Optimized radiographic spectra for small animal digital subtraction angiography

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Radiology

Background:

• Small animal imaging is crucial for basic research.
• Digital subtraction angiography (DSA) is a promising functional imaging technique for small animals.
• Optimizing X-ray parameters is essential for high-quality small animal DSA.

Purpose of the Study:

• To determine the optimal X-ray target source (molybdenum or tungsten) and technique for small animal DSA.
• To maximize contrast and signal-difference-to-noise ratio squared (SdNR2) for functional angiograms.
• To evaluate trade-offs between image quality, radiation dose, and tube loading.

Main Methods:

• Simulated image contrast and SdNR2 using an established X-ray model under dose and tube loading normalization.
• Acquired DSA images of live rats using tungsten (W) and molybdenum (Mo) sources at various tube potentials.
• Analyzed image quality based on contrast and SdNR2.

Main Results:

• Molybdenum (Mo) sources yielded higher contrast in small animal DSA.
• Tungsten (W) sources achieved superior SdNR2, particularly above 60 kVp, which is critical for digital detectors.
• Optimal SdNR2 was observed above 90 kVp, but a practical compromise around 70 kVp offers significant gains with manageable dose and tube load.

Conclusions:

• Tungsten (W) X-ray sources are preferable for small animal DSA when prioritizing SdNR2 with digital detectors.
• Operating at approximately 70 kVp represents a balanced approach, maximizing SdNR2 improvement while managing dose and tube load.
• This optimization aids in producing high-quality functional imaging for small animal research.