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Monte Carlo simulations and TLD dosimetry have been performed to determine the dose distributions along the central axis of the 12 mm COMS eye plaques loaded with IRA1-103Pd seeds. Several simulations and measurements have been employed to investigate the effect of Silastic insert and air in front of the eye on dosimetry results along the central axis of the plaque and at some critical ocular structures. Measurements were performed using TLD-GR200A circular chip dosimeters in a PMMA eye phantom. The central axis TLD chips locations were arranged in one central column of eye phantom, in 3 mm intervals. The off-axis TLD chips locations were arranged in three off-axis columns around the central axis column. Version 5 of the MCNP code was also used to evaluate the dose distribution around the plaque. The presence of the Silastic insert results in dose reduction of 14% at 5 mm; also about 7% dose reduction appears at the interface point, due to the air presence and lack of the scattering condition. The overall dosimetric parameters for the COMS eye plaque loaded with new palladium seeds are similar to a commercial widely used seed such as Theragenics200. As the dose calculations under TG-43 assumptions do not consider the effect of the plaque backing and Silastic insert for accurate dosimetry, it's suggested to apply the effect of the eye plaque materials and air on dosimetry results along the central axis of the plaque and at some critical ocular structures.

Derived from AAPM task group No. 60/149 protocol, applicable in treatment planning In this study, the two-dimensional dose distributions in water for a 32P intravascular brachytherapy stent have been calculated. The pure beta emitter source 32P which has been coated on Palmaz-Schatz stent is discussed. The dosimetric parameters required by the AAPM TG-60/149 formalism are discussed and calculated. Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate the dosimetry parameters around the source. The Monte Carlo calculated dose rate at the reference point is found to be 2.8 Gy/μCi. Also in this study, the geometry function, G(r,θ), radial dose function, g(r), and the anisotropy function, F(r,θ), have been calculated at distances from 1.8 to 9 mm. The results of these calculations have been compared with other published calculated and measured values for an actual same source. High dose variants were visible near the 32P stent surface, but these values decreased with depth in water rapidly. There is an acceptable agreement between the calculated data in this study and other published data for the same source, which validate our simulations method.

In this study, design and fabrication of 103Pd brachytherapy seed was investigated. The excitation functions of 103Rh(p,n) 103Pd and 103Rh(d,2n)103Pd reactions were calculated using EMPIRE (version 3.1 Rivoli), ALICE/ASH and TALYS-1.2 codes, the TENDL-2010 database and compared with the published data. Production of 103Pd was done via 103Rh(p,n)103Pd nuclear reaction. The target was bombarded with 18 MeV protons at 200 μA beam current for 15 h. After irradiation and radiochemical separation of the electroplated rhodium target, the optimum condition for absorption of 103Pd into Amberlite®IR-93 resin was achieved at 0.5 M HCl. Version 5 of the (MCNP) Monte Carlo radiation transport code was employed to calculate the dosimetric parameters around the 103Pd brachytherapy seed. Finally the calculated results were compared with published results for other commercial sources. © 2011 Elsevier Ltd. All rights reserved.

This work presents experimental dosimetry results for a new P103d brachytherapy seed, in accordance with the AAPM TG‐43U1 recommendation that all new low‐energy interstitial brachytherapy seeds should undergo one Monte Carlo (MC) and at least one experimental dosimetry characterization. Measurements were performed using TLD‐GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. The Monte Carlo N‐particle (MCNP) code, version 5 was used to evaluate the dose‐rate distributions around this model P103d source in water and Perspex phantoms. The consensus value for dose‐rate constant of the IR06‐P103d source was found equal to 0.690 cG⋅h−1⋅U−1. The anisotropy function, F(r, θ), and the radial dose function, gL(r), of the seed were measured in Perspex phantom and calculated in both Perspex and liquid water phantom. The measured values were also found in good agreement with corresponding MC calculations. PACS number: 87.53.Jw

Purpose For the treatment of some cancerous tumors using brachytherapy, an American Association of Physicists in Medicine (AAPM) Task Group No. 43U1 report recommends that the dosimetric parameters of a new brachytherapy source must be determined in two experimental and Monte Carlo theoretical methods before using each new source clinically. This study presents the results of Monte Carlo calculations of the dosimetric parameters for a Ir2.A85-2 brachytherapy source design.

