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1
Content available remote Dose assessment in high dose rate brachytherapy with cobalt-60 source for cervical cancer treatment: a phantom study
Bour Bright Kwadwo, Inkoom Stephen, Tagoe Samuel Nii Adu, Amuasi John Humphrey, Sasu Evans, Hasford Francis
Polish Journal of Medical Physics and Engineering
|
2020
|
Vol. 26, Iss. 4
243--250
EN
Transition from low dose rate brachytherapy to high dose rate brachytherapy at our department necessitated the performance of dose verification test, which served as an end-to-end quality assurance procedure to verify and validate dose delivery in intracavitary brachytherapy of the cervix and the vaginal walls based on the Manchester system. An inhouse water phantom was designed and constructed from Perspex sheets to represent the cervix region of a standard adult patient. The phantom was used to verify the whole dose delivery chain such as calibration of the cobalt-60 source in use, applicator, and source localization method, the output of treatment planning with dedicated treatment planning system, and actual dose delivery process. Since the above factors would influence the final dose delivered, doses were measured with calibrated gafchromic EBT3 films at various points within the in-house phantom for a number of clinical implants that were used to treat a patient based on departmental protocol. The measured doses were compared to those of the treatment planning system. The discrepancies between measured doses and their corresponding calculated doses obtained with the treatment planning system ranged from -29.67 to 40.34% (mean of ±13.27%). These compared similarly to other studies.
2
Content available remote Monte Carlo study on the gold and gadolinium nanoparticles radio-sensitizer effect in the prostate 125I seeds radiotherapy
Ghasemi-Jangjoo Amir, Ghiasi Hosein
Polish Journal of Medical Physics and Engineering
|
2019
|
Vol. 25, Iss. 3
165--169
EN
Monte Carlo and TL dosimetry applied to the characterization of 125I brachytherapy with a different design with other 125I seeds. In a water phantom, lattice configuration simulated with 125I seed in the center and 10 nm gold and gadolinium nan-particle filed voxels. This simulation conducted to the characterization of the nano-particles DEF in low energy and prostate tissue. To study of the prostate brachytherapy, a humanoid computational phantom developed by CT slices applied. KTMAN-2 computational phantom contains 29 organs and 19 skeletal regions and was produced from cross-sectional x-ray computed tomography (CT slices) images. The simulated seed was 125I seed having an average energy of 28.4 keV for photons, a half-life of 59.4 days. DEF factor in the seed radiation energy (28.4 keV) DEF factor was found to be two times higher for the gold nano-particles. It was revealed than gold-nano-particles posing Z about 1.24 times higher than gadolinium led to around 200% DEF increasing in the same conditions and the nano-particles size. It was concluded that in low energy sources brachytherapy, photoelectric is dominant in the presence of relative high element nanoparticles. This leads to a high dose increasing in some micro-meters and causes a dramatic dose gradient in the vicinity of a nano-particle. This dose gradient effectively kills the tumor cells in continuous low energy irradiation in the presence of a high Z material nano-scaled particle. Application of gold nano-particles in low energy brachytherapy is recommended.
3
Content available remote A Monte Carlo study on the radio-sensitization effect of gold nanoparticles in brachytherapy of prostate by 103Pd seeds
Jangjoo Amir Ghasemi, Ghiasi Hosein, Mesbahi Asghar
Polish Journal of Medical Physics and Engineering
|
2019
|
Vol. 25, Iss. 2
87--92
EN
103Pd seed is being used for prostate brachytherapy. Additionally, the dose enhancement effect of gold nanoparticles (GNP) has been reported in previous studies. The aim of this study was to characterize the dosimetric effect of gold nanoparticles in brachytherapy with a 103Pd source. Two brachytherapy seeds including 103Pd source was simulated using MCNPX Monte Carlo code. The seeds’ models were validated by comparing the MC with reported results. Then, GNPs (10 nm in diameter) with a concentration of 7mg Au/g were simulated uniformly inside the prostate of a humanoid computational phantom. Additionally, the dose enhancement factor (DEF) of nanoparticles was calculated for both modeled brachytherapy seeds. A good agreement was found between the MC calculated and the reported dosimetric parameters. For both seeds, an average DEF of 23% was obtained in tumor volume for prostate brachytherapy. The application of GNPs in conjunction with 103Pd seed in brachytherapy can enhance the delivered dose to the tumor and consequently leads to better treatment outcome.
