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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

Purpose: To study Intensity Modulated Proton Therapy (IMPT) with a new treatment planning optimization software. The aim was also to make a comparative study between existing conventional photon plans, Intensity Modulated X-ray Therapy (IMXT) plans and IMPT plans for three different cancer diagnoses. Materials and methods: The conventional photon plans and the IMXT plans were optimized in Oncentra

Functional Magnetic Resonance Imaging, fMRI, is a non invasive method to map brain activation with a magnetic resonance camera. In this thesis we propose a method to deal with motion induced artefacts in functional fMRI, using Independent Component Analysis, ICA. Patient movement can induce false activation or cause loss of true activation. Movement is one of the most common causes of fMRI failure

The Monte Carlo method has become increasingly used to simulate imaging systems like the scintillation camera and SPECT systems. In order to investigate intrinsic properties of SPECT systems the Monte Carlo based application SIMIND (Simulating Medical Imaging Nuclear Detectors) has been developed. Up to now, it has not been able to simulate a pinhole-imaging device with SIMND. The aim of this work

Vattenmolekyler är i ständig slumpmässig rörelse som beror på systemets termisk energi, dvs temperaturen. Diffusionsrörelsen kallas även Brownsk rörelse efter den engelske botanikerns Brown, som upptäckte fenomenet på 1800 talet. Människokroppen består till 70 % av vatten, vilket gör det lämpligt att använda MRT för att studera diffusionsegenskaper i biologisk vävnad och för klinisk diagnostik av Magnetic resonance imaging (MRI) is still a fast growing area of research and is an important part of the clinical tools used for diagnosis of various diseases. The diagnostic values of diffusion imaging are well known especially for ischemic stroke in the acute phase. This work concerns whether the apparent diffusion coefficient (ADC) and the full width at half maximum (FWHM) changes when the ima

Small-animal positron emission tomography (PET) has proven to be a promising and useful modality for preclinical pharmacokinetic studies. Thanks to high sensitivity and spatial resolution in the range of a few millimetres, the possibility to perform reliable and accurate quantification and absorbed dose estimates is within reach. In preclinical radioimmunotherapy (RIT), the slow targeting and clea

"Diffusion magnetic resonance imaging (MRI) is today a well-established method in clinics around the world. For example it is a leading method or diagnosing ischaemic stroke at an early stage. Trough research it is a continuously growing field applicable to many different tasks. Alternatively, the diffusion MRI can be used for morphologic studies by the use of q-space analysis. q-space imag

Vid strålbehandling används olika typer av strålning beroende på vad man ska behandla. Mätningarna i min undersökning gjordes på joniserande strålning med låg energi jämfört med den typ man vanligtvis förknippar med strålbehandling. Den sortens strålning som jag mätte på används främst vid behandling av åkommor som är relativt ytliga, till exempel hudcancer eller psoriasis. Läkarna ordinerar hur sAbsorbed dose was determined under reference conditions at four x-ray qualities; 30, 80, 120 and 200 kV using five different dosimetry protocols and codes of practice; IAEA TRS-398, AAPM, IPEMB, NCS and DIN. The dose determined by the IAEA protocol was chosen as reference. The dosimetry protocols use different formalisms for determining the absolute dose in a reference point. The IAEA and DIN prot

Varje år diagnostiseras i Sverige ungefär 1100 personer med cancer i huvudhalsregionen. Typiska diagnoser är tungcancer, läppcancer och cancer i struphuvudet. I och runt om munhålan finns det stora skillnader i densitet mellan till exempel vävnad och tänder och vävnad och tandlagningar. I detta arbete så har effekterna av ett antal olika tandlagningsmaterial på dosberäkningarna undersökts. För a"Introduction: Around 1.000 people are diagnosed with head and neck cancer in Sweden every year. Radiotherapy is often used to treat these tumors. When irradiating patients in the head and neck area there are some problems. One of these problems is the large difference in density between the oral tissue and dental materials. Another problem is the image artifacts due to high-density materials