Dosimetry of two new interstitial brachytherapy sources With increased demand for low 103Pd (palladium) seed sources, to treat prostate and eye cancers, new sources have been designed and introduced. This article presents the two new palladium brachytherapy sources, IR03-103Pd and IR04-103Pd that have been developed at Nuclear Science and Technology Research Institute. The dosimetry parameters such as the dose rate constant Λ, the radial dose function g(r), and the anisotropy function F(r,θ), around the sources have been characterized using Version 5 Monte Carlo radiation transport code in accordance with the update AAPM Task Group No. 43 report (TG-43U1). The results indicated the dose rate constant of 0.689±0.02 and 0.667±0.02 cGy h-1 U-1 for the IR03-103Pd and IR04-103Pd sources respectively, which are in acceptable agreement with other commercial seeds. The calculated results were compared with published results for those of other source manufacturers. However, they show an acceptable dose distribution, using for clinical applications is pending experimental dosimetry.

Rhenium-186, having a half-life of 90.64 h, is an important radionuclide, used in metabolic radiotherapy and radio immunotherapy. 186 Re hydroxyethylidene diphosphonate (HEDP) is a new compound used for the palliation of painful skeletal metastases. Its production is achieved via charged-particle-induced reactions; the data are available in EXFOR library. For the work discussed in this paper, production of 186 Re was done via nat W(p,n) 186 Re nuclear reaction. Pellets of nat W were used as targets and were irradiated with 15, 17.5, 20, 22.5, 25 MeV proton beams at 5 μA current. The radiochemical separation was performed by the ion exchange chromatography method. The production yield achieved at 25 MeV was 1.91 MBq·μA -1 ·h -1 . Excitation functions for the 186 Re radionuclide, via 186 W(p,n) 186 Re and 186 W(d,2n) 186 Re reactions were calculated by ALICEASH and TALYS-1.0 codes to validate and fit the experimental data and to obtain a recommended set of data for 186 W(p,n) 186 Re reaction. Required thickness of the targets was obtained by SRIM code for each reaction.

Purpose: For the treatment of some canceroustumors using brachytherapy methods and low-energy photon sources, such as I 125 and P 103 d , the American Association of Physicists in Medicine Task Group No. 43U1 report recommends that the dosimetric parameters of a new brachytherapy source must be determined in two experimental and Monte Carlo theoretical methods before using each new source clinically. This study presents the results of Monte Carlo calculations of the dosimetric parameters for IR08- P 103 d brachytherapy source design. IR08- P 103 d seed has been manufactured at the Agricultural, Medical and Industrial Research School. Methods: Version 5 of the (MCNP) Monte Carloradiation transport code was used to calculate the dosimetry parameters around the source. Three geometric models of the seed, based on different locations of beads inside the titanium capsule, were simulated. The seed contains five resin beads of 0.6 mm diameter having P 103 d uniformly absorbed in the bead volume, which were contained within a cylindrical titanium capsule having 0.8 mm outside diameter and 4.8 mm length. Results: The Monte Carlo calculated dose rate constant Λ of the IR08- P 103 d seed was found to be 0.695 ± 0.021 cGyU − 1 h − 1 . Also in this study, the geometry function G ( r , θ ) , line and point-source radial dose functions g L ( r ) and g P ( r ) , and the anisotropy function F ( r , θ ) , have been calculated at distances from 0.25 to 7 cm. The results of these calculations have been compared with measured values for an actual IR08- P 103 d seed. Conclusions: There are no statistical significant dosimetric differences among the three seed orientations in this study (i.e., ideal, vertical, and diagonal). However, the observed differences between the calculated and measured values could be explained by the measurement uncertainty and the configuration of the resin beads within the capsule and capsule orientation.

The Monte Carlo method is a numerical technique that using random numbers and proba‐ bility to solve problems. It represents an attempt to model nature through direct simulation for any possible results, by substituting a range of values (a probability distribution) for any factor that has inherent uncertainty. The method is named after the city in the Monaco prin‐ cipality, because of roulette, a simple random number generator. The name and the system‐ atic development of Monte Carlo method dates from about 1944.The name “Monte Carlo” refers to the Monte Carlo Casino in Monaco because of the similarity of statistical simulation to games of chance and was coined by Metropolis during the Manhattan Project of World War II, [1].

In this Study characteristics of a new 170Tm brachytherapy seed using thermoluminescent dosimeter and also the Monte Carlo simulations to evaluate between calculated and measured values was determined. Titanium tube contained Tm(NO3)3 powders bombardment at the Tehran Research Reactor (TRR) for a period of 7 days at a flux of 2–3 × 1013 neutrons/cm2 s. To obtain the radial dose function, g(r), and the anisotropy function, F(r, θ), according to the AAPM TG-43U1 recommendations, 30 cm × 30 cm × 15 cm phantoms of Perspex slabs were used. Brachytherapy dose distributions were simulated with the MCNP5 Monte Carlo (MC) radiation transport code. The MCPLIB04 photon cross-section library was applied using data from ENDF/B-VI. Cell-heating tally, F6 was employed to calculate absorbed dose in two separate runs for both beta and gamma particles. The calculated dose rate constant for the HDR source was found to be 1.113 ± 0.021 cGyU−1 h−1. Nominal uncertainty in the measured and calculated radial dose functions, g(r), for the IR-170Tm source in Perspex is tabulated is approximately 6% (ranging from 2% to 9%). The anisotropy function, F(r, θ), of the IR-170Tm source was measured at radial distances of r = 1.5, 2, 3, 5 cm relative to the seed center, and polar angles θ ranging from 0° to 330° in 30° increments.

