Search results for " Radioisotope"
showing 10 items of 246 documents
Monte Carlo calculation of dose rate distributions around 192Ir wires.
1997
Monte Carlo calculations of absolute dose rate in liquid water are presented in the form of away-along tables for 1 and 5 cm 192 Ir wires of 0.3 mm diameter. Simulated absolute dose rate values can be used as benchmark data to verify the calculation results of treatment planning systems or directly as input data for treatment planning. Best fit value of attenuation coefficient suitable for use in Sievert-integrals-type calculations has been derived based on Monte Carlo calculation results. For the treatment planning systems that are based on TG43 formalism we have also calculated the required dosimetry parameters.
Monte Carlo calculation of dose rate distributions around the Walstam CDC.K-type137Cs sources
2001
Basic dosimetric data for the Walstam CDC.K-type low dose rate 137Cs sources in water have been calculated using Monte Carlo techniques. These sources, CDC.K1 -K3 and CDC.K4, are widely used in a range of applicators and moulds for the treatment of intracavitary and superficial cancers. Our purpose is to improve existing data about these sources using the Monte Carlo simulation code GEANT3. Absolute dose rate distributions in water have been calculated around these sources and are presented as conventional 2D Cartesian look-up tables. Also the AAPM Task Group 43 formalism for dose calculation has been applied. The calculated dose rate constant for the CDC.K1-K3 source is A = 1.106 +/- 0.001…
Monte Carlo dosimetry of the Buchler high dose rate 192Ir source.
2001
In this study a complete set of dosimetric data is presented for the high dose rate (HDR) source from Amersham used in the Buchler remote afterloading HDR unit. These data have been calculated by means of the Monte Carlo simulation code GEANT taking into account the detailed geometry of the source. Absolute dose rate distributions in water were calculated around this source and are presented as conventional 2D Cartesian look-up tables. All dosimetric quantities recommended by the AAPM Task Group 43 report have been calculated. Quantities determined are: dose rate constant, radial dose function, anisotropy function, anisotropy factor and anisotropy constant. The dose rate distributions of th…
Dosimetry characteristics of the Plus and 12i Gammamed PDR 192Ir sources.
2001
In this study a complete set of dosimetric data for the Plus and 12i Gammamed PDR (pulsed dose rate) 192 Ir sources is presented. These data have been calculated using the Monte Carlo simulation code GEANT3. Absolute dose rate distributions in water around these sources were calculated and are presented in form of conventional two dimensional (2D) Cartesian look-up tables. All dosimetric quantities recommended by the AAPM Task Group 43 report have been also calculated. These quantities are dose rate constant, radial dose function, anisotropy function and anisotropy factor. The dose rate distribution of the 12i source was compared with the corresponding data for the microselectron PDR source…
A Monte Carlo investigation of the dosimetric characteristics of the CSM11 137Cs source from CIS
2000
The purpose of this study is to calculate basic dosimetry data for a CSM11 low dose rate 137Cs source in water. This source is widely used in afterloadable dome cylinders designed to homogeneously irradiate the vaginal cuff alone or additional areas of the vagina in hysterectomized patients. In this study, the Monte Carlo simulation code GEANT, incorporating in detail source geometry, is used to investigate the dosimetric characteristics of the source. The calculated data were analyzed using a fitting procedure that is described in detail. Absolute dose rate distributions in water were calculated around this source and are presented as conventional 2D Cartesian lookup tables (classically al…
Monte Carlo dosimetric characterization of the Cs-137 selectron/LDR source: evaluation of applicator attenuation and superposition approximation effe…
2004
The purpose of this study is to calculate the dose rate distribution for the Amersham Cs-137 pellet source used in brachytherapy with the Selectron low-dose-rate remote afterloading system in gynaecological applications using the Monte Carlo code GEANT4. The absolute dose rate distribution for the pellet source was obtained and presented as a one-dimensional absolute dose rate table as well as in the Task Group 43 dose-calculation formalism. In this study, excellent agreement was found between the point source theoretical model using fitted polynomial values and Monte Carlo calculations of the dose rate distribution for the pellet source. A comparison study was also made between the dose ra…
Technical note: Monte-Carlo dosimetry of the HDR 12i and Plus 192Ir sources.
2001
In this study a complete set of dosimetric data for the GammaMed high dose rate (HDR) 12i and Plus 192 Ir sources are presented. These data have been calculated by means of the Monte Carlo simulation code GEANT3. Absolute dose rate distributions in water are presented as conventional two dimensional (2D) Cartesian look-up tables, and in the TG43 formalism.
Image-Guided Synthesis Reveals Potent Blood-Brain Barrier Permeable Histone Deacetylase Inhibitors
2014
Recent studies have revealed that several histone deacetylase (HDAC) inhibitors, which are used to study/treat brain diseases, show low blood-brain barrier (BBB) penetration. In addition to low HDAC potency and selectivity observed, poor brain penetrance may account for the high doses needed to achieve therapeutic efficacy. Here we report the development and evaluation of highly potent and blood-brain barrier permeable HDAC inhibitors for CNS applications based on an image-guided approach involving the parallel synthesis and radiolabeling of a series of compounds based on the benzamide HDAC inhibitor, MS-275 as a template. BBB penetration was optimized by rapid carbon-11 labeling and PET im…
Radio-metabolite analysis of carbon-11 biochemical partitioning to non-structural carbohydrates for integrated metabolism and transport studies.
2013
Metabolism and phloem transport of carbohydrates are interactive processes, yet each is often studied in isolation from the other. Carbon-11 ((11)C) has been successfully used to study transport and allocation processes dynamically over time. There is a need for techniques to determine metabolic partitioning of newly fixed carbon that are compatible with existing non-invasive (11)C-based methodologies for the study of phloem transport. In this report, we present methods using (11)C-labeled CO2 to trace carbon partitioning to the major non-structural carbohydrates in leaves-sucrose, glucose, fructose and starch. High-performance thin-layer chromatography (HPTLC) was adapted to provide multis…
A low-level spectrometer with a planar low-energy HPGe: shielding arrangement tests and system performance for 210Pb determination in air filter samp…
2001
A system for low-energy photon spectrometry using a planar germanium detector with appropriate specifications is presented. A spectrometric background investigation has been carried out with various detector shielding arrangements. The characteristics of the system for measurements of 210Pb in air-particulate matter on filters have been determined.