The commentary responds to a short communication by Hamm and colleagues describing computed tomography-guided percutaneous marking of lung nodules using two well-established agents: patent blue V, a visible dye, and indocyanine green, a fluorescent tracer that glows under near-infrared light. The German team also explored indocyanine green-soaked coils, small metallic spirals drenched in the fluorescent dye before deployment. In their reported series, all patients underwent complete resection without conversion to open surgery, a result the commentary authors describe as underscoring the technical reliability of the approach. What makes the technique attractive, they note, is its accessibility and workflow flexibility: the marking is performed percutaneously in the radiology suite, avoiding rigid transpleural devices that must stay in place until resection, and eliminating the need for intraoperative fluoroscopy altogether.

That last point matters more than it might first appear. Robotic-assisted thoracic surgery has transformed minimally invasive lung resection, offering articulated instruments, high-definition three-dimensional vision, and steady precision within a confined chest cavity. But robotic operating environments are notoriously unfriendly to techniques that require a fluoroscope to be wheeled in mid-operation. Hybrid operating rooms equipped with integrated imaging remain scarce and expensive, particularly outside major academic centres. A localisation strategy that relies on preoperative computed tomography guidance and then hands off to near-infrared fluorescence, which integrates seamlessly into robotic camera platforms, preserves operative ergonomics and could allow hospitals without hybrid theatres to offer minimally invasive sublobar resection to their patients. In this sense, the commentary frames computed tomography-guided fluorescence as a platform technology reinforcing the expanding role of interventional radiology in precision thoracic oncology.

To understand where the field is heading, the authors propose a generational framework for pulmonary localisation strategies. The first generation was hook-wire localisation, in which a thin wire with a hooked tip is placed into or adjacent to the nodule under imaging guidance. Wires are effective but carry well-known drawbacks: they can displace, they puncture the pleura and can cause pneumothorax, and the rigid external component must be managed carefully until the surgeon removes it. The second generation was percutaneous dye injection, simple and cheap, but vulnerable to two failure modes: dyes diffuse through the soft lung parenchyma and they fade over time, so the target zone a surgeon sees may no longer correspond to where the dye was originally placed. The third generation introduced coil-assisted fluorescence, in which a metallic coil provides mechanical containment for the fluorescent dye, improving durability and visibility.

It is the fourth generation, still emerging, that excites the commentary’s authors most: stabilised fluorescent matrices designed to optimise spatial fidelity. The central insight is that diffusion control is not a minor technical detail but the very heart of localisation accuracy. When liquid dye is injected into lung tissue, it spreads laterally through the interstitium, creating a fluorescent zone that grows and blurs over time. Visibility without spatial fidelity, the authors warn, risks misleading surgical guidance. In a lobectomy, where the entire lobe is removed, a few millimetres of dye drift are inconsequential. But in a sublobar resection, a segmentectomy or wedge resection intended to preserve as much healthy lung as possible, margin geometry is everything. If the fluorescent cloud has migrated, the surgeon may resect around the wrong centre, compromising the distance between the tumour edge and the cut margin.

The stakes of margin integrity have been raised sharply by randomised evidence. The Japanese JCOG0802/WJOG4607L trial, a multicentre phase 3 study published in The Lancet in 2022, demonstrated that segmentectomy is non-inferior to lobectomy for small peripheral non-small-cell lung cancer, validating lung-preserving surgery for selected early-stage patients. That victory for tissue-sparing oncology, however, makes the localisation problem more acute rather than less. When the goal shifts from removing an entire lobe to carving out a precise wedge around a ten-millimetre lesion, the surgeon depends absolutely on the fidelity of whatever marker was placed the day before. Margin distance and local recurrence become the decisive metrics, and any localisation technique that cannot guarantee spatial accuracy becomes the weak link in an otherwise elegant chain.

This is why the commentary insists that future localisation research be framed by oncologic endpoints rather than technical success alone. Viana and Nunes call for systematic reporting of lesion depth, minimal margin distance, and longitudinal local recurrence in every study of nodule marking. Complete resection rates, while reassuring, are a blunt instrument; a resection can be complete yet carry a margin so narrow that recurrence risk rises. They also urge multicentre prospective validation within robotic workflows, recognising that single-centre feasibility studies, however encouraging, cannot establish whether a technique performs consistently across different operators, scanner platforms, and patient anatomies. Whether molecular stabilisation of fluorescent dyes translates into superior oncologic precision, they acknowledge, requires exactly this kind of prospective evaluation, but the conceptual evolution is notable.

The stabilised matrix concept represents a genuinely biochemical approach to a problem that previous generations attacked mechanically. Rather than containing dye with a coil or accepting its diffusion as inevitable, these formulations modulate dye distribution at the injection site itself, reducing lateral spread and potentially improving margin predictability. The commentary’s authors have direct experience in this territory: they previously published a technical note on computed tomography-guided dual-fluorescent marking for robotic sublobar resection covering 84 consecutive cases, work cited in their commentary as part of the field’s progression. Their argument is that these four generations, hook-wires, dye injections, coil-assisted fluorescence, and stabilised matrices, should be understood not as competitors but as iterative refinements, each responding to a clearly identified limitation of its predecessor.

