- Email: [email protected]
Intensity modulated radiotherapy-computational studies
NCI
Academic Radiology, Vol 10, No 8, August 2003
fit a great number of women than current protocols that are targeted only at women at very high risk. Thesaurus Terms: bioimaging/biomedical imaging, breast neoplasm, breast neoplasm/cancer diagnosis, diagnosis design/evaluation computer program/software clinical research, female, human subject, magnetic resonance imaging, women’s health
Institution:
Fiscal Year: Department: Project Start: Project End: ICD: IRG:
Stanford University 1215 Welch Road, Modular A Stanford, CA 94305 2003 Radiology 01-Aug-1997 28-Feb-2006 National Cancer Institute ZRG1
DENOISING ON MONTE CARLO DOSE DISTRIBUTIONS Grant Number: PI Name:
1R01CA090445-01A1 Deasy, Joseph O.
Abstract: Radiation therapy treatment planning requires accurate dose calculations in order to maximize the tumoricidal effects of precisely directed radiation while minimizing doses delivered to nearby normal tissues. Monte Carlo (MC) radiation transport is the only method that is capable of fulfilling this need in all situations of clinical interest. However, MC dose computations must be run until statistical fluctuations (“noise”) in the resulting dose distributions are adequately reduced. We have discovered that MC precision can be greatly improved through statistical estimation of the actual noise-free underlying dose distribution from the noisy simulation output, a process we term “denoising.” We have shown that denoising is capable of reducing MC calculation times at least several-fold. We propose to investigate the application of denoising to conformal photon therapy and intensity modulated radiation therapy (IMRT) dose calculations. Metrics for quantifying denoising performance will be developed under Specific Aim #1. A benchmark test suite of MC dose distributions, including photon beam, IMRT pencil beam, and optimized IMRT dose distributions, will be developed under Specific Aim #2. Wavelet shrinkage threshold denoising will be developed under Specific Aim #3. Denoising using spatially adaptive iterative filtering will be developed under Specific Aim #4. The relative performance and clinical acceptability of the two denoising methods will be tested against the benchmark test suite with the metrics developed under Specific Aim #1. Under Specific Aim #5 we propose to use discrete wavelet transforms to denoise and compress three dimensional MC- generated pencil beam (PB) dose distributions, and to efficiently compute IMRT
942
fluence-weighted PB dose distributions. Specific Aim #6 will establish maximum MC PB noise levels acceptable for IMRT treatment planning. We hypothesize that optimal denoising algorithms for external photon beams and IMRT PBs will decrease MC computation times by at least a factor of 5-10. We further hypothesize that wavelet-based dose computation methods will: (a) enable use of accurate MC-based PB dose distributions for IMRT treatment planning, (b) apply to MC or any other PB dose calculation algorithm, and (c) be far more computationally efficient than complete dose recalculations at each IMRT optimization iteration. These results would achieve our overall goal of increasing the clinical effectiveness of radiation therapy treatment planning. Thesaurus Terms: mathematical model, radiation therapy dosage, statistics/biometry cost effectiveness, electromagnetic radiation, head/neck neoplasm, lung neoplasm, method development, neoplasm/cancer radiation therapy, outcomes research, prostate neoplasm computer program/software
Institution:
Fiscal Year: Department: Project Start: Project End: ICD: IRG:
Washington University Lindell And Skinker Blvd St. Louis, MO 63130 2002 Radiology 01-Jan-2002 31-Dec-2005 National Cancer Institute RAD
INTENSITY MODULATED RADIOTHERAPY–COMPUTATIONAL STUDIES Grant Number: PI Name:
5R29CA085181-04 Deasy, Joseph O.
