That's me

Dynamic Ventilation from 4DCT

Thoracic Motion Model


DIR-Lab Home Page

UTMB Radiation Oncology

Radiation Science Seminar Series 2014

Richard Castillo, Ph.D., DABR

My research is largely focused on the use of deformable image registration (DIR) in medical image analysis and functional lung imaging from computed tomography (CT). Deformable registration is a quickly developing technology with many potential applications in diagnostic imaging and radiotherapy. However, methods for evaluation and formal validation of novel DIR models and implementations are lacking. My research in this area involves investigation of quantitative/statistical methods for evaluation of DIR spatial accuracy for purposes of validation and acceptance testing, as well as quality assurance in routine clinical application.

I am also actively investigating methods for utilizing DIR output to extract functional information, including quantitative pulmonary ventilation and perfusion, from treatment planning 4D CT, as well as from breath-hold CT image pairs acquired in the diagnostic setting. The incorporation of such function information into radiotherapy treatment planning for purposes of functional avoidance or dysfunctional allowance may prove to be a superior planning practice for the treatment of thoracic malignancies.

** 2012 recipient of the University of Texas Graduate School of Biomedical Sciences Aaron Blanchard Award for Medical Physics **

** 2012 recipient of an NIH Extramural Loan Repayment Award (LRP) **

** 2013 recipient of an NIH Research Scientist Development Award (K-01) **

Contact Information

Mailing Address:

Richard Castillo, Ph.D., DABR
Assistant Professor
Department of Radiation Oncology
The University of Texas Medical Branch
301 University Blvd.
Galveston, TX 77555-0711

Phone: +1-409-772-7167

Curriculum Vitae



Peer Reviewed Publications:

