EMI CT Scanner

Early Days of CT: Innovations
(Both Good and Bad)
Robert G. Gould
Department of Radiology
University of California San Francisco

The Names: An Incomplete List
•
•
•
•
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Johann Karl August Radon 1887‐1956
William Henry Oldendorf 1925‐1992
Allan McLeod Cormack 1919‐2004
Godfrey Newbold Hounsfield 1919‐2004
Robert Ledley 1924‐

Sir Godfrey Hounsfield
• Elected to Royal Society
1975
• Nobel prize 1979 shared with Allan Cormack
1919‐2004

EMI Head Scanner

First clinical image (Atkinson‐
Morley Hospital London

EMI Head Scanner

Dose information

1972 sales brochure

EMI Head Scanner

X‐Ray Controls

Geometry:

Translate rotate, pencil beam

Scan time:

4.5‐20 min

Rotation Angle:

1°

Number of views:

180

Samples per view:

160

Total samples:

28,800

Matrix:

80 x 80

FOV:

23.5 cm

Pixel size:

3 x 3 mm

Slice thickness:

13 mm or 8 mm

X‐ray tube:

Fixed anode

Technique Factors:

100 (40), 120 (32), 140 (27) [
KVp (mA)]

Detectors:

NaI‐PMT

Cost:

~$350,000

Question: What machine was the first multislice CT?

Answer: EMI head scanner!
It had 2 detectors along the
Z‐axis.

EMI Head Scanner
• ‘Print out scale’
+ 500

First truly digital device in radiology

1972 sales brochure

EMI Head Scanner

1972 sales brochure

EMI: Rise and Fall
1971:

Prototype head scanner installed at Atkinson
Morley Hospital
1972: First clinical results presented by James Ambrose,
MD on 70 patients
1973: Clinical production, two units installed in the US at
Mayo Clinic and at MGH
1974: ACTA whole body scanner installed
1975: 3rd generation machines installed
1975: 10 companies now make CT scanners including all of the major equipment manufacturers
1978: EMI loses $56 million
1979: EMI introduces the 7070 nutating ring scanner
1979: EMI sells business to Thorn Electrical Industries
1980: GE buys scanner business from Thorn for $37.5 million EMI: Rise and Fall
The saga of EMI’s CT scanner business became a case study at the Harvard Business School:
• Although