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Effect of the nitrogen flushing on stability of the TL dosimeter for Harshaw TLD 3500
KUBÍNOVÁ, Kateřina
It is absolutely necessary to know the achieved doses during patient irradiation for radiotherapy and doses management. Critical spots of the patient body are covered by dosimeters during whole-body irradiation via rotational technique. Thermoluminiscent detectors TLD 100 are used for in-vivo dosimetry at Nemocnice České Budějovice, a.s., (Hospital České Budějovice Ltd.). Evaluation of results is done by a Harshaw 3500 device. Nitrogen atmosphere is required by the manufacturer for evaluation of the dosimeters. The main point of this bachelor thesis is to compare the sensitivity of the dosimeter evaluation in standard and nitrogen atmosphere. The zero hypothesis was confirmed by experimental investigation and statistic evaluation. The zero hypothesis assumes that mean values of the dosimeter response sensitivity factor are the same in both cases. The found results support the assumption that there is no need to change anything on the practice at the department of oncology and that dosimeter evaluation follows the best practice. Stability of the evaluation is ensured by annealing in TLD furnace. It eliminates the influence of small impurities and grease from the patient sessions. At the same time, annealing prevents the influence of fading.
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The use of the TL dosimeters for measuring inhomogeneities irradiation
CANDROVÁ, Daniela
Radiotherapy has commonly been utilised to cure cancer for more than a century. It is counted among the fundamental branches of medicine and represents an effective local or locally-regional method of curing both cancer and some non-cancerous conditions. It utilises ionising radiation which unfortunately eliminates tumour cells along with healthy ones. This is why a wide range of harmful effects of the radiation can be observed on humans. Patients treated with radiotherapy are in some cases monitored with dosimeters so that the intended dose can be compared with what is really absorbed. Nemocnice České Budějovice, a. s. monitors the dose in expected locations of non-homogeneous irradiation using the aforementioned TL dosimeters during the process of rotary irradiation of Mycosis fungoides. Before actually being used in an in vivo dosimetry, these dosimeters must be properly calibrated and have their sensitivity adjusted. Other than that, they are fairly easy to use, do not require much time or money invested and are able to constantly monitor the dose received by a patient treated with rotary irradiation. This diploma thesis discusses the usage of TL dosimeters to measure non-homogeneity of irradiation. It therefore compares the doses received by patients in various parts of the body during irradiation by the TSEI method. These 22 irradiated patients had thorough measurements taken of the doses they received in the so-called black hole region, their axillae and neck while holding their arms up and with arms loosely positioned close to the body. The thesis also suggests the possibility of the dosimeters being used by the integrated emergency service to assist during rescues and demolitions performed in emergency situations when a leak of ionising radiation occurs. Using TL dosimeters would mean more precise measurements of the dose received by the involved personnel in various parts of their body. If a patient is treated with the TSEI method, the dose received is monitored in a reference point, critical areas and areas with residual infiltrations or tumours. Doses measured in critical areas indicate that should the acral parts of limbs be left uncovered, they absorb larger doses than the rest of the body. They thus exceed the intended dose significantly. In the case of fingers, the dose tends to reach as much as 3 Gy. Depending on clinical picture, the attending physician determines whether special covering should be used. This covering reduces the doses received to merely a few tenths of a Gy. There also tends to be a large difference in absorbed doses in axillar areas and the neck, depending on whether the patient's arms are held up or close to the body respectively. Test results indicate that holding arms up or keeping them close to the body on a particular side have always had a profound effect on the dose absorbed by the patient in this particular area. This means that the position of the body greatly influences how much is absorbed in various parts of the body. TL dosimeters are also used in other areas than in vivo dosimetry in radiotherapy. An example of this could be determining the dose received in upper limbs of the workers monitored with thermoluminescent dosimeters in the form of bracelets or rings. They also serve to monitor the external irradiation of persons within the limits of the Czech Republic (TLD network). In radiation therapy, both the doses in skin and body are taken into account when conducting measurements. Depending on the data extracted, it is then possible to assess the course of treatment and ensure safe implementation of ionising radiation. Integrated emergency service teams deployed in cases of radiation emergencies are not considering using TL dosimeters so far, although they could most likely be used to ascertain the exact doses absorbed. Further research would however need to be conducted to either confirm or disprove the benefits of using TLD.
