interaction. Microbeams can irradiate selectively either the external membrane, the cytoplasm and the cell nucleus. These studies have shown that cell survival is greatly reduced when the nucleus is irradiated, but that this is not the case when cytoplasm or cell membrane is irradiated. Thus, DNA is a very sensitive site to ionizing radiation and ROS. For this reason, DNA has long been considered the most important molecule to explain radiobiological effects such as cell death. However, this concept has been challenged recently by new experimental results that have shown that cells which have not been directly in contact with radiation are also affected. This is called the bystander effect. Further studies have shown that a group of cells and their environment reacts collectively to radiation. A hypothesis put forward to explain this radiobiological phenomenon is that a irradiated cell will secrete signalling molecules that will affect non-irradiated cells. The implicated phenomenon and molecules are poorly understood at this moment. The purpose of this work is to improve our comprehension of the phenomenon in the microsecond that follows the irradiation. To these ends, a new Monte-Carlo simulation program of water radiolysis by photons has been generated. For photons of energy <2 MeV, they interact with water mainly by Compton and photoelectric effects, which create energetic electrons in water. The created electrons are then followed by our existing programs to simulate the radiolysis of water by photons. Similarly, a new code has been built to simulate the neutrons interaction with water. This code simulates the elastic collisions of a neutron with water molecules and calculates the number and energy of recoil protons and oxygen ions. The main part of this Ph.D. work was the generation of a non-homogeneous Monte-Carlo Step-By-Step (SBS) simulation code of non-homogeneous radiation chemistry. This new program has been used successfully to simulate radiolysis of water by ions of various LET, pH, ion types ([superscript 1]H[superscript +], [superscript 4]He[superscript 2+], [superscript 12]C[superscript 6+]) and temperature. The program has also been used to simulate the dose-rate effect and the Fricke and Ceric dosimeters. More complex systems (glycine, polymer gels and HCN) have also been simulated.

Irradiadores comerciais de grande porte são projetados para processarem grandes quantidades de produtos com altas doses, por exposição à radiação gama. A irradiação em escala industrial é efetuada de forma dinâmica, em que os produtos percorrem um caminho em torno de uma fonte de radiação, geralmente de 60Co, cuja atividade é da ordem de TBq a PBq (kCi a MCi). A dose será diretamente proporcional ao tempo transcorrido pelo material para percorrer este trajeto em torno da fonte. Entretanto, em algumas situações, principalmente para pesquisas ou processos de validação de clientes seguindo a norma ISO 11137, se faz necessário irradiar pequenas amostras com doses fracionadas na posição de irradiação estática. Nesta posição as amostras são colocadas dentro da sala de irradiação a uma distância fixa da fonte e as doses recebidas são determinadas utilizando-se dosímetros. Portanto, a dose somente será conhecida depois da irradiação, pela leitura dos mesmos. Entretanto, em irradiadores industriais, diferentes tipos de produtos com diferentes densidades atravessam o caminho entre a fonte e a posição de irradiação estática, onde estão as amostras. Conseqüentemente, a taxa de dose variará dependendo da densidade do produto, que está sendo irradiado dinamicamente. Uma metodologia adequada seria monitorar a dose recebida pelas amostras em tempo real, medindo a dose por meio de um detector de radiação, com uma melhor precisão e exatidão. Neste trabalho foi desenvolvida uma câmara de ionização cilíndrica de 0.9 cm3, para monitorar as altas doses recebidas por amostras em tempo real, na posição de irradiação estática de um irradiador gama de 60Co. Os gases de nitrogênio e de argônio a pressão de 10exp5 Pa (1 bar) foram utilizados para preencherem a câmara de ionização e determinar uma configuração de trabalho apropriada, para o detector ser utilizado em medidas de altas doses. Cabos de isolação mineral foram soldados diretamente ao corpo da câmara de ionização, para a transmissão do sinal gerado pelo detector até a eletrônica associada, distante cerca de 20 m. O sinal obtido foi cerca de 100 vezes maior do que o ruído de fundo. Este sistema dosimétrico foi testado em um irradiador gama de categoria I e na posição de irradiação estática de um irradiador de grande porte, em que diferentes taxas de dose foram obtidas utilizando materiais absorvedores. Foi encontrada uma boa linearidade do detector entre a dose e a carga, independentemente das diferentes taxas de dose. As incertezas de todas as curvas ficaram abaixo dos +/- 5 %, valor de incerteza máxima recomendada para um sistema