Benjamin Reichardt  

Home Institution
Georg-August-Universität, Göttingen
Faculty of Medicine and Faculty of Physics

Host Institution(s)
Harvard Medical School, Boston
Cardiac MR and CT Program, Cimit Ultra High Resolution Flat Panel Volume CT
Mentor: Rajiv Gupta, M.D., Ph.D.

E-Mail: FlyingDoc@haeckser.de
Research Topic
see Abstract
Personal Reactions to the U.S. Experience
To stay and work as a researcher in the U.S., and especially at MGH, was great.
During my stay I lived in a house close to the Harvard Square in Cambridge. Seven highly qualified persons shared nearly everything.
Absolutely the best thing to happen in Boston was to meet Nadine Gaab. She showed me how to write A+ papers, and with every publication we had a "paper-party"! The best paper-party was her NATURE-paper!
In Boston I had some of the best times of my life. I worked very hard, but everyone should use this opportunity to learn, to improve skills, to build up a network, or just to relax from the hard student's life.
Most humorous incident
There are so many:
A friend and I were on a flight from Cape Cod to Boston. We started the trip in the morning, flying a small chartered Cessna 172. In the late afternoon we took off, without a check to see if the instruments lights are working. They were not.
I crawled from my seat to the back and checked Soenke´s bag for his eye-flashlight. I found it. Unfortunately I also lost it, so I had to crawl around again. The facts that darkness surrounded us and that I lost the flashlight, led to panic in Soenke´s face.
Worst moment: When I found out that my new colleague, who came from Munich, had submitted the same study one week before I met him.
Helpful Hints for Future Students
  • Get a Deutsche Bank Account
  • Try to get a letter stating that you have the equivalent of a Bachelors Degree, so that MGH is able to issue the J1-visa.
  • LEARN to FLY at Hanscom Airfield! Go Glider flying in Springfield with the MIT Soaring Club.
  • Sign up for car-sharing, if you want to travel around.
  • Visit the Euro-Club and meet me there; best party tips!!!
  • Seize your day and stay.

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Abstract on Research Topic
Real-Time Fluorscopy on a Tomographic Machine: Feasibility Demonstration and Early Experience
Authors:
B. Reichardt MS¹*, A. Mitha MD², M. Grasruck PhD³, T. Brady MD¹, C. Ogilvy MD², R. Gupta PhD MD¹

¹Massachusetts General Hospital, Boston, MA, USA, Dept. of Radiology, ²Massachusetts General Hospital, Boston, MA, USA, Dept. of Neurosurgery, ³ Siemens Medical Solution, Forchheim, Germany, * medical student of University of Goettingen, Germany

Purpose:
Flat-panel Volume CT (fpVCT) scanner, in addition to tomographic imaging, enable real-time fluoroscopy from any arbitrary angle in space. We assessed the accuracy, precision, and procedural ease of use of the fluoroscopy mode of a fpVCT scanner in performing stereoscopic automated biopsies and catheter angiography.

Methods and Materials:
The digital fpVCT scanner consisted of a 30cm x 40cm a-Si based CsI digital flat panel detector mounted on a Sensation-64 gantry. The large z direction field of view provides whole organ coverage. The fluoroscopy mode was implemented by allowing orientation of the imaging chain along any user-selected angular position to acquire real-time images at 30 frames/second. A foot paddle was used to operate the X-ray tube and a second display next to the gantry enabled real-time visualization of interactive procedures. Eight New Zealand rabbits were catheterized and imaged, pre and post clipping or coiling of a surgically created aneurysm in the proximal right common carotid artery (n = 16). A simulated breast biopsy using a 3D-automated-needle-guidance system was performed in order to assess the accuracy of accessing internal structures via fluoroscopic guidance. Eight 1.5mm markers were targeted at a depth of 10 cm in the tissue. Stereoscopic image-guidance for targeting was provided by two orthogonal views from fpVCT.

Results:
Catheter angiography could be performed with ease and without any major limitations because of the nature of the gantry using the fpVCT fluoroscopic mode. The acquired data sets are similar to those from standard C-arms. Fast frame-rate of 30/sec allows imaging of arterial, capillary and venous phases during bolus-transit from any chosen angle. The lack and time-consuming changing of C-arm direction and of the standard fluoroscopy table was offset by quick orientation of the gantry along any arbitrary angle. The change from AP to LAT projection was much quicker than that in standard C-arm gantry. Quick transition from fluoroscopic to tomographic mode enabled confirmation of catheter tip position. Further developments are needed in providing road-mapping and DSA capabilities in the CT-based fluoroscopic mode. For lesion targeting, a maker 1.5mm in diameter could be repeatedly and reliably reached at a distance of 10cm. The over all radiation was approximately equal to one head CT for each 20 seconds of operation.

Conclusions:
As we have shown the large z-coverage and high frame rate of the fpVCT scanners allows fluoroscopic investigations of rapidly evolving processes, interventional procedures and catheter angiography. Quick transition from fluoroscopy to tomography is useful in positional verification. Such Omni-scanning capability, when fully developed, can be extremely useful in intervention of heart and vascular diseases or interventional spinal and neurological procedures.