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The radio therapy process planning
Slavíček, Tomáš ; Kolářová, Jana (referee) ; Hrozek, Jan (advisor)
This thesis aims to bring reader to the problems of radiotherapy, to give him an overview of basic principles and methods used to treat patients with cancer by ionizing radiation. The first part is devoted to the physical description of radiation and means of quantification. Interactions of radiation with matter are discussed next following with characterization of radiation effects on living cells and tissues. In the next part there is a description of the devices used in the treatment by ionizing radiation and an explanation of the various acts of patient's preparation from the target localization to irradiation. The final chapter describes created program with a graphical environment, which includes the key elements of commercial planning systems for the creation of the irradiation plan. This program uses real CT images and provides the user a basic idea of creating radiotherapeutic plan. The user has several functions for creating and optimizing the plan. The output of the program is a graphical representation of the spatial distribution of dose in the patient's body.
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4D radiotherapy
RYBÁKOVÁ, Aneta
This bachelor's thesis deals with 4D radiotherapy. Four-dimensional conformal radiotherapy, or 4D radiotherapy, focuses on the position of an irradiated volume at the current time, which changes mainly due to respiratory movements. Its main principle is the synchronization of radiation with "changing - moving target volume". It is used in treating patients with chest tumors, lung cancers and left-sided breast cancer. The technique of irradiation of 4D radiotherapy is Respiratory gating simultaneously using image-controlled radiotherapy. The theoretical part of the thesis describes the individual elements of the process of preparation for irradiation, evaluation of the irradiation plan, verification processes in radiotherapy and modern irradiation methods of 3D conformal radiotherapy. The theoretical processing of the topic, a key part of the thesis, describes the methods and properties of 4D radiotherapy, treatment planning, lists indications suitable for 4D radiotherapy and a describes the fractionation of treatment. In the practical part of this thesis, the irradiation plans of patients treated with 4D radiotherapy at the Radiotherapy Department of Nemocnice České Budějovice, a.s. are compared with irradiation plans obtained from more conventional 3D radiotherapy. In this department, one of the methods of 4D radiotherapy called deep inspiration breath hold (DIBH), has been used since 2019. The objective of the practical part was to demonstrate the benefit of using 4D radiotherapy in the irradiation of left breast cancer, comparing the doses to critical organs (heart, lungs, spinal cord) of patients treated with Respiratory gating with critical organs doses of randomly selected patients treated with conventional 3D radiotherapy. The results of this thesis and the methodology of the workplace mainly pointed out that the choice of 4D radiotherapy is subjected to a consistent selection of patients. The Respiratory gating technique should not be used in patients who are affected by irregular or difficult breathing or insufficiently by the departure of the chest wall from the heart when inhaled. The conclusion of the thesis supports a trend commonly found in the literature describing the advantage of using Respiratory gating in left-sided breast cancers to reduce radiation toxicity to the heart. This may represent, for example, the development of ischaemic heart disease or myocardial fibrosis. It is therefore necessary to pay attention to modern methods that try to eliminate this undesirable consequence of breast irradiation.
