| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Correspondence |
I would like to express my concern after some comments made at the memorial lectures held at the Royal Society on 25 May 2005.
Sir Godfrey Hounsfield was well aware of the possibility of what at EMI was called volume scanning. He appreciated the difference between single slice and multiple slice data acquisition. At EMI, the former idea was based on movement of the patient through the scanner while the continuous (slip-ring) gantry rotated using a continuous power X-ray source. The latter technique was to have involved the collection of data from set of contiguous slices at the same time, a technique originally described in Sir Godfrey's first CT patent.
It was to achieve volume scanning that the TOPAZ geometry was invented. The patent makes clear the continuous rotation nature of the scanner. This system was conceived in the mid 1970s with discussion for implementation with the commercial Division later the same decade. This system used solid-state detectors and an X-ray tube with a directly oil cooled anode. A photograph of the prototype, built by the Research team in the Central Research Laboratories of EMI, was shown on the 25 May 2005. It is clear that this geometry was the first to make possible the matching of continuous rotation with a continuous power X-ray source. The apparent falter in the development of CT in the 1980s can be traced to other causes and not to a lack of technical innovation.
The nature of the TOPAZ configuration also uniquely enabled focused layers to be obtained from the scannogram or pilot scan data (Zonogram).
In the mid 1980s a 1 s, 1 mm slice thickness, version of the system, based on Sir Godfrey's ideas, was successfully built and fully tested. From the scanner volume clinical scans were obtained from which 3D images were reconstructed.
The implication that there were any constraints placed on the future of CT by Sir Godfrey is therefore wholly inaccurate. If not the father of volume scanning, Sir Godfrey Hounsfield must indeed be considered to be the grandfather.
Yours etc.,
We hope the article in this issue by E Beckmann (p. 5) and this letter will rectify any omission—Editor.
Engineering Manager EMI Medical Ltd (retired), Broombank, 267 Penistone Road, Kirkburton, Huddersfield, HD8 0PF
Received for publication August 16, 2005. Accepted for publication August 22, 2005.
| ||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| BJR | DMFR | IMAGING | ALL BIR JOURNALS |