4
Content available remote A Monte Carlo investigation of the dose distribution for new I-125 Low Dose Rate brachytherapy source in water and in different media
Fardi Zeinab, Taherparvar Payvand
Polish Journal of Medical Physics and Engineering
|
2019
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Vol. 25, Iss. 1
15--22
EN
Permanent and temporary implantation of I-125 brachytherapy sources has become an official method for the treatment of different cancers. In this technique, it is essential to determine dose distribution around the brachytherapy source to choose the optimal treatment plan. In this study, the dosimetric parameters for a new interstitial brachytherapy source I-125 (IrSeed-125) were calculated with GATE/GEANT4 Monte Carlo code. Dose rate constant, radial dose function and 2D anisotropy function were calculated inside a water phantom (based on the recommendations of TG-43U1 protocol), and inside several tissue phantoms around the IrSeed-125 capsule. Acquired results were compared with MCNP simulation and experimental data. The dose rate constant of IrSeed-125 in the water phantom was about 1.038 cGy·h−1U−1 that shows good consistency with the experimental data. The radial dose function at 0.5, 0.9, 1.8, 3 and 7 cm radial distances were obtained as 1.095, 1.019, 0.826, 0.605, and 0.188, respectively. The results of the IrSeed-125 is not only in good agreement with those calculated by other simulation with MCNP code but also are closer to the experimental results. Discrepancies in the estimation of dose around IrSeed-125 capsule in the muscle and fat tissue phantoms are greater than the breast and lung phantoms in comparison with the water phantom. Results show that GATE/GEANT4 Monte Carlo code produces accurate results for dosimetric parameters of the IrSeed-125 LDR brachytherapy source with choosing the appropriate physics list. There are some differences in the dose calculation in the tissue phantoms in comparison with water phantom, especially in long distances from the source center, which may cause errors in the estimation of dose around brachytherapy sources that are not taken account by the TG43-U1 formalism.
5
Content available remote Pomiary aktywności źródła Ir-192 przy użyciu zestawów elektrometrów z komorą studzienkową i komorami naparstkowymi (pomiary krosowe i pomiary aktywności)
Oborska-Kumaszyńska D., Matharu T., Northover D., Pater E.
Inżynier i Fizyk Medyczny
|
2016
|
Vol. 5, nr 1
29--37
PL
W artykule opisano pomiary wykonane w celu wyznaczenia aktywności źródła Ir-192 stosowanego w brachyterapii HDR. W pomiarach zastosowano różne zestawy elektrometrów z różnymi typami komór jonizacyjnych: elektrometr z komorą studzienkową, dwa elektrometry z komorami naparstkowymi typu Farmer i elektrometr z komorą NPL „secondary standard”. Pomiary wykonano w celu wyznaczenia współczynników kalibracyjnych dla komór naparstkowych typu Farmer (0,6 cm3) w wyniku porównania krosowego z komorą studzienkową i komorą NPL „secondary standard”. Porównano również wyniki dla pomiarów uzyskanych z różnych zestawów i obliczeń aktywności źródła, wykorzystując formułę obliczeniową dla RAKR. Uzyskane wyniki pozwalają uznać metody za ekwiwalentne, przy uznaniu większej niepewności pomiarowej dla komór typu Farmer. Pozwala to na wprowadzenie alternatywnej metody pomiarowej w stosunku do komory studzienkowej uznanej za standard pomiarowy dla źródeł radioaktywnych w brachyterapii.
