|
|
The role of fermions and bosons in magnetic resonance imaging
ADAMEC, Filip
Abstract Currently, there are only partial theories describing the role and application of fermions and bosons in magnetic resonance imaging, but there are no interdisciplinary theories. I believe, that by combining diverse disciplines (physics, mathematics and the medical nature of MR), an interdisciplinary theory may emerge, that can also be used as a material to deepen the knowledge of future or already active radiologists in radiological physics and magnetic resonance imaging. The following objectives have been set for this Bachelor thesis: Global target: Creation of an expert description of the role of fermions and bosons in magnetic resonance imaging using interdisciplinary communication. Sub-objectives: C1: Data processing - physics of elementary particles C2: Data processing - classical form of electromagnetic field theory C3: Data processing - structure of magnetic resonance imaging C4: Data processing - quantum mechanics of protons Due to the goals of this bachelor thesis, the following hypotheses were made: H1: The classical dimension of the physical nature of MR can be created by comparison of the structure of magnetic resonance and the classical form of electromagnetic field H2: The quantum dimension of the physical nature of MR can be created by comparison of the structure of magnetic resonance and the quantum mechanics of protons H3: The role of fermions and bosons in the description of the physical nature of magnetic resonance can be described by the comparative structure of magnetic resonance and the quantum dimension of the physical substance of magnetic with the standard model of elementary particles and their interactions In the introduction to the theoretical part of the work, I dealt with elementary particles, their physics and mutual interactions. Furthermore, these particles were divided into fermions and bosons, which were described in more detail. I devoted another part of the theory to the classical form of the electromagnetic field, where I discussed mainly Maxwell's equations. The next part was devoted to quantum mechanics of particles and at the end of the theoretical part I focused on the medical part of magnetic resonance. The practical part compares the knowledge gained in the theoretical part of this work. The results were divided into two sections, according to established hypotheses. The results of this bachelor thesis point to the relatively crucial role of fermions and bosons in magnetic resonance imaging, thus confirming all three established hypotheses. The results of this bachelor thesis point out the relatively crucial role of fermions (electrons, protons) and bosons (photons, Cooper pairs) based on verified and accepted hypotheses.
|
|
|
Cross-Sections Of Nuclear Isomers In The Interaction
Of Protons On Thin Thorium Target
Golomb, Robert
The paper shows the results of experimental gamma spectra obtained with thorium 232Th target, and an aluminum collector irradiation with protons at an energy JINR Synchrocyclotron 100 and 660 MeV. For Th232, identified 258 and 222 gamma lines that belong to 45 and 55 nuclides. For Al - 238, 330 lines and 81, 119 nuclides respectively. The cross sections of fragmentation of the 232Th and Al nuclei under the interaction of protons 100 and 660 MeV were determined. A comparison of the obtained cross sections of the reaction with theoretical calculations was made.
|
|
|
Unfolding of energies of fusion products measured by the activation probe at JET
Ficker, Ondřej ; Mlynář, Jan ; Bonheure, G. ; Murari, A. ; Popovichev, S.
Providing a detection method for diagnostic of charged fusion products in tokamaks presents a major challenge, while its absolute calibration with a sufficient accuracy and its capability to withstand harsh fusion reactor environment will be required. A novel type of detector that meets most of these requirements, based on an activation probe, was tested in JET and other European facilities. This probe proved to be extremely robust due to its simple construction. It is equipped with samples of well defined isotopic abundance. The amounts of activated nuclei due to the reactions in these materials could be measured via ultra-low-level gamma spectroscopy. The feasibility of the proton spectrum reconstruction from measured activities is examined in this contribution with the help of the algorithm based on the Tikhonov regularisation constrained by minimum Fisher information. The reliability of the method was previously illustrated using synthetic proton data.
|
|
|
Comparison of doses in the target volume and critical organs for Intensity Modulated Radiation Therapy (IMRT) and proton therapy
STIEBLINGOVÁ, Tereza
The topic of this thesis is a view at the two selected modern irradiation techniques - IMRT (Intensity-Modulated Radiation Therapy) and proton therapy. I compared them at a general level in the theoretical part, and in the practical part I focused on the absorbed doses in selected critical organs in patients with prostate cancer. In the theoretical part I worked with specialized literature and articles from medical journals and also with a number of internet sources. For example I worked with a publication titled Radiační onkologie by Pavel Šlampa or Klinická onkológia a rádioterapia by Ľudovit Jurga. I made a concept based on the obtained information, which is composed of generally related topics, e.g. the position of radiotherapy in the treatment of oncological diseases, characteristics of ionizing radiation, the process of radiation treatment planning etc. After these introductory chapters I focused specifically on photon IMRT technique and proton therapy which are among the most modern methods of contemporary radiation oncology. In the theoretical part I set the description of these selected techniques as a goal, with an emphasis on their advantages and disadvantages. In the practical part I analyzed these two techniques in terms of received minimum, medium and maximum doses in selected critical organs rectum, bladder and both femoral heads using different fractionation schemes. The results were compared with information from the theoretical part. In the practical part, the testing of this hypothesis was set as my goal: During the treatment of prostate cancer with accelerated protons the healthy surrounding tissue and critical organs will receive smaller amount of radiation dose than IMRT technique. Proton Therapy Center (PTC) in Prague provided me with some irradiation plans including CT scans from 20 anonymous patients diagnosed with prostate cancer and treated with protons. Then I worked with these plans in planning program to create a photon IMRT plan for each proton plan and in order to be able compare these two techniques in each patient in different fractionation schemes. When I compared IMRT technique and proton therapy, both in norm-fractionated scheme, moderate doses were lower with protons in all 20 patients in all selected critical organs. The average difference in moderate doses of these techniques in all selected critical organs is 11,022 Gy. Specifically, from the results is further evident, that the bladder and the rectum absorb less minimal and medium dose if proton therapy has been used in any fractional mode (short, long, norm-fractionated scheme) than in the photon IMRT therapy. These results were obtained in all 20 patients. When I compared IMRT technique and proton therapy, both in short scheme or long scheme, in terms of the maximum doses in the bladder and rectum, the values were comparable in the both critical organs. In none of the literature used as a source is a mention of minimal and medium doses on heads of both femurs. But if I compare the median doses proton's therapy with doses IMRT's photon therapy, both in norm-fractionated scheme, the medium doses were lower if proton therapy had been used. The results of minimal doses are contradictory and conclusions are not so unequivocal. The values of the maximum doses of the right and left femoral head were lower in overwhelming majority of 20 patients in proton therapy (in the short and also in long scheme). The average difference in the left head of femur is 3,434 Gy (proton's short scheme vs. photon's short scheme), respectively 6,654 Gy (proton's long scheme vs. photon's long scheme). The average difference in the right head of femur is 5,422 Gy (proton's short scheme vs. photon's short scheme), respectively 9,273 Gy (proton's long scheme vs. photon's long scheme).
|
guest ::
