Intensity modulated high dose rate ocular brachytherapy using Se-75.

Purpose: We propose an alternative to LDR brachytherapy for the treatment of ocular melanomas by coupling intensity modulation, through the use of a gold shielded ring applicator, with a middle energy HDR brachytherapy source, Se-75. In this study, we computationally test this proposed design using MCNP6.

Methods And Materials: An array of discrete Se-75 sources is formed into a ring configuration within a gold shielded applicator, which collimates the beam to a conical shape.

Shielded high dose rate ocular brachytherapy using Yb-169.

We propose an approach for treating ocular melanoma using a new type of brachytherapy treatment device. This device couples Yb-169, a middle-energy high dose rate (HDR) brachytherapy source, with a gold shielded ring applicator to better conform radiation exposures to the tumor. In this study, we computationally test the dosimetric output of our proposed shielded ring applicator design using MCNP6 and validate it against an I-125 COMS plaque.

Monte Carlo dosimetric characterization of a new high dose rate Yb brachytherapy source and independent verification using a multipoint plastic scintillator detector.

Purpose: A prototype Yb source was developed in combination with a dynamic rotating platinum shield system (AIM-Brachy) to deliver intensity modulated brachytherapy (IMBT). The purpose of this study was to evaluate the dosimetric characteristics of the bare/shielded Yb source using Monte Carlo (MC) simulations and perform an independent dose verification using a dosimetry platform based on a multipoint plastic scintillator detector (mPSD).

Methods: The TG-43U1 dosimetric parameters were calculated for the source model using RapidBrachyMCTPS.

Changes in Occupational Radiation Exposures after Incorporation of a Real-time Dosimetry System in the Interventional Radiology Suite.

A statistical pilot study was retrospectively performed to analyze potential changes in occupational radiation exposures to Interventional Radiology (IR) staff at Lawrence General Hospital after implementation of the i2 Active Radiation Dosimetry System (Unfors RaySafe Inc, 6045 Cochran Road Cleveland, OH 44139-3302). In this study, the monthly OSL dosimetry records obtained during the eight-month period prior to i2 implementation were normalized to the number of procedures performed during each month and statistically compared to the normalized dosimetry records obtained for the 8-mo period after i2 implementation. The resulting statistics included calculation of the mean and standard deviation of the dose equivalences per procedure and included appropriate hypothesis tests to assess for statistically valid differences between the pre and post i2 study periods.

A brachytherapy photon radiation quality index Q(BT) for probe-type dosimetry.

Introduction: In photon brachytherapy (BT), experimental dosimetry is needed to verify treatment plans if planning algorithms neglect varying attenuation, absorption or scattering conditions. The detector's response is energy dependent, including the detector material to water dose ratio and the intrinsic mechanisms. The local mean photon energy E¯(r) must be known or another equivalent energy quality parameter used.

Dosimetric characterization of the M-15 high-dose-rate Iridium-192 brachytherapy source using the AAPM and ESTRO formalism.

The Source Production & Equipment Co. (SPEC) model M-15 is a new Iridium-192 brachytherapy source model intended for use as a temporary high-dose-rate (HDR) brachytherapy source for the Nucletron microSelectron Classic afterloading system. The purpose of this study is to characterize this HDR source for clinical application by obtaining a complete set of Monte Carlo calculated dosimetric parameters for the M-15, as recommended by AAPM and ESTRO, for isotopes with average energies greater than 50 keV.

Variation in the calibrated response of LiF, Al2O3, and silicon dosimeters when used for in-phantom measurements of source photons with energies between 30 KeV AND 300 KeV.

The MCNP5 radiation transport code was used to quantify changes in the absorbed dose conversion factor for LiF, Al2O3, and silicon-based electronic dosimeters calibrated in-air using standard techniques and summarily used to measure absorbed dose to water when placed in a water phantom. A mono-energetic photon source was modeled at energies between 30 keV and 300 keV for a point-source placed at the center of a water phantom, a point-source placed at the surface of the phantom, and for a 10-cm radial field geometry. Dosimetric calculations were obtained for water, LiF, Al2O3, and silicon at depths of 0.

Dosimetric characterization of the GammaClip™ 169Yb low dose rate permanent implant brachytherapy source for the treatment of nonsmall cell lung cancer postwedge resection.

Purpose: A novel (169)Yb low dose rate permanent implant brachytherapy source, the GammaClip™, was developed by Source Production & Equipment Co. (New Orleans, LA) which is designed similar to a surgical staple while delivering therapeutic radiation. In this report, the brachytherapy source was characterized in terms of "Dose calculation for photon-emitting brachytherapy sources with average energy higher than 50 keV: Report of the AAPM and ESTRO" by Perez-Calatayud et al.

Selection of an appropriate air kerma rate constant for 75Se sources.

Monte Carlo simulation techniques using a Monte Carlo N-Particle code (MCNP5) analyzed six Source Production & Equipment Co., Inc., Se industrial radiography sources to determine an appropriate air kerma rate constant for Se, factoring in source encapsulation and compared to a theoretical approximation.

Introduction to radiation safety and monitoring.