For readers wondering why this seemingly niche surgical debate deserves broader attention, the answer lies in the convergence of three trends that are reshaping cancer care worldwide. Screening programmes are expanding, which means more small nodules will be found and more of them will be operated on. Robotic platforms are proliferating, which means more of those operations will be performed with instruments that cannot palpate a lesion hidden in deflated lung tissue. And lung-preserving resection is gaining evidence-based legitimacy, which means the precision demands on localisation will only intensify. The commentary’s closing line captures the moment succinctly: if feasibility has defined the past decade of computed tomography-guided localisation, precision will define the next. What began as a practical question of how to mark a spot in the lung is maturing into a rigorous discipline of spatial oncology, where the biochemistry of a dye, the geometry of a surgical margin, and the long-term risk of cancer recurrence are inseparably linked.

There are, of course, caveats that the commentary itself makes explicit. The heterogeneity of marking techniques currently in use, spanning simple dye injection and coil-assisted fluorescence, reflects an important developmental phase but may limit standardisation, making head-to-head comparisons difficult. The stabilised fluorescent matrices remain conceptually promising rather than prospectively proven, and their advantage over coil containment must be demonstrated in controlled studies. Nor does the commentary claim that any single technique is universally superior; instead, it offers a roadmap for how the field should evaluate its options. For a specialty in which a few millimetres of tissue can determine whether a patient keeps half a lung or loses a whole one, that shift in standards, from visible to verifiable, from feasible to faithful, may prove to be the most consequential development in thoracic surgical oncology this decade.

Subject of Research: Computed tomography-guided fluorescent localisation of small pulmonary nodules for robotic thoracic surgery

Article Title: Evolving generations of computed tomography-guided lung nodule localisation toward stabilised fluorescent precision in robotic thoracic oncology

Article References: Viana, P. C. C., & Nunes, T. F. (2026). Evolving generations of computed tomography-guided lung nodule localisation toward stabilised fluorescent precision in robotic thoracic oncology. CVIR Oncology, 2(1), Article 31. https://doi.org/10.1007/s44343-026-00036-4

Image Credits: AI Generated

DOI: 10.1007/s44343-026-00036-4

Keywords: lung nodule localisation, computed tomography guidance, indocyanine green, patent blue V, fluorescence imaging, robotic thoracic surgery, sublobar resection, segmentectomy, surgical margins, interventional radiology, precision oncology, stabilised fluorescent matrices

The report, led by interventional radiologist Charlie A. Hamm and colleagues, is framed as a technical roadmap rather than a large trial, but its results are striking in their consistency. Eleven patients, four women and seven men ranging in age from 34 to 77, underwent CT-guided dye-based marking of twelve lung nodules before minimally invasive, lung-sparing resection. The median nodule diameter was just 8.5 millimeters. Every single marking procedure was technically successful, every lesion was completely resected, and no operation had to be converted to open surgery or an entire lobectomy because the surgeon could not find the target. Seven of the twelve lesions turned out to be malignant, underscoring how much rides on getting the localization right.

The clinical backdrop explains why this matters. Randomized screening trials such as the Dutch-Belgian NELSON study showed that volume-based CT screening reduces lung cancer mortality, and more recent cohort work like the SUMMIT study has confirmed that the majority of screen-detected cancers are diagnosed at stage I or II, when surgery is the primary treatment. That shift has pushed thoracic surgeons toward sublobar resection, removing a wedge of lung or a single segment rather than the whole lobe, to preserve as much healthy parenchyma as possible. But the smaller the lesion and the more tissue-sparing the operation, the more critical it becomes to know exactly where the target sits before the first incision is made.

The traditional answer has been the hook-wire, a thin barbed wire placed through the chest wall into or next to the nodule on the morning of surgery. Hook-wires work, but they come with real drawbacks. They typically force same-day scheduling of two procedures, they can dislodge or migrate before the surgeon reaches them, and a rigid wire protruding through the pleura is uncomfortable and potentially hazardous for the patient, who must be transported carefully to avoid tearing lung tissue. The Berlin team’s dye-based approach eliminates the transpleural hardware entirely, which the authors note has been reported to cause less patient discomfort and stress and reduces the risk of marker displacement.

The first of the two dye techniques relies on patent blue V, a synthetic triphenylmethane dye that has long been used to trace lymphatic drainage in breast surgery and melanoma staging. It is water-soluble, renally excreted, and has a low toxicity profile, with allergic reactions occurring in fewer than one percent of patients. Under CT-fluoroscopic guidance, the radiologist advances a fine 22-gauge Chiba needle until its tip sits immediately adjacent to the nodule, deliberately avoiding puncture of the lesion itself, which reduces the theoretical risk of tumor seeding along the needle track and avoids compromising the pathology specimen. Then 0.1 to 0.4 milliliters of dye is injected through a small Luer-lock syringe, and the needle is withdrawn promptly without a saline flush, which would dilute the dye and could tattoo the skin along the exit path.

