Christopher J. Watchman, PhD, DABR

Christopher J. Watchman, PhD, DABR

Medical Physics Graduate Program Director


Associate Professor

Contact Information

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Phone Number: 


Dr. Watchman earned his undergraduate degree in physics and exercise physiology at Brigham Young University. He received a graduate degree in health physics at Idaho State University, and a doctorate in medical physics at University of Florida. Prior to his appointment as assistant professor at the University of Arizona Cancer Center, Dr. Watchman completed residency training in radiation oncology physics at the University of Arizona in 2007. He is an American Board of Radiology certified medical physicist.

Dr. Watchman is involved in image guided therapy research. Additionally, he is interested in multi-modality imaging methods for the assessment of treatment efficacy, molecular radiotherapy, radiation dosimetry and target localization. Dr. Watchman's current research interests include radiation induced pneumonitis for patients with lung tumors, where models are utilized to evaluate how margin size and location may effect pneumonitis induction during radiation therapy, investigation of dosimetry models for use in skeletal dosimetry, primarily alpha emitter dosimetry models, stem cell localization in bone marrow, pediatric dose models, and use of TomoTherapy in the treatment of cancer.

Dr. Watchman is the graduate program director of the joint Physics and Radiation Oncology Professional Science Master’s Degree program in Medical Physics. In this role he is actively involved in the teaching of graduate students from multiple disciplines at the University of Arizona. He teaches courses in radiation dosimetry, health physics, radiation therapy and clinical medical physics. He is an active member of the Radiation Oncology Medical Physics Residency program and is currently the head of the admissions committee.

Professional Affiliations: 
  • Health Physics Society (HPS)
  • American Association of Physicists in Medicine (AAPM)
  • Society of Nuclear Medicine (SNM)
  • American Society of Therapeutic Radiation Oncology (ASTRO)
  • American Brachytherapy Society (ABS)
  • Arizona Chapter of AAPM (AAAPM)
  • American College of Radiology (ACR)


Board Certifications: 

State of Arizona Therapy Physicist License 2185 T (renewable on 12/31/13) American Board of Radiology Therapeutic Medical Physics P3747  

Clinical Practice Sites: 
Radiation Oncology


University of Florida
Master's Degree: 
Idaho State University
Undergraduate School: 
Brigham Young University


Summary of Research Activity: 

Radiation Dosimetry (macro and microscopic), Lung Radiotherapy, IGRT, Molecular Radiotherapy, Bone Marrow Dosimetry

Selected Publications: 