Abstract: Proposed intensity modulated radiation therapy (IMRT) techniques aim to provide higher tumor dose irradiation, and thereby better tumor control, while reducing dose to nearby important normal tissues. The main goal of this project is to use computer simulations to understand the potential benefits of a range of proposed photon and proton IMRT techniques relative to conventional techniques. In the first phase, technical issues relating to IMRT treatment planning will be investigated, including: global vs. local optimization, effects of tumor control probability (TCP) model assumptions, the effect of treatment margins and geometrical uncertainties, number and angles of incident fields needed for optimal irradiation, and type of intensity modulation (full resolution vs. segmental). These questions will be studied in detail using a suite of two- dimensional (2D) test problems, derived from patient CT data sets, which will cover a wide range of potential IMRT planning problems. Results from this phase of 2D simulations will be tested in more limited
ABSTRACTS OF NIH GRANTS
Academic Radiology, Vol 10, No 8, August 2003
three-dimensional (3D) simulations. In the second phase, 2D and 3D simulations will be made comparing several proposed IMRT techniques, including: few- and many-field intensity modulated coplanar photon delivery, intensity-modulated arc therapy, and a novel intensity modulated proton beam method. Each plan will be optimized with alternative objective functions, maximum TCP and maximum minimum target dose, but constrained to the same normal tissue dosevolume limits. Those plans will be compared with conventional photon technique plans. At least four different sites will be studied in full 3D for all the IMRT techniques: lung, prostate, head and neck, and abdominal tumors. We will investigate the anatomical and geometrical factors that may indicate a dosimetric superiority of one IMRT technique over another. Proposed IMRT techniques will be difficult to compare directly in clinical trials except on a limited scale. The approach in this project is to conduct computational comparisons of a range of proposed IMRT techniques, using the same radiobiological and dosimetric assumptions, in order to help understand the relative potential benefits of each technique compared with conventional treatment. We hypothesize that IMRT will require more than 3-5 fields, using radiobiologically realistic and fully 3D planning methods, to reach the level of TCP possible using many-field delivery. Thesaurus Terms: computer simulation, neoplasm/cancer radiation therapy, technology/technique development computer program/software, radiation dosage clinical research, human data
Institution:
Fiscal Year: Department: Project Start: Project End: ICD: IRG:
Washington University Lindell And Skinker Blvd St. Louis, MO 63130 2002 Radiology 01-Jul-1999 30-Jun-2004 National Cancer Institute RAD
TOMOSYNTHESIS FOR IMPROVED PULMONARY NODULE DETECTION Grant Number: PI Name:
2R01CA080490-04 Dobbins, James T.
Abstract: Description (provided by applicant): The purpose of these studies is to evaluate whether digital tomosynthesis can serve as an adjunct to conventional chest radiography for improving clinical detection of pulmonary nodules. Digital tomosynthesis augments a conventional chest exam by providing three-dimensional information through a series of longitudinal slice images. These slice images are reconstructed from a set of discrete projection images acquired at different angles, using a conventional x-ray tube and a new digital
flat-panel x-ray detector. The tomosynthesized images may be viewed slice-by-slice or as a 3-D volume-rendered projection in a “virtual fluoroscopy” viewing environment. The diagnostic benefit of tomosynthesis is the use of 3-D information to improve detection and discrimination of pulmonary nodules by eliminating the confusion of overlying structures. CT would remain the gold standard for clinical workup once nodules are detected, with tomosynthesis providing a low-dose/low-cost method for improving initial detection accuracy. Clinically the tomosynthesis images would be acquired whenever a digital PNlateral chest exam is taken, but with reduced exposure for the lateral image such that the total patient dose from the PA/lateral/tomosynthesis exam would be about comparable to the overall dose from a conventional PNlateral chest exam. It is anticipated that tomosynthesis will enable higher sensitivity and specificity for pulmonary nodule detection than conventional chest radiography alone, and hence will potentially lead to earlier detection of lung cancer, at a cost significantly less than low-dose CT. This proposal is a competing continuation of a previous study that developed and optimized the tomosynthesis technique. The present study will conduct a clinical evaluation of tomosynthesis for pulmonary nodule detection in a cohort of human subjects with CT-proven nodules. This study will have three parts: (1) an evaluation of tomosynthesis using radiologists as observers, (2) development and evaluation of a computer-aided diagnosis (CAD) method using three-dimensional tomosynthesis data for pulmonary nodule detection, and (3) a measurement of the accuracy with which radiologists can use tomosynthesis to localize the depth and diameter of nodules. The specific aims of the project also include pilot studies to optimize the tomosynthesis method before the large-scale collection of human subject data. These pilot studies will characterize and minimize effects of patient motion, optimize the number of reconstructed planes and patient entrance exposure, and evaluate slice viewing vs. volume rendering. Thesaurus Terms: digital imaging, image enhancement, lung neoplasm, pneumoradiography, radiodiagnosis, technology/technique development, tomography computer assisted diagnosis, diagnosis design/evaluation, mathematical model, phantom model bioimaging/biomedical imaging, clinical research, human data, human subject
Institution: Fiscal Year: Department: Project Start: Project End: ICD: IRG:
Duke University Durham, NC 27706 2002 Radiology 01-Dec-1998 31-Jul-2006 National Cancer Institute ZRG1
943
Academic Radiology, Vol 10, No 8, August 2003
fit a great number of women than current protocols that are targeted only at women at very high risk. Thesaurus Terms: bioimaging/biomedical imaging, breast neoplasm, breast neoplasm/cancer diagnosis, diagnosis design/evaluation computer program/software clinical research, female, human subject, magnetic resonance imaging, women’s health
Institution:
Fiscal Year: Department: Project Start: Project End: ICD: IRG:
Stanford University 1215 Welch Road, Modular A Stanford, CA 94305 2003 Radiology 01-Aug-1997 28-Feb-2006 National Cancer Institute ZRG1
DENOISING ON MONTE CARLO DOSE DISTRIBUTIONS Grant Number: PI Name:
1R01CA090445-01A1 Deasy, Joseph O.
