Near infrared spectroscopy: A diagnostic tool to evaluate effects of radiotherapy in the mandible?

Abstract

Abstract.Purpose. This study tests the hypothesis that near infrared spectroscopy can be used to detect changes in haemoglobin oxygenation status in the mandible, and therefore can be used to monitor the deleterious effects of radiotherapy and the possible reversion of these effects with therapeutic ultrasound.Methods. A probe was used to calculate the concentrations of deoxyhaemoglobin in the mandible bone of 30 volunteers with no known malignancies and 10 patients with malignancies in the head and neck region treated with radiotherapy.Results. Although the variability of the measurements was very high, when comparing the right side to the left side of the mandible, the measurements remained relatively similar. There was a great variability between the data for each patient, there was no correlation with age.Conclusions. The near infrared spectroscopy validation for the measurement of deoxyhaemoglobin concentrations in the mandible showed that the variability of the measurements was very high, therefore it is not appropriate to be used diagnostically for the evaluation of radiotherapy effects on the mandibular blood flow and metabolic status.

Use of near‐infrared systems for investigations of hemodynamics in human in vivo bone tissue: A systematic review

“…Twenty‐one studies were identified using near infrared spectroscopy (NIRS) and 10 studies were identified using photoplethysmography (PPG) non‐invasively on in vivo bone tissue . Fifty‐seven studies were identified using laser Doppler flowmetry (LDF) in vivo of which 56 were intra‐operative.…”

“…The oxygen saturation is the mean saturation across the arterioles, capillaries, and venules. All were using reflectance spectroscopy (light scattered back from tissue) apart from transmission spectroscopy (light scattered through tissue) studies looking at the calcaneus and mandible . For reflectance spectroscopy, probe spacing (affecting the depth of tissue measured) varied from 10, 20, 25, 30, and 40 mm .…”

“…Use of time resolved spectroscopy systems are reported in five studies . These allow measurements of absorption and scattering coefficients for bone tissue and, therefore, absolute concentrations of oxygenated and deoxygenated hemoglobin are calculated with participants at rest (in μM) . Farzam et al also reports on use of a frequency domain based NIRS system utilizing 15 NIR laser sources (5 each at 3 different wavelengths) based around 2 photomultiplier detectors …”

“…Six studies used NIRS systems utilizing a broadband spectrum of NIR light enabling the system to calculate absolute concentrations of hemoglobin and in some cases also water, collagen, mineral, and lipid content in the bone tissues sampled . Additionally, four studies also measured markers of blood flow rates utilizing emerging diffuse correlation spectroscopy technology …”

“…The clinical utility of NIRS has been explored in the mandible and sternum . In a case‐control manner, mandibular conditions such as osteoradionecrosis post‐radiotherapy, and fibular grafting post‐tumor removal, as well as chest wall measurements taken post‐cardiac surgery . were explored.…”