Public examination of a doctoral dissertation in the field of medical physics
Doctoral candidate: M.Sc. Techn Janne Karjalainen
Date and venue: 17.6.2011 at 12 noon, L22, Snellmania, Kuopio campus
It has been estimated that 200 million individuals suffer from osteoporosis wordwide. However, about 75% of people with the condition are not diagnosed and do not receive proper treatment. It is not realistic to apply the current gold standard diagnostic method, Dual-Energy X-Ray Absorptiometry (DXA), in primary healthcare in order to improve the coverage of diagnostics. This thesis describes novel ultrasound methods based on pulse-echo measurements of reflection and backscattering in bone. These methods may be feasible for use in primary healthcare due to their cost effectiveness and non-existent radiation dose. The soft tissues overlying the bone have represented a significant obstacle to quantitative ultrasound measurements of bone at the most important fracture sites.
A dual frequency ultrasound (DFUS) method has been developed to eliminate these soft tissue induced errors. In this thesis, the ultrasound methods were first evaluated in laboratory experiments of human and bovine bone samples. Then the methods were implemented into a portable device for use in a clinical trial in patients with and without previous fractures. Furthermore, a simple and accurate pulse-echo ultrasound method was introduced for the determination of cortical bone thickness. The present results indicate that the ultrasound backscatter measurements provide valuable, frequency dependent information on the composition, structure and mechanical properties of human trabecular bone.
The DFUS method can minimize the soft tissue related errors in ultrasound measurement of bone in vivo. In the clinical trial, the ultrasound methods were able to distinguish between subjects with fractures from their age matched controls. In addition, simple combination of subject characteristics and multi-site ultrasound measurements provided a useful estimate of femoral neck BMD. Therefore, the methodology introduced in this thesis may help to create a foundation for osteoporosis diagnostics at the primary healthcare level.
The doctoral dissertation of M.Sc. Techn Janne Karjalainen entitled “Novel Pulse-Echo Ultrasound Methods for Diagnostics of Osteoporosis”. The opponent in the public examination is Professor Kay Raum, Charité - Universitätsmedizin Berlin and the custos is Professor Jukka Jurvelin of the University of Eastern Finland will be examined at the Faculty of Science and Forestry.
Photo available for download at http://www.uef.fi/vaitoskuvat
Contact: Janne Karjalainen, tel. +358 40 707 9892, email@example.com
Publishing year: 2011Back to this years article listing