Sökning: "monitor unit calculation"

Hittade 5 avhandlingar innehållade orden monitor unit 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. 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

4. 3. 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

5. 4. Quality Assurance in Radiotherapy - Development and evaluation of new tools for improved patient safety

   Författare :Fredrik Nordström; Malmö Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; monitor unit verification; in vivo dosimetry; real-time verification; gel dosimetry; 4D dosimetry; IMRT; VMAT; data integrity; radiotherapy; Quality assurance;

   Sammanfattning : Preparation for radiotherapy is a complex procedure that involves many different technologies and groups of professionals. The rapid development and introduction of new technologies throughout the last decade have made it possible to deliver highly conformal, individually-shaped dose distributions with high accuracy. LÄS MER

7. 5. Model Studies of Electron Transfer and Reaction Dynamics at Surfaces

   Författare :Johan Strömquist; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; dissociation; desorption; oxidation; hot precursors; surface chemical reaction; chemiluminescence; surface harpooning; charge transfer; electron emission; transient mobility; non-adiabaticity;

   Sammanfattning : Charge-transfer is of key importance in many physical, chemical and biological processes, including surface reactions. This thesis consists of several theories for and model studies of surface reactions that are initiated by electron transfer between the surface to a molecule. LÄS MER