Medicine and Health Sciences Commons^™

An Analytical Expression For R50% Dependent On Ptv Surface Area And Volume: A Cranial Srs Comparison, Dharmin D. Desai, Ellis Lee Johnson, Ivan L. Cordrey

Radiation Medicine Faculty Publications

The intermediate dose spill for a stereotactic radiosurgery (SRS) plan can be quantified with the metric R50%, defined as the 50% isodose cloud volume (V_IDC50%) divided by the volume of the planning target volume (PTV). By coupling sound physical principles with the basic definition of R50%, we derive an analytical expression for R50% for a spherical PTV. Our analytical expression depends on three quantities: the surface area of PTV (SA_PTV), the volume of PTV (V_PTV), and the distance of dose drop-off to 50% (Δr). The value of ∆r was obtained from a simple set …

Comparative Effectiveness Of Intensity Modulated Radiation Therapy To 3-Dimensional Conformal Radiation In Locally Advanced Lung Cancer: Pathological And Clinical Outcomes., Sarit Appel, Jair Bar, Alon Ben-Nun, Marina Perelman, Dror Alezra, Damien Urban, Maoz Ben-Ayun, Nir Honig, Efrat Ofek, Tamar Katzman, Amir Onn, Sumit Chatterji, Sergey Dubinski, Lev Tsvang, Shira Felder, Judith Kraitman, Ory Haisraely, Tatiana Rabin Alezra, Sivan Lieberman, Edith M. Marom, Nir Golan, David Simansky, Zvi Symon, Yaacov Richard Lawrence

Department of Radiation Oncology Faculty Papers

OBJECTIVE: Intensity-modulated radiotherapy (IMRT) has better normal-tissue sparing compared with 3-dimensional conformal radiation (3DCRT). We sought to assess the impact of radiation technique on pathological and clinical outcomes in locally advanced non-small cell lung cancer (LANSCLC) treated with a trimodality strategy.

METHODS: Retrospective review of LANSCLC patients treated from August 2012 to August 2018 at Sheba Medical Center, Israel. The trimodality strategy consisted of concomitant chemoradiation to 60 Gray (Gy) followed by completion surgery. The planning target volume (PTV) was defined by co-registered PET/CT. Here we compare the pathological regression, surgical margin status, local control rates (LC), disease free (DFS) …

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 …

Body Mri Artifacts In Clinical Practice: A Physicist's And Radiologist's Perspective., Martin J Graves, Donald Mitchell

Department of Radiology Faculty Papers

The high information content of MRI exams brings with it unintended effects, which we call artifacts. The purpose of this review is to promote understanding of these artifacts, so they can be prevented or properly interpreted to optimize diagnostic effectiveness. We begin by addressing static magnetic field uniformity, which is essential for many techniques, such as fat saturation. Eddy currents, resulting from imperfect gradient pulses, are especially problematic for new techniques that depend on high performance gradient switching. Nonuniformity of the transmit radiofrequency system constitutes another source of artifacts, which are increasingly important as magnetic field strength increases. Defects in …

Towards Omni-Tomography -- Grand Fusion Of Multiple Modalities For Simultaneous Interior Tomography, Ge Wang, Jie Zhang, Hao Gao, Victor Weir, Hengyong Yu, Wenxiang Cong, Xiaochen Xu, Haiou Shen, James Bennett, Mark Furth, Yue Wang, Michael Vannier

Radiology Faculty Publications

We recently elevated interior tomography from its origin in computed tomography (CT) to a general tomographic principle, and proved its validity for other tomographic modalities including SPECT, MRI, and others. Here we propose "omni-tomography", a novel concept for the grand fusion of multiple tomographic modalities for simultaneous data acquisition in a region of interest (ROI). Omni-tomography can be instrumental when physiological processes under investigation are multi-dimensional, multi-scale, multi-temporal and multi-parametric. Both preclinical and clinical studies now depend on in vivo tomography, often requiring separate evaluations by different imaging modalities. Over the past decade, two approaches have been used for multimodality …

Imaging Spontaneous Mmtvneu Transgenic Murine Mammary Tumors: Targeting Metabolic Activity Versus Genetic Products., Mathew L Thakur, Devakumar Devadhas, Kaijun Zhang, Richard G Pestell, Chenguang Wang, Peter Mccue, Eric Wickstrom

Department of Radiology Faculty Papers

INTRODUCTION: Despite the great strides made in imaging breast cancer (BC) in humans, the current imaging modalities miss up to 30% of BC, do not distinguish malignant lesions from benign ones, and require histologic examinations for which invasive biopsy must be performed. Annually in the United States, approximately 5.6 million biopsies find benign lesions. More than 50% of human BCs overexpress cyclin D1, and all BCs exhibit VPAC1 oncogene products. Together, these gene products may provide an excellent biomarker for the early and accurate detection of BC. We have evaluated 4 biologically active peptide analogs that have high affinity for …

Biological Impact Of Geometric Uncertainties: What Margin Is Needed For Intra-Hepatic Tumors?, Hsiang-Chi Kuo, Wen-Shan Liu, Andrew Wu, Dennis Mah, Keh-Shih Chuang, Linda Hong, Ravi Yaparpalvi, Chandan Guha, Shalom Kalnicki

Department of Radiologic Sciences Faculty Papers

BACKGROUND: To evaluate and compare the biological impact on different proposed margin recipes for the same geometric uncertainties for intra-hepatic tumors with different tumor cell types or clinical stages. METHOD: Three different margin recipes based on tumor motion were applied to sixteen IMRT plans with a total of twenty two intra-hepatic tumors. One recipe used the full amplitude of motion measured from patients to generate margins. A second used 70% of the full amplitude of motion, while the third had no margin for motion. The biological effects of geometric uncertainty in these three situations were evaluated with Equivalent Uniform Doses …

Dosimetric Evaluation Of Heterogeneity Corrections For Rtog 0236: Stereotactic Body Radiotherapy Of Inoperable Stage I-Ii Non-Small-Cell Lung Cancer., Ying Xiao, Lech Papiez, Rebecca Paulus, Robert Timmerman, William L. Straube, Walter R. Bosch, Jeff Michalski, James M. Galvin

Department of Radiation Oncology Faculty Papers

PURPOSE: Using a retrospective analysis of treatment plans submitted from multiple institutions accruing patients to the Radiation Therapy Oncology Group (RTOG) 0236 non-small-cell stereotactic body radiotherapy protocol, the present study determined the dose prescription and critical structure constraints for future stereotactic body radiotherapy lung protocols that mandate density-corrected dose calculations.

METHOD AND MATERIALS: A subset of 20 patients from four institutions participating in the RTOG 0236 protocol and using superposition/convolution algorithms were compared. The RTOG 0236 protocol required a prescription dose of 60 Gy delivered in three fractions to cover 95% of the planning target volume. Additional requirements were specified …