Publications by authors named "Tania Karan"
Article Synopsis
- - The study investigates the oxygen depletion hypothesis to explain how FLASH-radiotherapy (FLASH-RT) protects normal tissues while maintaining tumor control, focusing on the DNA Damage Response (DDR) in 3D multicellular spheroids.
- - Experiments were conducted using a Truebeam linear accelerator on spheroids with varying oxygen and temperature conditions, with findings showing different responses of DDR markers (pDNA-PK and γH2AX) to FLASH vs. standard dose rates.
- - Results indicate that FLASH-RT protection is more effective in well-oxygenated tissues and that transient oxygen depletion influences DNA damage markers, suggesting better outcomes for FLASH-RT in tissues with higher oxygen levels.
Introduction: Dynamic tumor tracking (DTT) is a motion management technique where the radiation beam follows a moving tumor in real time. Not modelling DTT beam motion in the treatment planning system leaves an organ at risk (OAR) vulnerable to exceeding its dose limit. This work investigates two planning strategies for DTT plans, the "Boolean OAR Method" and the "Aperture Sorting Method," to determine if they can successfully spare an OAR while maintaining sufficient target coverage.
View Article and Find Full Text PDFPurpose: To assess the feasibility of using the diaphragm as a surrogate for liver targets during MDTT.
Methods: Diaphragm as surrogate for markers: a dome-shaped phantom with implanted markers was fabricated and underwent dual-orthogonal fluoroscopy sequences on the Vero4DRT linac. Ten patients participated in an IRB-approved, feasibility study to assess the MDTT workflow.
Purpose: To assess dynamic tumor tracking (DTT) target localization uncertainty for in-vivo marker-based stereotactic ablative radiotherapy (SABR) treatments of the liver using electronic-portal-imaging-device (EPID) images. The Planning Target Volume (PTV) margin contribution for DTT is estimated.
Methods: Phantom and patient EPID images were acquired during non-coplanar 3DCRT-DTT delivered on a Vero4DRT linac.
Purpose: In this study we present a novel method for re-calculating a treatment plan on different respiratory phases by accurately modeling the panning and tilting beam motion during DTT (the "rotation method"). This method is used to re-calculate the dose distribution of a plan on multiple breathing phases to accurately assess the dosimetry.
Methods: sIMRT plans were optimized on a breath hold computed tomography (CT) image taken at exhale (BH ) for 10 previous liver stereotactic ablative radiotherapy patients.
Purpose: To assess dosimetric properties and identify required updates to commonly used protocols (including use of film and ionization chamber) pertaining to a clinical linac configured into FLASH (ultra-high dose rate) electron mode.
Methods: An 18MV photon beam of a Varian iX linac was converted to FLASH electron beam by replacing the target and the flattening filter with an electron scattering foil. The dose was prescribed by entering the MUs through the console.