Sökning: "dose calculation"

Visar resultat 1 - 5 av 49 avhandlingar innehållade orden dose calculation.

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

   Författare :Stefan Johnsson; Lund Medicinsk strålningsfysik; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

3. 2. Developing and evaluating dose calculation models for verification of advanced radiotherapy

   Författare :Jörgen Olofsson; Mikael Karlsson; Anders Ahnesjö; Crister Ceberg; Umeå universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiation therapy; high-energy photons; dose calculation; multi-source model; pencil kernel; uncertainties; action levels; Radiological physics; Radiofysik;

   Sammanfattning : A prerequisite for modern radiotherapy is the ability to accurately determine the absorbed dose (D) that is given to the patient. The subject of this thesis has been to develop and evaluate efficient dose calculation models for high-energy photon beams delivered by linear accelerators. LÄS MER

4. 3. Verification of dose calculations in radiotherapy

   Författare :Tufve Nyholm; Mikael Karlsson; Ben Mijnheer; Umeå universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; radiotherapy; dose calculation; quality control; pencil kernel; Radiological physics; Radiofysik;

   Sammanfattning : External radiotherapy is a common treatment technique for cancer. It has been shown that radiation therapy is a both clinically and economically effective treatment for many types of cancer, even though the equipment is expensive. The technology is in constant evolution and more and more sophisticated and complex techniques are introduced. LÄS MER

5. 4. Probabilistic treatment planning based on dose coverage : How to quantify and minimize the effects of geometric uncertainties in radiotherapy

   Författare :David Tilly; Anders Ahnesjö; Erik Grusell; Uwe Oelfke; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Radiotherapy; treatment simulation; probabilistic planning; dose calculation; probabilistic optimization; statistical shape model; Medicinsk radiofysik; Medical Radiophysics;

   Sammanfattning : Traditionally, uncertainties are handled by expanding the irradiated volume to ensure target dose coverage to a certain probability. The uncertainties arise from e.g. the uncertainty in positioning of the patient at every fraction, organ motion and in defining the region of interests on the acquired images. LÄS MER

7. 5. Verification of Dose Calculation Algorithms in Treatment Planning Systems for External Radiation Therapy: A Monte Carlo Approach

   Författare :Elinore Wieslander; Lund Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; radiologi; tomografi; medicinsk instrumentering; radiotherapy; dose calculation algorithm; verification; Monte Carlo calculation; electron beam; photon beam; Clinical physics; radiology; tomography; medical instrumentation; Klinisk fysiologi; treatment planning system;

   Sammanfattning : This thesis presents a new verification concept, the virtual accelerator, for dose calculation algorithms used in treatment planning systems (TPSs) for external beam radiotherapy. The algorithm input data required to implement a treatment unit in the TPS are generated by Monte Carlo simulations as are the beam reference data needed for the subsequent evaluation of the dose calculation algorithm. LÄS MER