Abstract
Introduction
Neuroblastoma (NB) is one of the most challenging diseases in paediatric oncology. Surgery is a cornerstone in treatment of NB, but resection is particularly demanding due to tumour adhesions and fibrosis following neoadjuvant chemotherapy. We aimed to assess fluorescence guided surgery (FGS) using short-wave infrared (SWIR) light (900–1400nm). This has the potential to enable deeper tissue penetration whilst avoiding visible background autofluorescence, allowing specific high-contrast delineation of tumour in real-time, supporting surgeons to maximise the completeness and safety of resection.
Methods
Clinically-used anti-GD2 monoclonal antibody (Dinutuximab-beta) was conjugated with IRDye800CW and IR-12-NHS. To assess sensitivity, 3 positive cell lines (LAN-1, KELLY, SUP-T1 GD2+ve) and 1 control cell line (SUP-T1 GD2-ve) were stained with 100nM of both anti-GD2-IR800 and anti-GD2-IR12 (Fig 1A). A novel multispectral SWIR fluorescence imaging device was constructed using a highly sensitive InGaAs sensor, filter wheel and 785nm laser illumination (Fig 1B). To assess depth-penetration, an emulsion intralipid phantom was used to simulate tissue scattering. To validate the system in vivo, mice (F, NSG, n=10) bearing subcutaneous NB were i.v. injected with 100 µg of the fluorescent probes and imaged at 24, 48, 72 and 96hrs using the multispectral SWIR imaging device.
Results/Discussion
Using SWIR fluorescence imaging of anti-GD2-IR800 or -IR12, the minimum detectable cell number was 250,000. IR800 was consistently ~3× brighter than IR12, so 250,000 cells were detected using 50ms exposures (compatible with real-time imaging) (Fig 1C–D). Though IR800 and IR12 emission decreases towards higher wavelengths, anti-GD2-IR800-stained cells were detected up to 1200nm, with exposures as low as 25ms (Fig. 1E). Even when using pure 20% intralipid (scattering ~10× that found in biological tissue), IR800-stained cells were detectable at a depth of 3.4mm (Fig. 1F–G). The spectral data suggest most of this light is in the NIR-I range (Fig. H).
Validation in a subcutaneous model of neuroblastoma shows that high-contrast transcutaneous delineation of tumour is possible using anti-GD-IR800. SWIR fluorescence >1150nm is able to sharply delineate deep tissues such as the off-target fluorescence of the liver and femur as shown in Fig. 2
Conclusions
Our results highlight the potential of multispectral SWIR FGS with anti-GD2-IR800. While clinically translatable SWIR-fluorophores are not yet available, the SWIR tail of IR800 emission shows promise for SWIR fluorescence. Over the coming years, we will continue to optimize this technique for translation into clinical practice, thus facilitating safer, more complete resection of neuroblastoma.
Neuroblastoma (NB) is one of the most challenging diseases in paediatric oncology. Surgery is a cornerstone in treatment of NB, but resection is particularly demanding due to tumour adhesions and fibrosis following neoadjuvant chemotherapy. We aimed to assess fluorescence guided surgery (FGS) using short-wave infrared (SWIR) light (900–1400nm). This has the potential to enable deeper tissue penetration whilst avoiding visible background autofluorescence, allowing specific high-contrast delineation of tumour in real-time, supporting surgeons to maximise the completeness and safety of resection.
Methods
Clinically-used anti-GD2 monoclonal antibody (Dinutuximab-beta) was conjugated with IRDye800CW and IR-12-NHS. To assess sensitivity, 3 positive cell lines (LAN-1, KELLY, SUP-T1 GD2+ve) and 1 control cell line (SUP-T1 GD2-ve) were stained with 100nM of both anti-GD2-IR800 and anti-GD2-IR12 (Fig 1A). A novel multispectral SWIR fluorescence imaging device was constructed using a highly sensitive InGaAs sensor, filter wheel and 785nm laser illumination (Fig 1B). To assess depth-penetration, an emulsion intralipid phantom was used to simulate tissue scattering. To validate the system in vivo, mice (F, NSG, n=10) bearing subcutaneous NB were i.v. injected with 100 µg of the fluorescent probes and imaged at 24, 48, 72 and 96hrs using the multispectral SWIR imaging device.
Results/Discussion
Using SWIR fluorescence imaging of anti-GD2-IR800 or -IR12, the minimum detectable cell number was 250,000. IR800 was consistently ~3× brighter than IR12, so 250,000 cells were detected using 50ms exposures (compatible with real-time imaging) (Fig 1C–D). Though IR800 and IR12 emission decreases towards higher wavelengths, anti-GD2-IR800-stained cells were detected up to 1200nm, with exposures as low as 25ms (Fig. 1E). Even when using pure 20% intralipid (scattering ~10× that found in biological tissue), IR800-stained cells were detectable at a depth of 3.4mm (Fig. 1F–G). The spectral data suggest most of this light is in the NIR-I range (Fig. H).
Validation in a subcutaneous model of neuroblastoma shows that high-contrast transcutaneous delineation of tumour is possible using anti-GD-IR800. SWIR fluorescence >1150nm is able to sharply delineate deep tissues such as the off-target fluorescence of the liver and femur as shown in Fig. 2
Conclusions
Our results highlight the potential of multispectral SWIR FGS with anti-GD2-IR800. While clinically translatable SWIR-fluorophores are not yet available, the SWIR tail of IR800 emission shows promise for SWIR fluorescence. Over the coming years, we will continue to optimize this technique for translation into clinical practice, thus facilitating safer, more complete resection of neuroblastoma.
| Original language | English |
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| Publication status | Published - 16 Mar 2022 |
| Event | European Molecular Imaging Meeting: 17th Annual Meeting of the European Society for Molecular Imaging - HELEXPO, Thessaloniki, Greece Duration: 15 Mar 2022 → 18 Mar 2022 |
Conference
| Conference | European Molecular Imaging Meeting |
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| Abbreviated title | EMIM 2022 |
| Country/Territory | Greece |
| City | Thessaloniki |
| Period | 15/03/22 → 18/03/22 |