Purpose: To determine how image quality linked to tumor detection is affected by reducing the absorbed dose to 50% and 30% of standard dose levels, i.e. an average glandular dose of 1.26 mGy for a standard breast according to European guidelines. Material and methods: Tumors were computer simulated and inserted into 40 out of 90 normal, unprocessed images acquired from the screening department at

Svår, elakartad och längre gången cancer är ett stort problem i förhindrande av spridda tumörceller i kroppen. I detta sjukdomsstadium är oftast en lindrande (palliativ) behandlingsform enda vägen att välja för att hjälpa patienten. För närvarande sker detta genom att patienten får genomlida extern strålbehandling eller cellgiftsbehandling. Radioaktivt märkta och ”målsökande” antikroppar injicerNew radionuclide therapies in humans should be preceded by experimental animal therapies, in order to evaluate the efficacy of the new therapy regime. These experimental studies have to be performed with a reliable and accurate quantification system, with properties that have been evaluated and where possible flaws have been corrected for. The aim of this work was to evaluate the SPECT pinhole col

Idag behandlas de flesta patienter som diagnostiserats med gliom, en otäck hjärntumör, med fotoner producerade i en linjäraccelerator på någon av landets strålbehandlingskliniker. Tumören växer inuti hjärnan på ett mycket aggressivt sätt, vilket gör den nästan omöjlig att bota. Det normala är att strålningen kombineras med cellgifter och kirurgi för att ge patienten så lång tid som är möjligt, tilIncreased accuracy in patient dosimetry in BNCT is needed. This need for more accurate individual patient dose estimations initiated this project at the Swedish BNCT facility at Studsvik. One possible way to achieve this is to use an HPGe detector. This project involves the complete construction and testing of such a system in a treatment representative environment.The system builds on an ORTEC GM

Purpose: The aim of this study was to investigate if the inverse planning available in the dedicated planning program VariSeed 7.1, can generate plans of equal quality to plans generated through manual planning.Materials and Methods: In this study the dedicated permanent seed implantation planning system VariSeed 7.1. (Varian, Paolo Alto California) was used for inverse planning, using a dose-volu

Curative radiotherapy for cancer of the cervix consists of a combination of extern beam radiotherapy (EBRT) and brachytherapy (BT). The most important prognostic factors are tumour size, tumour extension and lymph node involvement.Traditional dose planning for BT of cervix cancer is based on two orthogonal films with the applicators in place in cervix. The dose distribution is related to the appli

Introduction: The Elekta Synergy machine for external beam radiation therapy is equipped with an x-ray tube for on-line kV imaging and correction of the patient setup. The system can provide both 2D and 3D data for image guided radiotherapy (IGRT). Different aspects of the imaging system (called XVI) has been evaluated, such as image quality, flex of the gantry rotation, accuracy for patient setup

Magnetresonans, förkortat MR, är ett fysikaliskt fenomen som tillämpas inom medicinsk diagnostik för bildtagning. Med hjälp av mycket starka magnetfält kan bilder erhållas, exempelvis på hjärnan, utan att joniserande strålning används. Förutom bilder kan MR-bildtagning även användas för att avbilda perfusion (kapillärblodflöde) och vattendiffusion i hjärnan. Ytterligare ett användningsområde är av

The purpose with this work has been to develop and construct a Niobium target for the production of [18F]fluoride with a MC 16 Scanditronix cyclotron. The future demand larger amounts of [18F]fluoride and to satisfy the forthcoming needs an enhanced target needs to be installed on the cyclotron. The old target could have provided the forthcoming needs but to obtain good margins it is important wit

Med röntgenstrålning går det i dagsläget att avbilda kroppens inre anatomi i antingen två eller tre dimensioner. Vid en vanlig slätröntgenundersökning (2D) tas en så kallad projektionsbild från en eller två vinklar, framifrån/bakifrån och från sidan. Detta genererar en tvådimensionell bild där alla (anatomiska) strukturer mellan röntgenröret och filmen överlagras, d.v.s. de går inte att separera fDuring the last century several attempts have been made to overcome the fundamental problem of X-ray imaging, i.e. that anatomical information existing in 3-dimensions has to be represented on a 2-dimensional radiograph. In this thesis, digital tomosynthesis, a rened version of conventional tomography, has been investigated. Digital tomosynthesisenables retrospective reconstruction of an arbitrary

Quantification in Nuclear Medicine Imaging is highly desirable for a number of reasons. In Targeted Radionuclide Therapy for example, accurate estimation of the absorbed dose delivered to the patient depends upon accurately quantified images. In Tracer Kinetic Studies quantification is also required in order to obtain accurate biodistribution data. One of the major problems connected with Nuclear

Background: To gain more knowledge of the mechanism behind the appearance of radiation induced cancer, the cellular response at low doses has to be studied. A Single Ion Hit Facility (SIHF) at the Lund Nuclear Microprobe Laboratory will be used for this purpose. The facility allows single MeV ions to hit single living cells.Purpose: The goals of this work were to i) design a suitable cell dish whe

