Characterization of continuous and pulsed emission modes of a hybrid micro focus x-ray source for medical imaging applications

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 853; pp. 70 - 77
• Main Authors: Ghani, Muhammad U., Wong, Molly D., Ren, Liqiang, Wu, Di, Zheng, Bin, Rong, John. X., Wu, Xizeng, Liu, Hong
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2017
• Subjects: Beam quality; Continuous beam; Pulsed beam emission; Spatial resolution; Beam quality; Spatial resolution; Pulsed beam emission; Continuous beam; spatial resolution; continuous beam; beam quality
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2017.02.030

The aim of this study was to quantitatively characterize a micro focus x-ray tube that can operate in both continuous and pulsed emission modes. The micro focus x-ray source (Model L9181-06, Hamamatsu Photonics, Japan) has a varying focal spot size ranging from 16µm to 50µm as the source output power changes from 10 to 39W. We measured the source output, beam quality, focal spot sizes, kV accuracy, spectra shapes and spatial resolution. Source output was measured using an ionization chamber for various tube voltages (kVs) with varying current (µA) and distances. The beam quality was measured in terms of half value layer (HVL), kV accuracy was measured with a non-invasive kV meter, and the spectra was measured using a compact integrated spectrometer system. The focal spot sizes were measured using a slit method with a CCD detector with a pixel pitch of 22µm. The spatial resolution was quantitatively measured using the slit method with a CMOS flat panel detector with a 50µm pixel pitch, and compared to the qualitative results obtained by imaging a contrast bar pattern. The focal spot sizes in the vertical direction were smaller than that of the horizontal direction, the impact of which was visible when comparing the spatial resolution values. Our analyses revealed that both emission modes yield comparable imaging performances in terms of beam quality, spectra shape and spatial resolution effects. There were no significantly large differences, thus providing the motivation for future studies to design and develop stable and robust cone beam imaging systems for various diagnostic applications. •A micro focus x-ray source that operates in both continuous and pulse emission modes was quantitatively characterized.•The source output, beam quality, focal spot measurements, kV accuracy, spectra analyses and spatial resolution were measured.•Our analyses revealed that both emission modes yield comparable imaging performances in terms of beam quality, spectra shape and spatial resolution.•There were no significantly large differences, thus providing the motivation for future studies to design and develop stable and robust cone beam imaging systems for various diagnostic applications.