Other types of masks. If bed allows place bed in trendelenburg. Shortness of breath- check oxygen tubing, adjust oxygen mask, and flowmeter. Thus x-ray can easily penetrate. An examples of negative contrasts is air.
Positive contrast are materials with high atomic numbers.
The agents cause a decrease in photographic density. They appear as white areas on a radiograph. These agents include barium sulfate, iodinated products and gadolinium products. The resulting electrolyte imbalance cause fluid to be drawn into the bloodstream from the surrounding tissue, which is believed by some to increase the risk of adverse reactions to ionic agents. Their molecular structure does not disassociate when it is injected into the bloodstream.