Dr Christopher F Njeh, PhD - California Cancer Center - Radiation Physicist

Dr Christopher F Njeh

PhD

California Cancer Center

Radiation Physicist

Fresno, Ca | United States

Main Specialties: Other

Additional Specialties: Radiation therapy


Top Author

Dr Christopher F Njeh, PhD - California Cancer Center - Radiation Physicist

Dr Christopher F Njeh

PhD

Introduction

Primary Affiliation: California Cancer Center - Fresno, Ca , United States

Specialties:

Additional Specialties:

Research Interests:

Education

Feb 2017
Sheffield Hallam University
Phd
Jul 2013
AAPM
Fellow

Publications

60Publications

292Reads

1150Profile Views

368PubMed Central Citations

Point/Counterpoint. Radiotherapy using hard wedges is no longer appropriate and should be discontinued.

Med Phys 2016 Mar;43(3):1031-4

Biomedical Engineering, Catholic University Medical College, Seoul 137-701, Republic of Korea (Tel: 822-2258-7234; E-mail:

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http://dx.doi.org/10.1118/1.4939262DOI Listing
March 2016
6 Reads
2.635 Impact Factor

Enhanced dynamic wedge output factors for Varian 2300CD and the case for a reference database.

J Appl Clin Med Phys 2015 09 8;16(5):271–283. Epub 2015 Sep 8.

Marshfield Clinic.

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http://dx.doi.org/10.1120/jacmp.v16i5.5498DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5690176PMC
September 2015
2 Reads
1.110 Impact Factor

Point/Counterpoint. Evaluation of treatment plans using target and normal tissue DVHs is no longer appropriate.

Med Phys 2015 May;42(5):2099-102

Department of Radiation Oncology, University of Texas Medical Branch at Galveston, Galveston, Texas 77555-0711 (Tel: 409-772-6560; E-mail:

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http://dx.doi.org/10.1118/1.4903902DOI Listing
May 2015
9 Reads
1 Citation
2.635 Impact Factor

Point/Counterpoint. IGRT has limited clinical value due to lack of accurate tumor delineation.

Med Phys 2013 Apr;40(4):040601

National Medical Physics Services, Tyler, Texas 75703, USA.

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http://dx.doi.org/10.1118/1.4789492DOI Listing
April 2013
2 Reads
4 Citations
2.635 Impact Factor

A validation of carbon fiber imaging couch top modeling in two radiation therapy treatment planning systems: Philips Pinnacle3 and BrainLAB iPlan RT Dose.

Radiat Oncol 2012 Nov 9;7:190. Epub 2012 Nov 9.

Department Texas Oncology, Radiation oncology, Texas 75702, USA.

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http://dx.doi.org/10.1186/1748-717X-7-190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3549905PMC
November 2012
10 Reads
2 Citations
2.550 Impact Factor

A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography.

Radiat Oncol 2012 Mar 27;7:49. Epub 2012 Mar 27.

Texas Oncology Tyler, Radiation Oncology Department, 910 East Houston Street, Tyler, TX, USA.

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http://dx.doi.org/10.1186/1748-717X-7-49DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337228PMC
March 2012
4 Reads
4 Citations
2.550 Impact Factor

Point/counterpoint: vendor provided machine data should never be used as a substitute for fully commissioning a linear accelerator.

Med Phys 2012 Feb;39(2):569-72

Radiation Oncology Department, Indiana University-School of Medicine, Indianapolis, IN 46202-5289, USA.

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http://dx.doi.org/10.1118/1.3658740DOI Listing
February 2012
8 Reads
1 Citation
2.635 Impact Factor

Accelerated partial breast irradiation using external beam conformal radiation therapy: a review.

Crit Rev Oncol Hematol 2012 Jan 3;81(1):1-20. Epub 2011 Mar 3.

Radiation Oncology Department, Texas Oncology Tyler, TX, USA.

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http://dx.doi.org/10.1016/j.critrevonc.2011.01.011DOI Listing
January 2012
3 Reads
9 Citations
4.030 Impact Factor

Point/counterpoint. The adoption of new technology in radiation oncology should rely on evidence-based medicine.

Med Phys 2011 Jun;38(6):2825-8

Tyler Cancer Center, Radiation Oncology Department, Tyler, Texas 75702, USA.

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http://dx.doi.org/10.1118/1.3533903DOI Listing
June 2011
8 Reads
2 Citations
2.635 Impact Factor

Citation and quotation errors: in regards to Qiu et al. (Int J Radiat Oncol Biol Phys 2010;78:288-296).

