Search for dissertations about: "absorbed dose distribution"

Showing result 1 - 5 of 39 swedish dissertations containing the words absorbed dose distribution.

  2. 1. Small-Scale Absorbed Dose Modelling in Selective Internal Radiation Therapy : Microsphere Distribution in Normal Liver Tissue

    Author : Jonas Högberg; Göteborgs universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; clusters; dosimetry; heterogeneity; liver; microspheres; radioembolisation; simulations; SIRT; surgery; yttrium-90;

    Abstract : Radioembolisation (RE), with yttrium-90 (90Y) labelled microspheres, is an increasingly common treatment method for unresectable liver tumours. The tolerable mean absorbed dose for normal liver (NL) tissue is higher in RE than in External Beam Radiation Therapy (EBRT); absorbed dose heterogeneity is thought to be one important reason, together with a low absorbed dose rate, but the knowledge of microsphere distributions is limited. READ MORE

  4. 2. Development and evaluation of an independent system for absorbed dose calculations in radiotherapy

    Author : Stefan Johnsson; Lund Medicinsk strålningsfysik; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; medicinsk instrumentering; tomografi; radiologi; Klinisk fysiologi; tomography; medical instrumentation; radiology; Clinical physics; cancer; Cytologi; onkologi; cancerology; oncology; Cytology; PDA; mini-phantom; in-air equivalence; primary kerma; transmission measurement; stopping power ratio; entrance dose; beam quality; quality control; error prevention; monitor unit calculation; radiation therapy; dose calculation;

    Abstract : The aim of this work was to develop, implement and evaluate an independent system with which to calculate the absorbed dose, delivered by high-energy X-ray beams, to the prescription point and the depth of dose maximum. The introduction of such a system in the clinical routine may help ensure high-quality treatment and avoidance of errors which may jeopardise the clinical outcome of the treatment (i. READ MORE

  5. 3. Absorbed Dose Determination and Characteristics of Degraded Electron Beams: Application to Intraoperative Radiation Therapy

    Author : Peter Björk; Internmedicin - epidemiologi; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Clinical physics; radiology; tomography; medical instrumentation; Klinisk fysiologi; radiologi; tomografi; medicinsk instrumentering; absorbed dose distribution; output factor; stopping-power ratio; beam characteristics; Monte Carlo calculation; electron beam dosimetry; applicator system; radiation therapy; linear accelerator; intraoperative radiotherapy;

    Abstract : The aim of this work was to quantify limitations of and uncertainties in commonly used dosimetric techniques for relative absorbed dose determination in degraded electron beams, such as those encountered in intraoperative radiation therapy (IORT) and small-electron-field radiotherapy. Three different detector types were investigated with regard to measurements of output factors and relative absorbed dose distributions: (1) a parallel-plate ionization chamber, (2) a p-type silicon diode detector and (3) a diamond detector. READ MORE

  6. 4. Radioiodine Therapy of Hyperthyroidism - Simplified patient-specific absorbed dose planning

    Author : Helene Jönsson; Malmö Institutionen för kliniska vetenskaper; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; radiobiologi; Radiofarmaceutisk teknik; Radiopharmaceutical technology; absorbed dose. optimise; hyperthyroidism; therapy; 131-I; radioiodine; Nukleärmedicin; radiobiology; Nuclear medicine;

    Abstract : Radioiodine therapy of hyperthyroidism is the most frequently performed radiopharmaceutical therapy. To calculate the activity of 131-I to be administered for giving a certain absorbed dose to the thyroid, the mass of the thyroid and the individual biokinetic data, normally in the form of uptake and biologic half-time, have to be determined. READ MORE

  7. 5. Cellular effects of ionizing radiation : Relevant for understanding cancer risk after medical and environmental radiation exposures

    Author : Pamela Chiaka Akuwudike; Andrzej Wojcik; Lovisa Lundholm; Kerstin Borgmann; Stockholms universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiation; DNA damage; radiation-induced carcinogenesis; second primary cancer; cisplatin chemoradiotherapy; dose fractionation; low dose; low dose rate; dose and dose rate effectiveness factor DDREF ; molekylär biovetenskap; Molecular Bioscience;

    Abstract : Radiation-induced cancers are stochastic and delayed effects of exposure to ionizing radiation. The dose-response relationship for radiation-induced cancers at both low dose/low dose rates and high doses (doses encountered during radiotherapy) remains unclear. READ MORE