- The technology is a first of its kind in the world wherein navigational assistance is provided through intra-operative probe that will help in surgical validation though being completely handheld.
- It’s a complete Made-in-India product. Starting from the Shielding Technology, Scintillators, Data Acquisition Systems, Software, AI detection and Prototyping – All were done in Sri Sathya Sai Institute of Higher Learning. Thus, the bill of materials is as less as 7 – 8 Lakhs rupees.
- 3. For the first time in the world, Gamma Imaging is being used intraoperatively to give live scanduring surgery itself without depending on the clinical
- For the first time in the world, a probe of this kind is undergoing clinical trials having successful validation across varieties of cancer like, Tongue Cancer, Throat Cancer, Breast Cancer, and Skin cancer.
- The device has produced 100% successful detection while correlating the results with clinical methods such as biopsy, frozen section, and histopathology. (Clinical methods generally take 3 – 4 days to generate reports while SAIGC-Torch can provide instant results.)
- All software incorporating the latest technologies have been created in-house.
- This device is being covered with seven IPs.
Abstract
The intricate anatomy and the presence of several vital structures in the neck render lymphatic mapping in this region more difficult than elsewhere in the human body. The surgeon has to rely mainly on the preoperative lymphoscintigraphy and the intraoperative gamma ray detection (an acoustic counter based) probe. As a result, the sentinel node identification rate is relatively low and the false- negative rate is high. Single photon emission computerized tomography with computed tomography (SPECT-CT) provides three-dimensional images and shows the sentinel node in its anatomic habitat, facilitating just the preoperative planning of the surgical approach. An additional intraoperative detection tool will improve the identification rate considerably, because sentinel nodes in the head and neck region often are located in close proximity to the injection site and high background signals can hamper sentinel node detection with the traditionally used counter-based probes. The need is to have a portable intraoperative gamma camera with better spatial resolution and capabilities than a counter probe. This set up coupled with a fluorescent based probe for visible inspection for identification of the exact sentinel lymph node will help the doctor to accurately locate the lymph for its removal.
Although ‘blue dyes’ have been used in the operative procedures, side effects of usage of the dyes have been widely reported medically. Surgeons prefer not to use vital blue dyes to prevent long-term tattooing effects. To avoid this drawback, a near-infrared fluorescent dye, such as Indocyanine green (ICG) is used which are invisible to the human eye. Moreover, nearinfrared dyes have an improved detection sensitivity and tissue penetration, which will facilitate the detection of a sentinel node and its afferent lymphatic duct. Yet like vital ‘blue dye’, ICG migrates quickly through the lymphatic system, providing considerable diagnostic time window. The project proposes design and development of a dual imaging set up. This prototype will have the facility of imaging nuclear distribution of the isotope thereby identifying the sentinel nodes diagnostically. Additionally, it also has the capability to image the fluorescent signals from the ICG compound providing the doctor with the facility for visual location identification.
Need and Usage
Surgical resection of cancer remains an important treatment modality despite advances in preoperative imaging. Surgery itself is primarily guided by the surgeon’s ability to locate pathology with conventional white light imaging. Intra operative visualization of tumors may not only allow more complete resections but also improve safety by avoiding unnecessary damage to normal tissue, which can also reduce operative time and decrease the need for second look surgeries. Surgery is a primary mode of treatment for many malignancies. For example, 63 to 98% of patients with lung, breast, bladder, and colorectal cancer undergo surgery. The goal of surgery is to safely remove as much cancer resect tumor currently relies on the visual localization of the tumor and/or the ability to palpate it. The former is limited by the low contrast between tumors and background tissue, and many small tumors may be missed. Moreover, the determination of tumor margins must often be done blindly, followed by frozen section pathologic analysis.
The presence of residual tumor cells after resection is considered a strong predictor of tumor recurrence and therefore survival. Many studies show that positive margins, defined as the identification of tumor cells at the cut edge of a surgical specimen, are associated with increased local recurrence and indicate a poor prognosis in most cancer types, including head and neck cancers, breast cancer and other regions.
Despite advances in pre operative imaging, such as computerized tomography, CT, magnetic resonance imaging, MRI, and positron emission tomography, PET, surgical margin positivity rate has not changed significantly over the past several decades with margin positivity rates of 15 to 60% across all cancers. Currently, the standard of care for achieving negative margins rests on visual inspection, palpation, and intraoperative histopathological analysis of frozen tumor margins, all of which have severe limitations.
The naked eye is limited in its ability to detect small tumors. Palpation is limited in sensitivity and is increasingly not used due to the increased utilization of robotic laparoscopic surgery. Intra-operative frozen section analysis is limited to certain tissue types, is time consuming and is prone to sampling error. Frozen section analysis is discrepant with permanent pathology in 5 to 15% of cases.
A number of non-optical imaging methods have been proposed during surgery. Typically, these methods are not targeted to the tumor per-se, but rely on anatomic abnormalities to define the tumor, like the intra operative CT and MRI. However, intra operative systems are costly, complex and require space. Moreover, their use interrupts the normal workflow of the surgical procedure, lengthening operative and anesthesia times. Hence there is an increased need to have a small handheld and high precision Intraoperative Sentinel lymph node navigational assistance using intraoperative probes.
The group previously worked on developing a new age portable gamma camera called SAIGC, which revolutionized gamma imaging with patented high resolution semiconductor detectors. This high speed all digital device can produce images five times higher in spatial resolution and speed, but it is 10 times lower in cost compared to commercially available models. This makes accurate diagnosis cheaper and more available to a common man. Clinical trials were performed with SAIGC and it produced concurrent results on all the subjects, thus proving the efficacy of SAIGC. Now the team is working on the intra operative probe called “SAIGC Torch.” This is a new age device which can solve the issues faced by surgeons in this regard. The device has a nuclear imaging modality to provide post operative validation along with fluorescence imaging for lymph node navigation to provide a frame of reference to the surgeon. The project is funded by the Department of Atomic Energy, Government of India. The device is handheld and the cost is cheaper by 10-fold. The clinical trials are being done in HCG cancer care in Bengaluru and is steered by a leading cancer surgeon, Doctor Vishal Rao. Currently, the team has successfully attempted eight surgeries that include cases of Buccal Mucosa, Tongue Cancer, Melanoma, and we are proud to report the detection success rate of 100%. The efforts are continued in this direction to successfully validate the device with statistical analysis correlating it with gold standard detection methods like histopathology and frozen section analysis.