Ionizing radiation is used in diagnostic imaging, external-beam radiation therapy, brachytherapy, and nuclear medicine to diagnose and treat a number of common conditions. To ensure the safety of patients, providers, and surrounding staff members, it is important that the health care community become familiar with the terminology, common equipment, and standard practices used in radiation safety and monitoring. The authors aim to provide an introduction to radiation safety and monitoring so that health care providers and support personnel who may have contact with patients, equipment, and facilities that use radioactive material may be more aware of the policies and precautions that are in place to ensure their safety.

Effects of breast-air and breast-lung interfaces on the dose rate at the planning target volume of a MammoSite catheter for Yb-169 and Ir-192 HDR sources.

Purpose: To study the effects of the breast-air and breast-lung interfaces on the absorbed dose within the planning target volume (PTV) of a MammoSite balloon dose delivery system as well as the effect of contrast material on the dose rate in the PTV.

Methods: The Monte Carlo MCNP5 code was used to simulate dose rate in the PTV of a 2 cm radius MammoSite balloon dose delivery system. The simulations were carried out using an average female chest phantom (AFCP) and a semi-infinite water phantom for both Yb-169 and Ir-192 high dose rate sources for brachytherapy application.

Dependence of Yb-169 absorbed dose energy correction factors on self-attenuation in source material and photon buildup in water.

Purpose: Absorbed dose energy correction factors, used to convert the absorbed dose deposited in a LiF thermoluminescent dosimeter (TLD) into the clinically relevant absorbed dose to water, were obtained for both spherical volumetric sources and for the model 4140 HDR Yb-169 source. These correction factors have a strong energy dependence below 200 keV; therefore, spectral changes were quantified as Yb-169 photons traveled through both source material (Yb2O3) and water with the corresponding absorbed dose energy correction factors, f(r, theta), calculated as a function of location in a phantom.

Methods: Using the MCNP5 Monte Carlo radiation transport simulation program, the Yb-169 spectrum emerging from spherical Yb2O3 sources (density 6.

Monte Carlo characterization of a new Yb-169 high dose rate source for brachytherapy application.

Purpose: The objective was to characterize a new Yb-169 high dose rate source for brachytherapy application.

Methods: Monte Carlo simulations were performed using the MCNP5 F6 energy deposition tallies placed around the Yb-169 source at different radial distances in both air-vacuum and water environments. The calculations were based on a spherical water phantom with a radius of 50 cm.

Polymethylmethacrylate and radioisotopes in vertebral augmentation: an explanation of underlying principles.

We recently reported a novel concept for combining radioactive isotope technology with polymethylmethacrylate (PMMA) cement used for vertebral augmentation and have advocated that pain physicians become aware of this new concept when treating malignant compression fractures. The use of vertebral augmentation for malignant compression fractures is steadily increasing, and the goal of this novel approach would be to stabilize the fractured vertebral body while also controlling proliferation of the tumor cells in the vertebral body that caused the vertebral fracture. This approach would therefore provide mechanical stabilization of the fractured vertebral body at the same time as direct targeting of the cancer cells causing the fracture.

Radioisotopes and vertebral augmentation: dosimetric analysis of a novel approach for the treatment of malignant compression fractures.

Purpose: Vertebral compression fractures (VCFs), a major cause of morbidity and debilitating pain, often results from secondary tumor metastases to the skeleton. Vertebral augmentation is a palliative technique developed to treat VCFs and involves the injection of polymethyl methacrylate (PMMA) to augment the fractured vertebral body. The authors investigate the feasibility of radionuclide therapy coupled with vertebral augmentation to treat both the tumor metastases and VCFs.

Monte Carlo characterization of the M-19 high dose rate Iridium-192 brachytherapy source.

The MCNP5 Monte Carlo code was used to simulate the dosimetry of an M-19 iridium-192 high dose rate brachytherapy source in both air/vacuum and water environments with the in-air photon spectrum filtered to remove low-energy photons below delta=10 keV. Dosimetric data was organized into an away-along table and was used to derive the updated AAPM Task Group Report No. 43 (TG-43U1) parameters including S(K), D(r, theta), lamda, gL(r), F(r, theta), phi an(r), and phi an, and their respective statistical uncertainties.

Monte Carlo characterization of an ytterbium-169 high dose rate brachytherapy source with analysis of statistical uncertainty.

An ytterbium-169 high dose rate brachytherapy source, distinguished by an intensity-weighted average photon energy of 92.7 keV and a 32.015 +/- 0.

Monte Carlo calculated TG-43 dosimetry parameters for the SeedLink 125Iodine brachytherapy system.

The SeedLink brachytherapy system is comprised from an assembly of I-Plant 3500 interstitial brachytherapy seeds and bioresorbable spacers joined together by a 6-mm-long titanium sleeve centered over each seed. This device is designed to maintain specified spacing between seeds during treatment thereby decreasing implant preparation time and reducing radionuclide migration within the prostate and periprostatic region. Reliable clinical treatment and planning applications necessitate accurate dosimetric data for source evaluation, therefore the authors report the results of a Monte Carlo study designed to calculate the AAPM Task Group Report No.