Visualization of subcutaneous insulin injections by x-ray computed tomography

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Pharmacology

Background:

• Subcutaneous injections are common for drug delivery, but understanding depot characteristics is crucial.
• Current methods for visualizing drug depots are limited.

Purpose of the Study:

• To visualize the 3D structure of subcutaneous insulin injections using X-ray computed tomography.
• To analyze depot shape, position, and drug concentration distribution.
• To assess the potential for improving insulin drug formulation and delivery devices.

Main Methods:

• Ex vivo porcine adipose tissue injections with an iodine-based contrast agent.
• Laboratory X-ray computed tomography (CT) scans with ~1-minute acquisition time.
• Modified Chan-Vese algorithm for depot segmentation and synchrotron radiation for artifact reduction.

Main Results:

• Successful 3D visualization of insulin injection depots with high resolution (109 μm² pixel size).
• Observed significant variations in depot shape and position among injections.
• Calculated spatial iodine concentration distribution, indicating drug dilution within the depot.

Conclusions:

• X-ray CT is a viable method for characterizing subcutaneous injection depots.
• Understanding depot morphology and drug distribution is key for optimizing insulin delivery.
• This technique supports advancements in drug formulation, injection devices, and predictive biomedical simulations.