Joyce H Keyak

picture of Joyce H Keyak

Professor in Residence, Radiological Sciences
School of Medicine
Professor in Residence, Mechanical & Aerospace Engineering
The Henry Samueli School of Engineering
Professor in Residence, Biomedical Engineering
The Henry Samueli School of Engineering

B.S., University of California, Berkeley, 1989, Mechanical Engineering

Ph.D., University of California, San Francisco/Berkeley, 1996, Bioengineering

Phone: (949) 824-9421

University of California, Irvine
Dept. of Radiological Sciences
Medical Sciences 1, Bldg. 811, Rm. B135
University of California
Mail Code: 5000
Irvine, CA 92697
Research Interests
bone mechanics,finite element modeling,quantitative computed tomography,prosthetic implants,osteoporosis,metastatic tumors in bone, radiation therapy
Academic Distinctions
• Named #10 in Image magazine’s 2009 “25 Most Influential in Radiology”, Sept. 7, 2009
• First Prize, 2007 Stradling Yocca Carlson & Rauth Business Plan Competition, UC Irvine; Novel treatment for spinal tumors using radioactive bone cement (Bone-Rad Therapeutics)
• Winner, 2007 Orange County Register People’s Choice Poll Award, for Bone-Rad Therapeutics
• Award of Excellence Symposium Poster Award, UC System-wide Biomedical Engineering Symposium, 2005 [co-author with TS Kaneko]
• Award of Excellence Symposium Poster Award, UC System-wide Biomedical Engineering Symposium, 2004 [co-author with GY Yang]
• Alice L. Jee Memorial Young Investigator Award, 34th International Sun Valley Workshop on Skeletal Tissue Biology, 2004 [co-author with M Meta]
• New Investigator Recognition Award, Orthopaedic Research Society, 1997
• Young Investigator Award, 1996 World Congress on Osteoporosis [co-author with T Lang]
• First Prize, 1993 Student Paper Competition, Southern Biomedical Engineering Society [co-author with KJ Bozic]
Research Abstract
As a bioengineer, Dr. Keyak applies the principles of engineering to improve the understanding and treatment of problems in bone. Her research currently focuses on:
• Development of radioactive bone cement for treatment of tumors in bone
• Bone strength assessment and treatment for osteoporosis and metastatic bone disease

Development of Radioactive Bone Cement for Treatment of Tumors in Bone

Dr. Keyak is developing a new method for treating metastatic tumors in the spine. This technique combines vertebroplasty with brachytherapy to provide a single procedure for alleviating pain and strengthening the bone while simultaneously delivering radiation to the tumor. In addition to convenience for the patient, significant advantages are that the spinal cord would receive little or no radiation and that adverse side effects would be minimal. Dr. Keyak is actively performing research at UCI in preparation for FDA approval of clinical trials and has also co-founded a company, Bone-Rad Therapeutics, Inc. (, to bring this treatment to market.

Bone Strength Assessment and Treatment for Osteoporosis and Metastatic Bone Disease

This research focuses on cutting-edge techniques for evaluating bone strength and hip fracture risk. Dr. Keyak pioneered a technique for rapidly creating patient-specific structural engineering models (finite element models) of the hip. This technique and variations of it are now used around the world to study bone. Research at UCI involves studies of:
• Treatments to strengthen the hip
• Bone loss due to long-duration spaceflight
• Causes of osteoporosis, e.g. radiation therapy and medications
Dr. Keyak is also involved with the UC Irvine Space Cycle, a proposed countermeasure for bone loss (
Available Technologies
Keyak JH, Meagher JM, Skinner HB, Mote CD, Jr.: Automated three-dimensional finite element modelling of bone: A new method. J Biomed Eng 12(5):389-397, 1990.

Anderson MJ, Keyak JH, Skinner HB: Compressive mechanical properties of human cancellous bone after gamma irradiation. J Bone Joint Surg [Am] 74-A(5):747-752, 1992.

Keyak JH, Skinner HB: Three-dimensional finite element modeling of bone: Effects of element size. J Biomed Eng 14(6):483-489, 1992.

Lee IY, Skinner HB, Keyak JH: Effects of variation of cement thickness on bone and cement stress at the tip of a femoral implant. Iowa Orthop J 13:155-159, 1993.

Keyak JH, Fourkas MG, Meagher JM, Skinner HB: Validation of an automated method of three-dimensional finite element modelling of bone. J Biomed Eng 15:505-509, 1993.

Les CM, Keyak JH, Stover SM, Taylor KT, Kaneps AJ: Estimation of material properties in the equine metacarpus with use of quantitative computed tomography. J Orthop Res 12:822-833, 1994.