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Verification of target volume position in radioterapy
LHOTÁKOVÁ, Vendula
This Bachelor thesis is concerned with the verification of the target volume setup in radiotherapy. With respect to technological advancement, the necessity to use verification systems for ensuring a quality treatment is highlighted. In its theoretical part, the objective of this Bachelor thesis is to summarize and delineate the imaging technologies used to verify the target volume setup. The objective of the practical part is to analyse deviations in the position of the target volume in IMRT technique for prostate radiation; the analysis is primarily directed at new functions in the correction of the position of the radiation table. The theoretical part of the thesis presents facilities used to verify the target volume and summarizes information relating to the two basic methods in radiotherapy: teletherapy and brachytherapy. Differences between X-ray and radionuclide irradiators and particle accelerators are explained. A brief description is given as to the structure of a linear accelerator, with a summary of irradiation techniques applied in radiotherapy. The data for the practical part were derived from results gained by the correction of the position of the target volume in verification imaging at the Radiotherapy Department in České Budějovice Hospital. For the analysis of deviations, a set of 50 patients who were treated for prostate cancer at the Radiotherapy Department in 2018 was selected. During radiotherapy, excepting daily MV-kV imaging, the total of 417 verification CTs was developed for these subjects. Based on these CT images, the deviation in directing the target volume was evaluated and the appropriate correction of the radiation table, and the given patient as well, was performed. The correction of the radiation table allows for the movement of six axes in total, as described in detail in the present thesis. The results gained from the data collected reveal that the correction of the setup of the irradiated volume is a necessity and it is amply used, specifically in all of the six axes. It was discovered that the functions of the table Lat, Lng, Rnt and Vrt are used at virtually all times, and in concrete terms, the newer function of the table Pitch is utilized at 95,03%, with the use of function Roll standing at 92,64%. The daily verification CBCT was performed in 10% of the patients in the set observed. The standard frequency of the use of the verification CBCT at the Radiotherapy Department in České Budějovice Hospital, for patients irradiated to prostate, is approximately 7 - 9 CBCT during the treatment, which includes a CBCT examination at the first setup and then twice during the first week of treatment, and subsequently only once a week during the radiotherapy procedure. The analysis results proved an abundant use of newly introduced options in the correction of the position of the radiation table, and in general, also an improvement in accuracy of directing the target volume. The improvement in accuracy, and therefore an improvement of quality of the administered radiation therapy, allows for changes in the size of the recorded target volumes, specifically the reduction in these volumes. As a consequence, it is logical that the volume of healthy irradiated issue is smaller, which brings (or might bring) for the patient a decrease in the occurrence or level of seriousness of undesired radiotherapy effects. The results of the research and its findings may serve for evaluating the quality of the verification process in radiotherapy, linked with installation of new technologies in the given healthcare department, or, as the case may be, as data and information to be used for preparation of articles published in specialized magazines.
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The radio therapy process planning
Slavíček, Tomáš ; Kolářová, Jana (referee) ; Hrozek, Jan (advisor)
This thesis aims to bring reader to the problems of radiotherapy, to give him an overview of basic principles and methods used to treat patients with cancer by ionizing radiation. The first part is devoted to the physical description of radiation and means of quantification. Interactions of radiation with matter are discussed next following with characterization of radiation effects on living cells and tissues. In the next part there is a description of the devices used in the treatment by ionizing radiation and an explanation of the various acts of patient's preparation from the target localization to irradiation. The final chapter describes created program with a graphical environment, which includes the key elements of commercial planning systems for the creation of the irradiation plan. This program uses real CT images and provides the user a basic idea of creating radiotherapeutic plan. The user has several functions for creating and optimizing the plan. The output of the program is a graphical representation of the spatial distribution of dose in the patient's body.
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The effect IMRT technique by the head and neck tumors looking on the total dose in the organs at risk and the target volumes
WOLFOVÁ, Barbora
The effect IMRT technique by the head and neck tumors looking on the total dose in the organs at risk and the target volumes This work compares two techniques of planning radiotherapy in the head and neck areas. The technique used will be IMRT - Intensity Modulated Radiotherapy. The development of new technologies in radiotherapy equipment has also brought a wider range of methods of treating carcinomas. The IMRT technique represents a breakthrough in this process and that is why it is dealt with in this work as far as its advantages, as compared with conventional radiotherapy methods, are concerned. I have focused mainly on the distribution of doses in target volumes and critical organs, in particular in the salivary glands and the spinal chord. The region of the head and throat is an area containing the kinds of tissue with various sensitivity and tolerance to radiotherapy. The damage to such tissues has an enormous impact on the patient. That is why the region is a very suitable place for assessing the advantages of the IMRT as compared with conventional techniques. Ten plans from a set of patients suffering from tumour in the area of head and throat have been evaluated in this work by means of DVH (Dose Volume Histogram). The individual plans have been interpreted, conventional plans and IMRT ones separately. I have focused on comparing mean doses and the subsequent comparison of doses of 5 per cent and 95 per cent of the irradiated volume PTV, maximum doses on the spinal chord, and doses of 50 per cent of the irradiated volume of the salivary glands in the individual plans.
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