For men who want to know if those frequent nighttime visits to the bathroom might indicate prostate cancer, the most common diagnostic tools are a blood test and a physician's finger.

Neither, however, is incredibly accurate. And neither can record changes in the prostate's size or hardness -- a possible indicator of cancerous tissue -- over time.

That's where Rick Carlson and Larry Getlin of ProUroCare come in. The Minnesota men are hoping that recent Food and Drug Administration approval of their device, the ProUroScan, will add their prostate medical imaging device to the diagnostic toolkit.

Using a hand-held rectal probe with sensors to measure the elasticity of the prostate, the ProUroScan can provide urologists with a 3D map that, together with a digital rectal exam (DRE) and a prostate specific antigen (PSA) blood test, can help detect, measure and map prostate abnormalities.

"Hard is lesion, soft is healthy tissue," said Carlson, ProUroCare's chief executive.

Said Getlin, a board member who helped the company gain FDA clearance: "This could help eliminate procedures."

Consider the search for prostate cancer, which strikes nearly 200,000 American men each year, a bit like searching through a hard-to-reach haystack for a hard-to-feel needle. Yet, according to ProUroCare, data from a number of studies show that DRE and PSA together still miss nearly half of prostate cancers.

Even when the tests find an abnormality, patients must be referred to urologists for more tests -- such as ultrasounds and biopsies. Yet, those tests can miss cancer as well. In addition, Carlson said, about 20 percent of biopsies result in infection.

Officials at the publicly traded Eden Prairie company, which now is casting its net for a distribution partner to launch its product at medical centers in key U.S. markets, believe their device can narrow the odds.

Besides detecting lesions and creating a 3D image of the prostate, the device can store data from multiple exams for doctors to analyze over time. Prostate cancer is often a slow-developing disease that can take many years to reach dangerous levels, Carlson said. ProUroScan can give doctors the data they need to track and treat the disease more effectively.

Currently, the ProUroScan is a probe connected to a computer on a cart. Carlson said the cart-based system costs about $20,000. The goal is to eventually move the scanning technology and visual display onto a tablet-type device, which could cut the hardware cost to about $5,000, he said.

The ProUroScan exam takes about a minute.

Artann Laboratories of Trenton, N.J., developed the technology -- using nearly $4 million in grants from the National Institutes of Health -- and has conducted more than 700 laboratory experiments, Carlson said. The technology was studied in clinical trials by Dr. Robert Weiss, a urologic oncologist with the Cancer Institute of New Jersey and a faculty member at the Robert Wood Johnson Medical School of Rutgers University. It has been used on more than 200 patients.

Weiss said the images created by the scanning device are very accurate and give doctors a valuable supplemental tool to use along with diagnostic tests. This can give doctors a more precise way to detect and measure prostate problems, he added.

"A DRE is a basic exam," said Weiss, who is not a company investor and has received no compensation. "The advantage of the picture is that it is objective. This can examine size, texture of the prostate."

Subsequent studies will be needed to show whether the device can be used as a diagnostic tool and how it compares to things like ultrasounds, he said.

Dr. Matthew Toffefson, a Mayo Clinic urologist who said he is not familiar with the ProUroScan, nonetheless agreed with Weiss that there is a "definite" need for better diagnostic technology.

"Really, right now, we don't have many tools to image the prostate," he said, noting that physicians are limited to conventional ultrasound and MRI. "And neither one is very reliable to identify nodules within the prostate gland."

The prostate gland is about the size of the heel of your hand. Prostate tumors tend to be smaller and show up in multiple places, Tollefson said. Yet, treatment of the cancer usually means removing the entire prostate gland or using radiation therapy on the whole prostate.

One of the benefits of better imaging technology is finding a way to better pinpoint treatment of the cancer, he said. And that could help reduce the side effects of treatment.

James Walsh • 612-673-7428