EN
The article describes the measurements made to determine the activity of the Ir-192 source used in HDR brachytherapy. The different electrometers with different types of ionization chambers have been used: electrometer with well chamber, two electrometers with Farmer thimble chambers (0.6 cm3) and electrometer withNPL „secondary standard” chamber. Themeasurements have been done to determine the calibration coefficients for the Farmer chambers. It was donebasing on comparison of readings of the Framer chambers with the well chamber and NPL „secondary standard” chamber. The results of measurements have been alsocomparedforallmeasurement sets and calculations of source activity using the RAKR formula. Itresulted conclusion that all used methods can be considered as equivalent, recognizing the greater measurement uncertainty for Farmer chambers. This allows to introduce an alternative measurement methods instead well chamber, considered as a standard to measure the radioactive sources in brachytherapy.
6
Content available remote Kontrola systemu planowania leczenia w brachyterapii
Wittych J., Sobiech M.
Inżynier i Fizyk Medyczny
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2015
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Vol. 4, nr 4
225--228
PL
Dla każdego etapu radioterapii istnieje szereg regulacji prawnych, które mają na celu głównie poprawę jakości i bezpieczeństwa realizacji całego procesu. Ze względu na konieczność zapewnienia bezwzględnej poprawności i powtarzalności obliczeń systemy planowania leczenia stosowane w radioterapii powinny być objęty kontrolą jakości. Użycie nieprawidłowowprowadzonych danych skutkuje błędami w obliczeniach i napromienianiu pacjenta. Właściwa kontrola powinna zagwarantować możliwość wykonania optymalnego planu leczenia z wykluczeniem błędów wynikających z nieprawidłowo zdefiniowanych danych w TPS. Opublikowano kilka raportów dedykowanych zapewnieniu jakości w radioterapii, w tym również poświęconych systemom planowania leczenia [1-9]. W pracy przedstawiono podstawowe wymogi kontroli systemu planowania leczenia w brachyterapii oparte głównie na zaleceniach Bookletu No. 8 European Society for Radiotherapy and Oncology [9].
EN
There are a lot of regulations in radiotherapy dedicated to quality assurance and safety of this treatment method process. It is also recommended to control used treatment planning systems. It is necessary to be sure that the calculations and reproducibility are correct. Using incorrect data and calculations cause the mistakes in patient irradiation. The reliable quality control ought to guarantee the possibility of calculated optimal and correct treatment plan. There were published some reports for quality control (QC) in radiotherapy especially for quality control of treatment planning systems (TPS) [1-9]. The main requirements for QC of TPS used in brachytherapy, based on recommendations of Booklet No. 8 European Society for Radiotherapy and Oncology [9], were put forward in this paper.
7
Content available remote Audyt dozymetryczny w brachyterapii PDR : metodologia, układy pomiarowe i wyniki
Oborska-Kumaszyńska D., Palmer A., Matharu T.
Inżynier i Fizyk Medyczny
|
2014
|
Vol. 3, nr 1
49--52
PL
Audyty dozymetryczne prowadzone w radioterapii stanowią element procesu zapewniania jakości, który umożliwia potwierdzenie parametrów dozymetrycznych, parametrów geometrycznych systemów oraz dokładności podawania dawki. Zwykle są one prowadzone przez fizyków z jednostek zewnętrznych lub reprezentujących instytucje profesjonalistów (np. IPEM, NPL).
8
Content available remote Współczesna brachyterapia
Bulski W., Kawczyńska M.
Inżynier i Fizyk Medyczny
|
2013
|
Vol. 2, nr 2
107--111
PL
Brachyterapia, nazywana czasami curieterapią (od nazwiska Marii Skłodowskiej- -Curie), jest terapią kontaktową. Polega na bezpośrednim napromienianiu zmian chorobowych przez umieszczenie źródła promieniowania w guzie lub jego sąsiedztwie. Podstawowym zastosowaniem brachyterapii jest leczenie zmian nowotworowych, ale jest ona wykorzystywana również w terapii chorób układu krążenia, w leczeniu keloidu, nadczynności tarczycy, czerwienicy prawdziwej, chorób gałki ocznej itd. Brachyterapię stosuje się zarówno jako samodzielne leczenie radykalne, jak i część skojarzonej terapii np. z chirurgią, teleradioterapią, leczeniem paliatywnym. Brachyterapia funkcjonuje również jako ratunkowa.
