Study Protocol for Radiation Exposure and Cancer Risk Assessment: The Taiwan Nuclear Power Plants and Epidemiology Cohort Study (TNPECS).

Background: This cohort was established to evaluate whether 38-year radiation exposure (since the start of nuclear reactor operations) is related to cancer risk in residents near three nuclear power plants (NPPs).

Methods: This cohort study enrolled all residents who lived within 8 km of any of the three NPPs in Taiwan from 1978 to 2016 (n = 214,502; person-years = 4,660,189). The control population (n = 257,475; person-years = 6,282,390) from three towns comprised all residents having lived more than 15 km from all three NPPs.

Assessment of resident doses near nuclear power plants in Taiwan for epidemiology study.

Dose assessments were required for the epidemiological study of residents living near nuclear power plants. In the present work, environmental pathway models have been applied to estimate radiation doses to residents living near the nuclear power plants in Taiwan. Best estimates of doses were made for residents by their age groups in different compass sectors centered at the nuclear power plants.

A Monte Carlo study of bone-tissue interface microdosimeters.

Radiation-induced bone diseases were frequently reported in radiotherapy patients. To study the diseases, microdosimeters were constructed with walls of A150-A150, A150-B100, B100-A150 and B100-B100 interfaces. Monte Carlo simulations of these microdosimeters were performed to determine the lineal energy spectra of an interface site at different depths in water for 230 MeV protons.

Radiosensitization of ultrasmall GNP-PEG-cRGDfK in ALTS1C1 exposed to therapeutic protons and kilovoltage and megavoltage photons.

Purpose: One of the promising radiosensitizers is the ultrasmall gold nanoparticle (GNP) with a hydrodynamic diameter <3 nm. We studied functionalized ultrasmall GNPs (1.8 nm diameter) coated by polyethylene glycol (PEG) and conjugated with cyclic RGDfK (2.

MCNPX simulation of proton dose distributions in a water phantom.

Background: This study presents the Monte Carlo N-Particles Transport Code, Extension (MCNPX) simulation of proton dose distributions in a water phantom.

Methods: In this study, fluence and dose distributions from an incident proton pencil beam were calculated as a function of depth in a water phantom. Moreover, lateral dose distributions were also studied to understand the deviation among different MC simulations and the pencil beam algorithm.

Microdosimetric relative biological effectiveness of therapeutic proton beams.

When compared to photon beams, particle beams have distinct spatial distributions on the energy depositions in both the macroscopic and microscopic volumes. In a macroscopic volume, the absorbed dose distribution shows a rapid increase near the particle range, that is, Bragg peak, as particle penetrates deep inside the tissue. In a microscopic volume, individual particle deposits its energy along the particle track by producing localized ionizations through the formation of clusters.

Fast Monte Carlo simulation of DNA damage induction by Auger-electron emission.

Purpose: A local damage model (LDM) was developed to estimate the biological efficiency of Auger-electron-emitting radionuclides.

Materials And Methods: The LDM required information on the local dose distribution, local energy spectrum, and clustered DNA damage yields in the cell nucleus. To apply the model, the nucleus was divided into concentric shells where each shell contributed its own local dose, energy spectrum, and damage yield.

Surveyed data for structural shielding calculations of radiographic x-ray installations in Taiwan.

The use of surveyed data on the x-ray tube workloads and clinical exposure parameters was suggested in NCRP Report No. 147 for the structural shielding design of medical x-ray installations. To guide the shielding design of radiographic x-ray rooms in Taiwan, a large-scale survey was conducted to collect information required for the computations of the transmissions from broad x-ray beams through shielding materials.

Monte Carlo simulations of therapeutic proton beams for relative biological effectiveness of double-strand break.

Purpose: The relative biological effectiveness (RBE) values relative to (60)Co for the induction of double-strand breaks (DSB) were calculated for therapeutic proton beams. RBE-weighted absorbed doses were determined at different depths in a water phantom for proton beams.

Materials And Methods: The depth-dose distributions and the fluence spectra for primary protons and secondary particles were calculated using the FLUKA (FLUktuierende KAskade) MC (Monte Carlo) transport code.

Cellular- and micro-dosimetry of heterogeneously distributed tritium.

Purpose: The assessment of radiotoxicity for heterogeneously distributed tritium should be based on the subcellular dose and relative biological effectiveness (RBE) for cell nucleus. In the present work, geometry-dependent absorbed dose and RBE were calculated using Monte Carlo codes for tritium in the cell, cell surface, cytoplasm, or cell nucleus.

Materials And Methods: Penelope (PENetration and Energy LOss of Positrins and Electrons) code was used to calculate the geometry-dependent absorbed dose, lineal energy, and electron fluence spectrum.

Model-based radiation dose correction for yttrium-90 microsphere treatment of liver tumors with central necrosis.

Purpose: The objectives of this study were to model and calculate the absorbed fraction ϕ of energy emitted from yttrium-90 ((90)Y) microsphere treatment of necrotic liver tumors.

Methods And Materials: The tumor necrosis model was proposed for the calculation of ϕ over the spherical shell region. Two approaches, the semianalytic method and the probabilistic method, were adopted.

Midline dose verification with diode in vivo dosimetry for external photon therapy of head and neck and pelvis cancers during initial large-field treatments.

During radiotherapy treatments, quality assurance/control is essential, particularly dose delivery to patients. This study was designed to verify midline doses with diode in vivo dosimetry. Dosimetry was studied for 6-MV bilateral fields in head and neck cancer treatments and 10-MV bilateral and anteroposterior/posteroanterior (AP/PA) fields in pelvic cancer treatments.

Measurement-based Monte Carlo dose calculation system for IMRT pretreatment and on-line transit dose verifications.

The aim of this study was to develop a dose simulation system based on portal dosimetry measurements and the BEAM Monte Carlo code for intensity-modulated (IM) radiotherapy dose verification. This measurement-based Monte Carlo (MBMC) system can perform, within one systematic calculation, both pretreatment and on-line transit dose verifications. BEAMnrc and DOSXYZnrc 2006 were used to simulate radiation transport from the treatment head, through the patient, to the plane of the aS500 electronic portal imaging device (EPID).

Mathematical estimation and in vivo dose measurement for cone-beam computed tomography on prostate cancer patients.

Background And Purpose: Cone-beam computed tomography (CBCT) increases the doses on normal tissues. Our study sought to develop a mathematical model that would provide an estimate of and verify in vivo rectal dose from CBCT in prostate cancer patients.

Materials And Methods: Thermoluminescent dosimeters (TLDs) and Rando phantoms were used to measure doses to the pelvic region.