Int J Radiat Oncol Biol Phys 2011 Mar;79(3):957

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http://dx.doi.org/10.1016/j.ijrobp.2010.10.051DOI Listing
March 2011
4 Reads
4.260 Impact Factor

Accelerated Partial Breast Irradiation (APBI): A review of available techniques.

Radiat Oncol 2010 Oct 4;5:90. Epub 2010 Oct 4.

Radiation Oncology Department, Texas Oncology Tyler, 910 East Houston Street, Tyler, Texas, USA.

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http://dx.doi.org/10.1186/1748-717X-5-90DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2958971PMC
October 2010
3 Reads
32 Citations
2.550 Impact Factor

Point/Counterpoint. Radiation departments should be certified to provide certain new technologies such as IGRT.

Med Phys 2009 Dec;36(12):5377-9

Department of Radiation Oncology, Tyler Cancer Center, Tyler, Texas 75702, USA.

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http://dx.doi.org/10.1118/1.3223359DOI Listing
December 2009
4 Reads
1 Citation
2.635 Impact Factor

Determination of the photon beam attenuation by the Brainlab imaging couch: angular and field size dependence.

J Appl Clin Med Phys 2009 Jun 2;10(3):2979. Epub 2009 Jun 2.

Radiation Oncology Department, Texas Oncology, Tyler, TX 75702, USA.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5720553PMC
June 2009
5 Reads
13 Citations
1.110 Impact Factor

Tumor delineation: The weakest link in the search for accuracy in radiotherapy.

Authors:
C F Njeh

J Med Phys 2008 Oct;33(4):136-40

Tyler Cancer Center (US oncology), Radiation Oncology Department, 910 East Houston Street, Tyler, Texas, 75702, USA.

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http://dx.doi.org/10.4103/0971-6203.44472DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2772050PMC
October 2008
4 Reads
39 Citations

The measurement of broadband ultrasonic attenuation in cancellous bone--a review of the science and technology.

IEEE Trans Ultrason Ferroelectr Freq Control 2008 Jul;55(7):1546-54

Fac. of Sci., Queensland Univ. of Technol., Brisbane, QLD, Brisbane, Australia.

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http://dx.doi.org/10.1109/TUFFC.2008.831DOI Listing
July 2008
5 Reads
8 Citations
1.512 Impact Factor

Sound-tissue interaction: the physical basis of bone ultrasonometry and limitations of existing methods.

J Clin Densitom 1998 ;1(3):295-301

Centre for Metabolic Bone Disease, University of Hull and Royal Hull Hospitals Trust, Hull, UK.

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February 2005
4 Reads
1.603 Impact Factor

Palangeal quantitative ultrasound, phalangeal morphometric variables, and vertebral fracture discrimination.

Calcif Tissue Int 2003 Apr 10;72(4):469-77. Epub 2003 Feb 10.

Department of Radiology, Division of Endocrinology, Scientific Institute Hospital Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy.

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http://dx.doi.org/10.1007/s00223-001-1092-0DOI Listing
April 2003
6 Reads
5 Citations
3.272 Impact Factor

Does osteoporosis classification using heel BMD agree across manufacturers?

Osteoporos Int 2002 Aug;13(8):613-7

Osteoporosis and Arthritis Research Group, Department of Radiology, University of California at San Francisco, San Francisco, CA, USA.

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http://dx.doi.org/10.1007/s001980200082DOI Listing
August 2002
4 Reads
4 Citations
4.170 Impact Factor

Universal standardization of forearm bone densitometry.

J Bone Miner Res 2002 Apr;17(4):734-45

Department of Radiology, University of California San Francisco, 94143-1349, USA.

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http://dx.doi.org/10.1359/jbmr.2002.17.4.734DOI Listing
April 2002
4 Reads
5 Citations
6.832 Impact Factor

Multisite bone ultrasound measurement on North American female reference population.

J Clin Densitom 2001 ;4(3):239-48

Osteoporosis Research Centre, University of British Columbia, Vancouver, Canada.

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February 2002
3 Reads
4 Citations
1.603 Impact Factor

Influence of region of interest and bone size on calcaneal BMD: implications for the accuracy of quantitative ultrasound assessments at the calcaneus.

Br J Radiol 2002 Jan;75(889):59-68

Osteoporosis and Arthritis Research Group, Department of Radiology, University of California, San Francisco, 350 Parnassus Avenue, San Francisco, CA 94134-1349, USA.