9
Content available remote Testy akceptacyjne i dopuszczające dla systemu PDR. Cz. 2
Tervinder M. S., Oborska-Kumaszyńska D., Ratcliffe A.
Inżynier i Fizyk Medyczny
|
2013
|
Vol. 2, nr 4
183--188
PL
Brachyterapia PDR jest znana i stosowana od początku lat 90. XX wieku, jednak w niewielu ośrodkach onkologicznych opublikowano wyniki leczenia nowotworów tą metodą. Podstawowym celem opracowania i wprowadzenia brachyterapii PDR było zastąpienie ciągłego napromieniania izotopami promieniotwórczymi o niskiej aktywności, stosowanymi w metodzie LDR i napromienianiem impulsami z określoną dla danego leczenia przerwą między nimi, przy zastosowaniu izotopów o wyższej aktywności. W pierwszej części artykułu [1] przedstawiono zagadnienia dotyczące wprowadzenia systemu do użytku klinicznego, procedury przeprowadzania testów krytycznych dla nowego systemu PDR, testów akceptacyjnych i bazowych oraz aplikatorów i pozycjonowania źródła.
10
Content available remote Testy akceptacyjne i dopuszczające dla systemu PDR
Tervinder M. S., Oborska-Kumaszyńska D., Ratcliffe A.
Inżynier i Fizyk Medyczny
|
2013
|
Vol. 2, nr 3
123--128
PL
Brachyterapia PDR jest znana i stosowana od początku lat 90. XX wieku, jednak w niewielu ośrodkach onkologicznych opublikowano wyniki leczenia nowotworów tą metodą. Podstawowym celem opracowania i wprowadzenia brachyterapii PDR było zastąpienie ciągłego napromieniania izotopami promieniotwórczymi o niskiej aktywności, stosowanymi w metodzie LDR, napromienianiem impulsami z określoną dla danego leczenia przerwą między nimi, przy zastosowaniu izotopów o wyższej aktywności (Rys. 1).
11
Content available Dose enhancement in brachytherapy in the presence of gold nanoparticles : a Monte Carlo study on the size of gold nanoparticles and method of modelling
Ghorbani M., Pakravan D., Bakhshabadi M., Meigooni A. S.
Nukleonika
|
2012
|
Vol. 57, No. 3
401-406
EN
The aim of this study was to evaluate the effect of the size of gold nanoparticles (GNPs) on dose enhancement in brachytherapy with photon emitting sources. Four photon emitting sources, 125I, 169Yb, 103Pd, and 192Ir were simulated and dose rate constant and radial dose functions were compared with published corresponding data for these sources. Dose enhancement factor in the presence of gold nanoparticles of 30 mg/ml concentration was calculated separately for nanoparticles with a diameter of 50, 100 and 200 nm. Gold nanoparticles were simulated precisely as nanospheres utilizing a lattice option in the MCNPX Monte Carlo code and the results were compared with those obtained with a simple model in which gold atoms are distributed uniformly in tumor volume as a simple mixture. Among the four mentioned sources, the dose enhancement related to 125I source is higher. Our results have shown that with gold nanoparticles of higher diameter, the level of dose enhancement is higher in the tested tumor. It has been also observed that the simple model overestimates the dose enhancement factor when compared with the precise model in which nanoparticles are defined according to the Monte Carlo code. In the energy range produced by the brachytherapy sources, the dose enhancement is higher when using brachytherapy sources with lower energy. Among the size range of gold nanoparticles used in medicine, it is predicted that nanoparticles with higher diameter can be more useful when are utilized in brachytherapy. It is also recommended that when calculating dose enhancements, a precise model be used for modelling of nanoparticles in the Monte Carlo simulations.
12
Content available Leakage test evaluation used for qualification of iodine-125 seeds sealing
Feher A., Rostelato M. E. C. M., Zeituni C. A., Calvo W. A. P., Somessari S. L., Moura J. A., Moura E. S., Souza C. D., Rela P. R.