  1. Sager Patel, Arnold Paulino, Danielle Johnston, Lee Wiederhold, Richard Castillo, Rajkumar Venkatramani. Gemcitabine induced radiation recall myositis in a patient with relapsed nasopharyngeal carcinoma. Practical Radiation Oncology. IN PRESS, 2016.
  2. Yevgeniy Vinogradskiy, Leah Shubert, Quentin Diot, Tim Waxweiller, Phillip Woo, Richard Castillo, Edward Castillo, Thomas Guerrero, Chad Rusthoven, Laurie Gaspar, Brian Kavanagh, Moyed Mifton. Regional lung function profiles of stage I and III lung cancer patients: An evaluation for functional avoidance radiation therapy. International Journal of Radiation Oncology*Biology*Physics. IN PRESS, 2016.
  3. Min Li, Zhikang Xiang, Liang Xiao, Edward Castillo, Richard Castillo, Thomas Guerrero. GPU-accelerated block matching algorithm for deformable image registration of lung CT images. Proceedings of IEEE Conference on Progress in Informatics and Computing, Nanjing, China, 2015.
  4. Douglas Brennen, Leah Schubert, Quentin Diot, Richard Castillo, Edward Castillo, Thomas Guerrero, Mary K. Martel, Derek Linderman, Laurie E. Gaspar, Moyed Miften, Brian D. Kavanagh, Yevgeniy Vinogradskiy. Clinical validation of 4DCT-ventilation with pulmonary function test data. International Journal of Radiation Oncology*Biology*Physics, 92 (2): 423-429, 2015.
  5. Richard Castillo, Ngoc Pham, Edward Castillo, Samantha Aso-Gonzalez, Sobiya Ansari, Brian Hobbs, Diana Palacio, Heath Skinner, Thomas Guerrero. Pre-radiotherapy FDG PET identifies esophageal cancer patients at high-risk for radiation pneumonitis. Radiology, 275 (3): 822-831. 201.
  6. Alexandra R. Cunliff, Samuel G. Armato III, Richard Castillo, Ngoc Pham, Thomas Guerrero, Hania Al-Hallaq. Lung texture in serial thoracic CT scans: Correlation of radiomics-based features with radiotherapy dose and radiation pneumonitis development. International Journal of Radiation Oncology*Biology*Physics, 91 (5): 1048-1056. 2015.
  7. Sarah Joy Castillo, Richard Castillo, Edward Castillo, Tinsu Pan, Geoffrey Ibbott, Peter Balter, Brian Hobbs, Thomas Guerrero. Evaluation of 4D CT acquisition methods designed to reduce artifacts. Journal of Applied Clinical Medical Physics, 16 (2): 23-32. 2015.
  8. David Fuentes, Jessica Contreras, Justin Yu, R. He, Edward Castillo, Richard Castillo, Thomas Guerrero. Morphometry based measurements of the structural response to whole brain radiation. International Journal of Computer Assisted Radiology and Surgery, 10 (4): 393-401. 2015.
  9. Abdallah S.R. Mohamed, Manee-Naad Ruangskul, Musaddiq J. Awan, Charles A. Baron, Jayashree Kalpathy-Cramer, Richard Castillo, Edward Castillo, Thomas M. Guerrero, Esengul Kocak-Uzel, Jinzhong Yang, Laurence Court, Michael E. Kantor, G. Brandon Gunn, Rivka R. Colen, Steven J. Frank, Adam S. Garden, David I. Rosenthal, Clifton D. Fuller. Quality assurance assessment of diagnostic and radiation therapy-simulation CT image registration for head and neck radiation therapy: Anatomic region of interest-based comparison of rigid and deformable algorithms. Radiology, 274 (3): 752-763. 201.
  10. Richard Castillo, Ngoc Pham, Sobiya Ansari, Dmitriy Meshkov, Sarah Castillo, Min Li, Adenike Olanrewaju, Brian Hobbs, Edward Castillo, Thomas Guerrero. Pre-radiotherapy FDG PET predicts radiation pneumonitis in lung cancer. Radiation Oncology, 9 (74), 2014.
  11. Edward Castillo, Richard Castillo, David Fuentes, Thomas Guerrero. Computing Global Minimizers to a Constrained B-spline Image Registration Problem from Optimal L1 Perturbations to Block Match Data. Medical Physics, 41 (4), 2014.
  12. Yevgeniy Vinogradskiy, Phillip J. Koo, Richard Castillo, Edward Castillo, Thomas Guerrero, Laurie Gaspar, Moyed Miften, Brian Kavanagh. Comparison of 4DCT-Ventilation with nuclear medicine ventilation-perfusion (VQ) imaging: a clinical validation study. International Journal of Radiation Oncology*Biology*Physics, 89 (1): 199-205, 2014.
  13. Sarah J. Castillo, Richard Castillo, Peter Balter, Tinsu Pan, Geoffrey Ibbott, Brian Hobbs, Ying Yuan, Thomas Guerrero. Assessment of a quantitative metric for 4D CT artifact evaluation by observer consensus. Journal of Applied Clinical Medical Physics, 15 (3): 190-201, 2014.
  14. Suyu Liu, Ying Yuan, Richard Castillo, Thomas Guerrero, Valen Johnson. Evaluation of Image Registration Spatial Accuracy Using a Bayesian Hierarchical Model. ARTICLE IN PRESS: Biometrics.
  15. Min Li, Edward Castillo, Hong-Yan Luo, Xiao-Lin Zheng, Richard Castillo, Dmitriy Meshkov, Thomas Guerrero. Deformable image registration for temporal subtraction of chest radiographs. ARTICLE IN PRESS: International Journal of Computer Assisted Radiology and Surgery.
  16. Min Li, Edward Castillo, Xiao-Lin Zheng, Hong-Yan Luo, Richard Castillo, Yi Wu, Thomas Guerrero. Modeling lung deformation: a combined deformable image registration method with spatially varying Young’s modulus estimates. Medical Physics, 40 (8), 2013.
  17. Min Li, Xiao-Lin Zheng, Hong-Yan Luo, Richard Castillo, Shao-Xiang Zhang, Li-Wen Tan, Edward Castillo, Thomas Guerrero. Automated segmentation of brain tissue and white matter in cryosection images from the Chinese Visible Human dataset. ARTICLE IN PRESS: Journal of Medical and Biological Engineering.
