Software Upgrading in a CT Scanner

Abstract

Purpose:

In an attempt to improve field uniformity and CT number stability, the software in a CT scanner was replaced with a new version. The purpose of the present study was to investigate the influence of the software upgrading on density measurements.

Material and Methods:

The upgrading influence was investigated by means of a torso phantom (European spinal). The phantom simulates a torso which contains 3 vertebrae of different densities.

Results:

Despite the use of a reference standard under the phantom, the software change resulted in: a) improved short-term precision; b) increased density values at 80 and 100 kVp, decreased at 130 kVp; and c) increased influence of the kVp on the values.

Conclusion:

The results of the present study suggest that conversion factors have to be used in density values for reference populations as well as in the values of patients undergoing follow-up studies.

Keywords

Computed tomography,quantitative bone mineral density radiation therapy software

Get full access to this article

View all access options for this article.

References

Cann

C. E.

: Quantitative computed tomography applications. Comparison of newer CT scanners. Radiology 162 (1987), 257.

Constantinou

Harrington

J. C.

: An electron density calibration phantom for CT-based treatment planning computers. Med. Phys. 19 (1992), 325.

Dequeker

Reeve

Pearson

: Multicenter European COMAC-BME study on the standardisation of bone mineral densitometry procedures. Technol. Health Care 1 (1993), 127.

El-Khatib

E. E.

Freeman

C. R.

Rybka

W. B.

Lehnert

Podgorsak

: The use of CT densitometry to predict lung toxicity in bone marrow transpant patients. Int. J. Radiat. Oncol. Biol. Phys. 16 (1989), 85.

Faulkner

K. G.

Glüer

C. C.

Crampp

Genant

H. K.

: Cross calibration of liquid and solid QCT calibration standards. Corrections to the UCSF normative data. Osteoporosis Int. 3 (1993), 36.

Glüer

C. C.

Engelke

Jergas

Hagiwara

Crampp

Genant

H. K.

: Changes in calibration standards for quantitative computed tomography recommendations for clinical practice. Osteoporosis Int. 3 (1993), 286.

Goitein

: Application of computed tomography in radiotherapy treatment planning. In: Progress in medical radiation physics, Vol 1, p. 195. Edited by Orton

C. G.

Plenum Press, New York 1982.

Goodsitt

M. M.

: Conversion relations for quantitative CT bone mineral densities measured with solid and liquid calibration standards. Bone Min. 19 (1992), 145.

Isherwood

Pulland

B. R.

Rutherford

R. A.

Strang

F. A.

: Electron density and atomic number determination by computed tomography. Br. J. Radiol. 50 (1977), 613.

10.

Kalender

W. A.

: A phantom for standardization and quality control in spinal bone mineral measurements by QCT and DXA. Design considerations and specifications. Med. Phys. 65 (1992), 931.

11.

Karantanas

A. H.

Kalef-Ezra

Glaros

: Quantitative computed tomography for bone mineral measurement. Technical aspects, dosimetry, normal data and clinical applications. Br. J. Radiol. 64 (1991), 298.

12.

Karantanas

A. H.

Kalef-Ezra

Glaros

: Limitations of quantitative CT in corticosteroid induced osteopenia. Acta Radiol. 42 (1991), 339.

13.

Ledley

R. S.

Di Chiro

Luessenhop

A. J.

Ywigg

H. L.

: Computed transaxial X-ray tomography of the human body. Science 186 (1974), 207.

14.

Pearson

Dequeker

Henley

: European semi-anthropomorphic spine phantom for the calibration of bone densitometers. Assessment of precision, stability and accuracy. The European Quantitation of Osteoporosis Study Group. Osteoporosis Int. 5 (1995), 174.