Phase‐sensitive fluorescence detector for parathyroid glands during thyroidectomy: A preliminary report

Abstract

Despite advances in medical technology, the parathyroid glands are still damaged during thyroid surgery. Our previous studies exploring methods for locating the parathyroid glands using autofluorescence have limitations, such as turning off the surgical light or requiring additional matching between the autofluorescence image and realsurgical field-of-view. We developed a probe-type parathyroid autofluorescence detector using a phase-sensitive process and optical filtering to overcome these limitations. A preliminary clinical trial was performed on eight parathyroid glands in four patients. The normalized mean signal of the normal parathyroid glands was 332% stronger than that of the thyroid, and 384%, 459% and 286% stronger than the signal of the muscle, trachea and fat, respectively. Additionally, the device also detected fluorescence from indocyanine green. K E Y W O R D Sautofluorescence, clinical, optical filter, parathyroid gland, phase-sensitive Abbreviations: FOV, field-of-view; ICG, indocyanine green; P/T ratio, parathyroid/thyroid intensity ratio; SNR, signal-to-noise ratio.

Recent Advances and the Potential for Clinical Use of Autofluorescence Detection of Extra-Ophthalmic Tissues

“…The NIR fluorophore(s) found in PTGs remain unknown, and conclusive suggestions about the source are likely incorrect, as no blueprint exists for the NIR excitation range-unlike for the other clinical AFI application scenarios. Based on the current evidence, PTG AF originates in a molecule that is significantly less abundant in the surrounding thyroid tissue [95,143]. Furthermore, it is probably only a single molecule that is excited by NIR light, as the excitation maximum was found to be in a narrow wavelength range (814−826 nm) [95].…”

“…Benmiloud et al quantified the duration of the operations, which was significantly longer in the NIR AFI group compared to the standard-care group (eight minutes between median values of both groups) [111]. Several attempts at intraoperative real-time monitoring of PTGs without delaying the operation were developed, and may even allow optimization of operation times without waiving intraoperative NIR AFI PTG detection [112,113,115,143]. A second limitation is that, foremost, only inexperienced surgeons profit from the intraoperative AFI guidance, requiring a case-to-case decision of whether or not to use intraoperative NIR AFI.…”

Optical spectroscopy for in vivo medical diagnosis—a review of the state of the art and future perspectives

“…Kim et al published a preliminary report on the use of a phase-sensitive NIR autofluorescence detector, dubbed the 'PG sensor' (TRL Group B), during thyroidectomy surgery [201]. The PG sensor probe set-up is shown in figure 4.…”