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Visar resultat 21 - 25 av 54 avhandlingar som matchar ovanstående sökkriterier.

1. 21. Double-contrast MRI for the staging of rectal carcinoma: Technical aspects and clinical experience

   Författare :Nils-Olof Wallengren; Lund Diagnostisk radiologi; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; radiology; Clinical physics; Double contrast; MR imaging; Preoperative staging; Rectal carcinoma; tomography; medical instrumentation; Klinisk fysiologi; radiologi; tomografi; medicinsk instrumentering;

   Sammanfattning : Aim of the study Today´s methods for the staging of rectal carcinoma: ultrasonography with transrectal probe, CT, MRI or MRI with a rectal coil, all have limitations. The aim was therefore to develop a new, double-contrast MRI method for evaluation of rectal carcinoma. LÄS MER

3. 22. 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

4. 23. Image Processing for Quantitative Scintillation-Camera Imaging. Application to Radionuclide Therapy

   Författare :Katarina Sjögreen Gleisner; Lund Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; tomografi; radiologi; Klinisk fysiologi; medical instrumentation; tomography; radiology; 131-I; Clinical physics; SPECT; conjugate-view; volume quantification; activity quantification; image registration; image segmentation; medicinsk instrumentering; Nuclear medicine; radiobiology; Nukleärmedicin; radiobiologi; Radiopharmaceutical technology; Radiofarmaceutisk teknik;

   Sammanfattning : Individual-based determinations of the absorbed dose in radionuclide therapy largely rely on absolute measurement of the activity distribution and its redistribution over time. Scintillation-camera imaging is the most commonly employed measuring technique, applied in planar or SPECT mode, sometimes in combination with structural images from CT. LÄS MER

5. 24. 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

7. 25. Internal Dosimetry Development and Evaluation of Methods and Models

   Författare :Lena M Jönsson; Lund Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; tomografi; Klinisk fysiologi; medical instrumentation; tomography; radiology; Clinical physics; crypt cells; intestine; radionuclide; scintillation camera; sestamibi; activity quantification; conjugate view method; Monte Carlo simulation; internal dosimetry; Nuclear medicine; radiobiology; Nukleärmedicin; radiobiologi; medicinsk instrumentering; radiologi;

   Sammanfattning : Radionuclide therapy requires patient-specific planning of the absorbed dose to target volumes, in most cases tumours, in order to achieve an expected biological effect, taking into account that the absorbed doses to normal organs and tissues should be kept as low as reasonably achievable. Therefore, the calculation of absorbed doses has to be as accurate as possible. LÄS MER