PET Scanners Good at Spotting Mesothelioma

Your mesothelioma doctor may soon be monitoring the success of the peritoneal mesothelioma treatments ordered for you by using a PET imager instead of a CT or MRI, which are more familiar tools.

PET — positron emission tomography — appears to be right up there with CT and MRI when it comes to locating and characterizing peritoneal mesothelioma tumors.

Researchers from Spain and New York City concluded this after completing a study of PET’s prowess as a mesothelioma diagnostic, surgical planning and postoperative management tool.

Writing in the April 14 online issue of the Quarterly Journal of Nuclear Medicine and Molecular Imaging, they made the case for using PET plus a tracer known as 18F-FDG to study mesothelioma tumors.

Fluorine-18 fluorodeoxyglucose is what 18F-FDG stands for. It’s actually a very common tracer for cancer studies. But only fairly recently have clinicians and researchers begun to explore its fuller potential for pre- and post-surgical mesothelioma.

Mesothelioma Diagnostic Tool

The study is valuable because it once was thought that only CT and MRI scans could show mesothelioma tumors with sufficient clarity to satisfy clinical requirements for surgery and follow-up.

CT — computed tomography — is best for the staging of mesothelioma tumors. MRI — Magnetic resonance imaging — is best for providing views of structures and soft tissues not possible with CT.

PET, on the other hand, shows in 3D pictures the extent of the mesothelioma tumor’s spread.

One of the overarching purposes of the Barcelona-New York research study was to try and understand how useful PET with the 18F-FDG tracer isotope would be in identifying peritoneal mesothelioma.

A second purpose was to see how well it would work as a tool for gauging the success of surgery.

With these objectives in mind, the researchers, working at the Universitat Autònoma de Barcelona and at the Columbia Mesothelioma Center, looked at images and charts for 34 women and 26 men.

The study subjects ranged in age from 18 to 80. They all were peritoneal mesothelioma victims.

The subjects received PET scans with 18F-FDG as part of their diagnostic workup before it was officially known that they had peritoneal mesothelioma. All received PET scans again later during treatment.

The researchers found that PET was able to detect the cancer 82 percent of the time.

Some Mesothelioma Clinics Take a Second Look

Unlike CT and MRI, PET involves nuclear medicine.

The 18F-FDG utilized in conjunction with a PET scan is radioactive and is injected into you before the scan begins.

But don’t panic. The 18F-FDG is only mildly radioactive and all but disappears from your body within a day.

The properties of 18F-FDG are such that cancerous cells gobble it up. It takes about an hour for the cancer cells to get their fill of it.

The PET scanner detects when cells are gorging on 18F-FDG. It makes note of which cells are doing the gorging, because those and only those will be the cancerous ones.

The scanner then renders a picture that shows the cancer cells and distinguishes them from the healthy non-cancer cells nearby.

PET scanning is promising, but the imaging technology has a few hurdles to leap over before it can join CT and MRI as gold standards for mesothelioma detection, staging and postoperative monitoring.

One is cost. The machines are very expensive. And because they’re expensive, not every mesothelioma clinic can afford to be equipped with one.

The other is the need for onsite processing of the 18F-FDG. The radioactivity is so short-lived that 18F-FDG must be produced the same day it’s going to be injected.

That means it can’t be ordered from a distant lab because by the time it arrives at your mesothelioma clinic too much of it has faded.

Unless the production lab is just around the corner, a mesothelioma clinic that wants to offer PET scanning must acquire and install its own 18F-FDG tracer isotope manufacturing facilities.

For some clinics, that can be a daunting undertaking. Too daunting, in fact.

But with the good news of the Barcelona-New York PET study, mesothelioma clinics that before found reasons not to offer PET scanning may find the time is right for a second look at it.