What happens next is a matter of physics and anatomy. The dye diffuses through the terminal vascular bed of the lung and reaches the pleural surface, where it creates a sharply demarcated blue patch that tells the surgeon precisely where the resection margin should fall. If the lesion lies more than three centimeters beneath the pleura, the dye is injected in increments as the needle is withdrawn, leaving a stained tract running from the nodule toward the chest wall. Because patent blue V gradually disperses into the bloodstream and pleural fluid, the color fades within hours, so surgery must be scheduled the same day, ideally within three hours of the marking. In the Berlin series, the five patients who received patent blue V injections had a median marking time of just seven minutes.

The second technique solves the fading problem with indocyanine green, or ICG, a tricarbocyanine fluorescent dye that binds readily to tissue proteins and glows bright emerald green when excited by near-infrared light. Injected alone, ICG diffuses more slowly than patent blue V and can remain visible in lung tissue for up to six days, a finding documented in prior experimental work. More importantly, near-infrared light penetrates soft tissue far better than visible light, so a fluorescence camera in the operating room can detect the glowing signal from millimeters to several centimeters beneath the pleural surface, effectively letting the surgical team see through the lung’s outer rim to a depth of roughly three centimeters. The six patients in the series who received ICG-based marking had a median procedure time of 16.5 minutes.

The most innovative variant described in the report goes one step further: instead of injecting liquid dye that will eventually disperse, the team deploys a tiny embolization coil soaked in ICG. The preparation is meticulous. ICG is mixed with ten milliliters of sterile water, and two to three milliliters of the solution are used to slowly flush the coil introducer outside the patient to prevent premature deployment. The markers are Tornado-type coils measuring 0.035 inches in diameter and 7 to 8 millimeters in length. After percutaneous puncture with an 18-gauge coaxial needle, the coil is advanced with the stiff end of a guidewire and deployed under CT-fluoroscopy immediately adjacent to the lesion, with care taken not to push it too far past the target. The coil acts as a physical scaffold that holds the dye in place, and because the fluorescence persists for days, surgery can be scheduled up to thirteen days after marking, giving hospitals valuable flexibility when operating rooms are crowded or schedules shift unexpectedly.

Safety data from the series align with the broader literature. Only one complication occurred, an asymptomatic pneumothorax during needle puncture that was managed conservatively without any intervention, consistent with reported pneumothorax rates of around six percent for CT-guided ICG injection in a retrospective analysis of 471 patients. The authors do caution that coil placement requires a larger 18-gauge needle than pure dye injection, which may influence complication rates. Prior studies have reported technical success rates above 98 percent for CT-guided dye injection and 100 percent for bronchoscopy-guided ICG-coil placement, and the addition of preoperative markings has been shown in other reports to drive conversion rates to open surgery close to zero.

What makes the Berlin report notable is the delivery route. ICG-soaked coil marking had previously been described through bronchoscopy, a technique that requires general anesthesia and specialized endoscopic equipment, and only recently through a percutaneous approach. The CT-guided percutaneous route can be performed in an outpatient workflow under local anesthesia alone, making it less resource-intensive and easier to slot into a busy hospital schedule. The authors emphasize that the technique is ultimately a story about multidisciplinary collaboration: the tumor board decides the patient needs lung-sparing surgery, the interventional radiologist plants the beacon, and the thoracic surgeon follows the glow. As robotic-assisted and uniportal thoracoscopic surgery become more common and screening programs continue to surface ever-smaller nodules, dye-based marking may become a routine bridge between the radiology suite and the operating room, turning invisible targets into ones a surgeon cannot miss.

Subject of Research: CT-guided preoperative dye-based marking of small lung nodules for minimally invasive surgical resection

Article Title: CT-guided percutaneous marking of lung nodules using patent blue V and indocyanine green

Article References: Hamm, C. A., Elsner, A., Fehrenbach, U., Savic, L. J., Bawaadam, H., Collettini, F., Neudecker, J., Gebauer, B., Rückert, J., & Auer, T. A. (2026). CT-guided percutaneous marking of lung nodules using patent blue V and indocyanine green. CVIR Oncology, 2(1), Article 2. https://doi.org/10.1007/s44343-026-00031-9

Image Credits: AI Generated

DOI: 10.1007/s44343-026-00031-9

Keywords: lung nodules, interventional radiology, indocyanine green, patent blue V, CT guidance, thoracic surgery, fluorescence imaging, preoperative localization, lung cancer screening, video-assisted thoracoscopic surgery, fiducial coils, lung-sparing resection