Bozic KJ, Keyak JH, Skinner HB, Bueff HU, Bradford DS: Three-dimensional finite element modeling of a cervical vertebra: An investigation of burst fracture mechanism. J Spinal Disorders 7(2):102-110, 1994.

Keyak JH, Lee IY, Skinner HB: Correlations between orthogonal mechanical properties and density of trabecular bone: Use of different densitometric measures. J Biomed Mater Res 28(11):1329-1336, 1994.

Lee IY, Skinner HB, Keyak JH: Effects of variation of prosthesis size on bone and cement stress at the tip of a femoral implant. J Biomed Mater Res 28:1055-1060, 1994.

Skinner HB, Kilgus DJ, Keyak JH, Shimaoka EE, Kim AS, Tipton JS: Correlation of computed finite element stresses to bone density after remodeling around cementless femoral implants. Clin Orthop Relat Res 305:178-189, 1994.

Skinner HB, Kim AS, Keyak JH, Mote CD, Jr.: Femoral prosthesis implantation induces changes in bone stress that depend on extent of porous coating. J Orthop Res 12:553-563, 1994.

Jergas MD, Majumdar S, Keyak JH, Lee IY, Newitt DC, Grampp S, Skinner HB, Genant HK: Relationships between young modulus of elasticity, ash density, and MRI derived transverse relaxation T2* in tibial specimens. J Comput Assist Tomgr 19(3):472-479, 1995.

Majumdar S, Newitt DC, Jergas M, Gies A, Chiu EJ, Osman D, Keltner J, Keyak J, Genant HK: Evaluation of technical factors affecting the quantification of trabecular bone structure using magnetic resonance imaging. Bone 17(4):417-430, 1995.

Keyak JH, Lee IY, Nath DS, Skinner HB: Postfailure compressive behavior of tibial trabecular bone in three anatomic directions. J Biomed Mater Res 31:373-378, 1996.

Les CM, Stover SM, Keyak JH, Taylor KT, Willits NH: The distribution of material properties in the equine third metacarpal bone serves to enhance sagittal bending. J Biomech 30:355-361, 1997.

Les CM, Keyak JH, Stover SM, Taylor KT: Development and validation of a series of three-dimensional finite element models of the equine metacarpus. J Biomech 30:737-742, 1997.

Lang TF, Keyak JH, Heitz MW, Augat P, Lu Y, Mathur A, Genant HK: Volumetric quantitative computed tomography of the proximal femur: precision and relation to bone strength. Bone 21:101-108, 1997.

Les CM, Stover SM, Taylor KT, Keyak JH, Willits NH: Ex vivo simulation of in vivo strain distributions in the equine metacarpus. Eq Vet J 30(3):260-266, 1998.

Namba RS, Keyak JH, Kim AS, Vu LP, Skinner HB: Cementless implant composition and femoral stress: A finite element analysis. Clin Orthop Rel Res 347:261-267, 1998.

Keyak JH, Rossi SA, Jones KA, Skinner HB: Prediction of femoral fracture load using automated finite element modeling. J Biomech 31:125-133, 1998.

Powers CM, Lee IY, Skinner HB, Keyak JH: The effects of distal cement voids on cement stress in total hip arthroplasty. J Arthroplasty 13:793-798, 1998.

Keyak JH, Rossi SA: Prediction of femoral fracture load using finite element models: an examination of stress- and strain-based failure theories. J Biomech 33:209-214, 2000.

Keyak JH: Relationships between femoral fracture loads for two load configurations. J Biomech 33:499-502, 2000.

Keyak JH, Skinner HB, Fleming JA: Effect of force direction on femoral fracture load for two types of loading conditions. J Orthop Res 19:539-544, 2001.

Keyak JH: Improved prediction of proximal femoral fracture load using nonlinear finite element models. Med Eng Phys 23:165-173, 2001. [Corrigendum published 25:615, 2003.]

Kim JY, Rosenfeld SR, Keyak JH: Increased prevalence of scoliosis in Turner syndrome. J Pediatric Orthop 21:765-766, 2001.

Les CM, Keyak JH, Stover SM, Taylor KT, Kaneps AJ: Stiff and strong material properties are associated with brittle post-yield behavior in compact bone. J Orthop Res 20:607-614, 2002.

Keyak JH, Rossi SA, Jones KA, Les CM, Skinner HB: Prediction of fracture location in the proximal femur using finite element models. Med Eng Phys 23:657-664, 2001.

Samii VF, Les CM, Schulz KS, Keyak JH, Stover SM: Computed tomographic osteoabsorptiometry of the elbow joint in clinically normal dogs. Am J Vet Res 63(8):1159-1166, 2002.