The term of brachytherapy, also known as “internal radiotherapy, sealed source radiotherapy, curietherapy or endocurietherapy” is from Greek work brachy means short distance and therapy (treatment) and also known as internal radiotherapy or sealed source radiotherapy. Brachytherapy is a special form of radiotherapy where a radioactive source is carefully placed on or inside the area to be treated. Brachytherapy sources are usually encapsulated; they can be used within the body cavities close to the tumor, placed in a lumen of organs, implanted in to the tumor or placed over the tissue to be treated. The main purpose in radiation therapy is controlling disease and reducing side effects. For a good clinical result one must assure the dose concentrate in the tumor mass and surrounding volume which is at risk of the tumor micro-extensions, while minimizing radiation received by the normal tissue. This can be verified by experimental measurement which is the base of Brachytherapy dosimetry. Due to the high dose gradient near the source and low signal to noise ratio at great distances, experimental dosimetry in Brachytherapy is very complicated or even in small distances is impossible. Also the dose variation with angle in 4┨ geometry of the source must be considered, since routine experimental measurement does not represent this. One of the widely used techniques for solving this problem is Monte Carlo simulation of radiation transport. The calculation of dose distributions at small distances and also validation of experimental measurement can be done by one of the powerful codes such as MCNP, BEAM, EGSnrc, PENELOPE, GEANT4, and ETRAN/ITS. One of the important parameters in the calculation process is validation of the Monte Carlo calculations with measurement results. This chapter starts with an introduction lecture about brachytherapy history and a short review of the different models for sealed Brachytherapy sources. A brief discuss of brachytherapy dosimetry with computer and measurement is provided. In 1995 the American Association of Physicists in Medicine (AAPM) Task Group No. 43 published a protocol including new formalism for brachytherapy dose calculation and updated in 2004 as TG-43U1. The concept of AAPM recommendation and TG 43 formalism are introduced. Application of Monte Carlo in simulation, guideline for Monte Carlo dosimetry, calculation methodology, requirement for simulation and validation of calculation are then outlined. A

Brachytherapy dose distributions are calculated for 15 mm ROPES eye plaque loaded with model Theragenics200 and IR06-(103)Pd seeds. The effects of stainless steel backing and Acrylic insert on dose distribution along the central axis of the eye plaque and at critical ocular structure are investigated. Monte Carlo simulation was carried out with the Version 5 of the MCNP. The dose at critical ocular structure by considering the eye composition was calculated. Results are compared with the calculated data for COMS eye plaque loaded with Theragenics200 palladium-103 seeds and model 6711 iodine-125 seed. The air kerma strength of the IR06-(103)Pd seed to deliver 85 Gy in apex of tumor in water medium was calculated to be 4.10 U/seed. Along the central axis of stainless steel plaque loaded with new (103)Pd seeds in Acrylic insert, the dose reduction relative to water is 6.9% at 5 mm (apex). Removal of the Acrylic insert from the plaque (replacing with water) did not make significantly difference in dose reduction results (~0.2%). The presence of the stainless steel backing results in dose enhancement near the plaque relative to water. Doses at points of interest are higher for ROPES eye plaque when compared to COMS eye plaque. The dosimetric parameters calculated in this work for the new palladium seed, showed that in dosimetry point of view, the IR06-(103)Pd seed is suitable for use in brachytherapy. The effect of Acrylic insert on dose distribution is negligible and the main effect on dose reduction is due to the presence of stainless steel plaque backing.

In this study version 5 of the MCNP photon transport simulation was used to calculate the dosimetric parameters for new palladium brachytherapy source design following AAPM Task Group No. 43U1 report. The internal source components include four resin beads of 0.6 mm diameters with 103 Pd uniformly absorbed inside and one cylindrical copper marker with 1.5 mm length. The resin beads and marker are then encapsulated within 0.8 mm in diameter and 4.5 mm long cylindrical capsule of titanium. The dose rate constant, Λ , line and point-source radial dose function, g L ( r ) and g P ( r ), and the anisotropy function, F ( r , θ ) of the IR01- 103 Pd seed have been calculated at distances from 0.25 to 5 cm. All the results are in good agreement with previously published thermoluminescence-dosimeter measured values [3] for the source. The dosimetric parameters calculated in this work showed that in dosimetry point of view, the IR01- 103 Pd seed is suitable for use in brachytherapy of prostate cancer.