Nukleonika
|
2011
|
Vol. 56, No. 4
375-379
EN
Brachytherapy is one of the possible treatments with ionizing radiation available for prostate cancer, in which small seeds containing iodine-125 radioisotope are implanted directly into the prostate. The seed consists of a sealed titanium tube containing a central silver wire with adsorbed iodine-125. The tube sealing is made with titanium at the ends, using plasma arc-welding (PAW) or laser process. This sealing must be leakage-resistant and free of cracks, therefore avoiding iodine-125 to deposit in the silver wire to escape and spread into the human body. To ensure that this problem is not occurring, rigorous leakage tests in accordance with the standard ISO-9978 should be applied. The aim of this study is to determine, implement and evaluate the leakage test to be used in the iodine-125 seeds production, in order to qualify the sealing procedure. The standard ISO-9978 presents a list of tests to be carried out according to the type of source. The preferential methods for brachytherapy sources are soaking and helium. To assess the seeds leakage, the method of immersion test at room temperature was applied. The seeds are considered leakage-free if the detected activity does not exceed 185 Bq (5 nCi). An iodine standard was prepared and its value determined in a sodium iodide detector. A liquid scintillation counter was calibrated with the standard for seed leakage tests. Forty-eight seeds were plasma arc-welded for these tests.
13
Content available Development of an automation system for iodine-125 brachytherapy seed encapsulated by Nd:YAG laser welding
Somessari S. L., Feher A., Sprenger F. E., Rostelato M. E. C. M., da Costa F. E., Calvo W. A. P.
Nukleonika
|
2011
|
Vol. 56, No. 4
369-374
EN
The aim of this work is to develop an automation system for iodine-125 radioactive seed production by Nd:YAG laser welding, which has been used successfully in low dose rate (LDR) brachytherapy treatment. This small seed consists of a welded titanium capsule, with 0.8 mm in diameter and 4.5 mm in length, containing iodine-125 adsorbed onto a silver rod. The iodine-125 seeds are implanted into the human prostate to irradiate the tumor for cancer treatment. Nowadays, the Radiation Technology Center, at Institute for Nuclear and Energy Research, Săo Paulo, Brazil (IPEN-CNEN/SP) imports and distributes 36,000 iodine-125 seeds per year, for the clinics and hospitals in the country. However, the Brazilian market potential is now over 8,000 iodine-125 seeds per month. The local production of these iodine-125 radioactive sources became a priority for the Institute, in order to reduce the price and the problems of prostate cancer management. It will permit to spread their use to a larger number of patients in Brazil. On the other hand, the industrial automation plays an important role for iodine-125 seeds in order to increase the productivity, with high quality and assurance, avoiding human factors, implementing and operating with good manufacturing practices (GMP). The technology consists of appliance electronic and electro-mechanical parts and components to control machines and processes. The automation system technology for iodine-125 seed production developed in this work was mainly assembled employing a programmable logic controller (PLC), a stepper motor, an Nd:YAG laser welding machine and a supervisory. The statistical repeatability of correctly encapsulated sealed sources with this automation system is greater than 95 per cent.
14
Content available Tubing decontamination during the leak test of iodine-125 seeds
Moura J. A., Moura E. S., Sprenger F. E., Nagatomi H. R., Zeituni C. A., Feher A., Manzoli J. E., Souza C. D., Rostelato M. E.
Nukleonika
|
2010
|
Vol. 55, No. 3
409-413
EN
Leak tests were made to detect any leakage of radioactive material from inside the iodine-125 seeds applied in brachytherapy. These seeds are used in prostate cancer treatment. In the quality control routine, during seed production, leak tests are performed according to the International Standard Organization – radiation protection – sealed radioactive sources – ISO-9978 standard, and require liquid transfer between recipients. Any leakage causes contamination of the liquid and tubes. The aim of this study is the establishment of decontamination routines for tubes, allowing their repeated use, in the automated assay process.
