Medicine and Health Sciences Commons^™

Numerical Chromosomal Instability Mediates Susceptibility To Radiation Treatment, Samuel F. Bakhoum, Lilian Kabeche, Matthew D. Wood, Christopher D. Laucius

Dartmouth Scholarship

The exquisite sensitivity of mitotic cancer cells to ionizing radiation (IR) underlies an important rationale for the widely used fractionated radiation therapy. However, the mechanism for this cell cycle-dependent vulnerability is unknown. Here we show that treatment with IR leads to mitotic chromosome segregation errors in vivo and long-lasting aneuploidy in tumour-derived cell lines. These mitotic errors generate an abundance of micronuclei that predispose chromosomes to subsequent catastrophic pulverization thereby independently amplifying radiation-induced genome damage. Experimentally suppressing whole-chromosome missegregation reduces downstream chromosomal defects and significantly increases the viability of irradiated mitotic cells. Further, orthotopically transplanted human glioblastoma tumours in which …

Quantifying Unnecessary Normal Tissue Complication Risks Due To Suboptimal Planning: A Secondary Study Of Rtog 0126., Kevin L. Moore, Rachel Schmidt, Vitali Moiseenko, Lindsey A. Olsen, Jun Tan, Ying Xiao, James Galvin, Stephanie Pugh, Michael J Seider, Adam P. Dicker, Walter Bosch, Jeff Michalski, Sasa Mutic

Department of Radiation Oncology Faculty Papers

PURPOSE: The purpose of this study was to quantify the frequency and clinical severity of quality deficiencies in intensity modulated radiation therapy (IMRT) planning in the Radiation Therapy Oncology Group 0126 protocol.

METHODS AND MATERIALS: A total of 219 IMRT patients from the high-dose arm (79.2 Gy) of RTOG 0126 were analyzed. To quantify plan quality, we used established knowledge-based methods for patient-specific dose-volume histogram (DVH) prediction of organs at risk and a Lyman-Kutcher-Burman (LKB) model for grade ≥2 rectal complications to convert DVHs into normal tissue complication probabilities (NTCPs). The LKB model was validated by fitting dose-response parameters relative …

On Voxel-By-Voxel Accumulated Dose For Prostate Radiation Therapy Using Deformable Image Registration., Jialu Yu, Nicholas Hardcastle, Kyoungkeun Jeong, Edward T. Bender, Mark A. Ritter, Wolfgang A. Tomé

Department of Radiation Oncology Faculty Papers

Since delivered dose is rarely the same with planned, we calculated the delivered total dose to ten prostate radiotherapy patients treated with rectal balloons using deformable dose accumulation (DDA) and compared it with the planned dose. The patients were treated with TomoTherapy using two rectal balloon designs: five patients had the Radiadyne balloon (balloon A), and five patients had the EZ-EM balloon (balloon B). Prostate and rectal wall contours were outlined on each pre-treatment MVCT for all patients. Delivered fractional doses were calculated using the MVCT taken immediately prior to delivery. Dose grids were accumulated to the last MVCT using …