Abstract: Radiation therapy treatment planning requires accurate dose calculations in order to maximize the tumoricidal effects of precisely directed radiation while minimizing doses delivered to nearby normal tissues. Monte Carlo (MC) radiation transport is the only method that is capable of fulfilling this need in all situations of clinical interest. However, MC dose computations must be run until statistical fluctuations (“noise”) in the resulting dose distributions are adequately reduced. We have discovered that MC precision can be greatly improved through statistical estimation of the actual noise-free underlying dose distribution from the noisy simulation output, a process we term “denoising.” We have shown that denoising is capable of reducing MC calculation times at least several-fold. We propose to investigate the application of denoising to conformal photon therapy and intensity modulated radiation therapy (IMRT) dose calculations. Metrics for quantifying denoising performance will be developed under Specific Aim #1. A benchmark test suite of MC dose distributions, including photon beam, IMRT pencil beam, and optimized IMRT dose distributions, will be developed under Specific Aim #2. Wavelet shrinkage threshold denoising will be developed under Specific Aim #3. Denoising using spatially adaptive iterative filtering will be developed under Specific Aim #4. The relative performance and clinical acceptability of the two denoising methods will be tested against the benchmark test suite with the metrics developed under Specific Aim #1. Under Specific Aim #5 we propose to use discrete wavelet transforms to denoise and compress three dimensional MC- generated pencil beam (PB) dose distributions, and to efficiently compute IMRT
942
fluence-weighted PB dose distributions. Specific Aim #6 will establish maximum MC PB noise levels acceptable for IMRT treatment planning. We hypothesize that optimal denoising algorithms for external photon beams and IMRT PBs will decrease MC computation times by at least a factor of 5-10. We further hypothesize that wavelet-based dose computation methods will: (a) enable use of accurate MC-based PB dose distributions for IMRT treatment planning, (b) apply to MC or any other PB dose calculation algorithm, and (c) be far more computationally efficient than complete dose recalculations at each IMRT optimization iteration. These results would achieve our overall goal of increasing the clinical effectiveness of radiation therapy treatment planning. Thesaurus Terms: mathematical model, radiation therapy dosage, statistics/biometry cost effectiveness, electromagnetic radiation, head/neck neoplasm, lung neoplasm, method development, neoplasm/cancer radiation therapy, outcomes research, prostate neoplasm computer program/software
Institution:
Fiscal Year: Department: Project Start: Project End: ICD: IRG:
Washington University Lindell And Skinker Blvd St. Louis, MO 63130 2002 Radiology 01-Jan-2002 31-Dec-2005 National Cancer Institute RAD
INTENSITY MODULATED RADIOTHERAPY–COMPUTATIONAL STUDIES Grant Number: PI Name:
5R29CA085181-04 Deasy, Joseph O.