For the treatment of some cancerous tumors using brachytherapy, an American Association of Physicists in Medicine (AAPM) Task Group No. 43U1 report recommends that the dosimetric parameters of a new brachytherapy source must be determined in two experimental and Monte Carlo theoretical methods before using each new source clinically. This study presents the results of Monte Carlo calculations of the dosimetric parameters for a Ir2.A85-2 brachytherapy source design.Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate the dosimetry parameters around the source.The Monte Carlo calculated dose rate constant, Λ, of the Ir2.A85-2 source was found to be 1.113 ± 0.033 cGyU(-1)h(-1). Also in this study, the line-source radial dose function, g ( l )(r) and the anisotropy function, F(r,θ), have been calculated at distances from 0.5 to 10 cm. The results of these calculations have been compared with the published data for the same source.All the results are in good concordance with previously published data, with a few exceptions in small angles and short distances. The dosimetric parameters calculated in this work can be used as input data in a treatment planning system (TPS) for exact brachytherapy treatment planning or to verify the calculations of the TPS used in brachytherapy.

For the treatment of some cancerous tumors using brachytherapy methods and low-energy photon sources, such as 125I and 103Pd, the American Association of Physicists in Medicine Task Group No. 43U1 report recommends that the dosimetric parameters of a new brachytherapy source must be determined in two experimental and Monte Carlo theoretical methods before using each new source clinically. This study presents the results of Monte Carlo calculations of the dosimetric parameters for IR08-103Pd brachytherapy source design. IR08-103Pd seed has been manufactured at the Agricultural, Medical and Industrial Research School.Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate the dosimetry parameters around the source. Three geometric models of the seed, based on different locations of beads inside the titanium capsule, were simulated. The seed contains five resin beads of 0.6 mm diameter having 103Pd uniformly absorbed in the bead volume, which were contained within a cylindrical titanium capsule having 0.8 mm outside diameter and 4.8 mm length.The Monte Carlo calculated dose rate constant of the IR08-103Pd seed was found to be 0.695 +/- 0.021 cGyU(-1) h(-1). Also in this study, the geometry function G(r, theta), line and point-source radial dose functions gL(r) and gP(r), and the anisotropy function F(r, theta), have been calculated at distances from 0.25 to 7 cm. The results of these calculations have been compared with measured values for an actual IR08-103Pd seed.There are no statistical significant dosimetric differences among the three seed orientations in this study (i.e., ideal, vertical, and diagonal). However, the observed differences between the calculated and measured values could be explained by the measurement uncertainty and the configuration of the resin beads within the capsule and capsule orientation.

Nuclear interactions of the projectile carbon ion in biological soft tissue for cancer treatment purpose are studied. Elastic interaction of carbon ion with carbon, oxygen and nitrogen nuclei existing in soft tissue leads to beam divergence especially in Bragg peak region, where the carbon ion is slowing down. Monte Carlo simulation shows the amount of carbon ion beam divergence in soft tissue. For carbon ion beam with 2.4 GeV energy and 2mm diameter, at 85mm penetration depth the beam spreads out to 4mm diameter. Non-elastic interactions are modeled as well. Such interactions are important due to secondary radiation produced in patient’s body. The product particles include positrons and neutrons, being important in therapeutic dose verification with PET imaging and extra dose in the hospital ambient, respectively. Computer code ALICE produces reaction cross sections that might be used to roughly estimate the neutron and positron yield. Computer code ALICE was used to assess the cross section and yield of products from carbon nuclei interaction with soft tissue.

With increased demand for low 103 Pd (palladium) seed sources, to treat prostate and eye cancers, new sources have been designed and introduced. This paper presents the two new palladium brachytherapy sources, IR03- 103 Pd and IR04- 103 Pd that have been developed at Agricultural, Medical & Industrial Research School . The dosimetric parameters, such as the dose rate constant Λ , the radial dose function g ( r ) and the anisotropy function F ( r , θ ), around the sources have been characterised using Version 5 Monte Carlo radiation transport code in accordance with the update AAPM Task Group No. 43 Report (TG-43U1). The results indicated the dose rate constant of 0.689 ± 0.02 and 0.667 ± 0.02 cGy h -1 U -1 for the IR03- 103 Pd and IR04- 103 Pd sources, respectively, which are in acceptable agreement with other commercial seeds. The calculated results were compared with published results for those of other source manufacturers. However, they show an acceptable dose distribution, using for clinical applications is pending experimental dosimetry.