Peer-Reviewed Publications

  1. DA Rajon, PW Patton, AP Shah, CJ Watchman, WE Bolch. “Surface Area Overestimation Within 3D Digital Images and Its Consequence for Skeletal Dosimetry”. DA Rajon, PW Patton, AP Shah, CJ Watchman and WE Bolch. Medical Physics 29(5)682-93, 2002.
  2. DA Rajon, DW Jokisch, PW Patton, AP Shah, CJ Watchman, and WE Bolch. “Voxel Effects within Digital Images of Trabecular Bone and Their Consequences on Chord-length Distribution Measurements”. Physics Medicine and Biology 47(10)1741-59, 2002.
  3. DA Rajon, AP Shah, CJ Watchman, JM Brindle, WE Bolch. “A hyperboloid representation of the bone-marrow interface within 3D NMR images of trabecular bone: applications to skeletal dosimetry”. Physics Medicine and Biology 48(12) 1721-40, 2003.
  4. CJ Watchman, DW Jokisch, PW Patton, DA Rajon, G Sgouros, WE Bolch. “Absorbed Fractions for Alpha Particles in Tissues of Trabecular Bone: Considerations of Marrow Cellularity within the ICRP Reference Male”. Journal of Nuclear Medicine 46(7)1171-85, 2005.
  5. AP Shah, DW Jokisch, DA Rajon, CJ Watchman, PW Patton, WE Bolch. “Chord Based versus Voxel Based Methods of Electron Transport in Skeletal Dosimetry”. Medical Physics 32(10)3151-9, 2005
  6. CJ Watchman, VA Bourke, JR Lyon, AE Knowlton, SL Butler, DD Grier, J Wingard, R Braylan, WE Bolch. “Spatial Distribution of Blood Vessels and CD34+ Hematopoietic stem and progenitor Cells within the Marrow Cavities of human cancellous bone”. Journal of Medical Physics 48(4) 645-654, 2007
  7. CJ Watchman, DA Hasenauer, WE Bolch. “Derivation of Skeletal Masses within the Current ICRP Age Series”. Physics Medicine and Biology (52) 3133 2007
  8. JG Hunt, CJ Watchman, WE Bolch. “Calculation of Absorbed Fractions to Human Skeletal Tissues Due to Alpha Particles Using the Monte Carlo and Chord Based Techniques”. Radiation Protection Dosimetry 2007 127(1-4):223-6
  9. WE Bolch, AP Shah, CJ Watchman, DW Jokisch, PW Patton, DA Rajon, M Zankl, N Petoussi-Henss, KF Eckerman. “Skeletal Absorbed Fractions for Electrons and Alpha Particle in the Adult Male – Consideration of a Revised 50-mm Definition of the Bone Endosteum.” Radiation Protection Dosimetry 2007 127(1-4):169-73
  10. LA Ewell, CJ Watchman K Wharton. “Sulci Density Map to Aid Use of Apparent Diffusion Coefficient for Therapy Evaluation”. Magnetic Resonance Imaging 26 (2008) 20-25
  11. 11. CJ Watchman, RJ Hamilton, B Stea, AJ Mignault. “Patient Positioning Using Implanted Gold Markers with the Novalis Body System in the Thoracic Spine”. Neurosurgery 62:A62-A68, 2008.
  12. 12. VA Bourke, CJ Watchman, JD. Reith, M Jorgensen, A Dieudonnè, and WE. Bolch. “Spatial Gradients of Blood Vessels and Hematopoeitic Stem and Progenitor Cells Within the Marrow Cavities of the Human Skeleton.” Blood 114(19) 4077-80, 2009.
  13. 13. DA Pafundi, C Lee, CJ Watchman, VA Bourke, J Arnis, N Shagina, J Harrison, T Fell, WE Bolch. “An Image Based Skeletal Tissue Model for the ICRP Reference Newborn.” Physics Medicine and Biology 54(14):4497-531 2009
  14. 14. CJ Watchman, WE Bolch. “Absorbed Fractions for Alpha Particles in Tissues of Cortical Bone”. Physics Medicine and Biology 54 (2009) 6009-6027
  15. 15. NP Nguyen, M Ceizyk, P Vos, V Vinh-Hung, R Davis, A Desai, D Abraham, SP Krafft, S Jang, CJ Watchman, LA Ewell, RJ Hamilton, L Smith-Raymond. “Effectiveness of Image Guided-Radiotherapy for Laryngeal Sparing in Head and Neck Cancer”. Oral Oncology (2010) 46(4) 283-6
  16. 16. NP Nguyen, SP Krafft, P Vos, V Vinh-Hung, M Ceizyk, SJ Jang, A Desai, D Abrahm, LA Ewell, CJ Watchman, RJ Hamilton, BH Jo, U Karlsson, L Smith-Raymond. “Feasibility of Tomotherapy for Graves’ Opthalmopathy.” Strahlentherapi und Onkologie 187(9)568-574 2011.
  17. 17. A Bhullar, CJ Watchman. “The Effective Depth of Cylindrical Ionization Chambers in Water for Clinical Proton Beams”. Physics Medicine and Biology Physics Medicine and Biology 57(1) 273 2012.
  18. RF Hobbs, H Song, CJ Watchman, WE Bolch, AK Aksnes, T Ramdahl, GD Flux, G Sgouros. “Bone Marrow Toxicity Considerations from 223Ra Alpha-emitter Radiopharmaceutical Therapy.” Physics Medicine and Biology 57 3207 (2012).
Book Chapters
  1. WE Bolch, CJ Watchman. “Current Topics in Medical Dosimetry” Operational Health Physics: Planning and Implementation. Health Physics Society 2005.
Peer Reviewed Conference Proceedings
  1. K Hadad, B Ganapol, RJ Hamilton, CJ Watchman. “Dose Verification in an Accelerated Partial Breast Irradiation”. 2009 International Conference on Advances in Mathematics, Computational Methods, and Reactor Physics, American Nuclear Society
  2. K Hadad, B Ganapol, RJ Hamilton, CJ Watchman, Y Xu. “Dose Assessment to Hear and Lungs in HDR Breast Brachytherapy”. 2009 American Nuclear Society Annual Meeting
  3. D Hasenauer, C Lee, DL Lodwick, CJ Watchman, WE Bolch. “Development of Hybrid Computational Newborn Phantom for Dosimetry Calculation: The Skeleton”. 2007 Computational Medical Physics Working Group Workshop 2.