Publications by authors named "P Tsiamas"

The current study evaluates dosimetric and spectral effects when platinum (Pt)-based chemotherapeutics and less toxic tungstophosphoric-acid (TPA) organometallics are present during x-ray radiotherapy. We hypothesize that the use of high energy photon beams (i.e.

View Article and Find Full Text PDF

Purpose: To model Head-and-Neck anatomy from daily Cone Beam-CT (CBCT) images over the course of fractionated radiotherapy using principal component analysis (PCA).

Methods And Materials: Eighteen oropharyngeal Head-and-Neck cancer patients, treated with volumetric modulated arc therapy (VMAT), were included in this retrospective study. Normal organs, including the parotid and submandibular glands, mandible, pharyngeal constrictor muscles (PCMs), and spinal cord were contoured using daily CBCT image datasets.

View Article and Find Full Text PDF

Purpose: To invent, design, construct, and commission an intensity modulated minibeam proton therapy system (IMMPT) without the need for physical collimation and to compare its resulting conformity to a conventional IMPT system.

Methods: A proton therapy system (Hitachi, Ltd, Hitachi City, Japan; Model: Probeat-V) was specially modified to produce scanned minibeams without collimation. We performed integral depth dose acquisitions and calibrations using a large diameter parallel-plate ionization chamber in a scanning water phantom (PTW, Freiburg, Germany; Models: Bragg Peak ionization chamber, MP3-P).

View Article and Find Full Text PDF

Purpose: The Small Animal Radiation Research Platform (SARRP) has been developed for conformal microirradiation with on-board cone beam CT (CBCT) guidance. The graphics processing unit (GPU)-accelerated Superposition-Convolution (SC) method for dose computation has been integrated into the treatment planning system (TPS) for SARRP. This paper describes the validation of the SC method for the kilovoltage energy by comparing with EBT2 film measurements and Monte Carlo (MC) simulations.

View Article and Find Full Text PDF
Article Synopsis
  • The study explores the use of gold nanoparticles as agents to improve radiation therapy by focusing on different energy targets to enhance tumor blood vessel dose.
  • The authors simulate three clinical photon beams using advanced methods to analyze how the energy spectra affect endothelial cell radiation exposure at varying tissue depths.
  • Results show that using a carbon target significantly increases low energy photon content, leading to much greater endothelial dose enhancements compared to standard beams, and allows for customizable energy delivery based on treatment needs.
View Article and Find Full Text PDF