  18. Yevgeniy Vinogradskiy, Richard Castillo, Edward Castillo, Susan L. Tucker, Zhongxing Liao, Thomas Guerrero, Mary K. Martel. Using 4DCT-based ventilation imaging to correlate lung dose and function with clinical outcomes. International Journal of Radiation Oncology*Biology*Physics, 86: 366-371, 2013.
  19. Matthew McCurdy, Derek P. Bergsma, Eric Hyun, Thomas Kim, Enid Choi, Richard Castillo, Edward Castillo, Thomas Guerrero. The Role of Lung Lobes in Radiation Pneumonitis and Radiation-Induced Inflammation in the Lung: A Retrospective Study. Journal of Radiation Oncology, 2: 203-208, 2013.
  20. Richard Castillo, Edward Castillo, David Fuentes, Moiz Ahmad, Abbie M. Wood, Michelle S. Ludwig, Thomas Guerrero. A reference dataset for deformable image registration spatial accuracy evaluation using the COPDgene study archive. Physics in Medicine & Biology, 58: 2861-2877, 2013.
  21. Alfredo E. Echeverria, Matthew R. McCurdy, Richard Castillo, Vincent Bernard, Natalia V. Ramos, William R. Buckley, Edward Castillo, Ping Liu, Eric D. Hyun, and Thomas Guerrero. Proton Therapy Radiation Pneumonitis Local Dose-Response in Esophagus Cancer Patients. Radiotherapy and Oncology, 106: 124-129, 2013.
  22. Lindsay Mathew, Andrew Wheatley, Richard Castillo, Edward Castillo, George Rodrigues, Thomas Guerrero, Grace Parraga. Hyperpolarized 3He Magnetic Resonance Imaging: Comparison with Four-dimensional x-ray Computed Tomography Imaging in Lung Cancer. Academic Radiology, 19: 1546-1553, 2012.
  23. Edward Castillo, Richard Castillo, Benjamin White, Javier Rojo, and Thomas Guerrero. Least median of squares filtering of locally optimal point matches for compressible flow image registration. Physics in Medicine & Biology, 57: 4827-4833, 2012.
  24. Matthew McCurdy, Richard Castillo, Josue Martinez, Mohammad N Al Hallack, Jessica Lichter, Nicolas Zouain, and Thomas Guerrero. [18F]-FDG Uptake Dose Correlates with Radiation Pneumonitis in Lung Cancer Patients. Radiotherapy and Oncology, 104: 52-57, 2012.
  25. Richard Castillo, Edward Castillo, Matthew R. McCurdy, Daniel R. Gomez, Alec M. Block, Derek Bergsma, Sarah Joy, and Thomas Guerrero. Spatial Correspondence of 4D CT Ventilation and SPECT Pulmonary Perfusion Defects in Patients with Malignant Airway Stenosis. Physics in Medicine & Biology, 57: 1855-1871, 2012.
  26. Yevgeniy Y. Vinogradskiy, Richard Castillo, Edward Castillo, Adam Chandler, Mary K. Martel, and Thomas Guerrero. Use of Weekly 4DCT-based Ventilation Maps to Quantify Changes in Lung Function for Patients Undergoing Radiation Therapy. Medical Physics, 39: 289-298, 2012.
  27. Richard Castillo, Edward Castillo, Josue Martinez, Thomas Guerrero. Ventilation from Four Dimensional Computed Tomography: Density versus Jacobian Methods. Physics in Medicine & Biology, 55: 4661-4685, 2010.
  28. Xuejun Gu, Hubert Pan, Yun Liang, Richard Castillo, Deshan Yang, Dongju Choi, Edward Castillo, Amitava Majumdar, Thomas Guerrero, Steven B. Jiang. Implementation and evaluation of various demons deformable image registration algorithms on GPU. Physics in Medicine & Biology, 55: 207-219, 2010.
  29. Edward Castillo, Richard Castillo, Josue Martinez, Maithili Shenoy, Thomas Guerrero. Four dimensional deformable image registration using trajectory modeling. Physics in Medicine & Biology, 55: 305-327, 2010.
  30. Edward Castillo, Richard Castillo, Yin Zhang, Thomas Guerrero. Compressible image registration for thoracic computed tomography images. Journal of Medical and Biomedical Engineering, 29: 222-233, 2009.
  31. Richard Castillo, Edward Castillo, Rudy Guerra, Valen Johnson, Travis McPhail, Amit K. Garg, Thomas Guerrero. A framework for evaluation of deformable image registration spatial accuracy using large landmark point sets. Physics in Medicine & Biology; 54: 1849-1870, 2009.**
  32. Thomas Guerrero, Richard Castillo, Josue Noyola-Martinez, Mylin Torres, Xinhui Zhou, Rudy Guerra, Dianna Cody, Ritsuko Komaki, Elizabeth Travis. Reduction of pulmonary compliance found with high-resolution computed tomography in irradiated mice. International Journal of Radiation Oncology*Biology*Physics, 67: 879-887, 2007.
  33. Thomas Guerrero, Richard Castillo, Kevin Sanders, Roger Price, Ritsuko Komaki, Dianna Cody. Novel method to calculate pulmonary compliance images in rodents from computed tomography acquired at constant pressures. Physics in Medicine & Biology, 51: 1101-1112, 2006.
  34. Tinsu Pan, Osama Mawlawi, Sadek A. Nehmeh, Yusuf E. Erdi, Dershan Luo, Hui H. Liu, Richard Castillo, Radhe Mohan, Zhongxing Liao, H. A. Macapinlac. Attenuation correction of PET images with respiration-averaged CT images in PET/CT. The Journal of Nuclear Medicine, 46: 1481-1487, 2005.

** Top 10 cited article in the past two years in the journal "Physics in Medicine & Biology" (Commendation in 2011) **


Conference Talks:

My Dissertation Defense Presentation:

Invited Lectures:


Student Resources