I keep having funny turns, and my doctor has ordered a ‘dopple’ test on the arteries in my neck. What will this involve?
What your doctor has ordered is a doppler ultrasound.
When listening to a fast-moving vehicle approaching you, its engine noise changes pitch as the vehicle passes you and moves away. This change in the pitch of a sound due to movement is known as the doppler effect. This same effect can be used to measure the movement of fluids (such as blood) within the body.
Using a blunt probe that is placed against the skin, a high pitched sound wave (ultrasound) is passed into the body, and the reflection of the sound wave from stationary tissue and moving blood is measured and compared. In this way, the rate at which the blood is flowing can be determined. The carotid artery in the neck is commonly one to be examined to see if there is any blockage or narrowing that may be responsible for your funny turns, but other arteries near the surface of the body (eg. in the groin) may also be checked to see if there is any blockage of the blood flow caused by a clot or build-up of a cholesterol plaque.
There is absolutely no discomfort to the patient during the procedure, it is completely safe, and you only have to lie still for a few minutes.

What is the test done to see if you have thin bones in old age?
Quite often osteoporosis (thin bones) can be seen on a plain X-ray of major bones, but there is also a specific test known as dual photon densitometry scan.
The density of bone can be ascertained from the amount of mineral contained in it. This type of scan is able to measure the mineral content of bone and is a way of diagnosing the onset of osteoporosis, or thinning of the bones. The machine is called an osteodensitometer. The whole body, or just the forearm of a patient can be tested.
In a whole body scan, the patient lies on a bed with a flat plate underneath as a (very mild) source of radiation, and a long-armed scanner then moves slowly down the body emitting photon beams which can determine the density of the tissue they are passing through. The procedure takes about half an hour and is completely painless.
A bone scan cannot necessarily predict osteoporosis in normal people, but is very useful for high-risk subjects or people who already have signs of osteoporosis, so that remedial treatment such as medications to replace the lost calcium, hormone replacement therapy and calcium supplements can be administered.
Dual photon densitometry costs are not rebateable under Medicare except in very specific circumstances.

My husband had a myelogram three weeks ago and has suffered from severe headaches and nausea ever since. Is this a normal side-effect of a myelogram? Can these side effects be prevented or treated?
Myelograms have largely been superseded by CAT and MRI scans, which give much the same information with fewer side effects, but sometimes a myelogram is still necessary to diagnose particular problems.
When a myelogram is performed, a needle is pushed through the skin low down on the back, and between two vertebrae so that the tip of the needle is in the spinal canal. This canal contains the spinal cord (which carries all the nerves from the brain to the body) and a fluid called cerebrospinal fluid.
A small amount of fluid is removed, and an equal amount of a dye is injected into the spinal canal. The patient is then tilted so that the dye runs up the canal. This dye is visible on X-rays, and as the patient is tilted backwards and forwards, numerous X-rays are taken of the back to see where the dye moves to. If there is a blockage in the spinal canal caused by a slipped disc, or any abnormality of the spinal cord, it should show up on the X-rays. At the end of the procedure, the dye is run back down to the area where the needle has been inserted, and as much dye as possible is removed, and an equal amount of saline solution is injected to keep the volume and pressure of the cerebrospinal fluid constant.
If the pressure changes significantly, a headache will occur. A headache (sometimes quite severe) is normal for a few days after the procedure, and these headaches are notoriously resistant to any treatment, but three weeks is excessive. It may be that too much or too little fluid was injected into, or removed from, the spinal canal, and this change in fluid pressure is causing the headache.
The other possibility is that the disease leading to the myelogram being performed may be responsible for the headache. In either case, you should return to see the specialist who ordered the myelogram as soon as possible for further assessment.