dosimétrico de rotina. A câmara de ionização desenvolvida se mostrou adequada para ser utilizada como um dosímetro em tempo real, independente da degradação do espectro causada pela absorção dos fótons da fonte de 60Co, pelo material em irradiação dinâmica. / Industrial gamma irradiators facilities are designed for processing large amounts of products, which are exposed to large doses of gamma radiation. The irradiation, in industrial scale, is usually carried out in a dynamic form, where the products go through a 60Co gamma source with activity of TBq to PBq (kCi to MCi). The dose is estimated as being directly proportional to the time that the products spend to go through the source. However, in some situations, mainly for research purposes or for validation of customer process following the ISO 11137 requirements, it is required to irradiate small samples in a static position with fractional deliver doses. The samples are put inside the irradiation room at a fixed distance from the source and the dose is usually determined using dosimeters. The dose is only known after the irradiation, by reading the dosimeter. Nevertheless, in the industrial irradiators, usually different kinds of products with different densities go through between the source and the static position samples. So, the dose rate varies in function of the product density. A suitable methodology would be to monitor the samples dose in real time, measuring the dose on line with a radiation detector, which would improve the dose accuracy and avoid the overdose. A cylindrical ionization chamber of 0.9 cm3 has been developed for high-doses real-time monitoring, during the sample irradiation at a static position in a 60Co gamma industrial plant. Nitrogen and argon gas at pressure of 10exp5 Pa (1bar) was utilized to fill the ionization chamber, for which an appropriate configuration was determined to be used as a detector for high-dose measurements. To transmit the signal generated in the ionization chamber to the associated electronic and processing unit, a 20 m mineral insulated cable was welded to the ionization chamber. The signal to noise ratio produced by the detector was about 100. The dosimeter system was tested at a category I gamma irradiator and at an industrial irradiation plant in static position, using different absorbing materials. A good linearity of the detector was found between the dose and the accumulated charge, independently of the different dose rates caused by absorbing materials. The uncertainties for all curves were less than 5%, which is recommended for a dosimetric system routine. The developed ionization chamber showed to be suitable as a dosimeter on line, independently of the spectrum degradation caused by the absorption of the 60Co photons in the material under dynamic irradiation.

Irradiadores comerciais de grande porte são projetados para processarem grandes quantidades de produtos com altas doses, por exposição à radiação gama. A irradiação em escala industrial é efetuada de forma dinâmica, em que os produtos percorrem um caminho em torno de uma fonte de radiação, geralmente de 60Co, cuja atividade é da ordem de TBq a PBq (kCi a MCi). A dose será diretamente proporcional ao tempo transcorrido pelo material para percorrer este trajeto em torno da fonte. Entretanto, em algumas situações, principalmente para pesquisas ou processos de validação de clientes seguindo a norma ISO 11137, se faz necessário irradiar pequenas amostras com doses fracionadas na posição de irradiação estática. Nesta posição as amostras são colocadas dentro da sala de irradiação a uma distância fixa da fonte e as doses recebidas são determinadas utilizando-se dosímetros. Portanto, a dose somente será conhecida depois da irradiação, pela leitura dos mesmos. Entretanto, em irradiadores industriais, diferentes tipos de produtos com diferentes densidades atravessam o caminho entre a fonte e a posição de irradiação estática, onde estão as amostras. Conseqüentemente, a taxa de dose variará dependendo da densidade do produto, que está sendo irradiado dinamicamente. Uma metodologia adequada seria monitorar a dose recebida pelas amostras em tempo real, medindo a dose por meio de um detector de radiação, com uma melhor precisão e exatidão. Neste trabalho foi desenvolvida uma câmara de ionização cilíndrica de 0.9 cm3, para monitorar as altas doses recebidas por amostras em tempo real, na posição de irradiação estática de um irradiador gama de 60Co. Os gases de nitrogênio e de argônio a pressão de 10exp5 Pa (1 bar) foram utilizados para preencherem a câmara de ionização e determinar uma configuração de trabalho apropriada, para o detector ser utilizado em medidas de altas doses. Cabos de isolação mineral foram soldados diretamente ao corpo da câmara de ionização, para a transmissão do sinal gerado pelo detector até a eletrônica associada, distante cerca de 20 m. O sinal obtido foi cerca de 100 vezes maior do que o