"The future of surgery is not about blood and guts; the future of surgery is about bits and bytes.”
/Dr. Richard Satava/

Friday, February 29, 2008

Aiming for the stars

This post will be a little bit irregular, but some people might be interested in the details about the Palomar observatory we visited this week within the frames of the 9th iSAIRAS conference in Los Angeles. We were given a extraordinary behind the scenes guided tour thanks to the kind staff.

The Palomar Observatory is located in between Los Angeles and San Diego, in an altitude of 1700 m (5600 feet). It contains the 200 inches (5.08 m) Hale telescope that used to be the biggest in the world for more than 40 years. George Ellery Hale was a real visionary, and managed to build six times the biggest telescope on Earth (always breaking his own record). This got finished in 1947, and got some mayor reparations since, but has been working very stable, conducting thousands of experiments. Recently, it has been able to capture the world’s clearest space images, overtaking even the Hubble space telescope (that is "only" 94"). The Hale takes advantage of its new adaptive lenses that are compensating for the blurring affect of the atmosphere adjusting the distortion of the mirror at a 2000 reconfiguration/min rate. It uses a powerful laser beam that projects an artificial "star" 90 km high, and can used as a reference.
The 200’ lenses were produced in Pasadena, at Caltech that is the owner and manager or the telescope. It is 23.5 – 19 inch thick, and the biggest surface irregularity is about 10 microns, the focal length is F3.3, looking as far as 11 billion lightyears. I took one month just to melt the glass needed, and then 10 months gradual cooling. While testing, it was replaced with a huge concrete phantom (weighting the same - 14 tons) that can still be seen.
The servos moving the telescope can deal with 150 tons, and it was the first that used pressurized oil to reduce friction. They use the telescope every night if the weather allows (on average 200 nights a year), and to protect it from heat deformation, the interior is always kept at the night time outside temperature (that meant 0C on our visit). There is a dedicated science project for every day, assigned months ahead. If you have bad weather, you have to ask for reschedule.
Besides the Hale telescope, there are other smaller ones nearby. These are all automated, robots are moving the lenses towards the target areas. The new 24” telescope is constantly keeping an eye on Titan’s weather. The 48” Schmidt wide-field telescope is the "rapid reaction force", that is able to focus on any point of interest within 2 min of localization by a satellite. The 20” searches for exoplanets by observing star eclipses, the 60” reflecting has mapped the entire northern hemisphere, and just about to do it again, and there is a fast moving one, that scans the sky three times a night looking for anything new.
Looking to the future, they are testing a new telescope system based in interferometry, and the plans are ready for a 30 m wide telescope, TMT, that would redefine space observation.
The Hale telescope is open for the public, even though it takes three hours to get up to the hills from Los Angeles, it worths the visit.

Saturday, February 9, 2008

Urology Robotics (URobotics) Lab


URobotics is a research and education program and lab dedicated to advance the technology used in Urology. The main focus of the lab has been in the development of robots for real-time Image-Guided Interventions under the directorate of Prof. Dan Stoianovici. The application range of the lab technologies extends behind the Urology field to other medical specialties (Interventional Radiology), education, and industry. They are involved in the development of both MRI, X-Ray and US guided mechatronic devices. They have built a completely MRI compatible and fully-actuated robot for easy access to the prostate.
They also have extensive experience in performing telementoring and telesurgical applications between the facility and various hospitals around the world. Four ISDN lines are typically used for the bidirectional audio-video connection and the control of instrumentation and robotics. Depending on the application remote control is performed for various laparoscopy instruments, the robotic laparoscope manipulator (Lap Driver), or image-guided robots (PAKY-RCM).

Thursday, February 7, 2008

Seminars


In the past two weeks there were several interesting lectures and seminars I will try to briefly cover here. Firstly, Dr. L.P. Nolte (University of Bern, Switzerland) held a seminar on Smart Device Technology for Orthopaedic Surgery. He went through the milestones of the field (1987 Robodoc, 1994 first free-hand navigation, etc.) He presented the concept of image-free surgical navigation in TKR operations, and showed their work with mobile isocentric C-arm 3D fluoroscopy and the Marvin research platform they have. He identified the main challenges of the field as:
- Finding new registration method
- Work flow optimization
- Non invasive referencing
- Automated computation of surrogate variables
- Extensive use of sensors and actuators
He talked about smart implants and micro sensors for Tool bending and instrument deformation sensing via tracking, sensors built in the meniscus and the vertebra to measure the load and many other surgical applications of results from fields such as mechatronics, micro-sensor and actuator technology, microelectronics.
At a lab meeting Ofri Sadowsky introduced the development of their project to reconstruct tomographic images using the cone.beam of a mobile C-arm they have in the other building. This may end up with a cheaper alternative for CT.
Lately Dr. Tina Ehtiati from Siemens Corporate Research presented about MR-based Attenuation Correction for PET. The multi-modality PET-MR machines recently developed combine the high soft tissue contrast of the Magnetic Resonance Imaging (MRI) and the functional information of the Positron Emission Tomography (PET). The quantitative analysis of the PET data requires the correction of tissue photon attenuation. She showed the results of an anathomycal atlas based version and another, where the key is the segmentation of patient MR images to different tissue types and assignment of corresponding attenuation values to the segmented regions.
Finally, I attended Ming Li's (University of Waterloo) lecture on Modern Homology Search. As GeneBanks double every 18 months and there are 600 eukaryote programs running, it is crucial so speed up the DNA related information processing. One of the key problems is to identify homologous sequences. However, as small diversions may still be in the focus of interest and given the enormous size of human genome, there is a computational problem. Serious compromises have to be made between speed and sensitivity of search. After a couple of trials they invented a method that is fast to find local alignments and similarities, using a blast search with optimal spaced seed patters that are always symmetric.