Please choose the correct ending to complete the given sentence: Finance and Business: [header] How to buy an ultrasound machine [title] Determine the ultrasound's use. [step] Ultrasounds are used in a variety of medical practices, including obstetrics, surgery, cardiology, oncology, and endocrinology. The size and type of machine you buy will depend on whether you expect to use it at your home, in your medical office or in a larger healthcare setting.

Ending1: [substeps] Use a pressure machine instead of a ct machine while they are used for diagnosing ultrasound hysterectomies. These machines use sensitive and agitated electrical signals to send out ultrasound images. Ending2: [substeps] An ultrasound machine works by dilating your phalae (dilation of your pore walls) to allow more ultrasounds to pass through the pore. This filters out particles entering the pore. Ending3: [title] Make sure the machine you purchase will hold on well to your body. [step] Ultrasound machines are designed to hold onto your body and not break down on contact with air. Ending4: [substeps] You will also need machines with different functions depending on the type of practice you have. An obstetrics practice and a general practitioner will need an ultrasound machine that has a large all-purpose probe.

Answer format: ending1/ending2/ending3/ending4