Posts Tagged ‘mri’

Prostate cancer: Pioneering new imaging method

Severely ill prostate cancer patients are helping researchers test a diagnostic tool that involves injecting a radioactive substance into their bodies. Norway has the fifth highest mortality rate for prostate cancer in Europe.

Four doses of a radioactive tracer called 18F- FACBC are on their way from Oslo to Trondheim in a private jet. Three NTNU researchers, one doctor, two radiographers and a bioengineer fidget nervously as they wait. They check the time.

The plane cannot be delayed. Today is a bad day for fog to descend around Oslo’s main airport, Gardermoen, or for there to be a traffic jam between the Trondheim airport and the city hospital, St. Olavs. Everything has to be on time.

Radioactive decay

From the second that 18F- FACBC is injected into its container, it begins to degrade. In 110 minutes, half of the radioactive substance is gone. If the plane is delayed too much, there won’t be any radioactivity left for the last patient. Then more doses have to be flown up from Oslo.

Now the plane is 20 minutes late. Time really is money when it comes to this radioactive substance. One dose costs NOK 30 000 (3700 Euros). The first patient is already on the table, ready for the procedure. He has an aggressive form of prostate cancer. Doctors fear that it has spread to his lymph nodes.

Now he is waiting to be examined with the most advanced imaging technology that can be found in Norway, a combined PET MRI scan with a price tag of NOK 50 million. He will have to lie still in what boils down to a tiny cave for over an hour while the machine scans and makes images of his blood, bones, and cancer cells.

Finding its way through the body

But this kind of advanced imaging requires a radioactive tracer. With its short half-life, 18F- FACBC (which is an abbreviation for 1-amino-3-fluorine 18-fluorocyclobutane-1-carboxylic acid) has just the right characteristics for the job.

The medical team works quickly when the doses finally arrive at the hospital.

Fortunately, the timing is perfect. First the patient is given an injection of the tracer in his arm, and then placed into the machine, where the tracer finds its way into his veins.

For the radioactive substance to find its way into cancer cells, it needs to have a carrier, a kind of pilot that is able to lead the way to the tumours. In this case, an amino acid acts as the carrier. This is because of cancer cells’ appetite for certain amino acids. A cancer cell is much more active than other cells. It needs more building blocks than other cells, more food. As a result, it attracts and absorbs the amino acid that has been injected into the body.

The radioactive tracer is picked up by detectors that are placed in a ring around the patient in the scanner, and the machine makes images of the cancer cells that light up from the tracer. At the same time, MRI photos of the area are taken, so that doctors get a unique package of information to help them determine which type of treatment is appropriate.

Eight private jets

After an hour, the scan is over and the patient is backed out of the PET MRI. A day later, all of the radioactivity will have left his body. In a few days, he will be in surgery. Hopefully, he has a number of healthy years left to live.

It will take a few years, however, before researchers will be able to conclude how PET MRI scans can be used to improve the diagnosis and treatment of prostate cancer. First, they need to conduct their study with 32 patients. Eight private jets of radioactive tracer will need to be flown to Trondheim, at a cost of NOK 960 000 for this substance.

Shorter, less surgery

This is the first research study in the world where amino acids and PET MRI are being used to try to improve the diagnosis of prostate cancer.[faktaboks=”1″ stillopp=”hoyre” storrelse=”liten”/]

Currently, doctors remove the lymph nodes found in the pelvis of patients with aggressive prostate cancer, without really knowing if it is necessary. Only by cutting into the lymph nodes after they have been removed can doctors determine if the cancer had actually spread.

The NTNU researchers’ goal is for PET MRI to be able to do this detective work before the patient has to undergo surgery, so that surgeons know whether or not removing a patient’s lymph nodes is actually necessary. As a result, some patients should be able to have shorter, less involved surgery, which means less side effects and potential complications.

Diagnoses and the answer key

Researcher will go through the images of all 32 study participants, and then compare these images to their “answer key,” which in this case are the lymph nodes that were removed and biopsied from the patients. Comparing the nodes with the PET MRI images will show whether or not the scans can be used to help in the diagnosis of prostate cancer.

source : http://www.sciencedaily.com/releases/2014/09/140904084500.htm

Prostate cancer diagnosis improves with MRI technology

An ultrasound machine provides an imperfect view of the prostate, resulting in an under-diagnosis of cancer, said J. Kellogg Parsons, MD, MHS, the UC San Diego Health System urologic oncologist who, along with Christopher Kane, MD, chair of the Department of Urology and Karim Kader, MD, PhD, urologic oncologist, is pioneering the new technology at Moores Cancer Center.

“With an ultrasound exam, we are typically unable to see the most suspicious areas of the prostate so we end up sampling different parts of the prostate that statistically speaking are more likely to have cancer,” said Parsons, who is also an associate professor in the Department of Urology at UC San Diego School of Medicine. “The MRI is a game-changer. It allows us to target the biopsy needles exactly where we think the cancer is located. It’s more precise.”

Armondo Lopez, a patient at Moores Cancer Center, had been given a clean bill of health using the traditional ultrasound biopsy method, but when his prostate-specific antigen (PSA) levels, a protein that is often elevated in men with prostate cancer, started to rise he began to worry. Parsons recommended a MRI-guided prostate biopsy. The new technology led to the diagnosis of an aggressive prostate cancer located in an area normally not visible using the ultrasound machine alone. The tumor was still in its early stage and treatable, said Parsons.

An early diagnosis typically improves a patient’s prognosis. In the United States, prostate cancer is the second leading cause of cancer death in men with more than 29,000 estimated deaths expected this year. The average age at the time of diagnosis is about 66.

Lopez is thankful he will be able to celebrate his 58th wedding anniversary with his wife.

“Life is going on as normal,” said Lopez. “This is the wave of the future. I see this new technology as the way to save thousands of lives. I commend Dr. Parsons for taking the lead in San Diego in this area.”

For patients, the only added step to the prostate examination is the addition of MRI imaging which occurs in a separate visit in advance of the biopsy exam. Working with David Karow, MD, PhD, a UC San Diego Health System radiologist, Parsons uses sophisticated new tools and software — DynaCAD for Prostate with the UroNav fusion biopsy system — to combine the MRI with real-time, ultrasound-guided biopsy images in the clinic resulting in what he calls a 3D road map of the prostate.

“The MRI-guided prostate biopsy will enhance the patient experience by reducing the number of false-positive biopsies and resulting in earlier diagnosis when cancer is present,” said Parsons.

source : http://www.sciencedaily.com/releases/2014/08/140812133501.htm