Senior Director & HOD, Neurosurgery, Fortis Hospital, Noida
Part 5 of 9 in Diagnosis and Management of Brain Tumour
Fluorescence-Guided Surgery and Real-Time Imaging Inside the Operating Theatre
September 6, 2026
An operating microscope is now a baseline requirement for brain tumour surgery, in Dr. Rahul Gupta's view, not an upgrade. It provides magnification, strong light and a recording system that lets the assisting staff follow the surgery on screen, and it is the platform onto which navigation and fluorescence technology are added. In his Jivo Healthcare masterclass, he explained how those add-ons work in practice.
Two dyes that light up malignant tissue
5-ALA is given orally before surgery begins; fluorescein is given intravenously just after the surgery starts. Both are picked up selectively by malignant tumour cells and become visible under special filters built into the microscope, separating tumour tissue from normal brain even where the visual border is unclear. The benefit is real-time, intraoperative, most useful for malignant tumours, and, in fluorescein's case, inexpensive. It is particularly valuable for tumours with ill-defined borders and those sitting in eloquent brain regions, where every millimetre of unnecessary resection carries a cost.
Two cases under the filter
In one case, a glioma showed up under the 5-ALA filter as a distinct pink region against otherwise normal-looking brain tissue on the standard microscope view, guiding a complete excision. In another, a diffuse lesion on the left side of the brain was managed with fluorescein instead, appearing as a yellow-tinted area under the filter that marked where the tumour actually was.
When the microscope alone is not enough
Some centres now have operating suites combined with an MRI or CT scanner, letting the surgical team check for residual tumour mid-procedure rather than waiting for a post-operative scan. Intraoperative ultrasonography serves a related purpose, giving a real-time anatomical picture that is especially useful for cystic lesions, since the cyst can be directly localised and aspirated. Grid electrodes placed on the surface of the brain add a further layer, mapping motor, sensory and speech areas, or an active epileptic focus, while the operation is still in progress.
This guide is based on a live Jivo Masterclass: Dr. Rahul Gupta taught doctors across Africa on February 9, 2025.
FROM THE LIVE Q&A
Moderator
How can post-operative complications be reduced in a resource-limited area?
Dr. Rahul Gupta
Four things are essential. MRI is mandatory, brain tumour surgery should not be performed without it. An operating microscope is needed for magnification, even a basic one without fluorescence or navigation add-ons. The anaesthetist needs to be equipped and experienced in controlling brain swelling and blood pressure during surgery, ideally with a year or two of experience at a neuro centre. And a post-operative ICU with ventilator support is needed, since some patients require ventilation for a day or two. Good post-operative ICU care alone can reduce complications by 25 to 30 percent. With these four in place, superficial tumours such as meningiomas, surface gliomas and straightforward intraventricular tumours can be safely removed; difficult tumours should still be referred to a better-equipped centre.
Frequently Asked Questions
What is the commonest brain tumour, and which type has the worst prognosis?▼
Metastasis used to be the most common brain tumour, but with better radiotherapy and chemotherapy most metastatic cases are now managed by radiation and medical oncology rather than surgery, except when a solitary large metastasis is causing a symptomatic mass effect. The tumours operated on most often today are gliomas and meningiomas. Gliomas run from grade 1 to grade 4, and grade 4 glioblastomas have the worst prognosis. Meningiomas usually have a good prognosis, though some are atypical or malignant and located at difficult skull-base sites near major vessels; those can be treated with modern radiotherapy such as gamma knife or cyberknife after a subtotal resection. Pituitary tumours are third most common and are usually benign, approached endoscopically through the nose.
After surgery, do all patients systematically need rehabilitation?▼
Yes. All patients need post-operative care from a team of physiotherapists and rehabilitative support. About 90 percent of patients who arrive without deficits leave hospital without one, but even they need psychological support, and patients with malignant tumours need considerably more of it given the chemotherapy and radiotherapy ahead. Patients need to see the neurosurgeon and physiotherapist regularly for at least 3 to 6 months, and continue lifelong follow-up MRIs.
What surgical technique is used for this kind of procedure?▼
The full presentation covered the range of techniques used, from neuronavigation and awake craniotomy to fluorescence-guided resection and endoscopic approaches, depending on the tumour's location and type.
Is a drain placed after surgery?▼
Yes, in around 80 percent of cases.
In the event of cerebral edema, what technique should be used?▼
Elective ventilation is used, along with decongestants such as mannitol or 3% saline. Sometimes the bone flap is deliberately not replaced immediately after surgery and is put back one to two months later.
What are the two dyes used for fluorescence-guided brain tumour surgery?▼
5-ALA, given orally before surgery, and fluorescein, given intravenously just after surgery starts. Both are selectively taken up by malignant tissue and made visible under special microscope filters.
Why is fluorescence guidance especially useful for tumours with unclear borders?▼
Because it separates malignant tumour tissue from normal brain even where the visual boundary is not obvious, letting the surgeon maximise tumour removal while minimising damage to normal tissue.
What does intraoperative ultrasonography add during brain tumour surgery?▼
A real-time anatomical picture, particularly useful for cystic lesions, since it lets the surgeon directly localise and aspirate the cyst during the operation.
In This Series: Diagnosis and Management of Brain Tumour
- 1.Diagnosis and Management of Brain Tumours
- 2.Recognising a Brain Tumour Early: Symptoms and Diagnostic Workup
- 3.The Principles Behind Every Brain Tumour Operation
- 4.Awake Craniotomy and Neuronavigation for Tumours in the Brain's Eloquent Areas
- 5.Fluorescence-Guided Surgery and Real-Time Imaging Inside the Operating Theatre
- 6.Reaching Pituitary and Vascular Brain Tumours Without a Wide Craniotomy
- 7.Brain Tumour Surgery in Children: Two Cases That Show What Changes
- 8.Recovery, Follow-Up and Prognosis After Brain Tumour Surgery
- 9.Delivering Safe Brain Tumour Surgery Where Resources Are Limited