15
Content available Zintegrowana linia radioterapeutyczna
Miloch W., Wtorek J.
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
|
2009
|
Nr 26
97-100
PL
Zintegrowana linia radioterapeutyczna (ZLR) stanowi złożenie sprzętu i oprogramowania służącego do precyzyjnej radioterapii. W pierwszej kolejności w referacie wyjaśniono różnice pomiędzy teleradioterapią, a brachyterapią, które stanowią podstawowe rodzaje radioterapii. Następnie przedstawiono budowę i funkcje poszczególnych części ZLR: tomografu komputerowego, systemu planowania leczenia, symulatora i akceleratora. W dalszej kolejności przedstawiono typy komputerów sterujących ich pracą. Opis ten zawiera krótką charakterystykę konfiguracji, systemu operacyjnego, sposobu zasilania i komunikacji z pozostałymi komputerami. W referacie przedstawiono także modyfikacje ZLR, które były konieczne do uzyskania zadawalającego poziomu bezpieczeństwa napromienianych pacjentów. Na zakończenie referatu poruszono problematykę rozwoju linii terapeutycznej dla części brachyterapii jak i teleradioterapii.
EN
The Integrated Radiotherapeutic Line (IRL) constitutes composition of hardware and software for accurate radiotherapy. First, the paper explains the differences between teleradiotherapy and brachytherapy. Next, a structure of IRL is presented and functions of separate parts are described. The types of control computers are presented as well as a short technical characteristic of hardware, computer network and operating system. Another issue of the paper presents modifications of the Integrated Radiotherapeutic Line, which were necessary to achieve an appropriate level of patient’s safety. Problems arising in the course of the line integration are also presented. Finally, the paper presents issues of development of therapeutic line for brachytherapeutic part and teleradiotherapy part.
16
Content available Determination of dosimetry parameters of ADVANTAGETM 103Pd brachytherapy seed using MCNP4C computer code
Ataeinia V., Raisali G., Sadeghi M.
Nukleonika
|
2009
|
Vol. 54, No. 3
181-187
EN
The IsoAid LLC Inc. has been introduced ADVANTAGETM 103Pd brachytherapy seed in 2006. The aim of this work is to determine the dosimetric characteristics of this seed according to AAPM’s recommendation in TG43-U1 using MCNP4C computer code. The dose rate constant has been determined to be 0.694š0.001 cGy.h–1.U–1. The radial dose function has been calculated at distances from 0.25 to 7 cm. Two-dimensional anisotropy function have been calculated at distances from 0.25 to 7 cm and at angles from 0 to 90 degrees centigrade at 10 degrees centigrade increments. The one-dimensional anisotropy function and anisotropy constant have been also calculated. The anisotropy constant in water has been calculated as 0.872š0.001. The results of this investigation are compared with the results of Meigooni et al. obtained by PTRAN code in 2006 and Sowards results obtained by PTRAN code in 2007. The comparison of the dose rate constant and the one-dimensional anisotropy function obtained from the two codes shows good agreement; also the radial dose function at distances lower than 3 cm and the two-dimensional anisotropy function at angles greater than 20 degrees centigrade are in good agreement. But, for the calculated radial dose function at distances beyond 3 cm, we observed differences between our values and Meigooni et al. and Sowards results. Also, differences between the calculated two-dimensional anisotropy function using the two codes for angles smaller than 20 degrees centigrade are considerable. The differences between the results of MCNP4C and PTRAN codes could be related to the different cross-section data libraries used in these two codes.
17
Content available Development and production of radioactive sources used for cancer treatment in Brazil
Rostelato M. E. C. M., Rela P. R., Zeituni C. A., Feher A., Manzoli J. E., Moura J. A., Moura E. S., Silva C. P. G.