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http://dx.doi.org/10.1259/bjr.75.889.750059DOI Listing
January 2002
5 Reads
4 Citations
1.533 Impact Factor

Evaluation of a gel-coupled quantitative ultrasound device for bone status assessment.

J Ultrasound Med 2001 Nov;20(11):1219-28

Osteoporosis and Arthritis Research Group, Department of Radiology, University of California San Francisco, 94143-1349, USA.

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November 2001
4 Reads
1.532 Impact Factor

Assessment of bone status using speed of sound at multiple anatomical sites.

Ultrasound Med Biol 2001 Oct;27(10):1337-45

Osteoporosis and Arthritis Research Group, Department of Radiology, University of California San Francisco, 350 Parnassus Avenue, Suite 607, San Francisco, CA 94143-1349, USA.

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October 2001
6 Reads
6 Citations
2.214 Impact Factor

Bone loss. Quantitative imaging techniques for assessing bone mass in rheumatoid arthritis.

Authors:
C F Njeh H K Genant

Arthritis Res 2000 3;2(6):446-50. Epub 2000 Aug 3.

Department of Radiology, University of California, San Francisco, California 94143, USA.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC128873PMC
http://dx.doi.org/10.1186/ar126DOI Listing
April 2001
4 Reads
6 Citations

Is quantitative ultrasound dependent on bone structure? A reflection.

Osteoporos Int 2001 ;12(1):1-15

Osteoporosis and Arthritis Research Group, Department of Radiology, University of California, San Francisco, 350 Parnassus Avenue, Suite 908, San Francisco, CA 94143-1349, USA.

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http://dx.doi.org/10.1007/PL00020939DOI Listing
April 2001
2 Reads
15 Citations
4.170 Impact Factor

Quantitative ultrasound of the tibia depends on both cortical density and thickness.

Osteoporos Int 2001 ;12(1):28-34

Osteoporosis and Arthritis Research Group, Department of Radiology, University of California, San Francisco, 350 Parnassus Avenue, Suite 607, San Francisco, CA 94143-1349, USA.

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http://dx.doi.org/10.1007/s001980170154DOI Listing
April 2001
3 Reads
14 Citations
4.170 Impact Factor

Comparison of six calcaneal quantitative ultrasound devices: precision and hip fracture discrimination.

Osteoporos Int 2000 ;11(12):1051-62

Department of Radiology, University of California, San Francisco 94143, USA.

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http://dx.doi.org/10.1007/s001980070027DOI Listing
March 2001
8 Reads
12 Citations
4.170 Impact Factor

Use of quantitative ultrasound to assess bone status in children with juvenile idiopathic arthritis: a pilot study.

J Clin Densitom 2000 ;3(3):251-60

Department of Nuclear Medicine, Queen Elizabeth Hospital, Birmingham, UK.

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January 2001
4 Reads
4 Citations
1.603 Impact Factor

Evaluation of a gel-coupled QUS device.

Authors:
C F Njeh H K Genant

Osteoporos Int 2000 ;11(8):726

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December 2000
2 Reads
4.170 Impact Factor

Estimation of wrist fracture load using phalangeal speed of sound: an in vitro study.

Ultrasound Med Biol 2000 Nov;26(9):1517-23

Osteoporosis and Arthritis Research Group, Department of Radiology, University of California, San Francisco, San Francisco, CA 94143-1349, USA.

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November 2000
2 Reads
1 Citation
2.214 Impact Factor

Association between QUS and structural parameters?

Calcif Tissue Int 2000 Sep;67(3):273-4

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September 2000
9 Reads
3.272 Impact Factor

Assessment of a new quantitative ultrasound calcaneus measurement: precision and discrimination of hip fractures in elderly women compared with dual X-ray absorptiometry.

Osteoporos Int 2000 ;11(4):354-60

Department of Radiology, University of California, San Francisco 94143-1349, USA.

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http://dx.doi.org/10.1007/s001980070125DOI Listing
August 2000
9 Reads
4 Citations
4.170 Impact Factor

Evaluation of a new body composition phantom for quality control and cross-calibration of DXA devices.

J Appl Physiol (1985) 2000 Aug;89(2):599-605

University of California San Francisco, 94143-1349, USA.

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http://dx.doi.org/10.1152/jappl.2000.89.2.599DOI Listing
August 2000
6 Reads
3 Citations

Prediction of bone strength of distal forearm using radius bone mineral density and phalangeal speed of sound.

