Ginny,
I too have worked in ultrasound (and other radiological devices) for many decades (and still am, being VP of an ultrasound manufacturer) and when they (the ultrasound manufacturer's) were attempting to make transrectal US prostate exams the "gold standard" exam, over digital (PSA was still in development then). The death rate went up 5% (due to sepsis), as a result of false positives and unneccessary biopsies. Transrectal prostate screening exams, with US, died a timely death as a result. US is still used for guided biopsy of the prostate but not for screening.

They are using US for breast for follow-up of suspicious areas and regions of interest (ROI). I am not sure that US has the resolution to pick up microcalcifications (which can be the size of a pixel) so I believe that mammograms will continue to be the gold standard.

I honestly have never seen any hard data on this issue (with the exception of transrectal for prostate cancer).

ALL scans are merely a component of the entire diagnostic workup and, as many of us have discovered, far from perfect. All of my first MRI's were terrible and I had much angst as a result until an entire year later when I finally had a "clean" one.

The term "false positive (or negative)" is used far more in conjunction with lab work than anything else. Manufacturer's of lab test reagent, etc. are required to submit extensive clinical data to the FDA concerning the false or negative positive rates and the hemotologist or your doctor typically knows that number.

Scans, on the other hand, are pretty much the responsibility of the reading radiologist and manufacturers are not required to submit data on false or negative results, only basic specifications for the device and indications and limitations for use. It could be rationalized that the false (or negative) postive rate is in the hands of the reading radiologist and that is the reason that congress enacted the Mammography Quality Assurance Act several years ago.

The ACR (American College of Radiology) has done a good job of training radiologists and certification of mammography scanning centers and you be sure that this also has played a role in the improvement of survival rates for breast cancer anyway.

This is also a good time to interject that this is one of the main reasons why we implore people to go to a CCC - the reading radiologists see almost nothing but cancer and are very skilled at reading it as a consequence.

PET is in a space by itself but PET/CT has upped the accuracy considerably.

It has always resorted back to the tried and true - direct visualization, palpation and biopsy if needed.

So there really isn't an answer for LisaB's question.