Abstract: Proposed intensity modulated radiation therapy (IMRT) techniques aim to provide higher tumor dose irradiation, and thereby better tumor control, while reducing dose to nearby important normal tissues. The main goal of this project is to use computer simulations to understand the potential benefits of a range of proposed photon and proton IMRT techniques relative to conventional techniques. In the first phase, technical issues relating to IMRT treatment planning will be investigated, including: global vs. local optimization, effects of tumor control probability (TCP) model assumptions, the effect of treatment margins and geometrical uncertainties, number and angles of incident fields needed for optimal irradiation, and type of intensity modulation (full resolution vs. segmental). These questions will be studied in detail using a suite of two- dimensional (2D) test problems, derived from patient CT data sets, which will cover a wide range of potential IMRT planning problems. Results from this phase of 2D simulations will be tested in more limited
ABSTRACTS OF NIH GRANTS
Academic Radiology, Vol 10, No 8, August 2003
three-dimensional (3D) simulations. In the second phase, 2D and 3D simulations will be made comparing several proposed IMRT techniques, including: few- and many-field intensity modulated coplanar photon delivery, intensity-modulated arc therapy, and a novel intensity modulated proton beam method. Each plan will be optimized with alternative objective functions, maximum TCP and maximum minimum target dose, but constrained to the same normal tissue dosevolume limits. Those plans will be compared with conventional photon technique plans. At least four different sites will be studied in full 3D for all the IMRT techniques: lung, prostate, head and neck, and abdominal tumors. We will investigate the anatomical and geometrical factors that may indicate a dosimetric superiority of one IMRT technique over another. Proposed IMRT techniques will be difficult to compare directly in clinical trials except on a limited scale. The approach in this project is to conduct computational comparisons of a range of proposed IMRT techniques, using the same radiobiological and dosimetric assumptions, in order to help understand the relative potential benefits of each technique compared with conventional treatment. We hypothesize that IMRT will require more than 3-5 fields, using radiobiologically realistic and fully 3D planning methods, to reach the level of TCP possible using many-field delivery. Thesaurus Terms: computer simulation, neoplasm/cancer radiation therapy, technology/technique development computer program/software, radiation dosage clinical research, human data
Institution:
Fiscal Year: Department: Project Start: Project End: ICD: IRG:
Washington University Lindell And Skinker Blvd St. Louis, MO 63130 2002 Radiology 01-Jul-1999 30-Jun-2004 National Cancer Institute RAD
TOMOSYNTHESIS FOR IMPROVED PULMONARY NODULE DETECTION Grant Number: PI Name:
2R01CA080490-04 Dobbins, James T.
Abstract: Description (provided by applicant): The purpose of these studies is to evaluate whether digital tomosynthesis can serve as an adjunct to conventional chest radiography for improving clinical detection of pulmonary nodules. Digital tomosynthesis augments a conventional chest exam by providing three-dimensional information through a series of longitudinal slice images. These slice images are reconstructed from a set of discrete projection images acquired at different angles, using a conventional x-ray tube and a new digital
flat-panel x-ray detector. The tomosynthesized images may be viewed slice-by-slice or as a 3-D volume-rendered projection in a “virtual fluoroscopy” viewing environment. The diagnostic benefit of tomosynthesis is the use of 3-D information to improve detection and discrimination of pulmonary nodules by eliminating the confusion of overlying structures. CT would remain the gold standard for clinical workup once nodules are detected, with tomosynthesis providing a low-dose/low-cost method for improving initial detection accuracy. Clinically the tomosynthesis images would be acquired whenever a digital PNlateral chest exam is taken, but with reduced exposure for the lateral image such that the total patient dose from the PA/lateral/tomosynthesis exam would be about comparable to the overall dose from a conventional PNlateral chest exam. It is anticipated that tomosynthesis will enable higher sensitivity and specificity for pulmonary nodule detection than conventional chest radiography alone, and hence will potentially lead to earlier detection of lung cancer, at a cost significantly less than low-dose CT. This proposal is a competing continuation of a previous study that developed and optimized the tomosynthesis technique. The present study will conduct a clinical evaluation of tomosynthesis for pulmonary nodule detection in a cohort of human subjects with CT-proven nodules. This study will have three parts: (1) an evaluation of tomosynthesis using radiologists as observers, (2) development and evaluation of a computer-aided diagnosis (CAD) method using three-dimensional tomosynthesis data for pulmonary nodule detection, and (3) a measurement of the accuracy with which radiologists can use tomosynthesis to localize the depth and diameter of nodules. The specific aims of the project also include pilot studies to optimize the tomosynthesis method before the large-scale collection of human subject data. These pilot studies will characterize and minimize effects of patient motion, optimize the number of reconstructed planes and patient entrance exposure, and evaluate slice viewing vs. volume rendering. Thesaurus Terms: digital imaging, image enhancement, lung neoplasm, pneumoradiography, radiodiagnosis, technology/technique development, tomography computer assisted diagnosis, diagnosis design/evaluation, mathematical model, phantom model bioimaging/biomedical imaging, clinical research, human data, human subject
Institution: Fiscal Year: Department: Project Start: Project End: ICD: IRG:
Duke University Durham, NC 27706 2002 Radiology 01-Dec-1998 31-Jul-2006 National Cancer Institute ZRG1
943