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The Radiation protection of Patients and staff in Nuclear Medicine.
DAŇOVÁ, Kristína
Open radioactive sources are used at the department of nuclear medicine for diagnoses and therapy, as well as for research purposes. Ionizing radiation is applied in all cases. Since a negative impact of this radiation has been depicted, it is necessary to systematically reduce the radiation on people, and protect the environment. The title of this bachelor thesis is: "Radiation protection of staff and operatives at the Department of Nuclear Medicine". This thesis is devided into several parts. The beginning of the theoretical part focuses on history of origins of radiation protection and institutions which deal with it. Further, nuclear medicine as such, its equipment, and structure of the department in general is described. The conclusion then introduces the DNM in the town of České Budějovice. Ionizing radiation and its biological effects on organisms were defined, as well as quantities and units which characterize it. A considerable part of this work focuses on principles of radiation protection, monitoring of the staff, workplace and releases. This work also deals with dosimetry and lists types of used dosimeters. It assesses the risks of outer and inner radiation. The aim of this thesis was to analyse laws and regulations which are connected to radiation protection and identify its effective application for staff and patiens of the DNM in České Budějovice. Another aim was to examine the radiation protection of patients at the Department of Nuclear Medicine, as well as the radiation protection of patients and staff at the inpatient ward. The research question was: "Is the radiation protection of patients and staff at the Department of Nuclear Medicine in hospital in the town of České Budějovice sufficiently optimized?" The method of research was assembling and recording materials of nuclear medicine in České Budějovice, compare doses of thermoluminescent dosimeters of the staff in outpatient and inpatient wards, and compare doses of finger and whole-body thermoluminescent dosimeters. The practical part provides detail information, charts and graphs of effective and equivalent doses of staff of outpatient and inpatient wards of the DNM in the town of České Budějovice between years 2009 and 2013. The outpatient ward comprises of fifteen employees. The inpatient ward of three nurses and one hospital attendant. These were observed in details for effective dose equivalents Hp(10) during each individual month for the period of five years. Results from the personal whole-body and finger dosimeters have been used for the analysis. The values of equivalent doses of HT from finger TLD are recorded for two of the employees. The data for the hospital in the town of České Budějovice was assessed by CSOD Ltd. In Prague, a company which has been providing dosimetric calculations in the Czech Republic for over tweny years. This data was compared with limits for radiation workers, which are regulated by State Office for Nuclear Safety no.389/2012 Sb., from November 16th, 2012, which changes the public notice of State Office for Nuclear Safety no.307/2002 Sb., about radiation protection as amended by public notice no.499/2005 Sb. The outcomes of the thesis have remitted a very high level of radiation protection and well-established measures in the protection of staff and patients against negative effects of ionizing radiation in the hospital of the town of České Budějovice. The thesis is then enhanced by a discussion, which reflects the outcomes compared with professional findings summarised in the theoretical part. The answer to the research quesion is: "Yes, radiation protection of the staff and patients at the Department of Nuclear Medicine in the hospital of the town of České Budějovice is sufficiently optimized." This bachelor thesis can be used as a study material for students of the field of study Radiology Assistant.
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Measurement of photons via electronic dosimeters for the acceleration of charged particles at the Institute of Physics ASCR in Prague.