Nukleonika
|
2008
|
Vol. 53, suppl. 2
99--103
EN
The number of cancer patients in Brazil is increasing and part of the patients are submitted to brachytherapy treatment using iridium-192 wire and iodine-125 radioactive seeds. The Nuclear Energy Research Institute established a programme to produce iridium-192 wire and iodine-125 radioactive seeds. With the purpose of settling a laboratory for iridium-192 sources production, a wire activation method was developed and a hot cell for the wire manipulation, quality assurance and packaging was built. The iodine-125 seeds consist of a welded titanium capsule containing iodine-125 adsorbed onto a silver rod. Concerning the setup of the local production, the following activities were carried out: superficial treatment of the silver rod, development of a process to absorb the iodine in the silver rod, welding methodology to seal the seeds, leakage and contamination test and source activity measurement.
18
Content available Determination of the geometry function for a brachytherapy seed, comparing MCNP results with TG-43U1 analytical approximations
Raisali G., Ghonchehnazi M. G., Shokrani P., Sadeghi M.
Nukleonika
|
2008
|
Vol. 53, No. 2
45-49
EN
Geometry function is the only dosimetry parameter of a brachytherapy source seed, introduced in TG-43U1 protocol which is determined using calculational methods rather than physical measurement. In order to evaluate the accuracy of point and line source approximations, for calculation of the geometry function, the MCNP computer code has been used for a typical brachytherapy seed and the results have been compared. The MCNP has been used to simulate the geometry and activity distribution of a Pd-103 seed in order to calculate the geometry function for various angles and distances from the source. The comparison of results shows that at distances close to the source, the values predicted with different methods are not in agreement. The difference between the MCNP calculations and line approximation for small angles from ? = 0 to 15° is about 27% at 0.25 cm from the seed center. This difference is so much higher for point source approximation (up to a factor of 3) even up to distances of 0.5 cm from the source. As ? increases, the difference between MCNP and approximate methods is reduced. Therefore, for small distances from brachytherapy seeds, it is recommended to calculate the geometry function using more detailed methods instead of point and linear source approximations. This will provide more accurate results for other TG-43U1 dosimetry parameters such as radial dose function or anisotropy function which for some points are calculated via interpolation or extrapolation of the available discrete dosimetry data.
19
Content available Radioisotopes for medical and industrial use during the 50-year history of the Institute of Nuclear Research
Mikołajczak R., Bazaniak Z., Iller E.
Nukleonika
|
2005
|
Vol. 50,suppl.3
83-87
EN
The paper summarises the 50-years long history of the development of research programmes related to the practical applications of radionuclides in various fields of the Polish economy. The changing trends of interest of the potential users are reflected in the research and development activities of the Radioisotope Centre POLATOM. In the 1960's and 1970's the main areas of activity were focused on the sealed sources and radiolabelled compounds for the investigation of industrial processes. The introduction to the routine practice of the RIA and the IRMA kits for hormonal in vitro diagnostics in the 70-ties and 80-ties resulted in the general availability of this diagnostic technique in Poland. The number of radioisotopes having the required radiation type, energy and half-life is steadily increasing due to the progress in irradiation facilities and in chemical separation processes. The need for modern radiopharmaceuticals, more specific and providing higher diagnostic and therapeutic potential as an alternative to other medical modalities is reflected in the research programmes carried out and implemented currently at the Radioisotope Centre POLATOM.
20
Content available X-ray tube with needle-like anode
Słapa M., Straś W., Traczyk M., Dora J., Snopek M., Gutowski R., Drabik W.
Nukleonika
|
2002
|
Vol. 47, nr 3
101-105
EN
An X-ray tube with a needle-like anode (NAXT) built in our Laboratory, its design and basic operating parameters are presented. The process of electron beam forming and influence of external and internal magnetic fields is discussed. The tube properties essential from the point of view of its application in X-ray generators as well as disadvantageous thermal effects caused by flow of heat generated in the tube target to irradiated objects are discussed. The tube is almost a point-like source of X radiation emitted into 4đ geometry; the dose rates are on the order of 1 Gy/min at the distance of 10 mm from the anode cap. Preliminary tests show the tube may be useful in brachytherapy of cancer tumors of diameter up to 30 mm. The tube may also be an interesting device in widely understood field of irradiation techniques.
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