Bone 2000 May;26(5):529-33

Osteoporosis and Arthritis Research Group, Department of Radiology, University of California, San Francisco, San Francisco, CA 94117-0784, USA.

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http://dx.doi.org/10.1016/S8756-3282(00)00250-7DOI Listing
May 2000
4 Reads
1 Citation

Comparison of ultrasound and bone mineral density assessment of the calcaneus with different regions of interest in healthy early menopausal women.

J Clin Densitom 1999 ;2(2):117-26

Department of Health Sciences, University of Jyväskylä, Jyväskylä, Findland, and Department of Radiology, UCSF, San Fransisco, CA.

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April 2000
3 Reads
1.603 Impact Factor

Doses from dual-Xray absorptiometry (DXA) scanning to reproductive tissues of females.

Authors:
C F Njeh G M Blake

J Clin Densitom 1999 ;2(2):191-3

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April 2000
5 Reads
1.603 Impact Factor

Factors affecting broadband ultrasound attenuation results of the calcaneus using a gel-coupled quantitative ultrasound scanning system.

Osteoporos Int 1999 ;10(6):495-504

Osteoporosis and Arthritis Research Group, University of California, San Francisco, California, USA.

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http://dx.doi.org/10.1007/s001980050260DOI Listing
April 2000
4 Reads
4 Citations
4.170 Impact Factor

Comparison of an imaging heel quantitative ultrasound device (DTU-one) with densitometric and ultrasonic measurements.

Br J Radiol 2000 Jan;73(865):23-30

Osteoporosis and Arthritis Research Group, University of California at San Francisco 94117, USA.

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http://dx.doi.org/10.1259/bjr.73.865.10721316DOI Listing
January 2000
5 Reads
1.533 Impact Factor

An in vitro investigation of the dependence on sample thickness of the speed of sound along the specimen.

Med Eng Phys 1999 Nov;21(9):651-9

Osteoporosis and Arthritis Research Group, Department of Radiology, University of Califormia, 350 Parnassus Avenue, Suite 908, San Francisco, CA 94117-1349, USA.

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November 1999
4 Reads
9 Citations
1.825 Impact Factor

Factors influencing the speed of sound through the proximal phalanges.

J Clin Densitom 1999 ;2(3):241-9

Osteoporosis and Arthritis Research Group, UCSF, San Francisco, CA 94117-1349, USA.

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November 1999
3 Reads
2 Citations
1.603 Impact Factor

Acoustic and ultrasonic tissue characterization--assessment of osteoporosis.

Proc Inst Mech Eng H 1999 ;213(3):261-9

University of Hull, UK.

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http://dx.doi.org/10.1243/0954411991534960DOI Listing
September 1999
3 Reads
1 Citation
1.144 Impact Factor

An evaluation of a new gel-coupled ultrasound device for the quantitative assessment of bone.

Br J Radiol 1999 Jul;72(859):691-700

Department of Radiology, University of California 94117-1349, USA.

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http://dx.doi.org/10.1259/bjr.72.859.10624327DOI Listing
July 1999
39 Reads
6 Citations
1.533 Impact Factor

Evaluation of finger ultrasound in the assessment of bone status with application of rheumatoid arthritis.

Osteoporos Int 1999 ;9(1):82-90

Department of Nuclear Medicine, Queen Elizabeth Hospital, Birmingham, UK.

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http://dx.doi.org/10.1007/s001980050119DOI Listing
June 1999
5 Reads
5 Citations
4.170 Impact Factor

Does combining the results from multiple bone sites measured by a new quantitative ultrasound device improve discrimination of hip fracture?

J Bone Miner Res 1999 Apr;14(4):644-51

Osteoporosis and Arthritis Research Group, University of California, San Francisco, USA.

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http://dx.doi.org/10.1359/jbmr.1999.14.4.644DOI Listing
April 1999
4 Reads
6 Citations
6.832 Impact Factor

Radiation exposure in bone mineral density assessment.

Appl Radiat Isot 1999 Jan;50(1):215-36

Department of Radiology, University of California, San Francisco, USA.

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January 1999
6 Reads
16 Citations
1.060 Impact Factor

Ultrasound velocity of trabecular cubes reflects mainly bone density and elasticity.

Calcif Tissue Int 1999 Jan;64(1):18-23

Osteoporosis and Arthritis Research Group, Department of Radiology, University of California, San Francisco, 505 Parnassus Avenue, M392, Box 0628, San Francisco, California 94143, USA.

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January 1999
3 Reads
8 Citations
3.272 Impact Factor

The use of quantitative ultrasound to monitor fracture healing: a feasibility study using phantoms.