Strålning kan medföra både skada och nytta. Inom strålbehandling utnyttjas strålningen för att bota eller lindra cancersjukdomar. Målet är att med hjälp av joniserande strålning slå ut alla tumörceller samtidigt som man försöker skona övriga friska celler. Strålningen som produceras i den vanligaste utrustningen för extern strålbehandling, nämligen linjäraccelerator, är elektronstrålning och fotonPurpose: Medical linear accelerators that operate above 10 MeV produce neutrons by photonuclear reactions which present a potential radiation hazard to the personnel. The purpose of this study was to estimate neutron dose contributions to the personnel working with external radiotherapy at Malmö University Hospital (UMAS), compare different kind of neutron detectors/dosimeters, and evaluate how to

Introduction: The main route of excretion of activity for most administered radiopharmaceuticals is via the urinary bladder and it is important to estimate the absorbed dose to the mucosal surface of the bladder wall, especially when radiopharmaceuticals are given for therapeutic purposes. The purpose of this thesis was to investigate how the absorbed dose varies with changes in the parameters, wh

Hals- och huvudregionen innehåller många luftkaviteter t.ex. luftstrupe, bihålor och munhåla. Detta arbete undersökte vad som händer i vävnaden kring dessa luftkaviteter när de blir bestrålade med fotoner och hur bra ett dosplaneringssystem för strålbehandling modellerar den absorberade dosen till ett heterogent medium. Dosberäkningarna gjordes med hjälp av ett Monte Carlo-simuleringsprogram somPurpose: To study the build-down and build up of the absorbed dose at the interface between air and tissue in the head and neck region. Monte Carlo simulations are compared to a treatment planning system that is used at the University Hospital in Lund. Materials and methods A virtual phantom was constructed to resemble an air cavity in the head and neck region. The phantom consisted of a water cyl

Varje år får cirka 50 000 svenskar diagnosen cancer. Mot detta är strålbehandling en vanlig behandlingsmetod och det uppskattas att cirka en tredjedel av alla som får cancer någon gång under sin behandling får strålbehandling. En viktig sak inom strålbehandling är att patienten får den dos som läkaren har ordinerat. Detta är en så vital detalj inom strålbehandling att SSI, Statens StrålskyddsinsIndependent dose calculations in radiotherapy are important as they help assure that the dose given to the patient is the same as the prescribed. The current version of software Radiation Verification Programme, RVP, does not take into account the effects that occur when a beam from a linear accelerator is moved off-axis. The aim with this project was to find a model for these effects, fit the par

Kvaliteten på kliniska bilder har stor betydelse för korrekt medicinsk diagnostik. I konventionella morfologiska MR-bilder är signalen normalt relativt hög i förhållande till bruset. Vissa nya MR-metoder för s.k. funktionsdiagnostik bygger emellertid på en avsiktlig degradering av signalen för att vissa kvantitativa parametrar skall kunna beräknas. I sådana studier kan följaktligen signal-till-bruNoise is a well-known problem in many imaging modalities. In magnitude magnetic resonance images, obtained by quadrature detection, the associated Rician distribution of noise constitutes a further complication. This type of noise is especially problematic at low signal-to-noise ratio (SNR) regions. The Rician noise distribution causes a non-zero minimum signal in the image, often referred to as t

Determination of absolute activity of 99mTc and 123I in organs for the purpose of patient-specific dosimetry in nuclear medicine examinations and therapy is of great importance. In order to make accurate quantification of the organ content from planar gamma camera images of phantoms, several corrections has to be made. The accuracy of a number of correction methods and different combinations of th

Introduction: To our knowledge a biomedical model for validation of combined MicroPET/MicroCAT studies of the thyroid with 124I has not yet been developed. Such an in vivo physiological rat model could be of great interest for enhancing the possibilities of studying common thyroid diseases realistically and repeatedly. Furthermore, a well developed, realistic, and flexible model can also be of gre

This work shows a contribution to a long-term study of lead in smelter workers where the objectives were to assess the historical lead (Pb) exposure and to study the relationships between lead concentrations in finger bone (Bone-Pb), whole blood (B-Pb), plasma (P-Pb), urine (U-Pb) and the duration of employment in workers at a secondary lead smelter. Moreover, results were compared with previous s

Syftet med denna studie var att utvärdera säkerhetsmarginalerna som läggs kring ett målorgan (tex prostata) vid extern strålterapi. Resultaten kan senare ligga till grund för reducering av säkerhetsmarginalerna, detta för att skydda strål-känslig frisk vävnad från onödig bestrålning. En delstudie var också att försöka finna ett mönster hos prostatans rörelse vid de inledande behandlingstillfällena"Introduction: This thesis is a study of the margins that are necessary in prostate cancer radio therapy treatment. The aim was to analyse the intrafraction motion of the prostate gland during treatment, by the use of portal imaging, in order to optimize the margin around the prostate gland and spare healthy tissue. One of the purposes was to find a common pattern in prostate movement in the