[Low-dose spiral CT of the lung in the follow-up of non-malignant lung disease].
OBJECTIVE
To assess image quality of chest CT with an 80 to 90 percent dose reduction in follow-up studies of patients with lung disease, dose and image quality of a low-dose protocol was investigated.


METHODS
A follow-up low-dose CT (ND-CT, 120 kV, 10 mAs/slice, 3 mm slice thickness) was performed on 35 patients with non-malignant lung disease and compared with the initial standard dose CT (= SD-CT, 100 mAs/slice, 3 or 5 mm slice thickness). The dose was measured by thermo-luminescence in an Alderson phantom. Image quality was assessed by four independent radiologists in six perihilar, central and peripheral lung regions using a 4-point-scale ("very good", "good", "moderate", and "poor").


RESULTS
Effective dose was 0.5 mSv for ND-CT and 4.0 - 5.0 mSv for SD-CT. The ratings "very good"/"good" were given in the perihilar regions in ND-CT 97.5 % versus SD-CT 99.3 % (n. s.), in the central regions in ND-CT 96.4 % versus SD-CT 94.6 % (n. s.), and in the peripheral regions in ND-CT 70.0 % versus SD-CT 88.2 % (p < 0.01).


CONCLUSIONS
Follow-up CT of pulmonary structures in patients with chronic lung disease can be performed with substantial dose reduction. A decrease of image quality may result in peripheral lung regions.
Coppenrath
E
E
Institut für Klinische Radiologie der Universität München-Innenstadt. Eva.Coppenrath@ikra.med.uni-muenchen.de
Mueller-Lisse
U G
UG
Lechel
U
U
Veit
R
R
Weber
C
C
Banac
S
S
Eibel
R
R
Bitterling
H
H
De Lorenzo
C
C
Fischer
R
R
Meindl
T
T
Reiser
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D013902:Radiography, Thoracic / Q000379:methods / Q000592:standards; D013997:Time Factors; D036542:Tomography, Spiral Computed / Q000379:methods / Q000592:standards