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see-trough technology. In Fig. 10 is illustrated the current and 
future use of computer—guided surgery according to (Peuchot, 
1993). 
C dem 
  
Figure 10. Graphics illustration of current and future use of 
computer-guided surgery according to (Peuchot 
1993) 
The task is to fulfil the clinical and technical requirements 
(Sect. 3.3). Nowadays, we are looking for the best see-trough 
technology. The displays currently available for enhanced- 
reality visualisation are less than optimal. Head-mounted 
displays are still heavy, awkward and have relatively low 
resolution. Conventional CRTs have better resolution but limit 
the applications of enhanced-reality visualisation. Our 
conceptual diagram is shown in Fig. 11. 
  
  
virtual scene 
vessels in safety margin | 
liver segment classification | 
real scene 
patient’s liver 
  
  
| virtuality (graphic) | 
  
  
  
  
fo | 
rendering of | tracking 
camera-position 
  
  
  
  
  
  
  
registration of 
virtuality with reality 
  
  
depiction of depiction of 
virtuality reality 
  
Figure 11. Conceptual diagram for augmented reality in liver 
surgery 
4. CONCLUSIONS 
New technologies and methods implemented in DKFZ’s 
ARION™ software will enable image-guided liver surgery. It is 
shown that many tools for preoperative planning and surgical 
interventions are available in the clinical environment, while the 
surgical procedures itself still lack computer assistance. On this 
basis, the Div. Medical and Biological Informatics, Deutsches 
Krebsforschungszentrum and the research group *AR-work" of 
Technical University Berlin derived strategies for an adequate 
AR-application. A technique will be developed in order to 
superimpose virtual computer-generated information with real 
patient image data using a see-through technology. 
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