Kaneko TS, Pejcic MR, Tehranzadeh J, Keyak JH: Relationships between material properties and CT scan data of cortical bone with and without metastatic lesions. Med Eng Phys 25:445-454, 2003.

Keyak JH, Falkinstein Y: Comparison of in situ and in vitro CT scan-based finite element model predictions of proximal femoral fracture load. Med Eng Phys 25(9):781-787, 2003.

Kaneko TS, Bell JS, Pejcic MR, Tehranzadeh J, Keyak JH: Mechanical properties, density, and quantitative CT scan data of trabecular bone with and without metastases. J Biomech 37(4):523-530, 2004.

Lian K, Lang TF, Keyak JH, Modin GW, Rehman Q, Do L, Lane NE: Differences in hip quantitative computed tomography (QCT) measurements of bone mineral density and bone strength between glucocorticoid-treated and glucocorticoid-naïve postmenopausal women. Osteoporosis Int 16:642-650, 2005. [Published online: 28 Sept 2004]

Keyak JH, Kaneko TS, Rossi SA, Pejcic MR, Tehranzadeh J, Skinner HB: Predicting the strength of femoral shafts with and without metastatic lesions. Clin Orthop Relat Res Oct (439):161-170, 2005.

Keyak JH, Kaneko TS, Tehranzadeh J, Skinner HB: Predicting proximal femoral strength using structural engineering models. Clin Orthop Relat Res Aug (437):219-228, 2005.

Meta M, Lu Y, Keyak JH, Lang T: Young-elderly differences in bone density, geometry and strength indices depend on proximal femur sub-region: a cross sectional study in Caucasian-American women. Bone 39(1):152-158, 2006. [Epub 2006 Feb 3]

Kaneko TS, Skinner HB, Keyak JH: Feasibility of a percutaneous technique for repairing proximal femora with simulated metastatic lesions. Med Eng Phys 29(5):594-601, 2007. [Epub 2006 Sep 1]

Cheng X, Li J, Lu Y, Keyak JH, Lang T: Proximal femoral density and geometry measurements by quantitative computed tomography: association with hip fracture. Bone 40(1):169-74, 2007.

Yang Y, Kaplan A, Pierre M, Adams G, Cavanagh P, Takahashi C, Kreitenberg A, Hicks J, Keyak J, Caiozzo V: Space cycle: A human-powered centrifuge that can be used for hypergravity resistance training. Aviat Space Environ Med 78(1):2-9, 2007.

Keyak JH, Kaneko TS, Skinner HB, Hoang BH: Effect of simulated metastatic lytic lesions on proximal femoral strength. Clin Orthop Relat Res 459:139-145, 2007.

Kaneko TS, Skinner HB, Keyak JH: Lytic lesions in the femoral neck: Importance of location and evaluation of a novel minimally invasive repair technique. J Orthop Res 26(8):1127-32, 2008. [Epub 2008 Mar 7]

Yang GY, Johnson G, Tang WC, and Keyak JH: Parylene-based strain sensor for bone. Sensors 7(12):1693-97, 2007.

Li W, Kezele I, Collins DL, Zijdenbos A, Keyak J, Kornak J, Koyama A, Saeed I, LeBlanc A, Harris T, Lu Y, Lang T: Voxel-based modeling and quantification of the proximal femur using inter-subject registration of quantitative CT images. Bone 41(5):888-95, 2007. [Epub 2007 Jul 17]

Lang TF, Koyama A, Li C, Li J, Lu Y, Saeed I, Gazze E, Keyak JH, Harris TB, Cheng X: Pelvic body composition measurements by quantitative computed tomography: Association with recent hip fracture. Bone 42(4):798-805, 2008. [Epub 2008 Jan 30]

Langton CM, Pisharody S, Keyak JH: Generation of a 3D proximal femur shape from a single projection 2D radiographic image. Osteoporosis Int 20(3):455-61, 2009. [Epub 2008 Jun 19]

Lee YS, Lee TQ, Keyak JH: Effect of an UHMWPE patellar component on stress fields in the patella: A finite element analysis. Knee Surg Sports Tramatol Arthrosc 17(1):71-82, 2009. [Epub 2008 Oct 1].

Keyak JH, Koyama AK, LeBlanc A, Lu Y, Lang TF: Reduction in proximal femoral strength due to long-duration spaceflight. Bone 44:449-53, 2009. [Epub 2008 Dec. 3].

Langton CM, Pisharody S, Keyak JH: Comparison of 3D finite element analysis derived stiffness and BMD to determine the failure load of the excised proximal femur. Med Eng Phys. 31(6):668-72, 2009. [Epub 2009 Feb 20].

