Gamma probes have been around for decades, but SENSEI, a new miniaturized probe for radio-guided laparoscopic and robotic surgery, may make it easier for surgeons who work in tight spaces to better detect radioactive hotspots representing cancerous disease.
“The revolutionary part of the technology that SENSEI brings is that it miniaturizes what we’ve had for a long time,” Manish Chand, MD, a consultant colorectal surgeon with University College London Hospital and a leading researcher in medical technology, told OR Management News.
“What this allows surgeons across many specialties to do is use the benefits of radioisotopes in a much more confined space, with a robot and a laparoscope—rather than a cumbersome piece of kit, which is what we have been used to for years.”
SENSEI, a product by Lightpoint Medical designed in collaboration with surgeons and nuclear medicine experts, is a multiple-use, disposable probe measuring just over 40 mm long. It can fit through a 12 mm port and be maneuvered to any area of interest via a laparoscopic or robotic grasper.
Like standard gamma probes, SENSEI picks up and quantifies gamma radiation emitted by body tissues or organs injected with a radiopharmaceutical agent. Doug Adams, MD, a cardiothoracic surgeon in Cincinnati, has long used gamma probes to identify suspicious lung nodules that otherwise can be difficult to locate. He recently employed the miniaturized version in about a dozen cases.
“It’s excellent. We [the thoracic surgical oncology team] have had 100% success in locating nodules, and it’s very easy to use,” Dr. Adams said.
The technetium is injected into the nodule under CT guidance before the patient is transported to the OR. There, the probe is used to localize the injected technetium in the nodule, he said.
“It only takes about a minute to locate the technetium injection. Another thing that’s nice is that the readings in the monitor can be displayed in the heads-up component of the robot, so you’re not looking back and forth. Localizing is precise and it’s important to be able to watch what you’re doing,” he noted.
Improvements in surgery are always about doing surgery better, according to Jim Adshead, MD, a consultant urologic robotic surgeon at Lister Hospital, East and North Herts NHS Trust, in Stevenage, England.
“We can perform beautiful, precise prostatectomies using robotics, but then in high-risk men, we’re doing this complete lymph node dissection. But since some of the molecular markers we have in prostate cancer are so good at spotting metastatic disease, we can now attach technetium to the PSMA [prostate-specific membrane antigen] molecules and use SENSEI to hunt and remove only the positive lymph nodes. This will hopefully reduce the morbidity for these men, as well as the time they are under anesthesia,” Dr. Adshead said.
In patients undergoing treatment for colorectal cancer, Dr. Chand said the clinical indications for SENSEI would be to better detect aberrant lymph nodes (lymph nodes outside the resection margin identified on cross-sectional imaging and recurrent disease).
“This is about using the existing expertise, MRI and PET imaging, then cherry-picking nodes that were not part of the original proposed surgery. I think using this with a combination of fluorescence, for example, will allow minimally invasive surgeons—particularly robotic surgeons—to better detect those PET-positive lymph nodes and remove them with greater accuracy and without disrupting the important anatomy around them,” Dr. Chand said.
Clinical data show that removing pelvic side wall nodes larger than 7 mm is associated with improvements in overall survival and local recurrence, Dr. Chand said, noting that Japanese surgeons have traditionally performed more radical surgeries than their American and European colleagues.
“But this type of surgery is associated with morbidity that may outweigh the benefits of removing them. In recent years, we’ve seen [a compromise] of giving radiotherapy, reassessing what the nodes are doing, and if they’re still positive and larger than 7 mm, cherry-picking them. This is different than doing an extended lymphadenectomy off the bat.”
In essence, the miniaturization of the technology will enable surgeons to use it in new ways, Dr. Chand said. “But alongside that, developing the clinical base that we know from recent literature is getting stronger. Now we need to try to prove it with the new device.”
SENSEI is both FDA and CE approved. and is authorized for sale in the United States, United Kingdom, European Union and Australia. It is already being used in lung, prostate and cervical cancer surgeries worldwide, and is being studied in several different types of surgeries, including robot-assisted colorectal cancer surgery.
Rutgers University Medical School
New Brunswick, N.J.
This article is from the December 2022 print issue.