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121 results on '"Yin, Fang Fang"'

22. A hybrid proton and hyperpolarized gas tagging MRI technique for lung respiratory motion imaging: a feasibility study

Author

Hu, Lei, primary, Huang, Qijie, additional, Cui, Taoran, additional, Duarte, Isabella, additional, Miller, G Wilson, additional, Mugler, John P, additional, Cates, Gordon D, additional, Mata, Jaime F, additional, de Lange, Eduard E, additional, Altes, Talissa A, additional, Yin, Fang-Fang, additional, and Cai, Jing, additional

Published
2019
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47. Dynamic electron arc radiotherapy (DEAR): a feasibility study.

Author

Rodrigues, Anna, Yin, Fang-Fang, and Wu, Qiuwen

Subjects
*RADIOTHERAPY, *THERAPEUTIC use of electron beams, *ELECTRON beam research, *CANCER radiotherapy research
Abstract

Compared to other radiation therapy modalities, clinical electron beam therapy has remained practically unchanged for the past few decades even though electron beams with multiple energies are widely available on most linacs. In this paper, we present the concept of dynamic electron arc radiotherapy (DEAR), a new conformal electron therapy technique with synchronized couch motion. DEAR utilizes combination of gantry rotation, couch motion, and dose rate modulation to achieve desirable dose distributions in patient. The electron applicator is kept to minimize scatter and maintain narrow penumbra. The couch motion is synchronized with the gantry rotation to avoid collision between patient and the electron cone. In this study, we investigate the feasibility of DEAR delivery and demonstrate the potential of DEAR to improve dose distributions on simple cylindrical phantoms. DEAR was delivered on Varian's TrueBeam linac in Research Mode. In conjunction with the recorded trajectory log files, mechanical motion accuracies and dose rate modulation precision were analyzed. Experimental and calculated dose distributions were investigated for different energies (6 and 9 MeV) and cut-out sizes (1×10 cm2 and 3×10 cm2 for a 15×15 cm2 applicator). Our findings show that DEAR delivery is feasible and has the potential to deliver radiation dose with high accuracy (root mean square error, or RMSE of <0.1 MU, <0.1° gantry, and <0.1 cm couch positions) and good dose rate precision (1.6 MU min−1). Dose homogeneity within ±2% in large and curved targets can be achieved while maintaining penumbra comparable to a standard electron beam on a flat surface. Further, DEAR does not require fabrication of patient-specific shields. These benefits make DEAR a promising technique for conformal radiotherapy of superficial tumors. [ABSTRACT FROM AUTHOR]

Published
2014
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49. Similarities between static and rotational intensity-modulated plans.

Author

Wu QJ, Yin FF, McMahon R, Zhu X, and Das SK

Subjects
Humans, Lymph Nodes radiation effects, Lymphatic Irradiation methods, Male, Models, Biological, Pelvis radiation effects, Prostate radiation effects, Prostatic Neoplasms radiotherapy, Radiotherapy Dosage, Radiotherapy Planning, Computer-Assisted methods, Rectum radiation effects, Seminal Vesicles radiation effects, Time Factors, Urinary Bladder radiation effects, Urogenital Neoplasms radiotherapy, Radiotherapy, Intensity-Modulated methods
Abstract

The aim of this study was to explore similarities between intensity-modulated radiotherapy (IMRT) and intensity-modulated arc therapy (IMAT) techniques in the context of the number of multi-leaf collimator (MLC) segments required to achieve plan objectives, the major factor influencing plan quality. Three clinical cases with increasing complexity were studied: (a) prostate only, (b) prostate and seminal vesicles and (c) prostate and pelvic lymph nodes. Initial 'gold-standard' plans with the maximum possible organ-at-risk sparing were generated for all three cases. For each case, multiple IMRT and IMAT plans were generated with varying intensity levels (IMRT) and arc control points (IMAT), which translate into varying MLC segments in both modalities. The IMAT/IMRT plans were forced to mimic the organ-at-risk sparing and target coverage in the gold-standard plans, thereby only allowing the target dose inhomogeneity to be variable. A higher target dose inhomogeneity (quantified as D5--dose to the highest 5% of target volume) implies that the plan is less capable of modulation. For each case, given a similar number of MLC segments, both IMRT and IMAT plans exhibit similar target dose inhomogeneity, indicating that there is no difference in their ability to provide dose painting. Target dose inhomogeneity remained approximately constant with decreasing segments, but sharply increased below a specific critical number of segments (70, 100, 110 for cases a, b, c, respectively). For the cases studied, IMAT and IMRT plans are similar in their dependence on the number of MLC segments. A minimum critical number of segments are required to ensure adequate plan quality. Future studies are needed to establish the range of minimum critical number of segments for different treatment sites and target-organ geometries.

Published
2010
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50. Using patient data similarities to predict radiation pneumonitis via a self-organizing map.

Author

Chen S, Zhou S, Yin FF, Marks LB, and Das SK

Subjects
Adult, Aged, Aged, 80 and over, Biophysical Phenomena, Biophysics, Databases, Factual, Female, Humans, Lung Neoplasms complications, Lung Neoplasms radiotherapy, Male, Middle Aged, Models, Biological, ROC Curve, Radiotherapy Dosage, Radiotherapy, Conformal adverse effects, Risk Factors, Radiation Pneumonitis etiology
Abstract

This work investigates the use of the self-organizing map (SOM) technique for predicting lung radiation pneumonitis (RP) risk. SOM is an effective method for projecting and visualizing high-dimensional data in a low-dimensional space (map). By projecting patients with similar data (dose and non-dose factors) onto the same region of the map, commonalities in their outcomes can be visualized and categorized. Once built, the SOM may be used to predict pneumonitis risk by identifying the region of the map that is most similar to a patient's characteristics. Two SOM models were developed from a database of 219 lung cancer patients treated with radiation therapy (34 clinically diagnosed with Grade 2+ pneumonitis). The models were: SOM(all) built from all dose and non-dose factors and, for comparison, SOM(dose) built from dose factors alone. Both models were tested using ten-fold cross validation and Receiver Operating Characteristics (ROC) analysis. Models SOM(all) and SOM(dose) yielded ten-fold cross-validated ROC areas of 0.73 (sensitivity/specificity = 71%/68%) and 0.67 (sensitivity/specificity = 63%/66%), respectively. The significant difference between the cross-validated ROC areas of these two models (p < 0.05) implies that non-dose features add important information toward predicting RP risk. Among the input features selected by model SOM(all), the two with highest impact for increasing RP risk were: (a) higher mean lung dose and (b) chemotherapy prior to radiation therapy. The SOM model developed here may not be extrapolated to treatment techniques outside that used in our database, such as several-field lung intensity modulated radiation therapy or gated radiation therapy.

Published
2008
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