X-ray tube focal spot sizes: comprehensive studies of their measurement and effect of measured size in angiography

Journal Article · Thu Jul 01 04:00:00 EDT 1982 · Radiology; (United States)

DOI:https://doi.org/10.1148/radiology.144.2.7089295· OSTI ID:5134090

Doi, K; Loo, L N; Chan, H P

Thirty-two focal spot sizes of four x-ray tubes were measured by the pinhole, star pattern, slit, and root-mean-square (RMS) methods under various exposure conditions. The modulation transfer functions (MTFs) and line spread functions (LSFs) were also determined. The star pattern focal spot sizes agreed with the effective sizes calculated from the frequencies at the first minimum of the MTF within 0.04 mm for large focal spots and within 0.01 mm for small focal spots. The focal spot size determined by the slit method was approximately equal to the width of the LSF at the cutoff level of 0.15 +/- 0.06 of the peak value. The RMS method provided the best correlation between the measured focal spot sizes and the corresponding image distributions of blood vessels. The pinhole and slit methods tended to overestimate the focal spot size, but the star pattern method tended to underestimate it. For approximately 90% of the focal spots, the average of the star and slit (or pinhole) focal spot sizes agreed with the RMS focal spot size within +/- 0.1 mm.

• Research Organization: Kurt Rossman Lab. For Radiologic Image Research, Chicago, IL
• OSTI ID: 5134090
• Journal Information: Radiology; (United States), Journal Name: Radiology; (United States) Vol. 144:2; ISSN RADLA
• Country of Publication: United States
• Language: English

Related Subjects

550602* -- Medicine-- External Radiation in Diagnostics-- (1980-)
62 RADIOLOGY AND NUCLEAR MEDICINE
BEAM OPTICS
BIOMEDICAL RADIOGRAPHY
BLOOD VESSELS
BODY
CARDIOVASCULAR SYSTEM
DIAGNOSTIC TECHNIQUES
ELECTROMAGNETIC RADIATION
ELECTRON TUBES
EQUIPMENT
IONIZING RADIATIONS
MEDICINE
NUCLEAR MEDICINE
ORGANS
RADIATIONS
RADIOLOGY
X RADIATION
X-RAY EQUIPMENT
X-RAY TUBES