Development and characterization of a brain tumor mimicking fluorescence phantom

Abstract

Fluorescence guidance using 5-aminolevulinic acid (5-ALA) for brain tumor resection is a recent technique applied to the highly malignant brain tumors. Five-ALA accumulates as protoporphyrin IX fluorophore in the tumor cells in different concentrations depending on the tumor environment and cell properties. Our group has developed a fluorescence spectroscopy system used with a hand-held probe intra-operatively. The system has shown improvement of fluorescence detection and allows quantification that preliminarily correlates with tumor malignancy grade during surgery. However, quantification of fluorescence is affected by several factors including the initial fluorophore concentration, photobleaching due to operating lamps and attenuation from the blood. Accordingly, an optical phantom was developed to enable controlled fluorescence measurements and evaluation of the system outside of the surgical procedure. The phantom mimicked the optical properties of glioma at the specific fluorescence excitation wavelength when different concentrations of the fluorophore were included in the phantom. To allow evaluation of photobleaching, kinetics of fluorophore molecules in the phantom was restricted by solidifying the phantoms. Moreover, a model for tissue autofluorescence was added. The fluorescence intensity's correlation with fluorophore concentration in addition to the photobleaching properties were investigated in the phantoms and were compared to the clinical data measured on the brain tumor.

Accurate three-dimensional virtual reconstruction of surgical field using calibrated trajectories of an image-guided medical robot

“…Future phantoms will require more translucent materials that provide multimodal contrast such as dyed gels containing scattering particles. 59 The versatile SFE can support multiple modes of imaging, such as reflectance using enhanced spectral imaging which enhances the contrast of the blood vessels and vascularized tissues, 21 and wide-field fluorescence imaging of NIR dye molecules that are conjugated to molecular specific probes that bind to brain tumor cells. 8 Additional SFE imaging modes that are molecular specific can also be included in a future phantom or ex vivo tissue model, such as autofluorescence imaging, 51 time-resolved fluorescence lifetime imaging and spectroscopy, 60 and coherent Raman imaging and spectroscopy.…”

Auditory display for fluorescence-guided open brain tumor surgery

“…These included zero signal, low signal, high signal, and error signal. The phantoms modeled the optical properties of the brain tumor using ink and intralipid 20% (Fresenius Kabi, Uppsala, Sweden) [18] including tissue autofluorescence (AF) by adding turmeric dissolved in ethanol (zero signal). In two phantom sets (low and high signal), 10 and 30 g/l of PpIX disodium salt (MP Biomedicals, France) was added to model the low and high fluorescence signals, respectively.…”

Nanoparticle‐assisted, image‐guided laser interstitial thermal therapy for cancer treatment

“…Tissue mimicking materials, such as phantoms, have been studied extensively to achieve optical and physical properties comparable to the tissue or the tumor of interest. Phantom material make-up and properties can range from simple to complex depending on what type of tissue is being mimicked (D'Souza et al, 2001;Haj-Hosseini et al, 2014;S. Liu, Doughty, et al, 2018).…”

“…Tissue mimicking materials, such as phantoms, have been studied extensively to achieve optical and physical properties comparable to the tissue or the tumor of interest. Phantom material make‐up and properties can range from simple to complex depending on what type of tissue is being mimicked (D'Souza et al, 2001; Haj‐Hosseini et al, 2014; S. Liu, Doughty, et al, 2018). Previous studies have used phantoms in combination with numerical modeling to study nanoparticle‐assisted LITT in the liver, prostate, and brain cancer (Assi et al, 2021; Elliott et al, 2010; S. Liu, Doughty, et al, 2018).…”