ruído de fundo. Este sistema dosimétrico foi testado em um irradiador gama de categoria I e na posição de irradiação estática de um irradiador de grande porte, em que diferentes taxas de dose foram obtidas utilizando materiais absorvedores. Foi encontrada uma boa linearidade do detector entre a dose e a carga, independentemente das diferentes taxas de dose. As incertezas de todas as curvas ficaram abaixo dos +/- 5 %, valor de incerteza máxima recomendada para um sistema dosimétrico de rotina. A câmara de ionização desenvolvida se mostrou adequada para ser utilizada como um dosímetro em tempo real, independente da degradação do espectro causada pela absorção dos fótons da fonte de 60Co, pelo material em irradiação dinâmica. / Industrial gamma irradiators facilities are designed for processing large amounts of products, which are exposed to large doses of gamma radiation. The irradiation, in industrial scale, is usually carried out in a dynamic form, where the products go through a 60Co gamma source with activity of TBq to PBq (kCi to MCi). The dose is estimated as being directly proportional to the time that the products spend to go through the source. However, in some situations, mainly for research purposes or for validation of customer process following the ISO 11137 requirements, it is required to irradiate small samples in a static position with fractional deliver doses. The samples are put inside the irradiation room at a fixed distance from the source and the dose is usually determined using dosimeters. The dose is only known after the irradiation, by reading the dosimeter. Nevertheless, in the industrial irradiators, usually different kinds of products with different densities go through between the source and the static position samples. So, the dose rate varies in function of the product density. A suitable methodology would be to monitor the samples dose in real time, measuring the dose on line with a radiation detector, which would improve the dose accuracy and avoid the overdose. A cylindrical ionization chamber of 0.9 cm3 has been developed for high-doses real-time monitoring, during the sample irradiation at a static position in a 60Co gamma industrial plant. Nitrogen and argon gas at pressure of 10exp5 Pa (1bar) was utilized to fill the ionization chamber, for which an appropriate configuration was determined to be used as a detector for high-dose measurements. To transmit the signal generated in the ionization chamber to the associated electronic and processing unit, a 20 m mineral insulated cable was welded to the ionization chamber. The signal to noise ratio produced by the detector was about 100. The dosimeter system was tested at a category I gamma irradiator and at an industrial irradiation plant in static position, using different absorbing materials. A good linearity of the detector was found between the dose and the accumulated charge, independently of the different dose rates caused by absorbing materials. The uncertainties for all curves were less than 5%, which is recommended for a dosimetric system routine. The developed ionization chamber showed to be suitable as a dosimeter on line, independently of the spectrum degradation caused by the absorption of the 60Co photons in the material under dynamic irradiation.

Introduction Treating localized prostate cancer with combination radiotherapy consisting ofexternal beam radiotherapy (EBRT) and high-dose-rate brachytherapy (HDR-BT) has beenproven to result in better disease outcome than EBRT only. There is, however, a decreasingtrend in utilization of combination therapy, partially due to concerns for elevated toxicityrisks. Aim To determine which parameters correlate to acute and late (≤ 6 months) urinary toxicity(AUT and LUT) and acute and late rectal toxicity (ART and LRT), and thereafter createpredictive models for rectal toxicity. Methods Data on toxicity rates and 32 patient, tumor and treatment parameters were collectedfrom 359 patients treated between 2008 and 2018 with EBRT (42 Gy in 14 fractions) andHDR-BT (14.5 Gy in 1 fraction) for localized prostate cancer at Örebro University Hospital.Bivariate analyses were conducted on all parameters and the outcome variables AUT, LUT,ART and LRT grade ≥ 1, graded according to the RTOG-criteria. Parameters correlating toART and LRT in this and previous studies were included in multivariate logistic regressionanalyses for creation of predictive models. Results Most toxicities, 86%, were of grade 0 or 1, only 9% of patients had grade 2 – 3toxicity. Only 2 – 4 parameters correlated to the respective toxicities in bivariate analyses.Logistic regressions generated no significant predictors of ART or LRT. Therefore, nopredictive models were obtained. Conclusion None of the included parameters have enough discriminative abilities regardingrectal toxicity. Predictive models can most probably be obtained by including otherparameters and more patients.