Med Eng Phys 1998 Dec;20(10):781-6

Medical Physics Department, Queen Elizabeth Hospital, Birmingham, UK.

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December 1998
3 Reads
5 Citations
1.825 Impact Factor

Quantitative ultrasound in bone status assessment.

Rev Rhum Engl Ed 1998 Jul-Sep;65(7-9):489-98

National Institute for Health and Medical Research (INSERM) U403, Edouard Herriot Teaching Hospital, Lyon, France.

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December 1998
3 Reads
7 Citations

Osteoclastic activation is the principal mechanism leading to secondary osteoporosis in rheumatoid arthritis.

J Rheumatol 1998 Jul;25(7):1282-9

Rheumatology and Rehabilitation Research Unit, University of Leeds, UK.

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July 1998
6 Reads
25 Citations
3.190 Impact Factor

Variation in bone mineral density between different anatomical sites in a normal local population.

Authors:
C F Njeh C M Boivin

Appl Radiat Isot 1998 May-Jun;49(5-6):685-6

Department of Nuclear Medicine, Queen Elizabeth Hospital, Birmingham, U.K.

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May 1998
3 Reads
1.060 Impact Factor

Prediction of human femoral bone strength using ultrasound velocity and BMD: an in vitro study.

Osteoporos Int 1997 ;7(5):471-7

Bone Densitometry Service, Queen Elizabeth Hospital, Birmingham, UK.

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January 1998
2 Reads
10 Citations
4.170 Impact Factor

The ability of ultrasound velocity to predict the stiffness of cancellous bone in vitro.

Bone 1997 Aug;21(2):183-90

Centre for Metabolic Bone Disease, University of Hull, UK.

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August 1997
2 Reads
4 Citations

Radiation dose and in vitro precision in paediatric bone mineral density measurement using dual X-ray absorptiometry.

Br J Radiol 1997 Jul;70(835):719-27

Medical Physics Department, University Hospital Birmingham NHS Trust, Edgbaston, UK.

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http://dx.doi.org/10.1259/bjr.70.835.9245884DOI Listing
July 1997
3 Reads
6 Citations
1.533 Impact Factor

The effect of cortical endplates on ultrasound velocity through the calcaneus: an in vitro study.

Br J Radiol 1997 May;70(833):504-10

Medical Physics Department, Queen Elizabeth Hospital, Birmingham, UK.

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http://dx.doi.org/10.1259/bjr.70.833.9227233DOI Listing
May 1997
3 Reads
1.533 Impact Factor

The role of ultrasound in the assessment of osteoporosis: a review.

Osteoporos Int 1997 ;7(1):7-22

Medical Physics Department, University Hospital Birmingham NHS Trust, UK.

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April 1997
2 Reads
34 Citations
4.170 Impact Factor

The non-linear relationship between BUA and porosity in cancellous bone.

Phys Med Biol 1996 Nov;41(11):2411-20

Centre for Metabolic Bone Disease, Hull, UK.

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November 1996
2 Reads
3 Citations
2.761 Impact Factor

Orthogonal relationships between ultrasonic velocity and material properties of bovine cancellous bone.

Med Eng Phys 1996 Jul;18(5):373-81

Health Research Institute, Sheffield Hallam University, UK.

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July 1996
3 Reads
1 Citation
1.825 Impact Factor

Prediction of mechanical properties of the human calcaneus by broadband ultrasonic attenuation.

Bone 1996 Jun;18(6):495-503

Centre for Metabolic Bone Disease, Hull, UK.

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June 1996
3 Reads
8 Citations

Radiological assessment of a new bone densitometer--the Lunar EXPERT.

Br J Radiol 1996 Apr;69(820):335-40

Medical Physics Department, University Hospital Birmingham NHS Trust, Edgbaston, UK.

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http://dx.doi.org/10.1259/0007-1285-69-820-335DOI Listing
April 1996
3 Reads
2 Citations
1.533 Impact Factor

Top co-authors

D Hans
D Hans

Geneva University Hospital

16
B Fan
B Fan

Sun Yat-Sen University

11
S Cheng
S Cheng

Weill Cornell Medical College

4
E Diessel
E Diessel

Freie Universität Berlin

4
Y Lu
Y Lu

Yong Loo Lin School of Medicine

4
J Li
J Li

University Hospital Hamburg-Eppendorf

3
Y He
Y He

Sichuan University

3
Christian M Langton
Christian M Langton

Institute of Health and Biomedical Innovation

3