Li W, Kornak J, Harris T, Keyak J, Li C, Lu Y, Cheng X, Lang T: Identify fracture-critical regions inside the proximal femur using statistical parametric mapping. Bone 44:596-602, 2009. [Epub 2008 Dec 24]

Li W, Kornak J, Harris T, Keyak J, Li C, Lu Y, Cheng X, Lang T: Bone fracture risk estimation based on image similarity. Bone 45(3):560-7, 2009. [Epub 2009 May 4]

Saeed I, Carpenter RD, Leblanc AD, Li J, Keyak JH, Sibonga JD, Lang TF: Quantitative computed tomography reveals the effects of race and sex on bone size and trabecular and cortical bone density. J Clin Densitom 12(3):330-6, 2009. [Epub 2009 Jul 4]

Kaneko TS, Sehgal V, Skinner HB, Al-Ghazi MS, Ramsinghani NS, Keyak JH. Evaluation of a radiation transport modeling method for radioactive bone cement. Phys Med Biol 55:2451-63, 2010. [Epub 2010 Apr 6]

Carpenter RD, Lang TF, Bloomfield SA, Bloomberg JJ, Judex S, Keyak JH, Midura RJ, Pajevic PD, Spatz JM: Effects of long-duration spaceflight, microgravity, and radiation on the neuromuscular, sensorimotor, and skeletal systems. J Cosmology 12:3778-80, 2010.

Farrokhi S, Keyak JH, Powers CM: Individuals with patellofemoral pain exhibit greater patellofemoral joint stress: A finite element analysis study. Osteoarthritis Cartilage 19(3):287-94. 2011. [Epub 2011 Dec 21]

Keyak JH, Sigurdsson S, Karlsdottir G, Oskarsdottir D, Sigmarsdottir A, Zhao S, Kornak J, Harris T, Sigurdsson G, Jonsson BY, Siggeirsdottir K, Eiriksdottir G, Gudnason V, Lang TF: Male-female differences in the association between incident hip fracture and proximal femoral strength computed by finite element analysis. Bone 48:1239-45, 2011. [PMC3095704]

Lang TF, Sigurdsson S, Karlsdottir G, Oskarsdottir D, Sigmarsdottir A, Chengshi J, Kornak J, Harris TB, Sigurdsson G, Jonsson BY, Siggeirsdottir K, Eiriksdottir G, Gudnason V, Keyak JH: Age-related loss of proximal femoral strength in elderly men and women: the Age Gene/Environment Susceptibility Study – Reykjavik. Bone 50:743-8, 2012. [Epub 2011 Dec 10]

Ascenzi MG, Kawas NP, Lutz A, Kardas D, Nackenhorst U, Keyak JH: Individual-specific multi-scale finite element simulation of cortical bone of human proximal femur. J Comput Phys 244:298-311, 2013.

Kaneko TS, Sehgal V, Skinner HB, Al-Ghazi MSAL, Ramsinghani NS, Marquez Miranda M, Keyak JH: Radioactive bone cement for the treatment of spinal metastases: a dosimetric analysis of simulated clinical scenarios. Phys Med Biol 57:4387-401, 2012.

Ho K, Hu HH, Keyak JH, Colletti PM, Powers CM: Measuring bone mineral density with Fat-Water MRI: Comparison with computed tomography. J Magn Reson Imaging 37(1):237-42, 2013.

LeBlanc A, Matsumoto T, Jones J, Shapiro J, Lang T, Shackelford L, Smith SM, Evans H, Spector E, Ploutz-Snyder R, Sibonga J, Keyak J, Nakamura T, Kohri K Ohshima, H: Bisphosphonates as a Supplement to Exercise to Protect Bone during Long Duration Space Flight. Osteoporos Int. [Epub 2013 Jan 19]

Carballido-Gamio J, Harnish R, Saeed I, Streeper T, Sigurdsson S, Amin S, Atkinson EJ, Therneau TM, Siggeirsdottir K, Cheng X, Melton LJ 3rd, Keyak J, Gudnason V, Khosla S, Harris TB, Lang TF: Proximal femoral density distribution and structure in relation to age and hip fracture risk in women. J Bone Miner Res 28(3):537-46, 2013. [Epub 15 Feb 2013]

Keyak JH, Sigurdsson S, Karlsdottir GS, Oskarsdottir D, Sigmarsdottir A, Kornak J, Harris TB, Sigurdsson G, Jonsson BY, Siggeirsdottir K, Eiriksdottir G, Gudnason V, Lang TF: Effect of finite element model loading condition on fracture risk assessment in men and women: The AGES-Reykjavik study. Bone. Accepted.
Professional Societies
Orthopaedic Research Society
American Society for Bone and Mineral Research
Graduate Programs
Mathematical and Computational Biology

Research Centers
Chao Family Comprehensive Cancer Center
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