ŽIDKOVÁ, Jana
The thesis is focused on summarizing the current issue of work with experimental lasers in the research center of Prague Asterix Laser System (PALS), which falls under the Institute of Physics and Institute of Plasma Physics. Experimental lasers used for experimental research in the field of powerful laser physics and laser-produced plasma. The main experimental facility PALS is a powerful pulsed laser system Asterix IV., The research center was purchased from the German Max Planck Institute for quadratic Optics in Garching near Munich for a symbolic 1 mark. Asterix is one of the three largest iodine lasers in Europe. Between the research programs being carried out on the experimental development of lasers include applications of plasma point sources of soft non-coherent radiation, development and application of laser plasma X-ray etc. Other facilities located in the research center include PALS laser system Ti - Sapphire power of 25 terawatts. In this system, a similar experiment was performed measuring photon film dosimeters. The experimental laser Asterix IV in the research center PALS have been no experiment with film or electronic dosimeters. This work deals with the possibility of using electronic personal dosimeters when working with lasers and detection sensitivity of the dosimeters, unlike other types of personal dosimeters. This was achieved by measuring the two independent measurements ongoing at the Asterix IV laser system. Possibilities of using electronic personal dosimeters for measuring the pulse field, even though they are designed to measure benefits only in the continuous field is particularly important for workers newly built ELI center in Prague. Center ELI will be the most modern laser equipment in the world. In it will be carried out the research and application projects involving the interaction of light with matter in intensity, which is about 10 times larger than the currently achievable. ELI will deliver ultrashort laser pulses lasting typically a few femtoseconds (10-15 fs) and produce power up to 10 PW. The ELI Center will be unlike PALS controlled area in which it is important to monitor external radiation workers. Therefore, the thesis is aimed at providing support for PALS measurement using electronic personal dosimeters Center ELI. We also compare the sensitivity of the most common types of personal dosimeters such as film and thermoluminescent dosimeters. In the theoretical part of the description and principle of laser Asterix IV. Furthermore, the definition of ionizing radiation and its species with a particular focus on gamma and X-rays. In this thesis remains missing definitions such as dosimetry, types of dosimeters, monitoring, radiation protection and value to it. In the methodology are then analyzed measurements that were carried out in two experiments using electronic personal dosimeters, film dosimeters and thermoluminescent dosimeters. Furthermore, also the deployment of the laser system, focusing mainly on the description of the interaction of the hall and the interaction chamber, where were measured. The methodology is also a series of photos of photos taken at the workplace PALS for easier orientation. In the results, the values of individual measurements recorded for better clarity in the tables and charts described. The discussion is focused on the confirmation of hypotheses. Are compared to results from electronic and film dosimeters and electronic dosimeters and termoluminescent. Results are based on one shot and statistically processed. In the event of a general summary of the work, it is recommended the use of electronic personal dosimeters to work with experimental lasers and supported the intention of the use of electronic personal dosimeters in the newly built Center ELI in Prague, mainly because of higher sensitivity than that with film and TLD and also for easier, faster, and economical evaluation of the benefits.
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Possibilities in Exploitation of Laboratory Equipment in Faculty of Health and Social Studies, University of South Bohemia
ONDROVÁ, Veronika
Bachelor thesis entitled Possibilities of measuring instruments in the laboratory ZSF JU is aimed at teaching personal dosimetry laboratory. In the introduction the problem of dosimetry - the types of ionizing radiation dosimetry tasks and objectives. Cooperation with other dosimetry disciplines and last but not least, the basic quantities and units that are used in dosimetry and radiation protection. The main objective was to develop a comprehensive overview of equipment and instrumentation in the laboratory personal dosimetry measurement and specify their characteristics. The following sections describe each personal dosimetry laboratory instruments - their general description, basic parts, setup, control, measurement procedures and equipment use in teaching.
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The use of personal dosimetry on nuclear power plants abroad
KAUCA, Michal
There is performed the analyse of the use of personal dosimetry on nuclear power plants abroad compared with the situation in Czech Republic in this work. There is made the quality compare the usage of particular kinds of personal dosimetry on basis of informations got from choice nuclear operations, and the compare it with the situation in Czech Republic. I chose the way of getting of data by e-mail. On basis of got informations I made the compare as was objective this work. By compare of situation in radiation protection was found, the used personal dosimeters abroad and in Czech Republic are the same type almost. Some states including Czech Republic go over to legalization of personal electronic dosimeter as primary instrument of radiation protection. The matter of interest is the situation in Slovakia, where is receded from this type of dosimeter as primary and they returned to the previous type of dosimeters. Another speciality are the authorised limits for radiation worker in controled zone also for pregnant women in Japan. It isn´t usual in other states. This work refers to influence of personal dosimetry over the level of radiation protection in nuclear establishment and also over the connection of safety disposal in personal dosimetry with approved legislative in choice states, over the necessity of the controle, the competence of personal and also the progressive research and development in personal dosimetry. It is necessary to see the radiation protection globally. The personal dosimetry will have been not only national problem but also international matter. The new development in the sphere of passive and electronic dosimeters up to the complete global concepts of control is operationed already today in many states and it is offered in the international market still more often.
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