Noninvasive diffuse optical measurement of blood flow and blood oxygenation for monitoring radiation therapy in patients with head and neck tumors: a pilot study

Abstract

This pilot study explores the potential of noninvasive diffuse correlation spectroscopy (DCS) and diffuse reflectance spectroscopy (DRS) for monitoring early relative blood flow (rBF), tissue oxygen saturation (StO(2)), and total hemoglobin concentration (THC) responses to chemo-radiation therapy in patients with head and neck tumors. rBF, StO(2), and THC in superficial neck tumor nodes of eight patients are measured before and during the chemo-radiation therapy period. The weekly rBF, StO(2), and THC kinetics exhibit different patterns for different individuals, including significant early blood flow changes during the first two weeks. Averaged blood flow increases (52.7+/-9.7)% in the first week and decreases (42.4+/-7.0)% in the second week. Averaged StO(2) increases from (62.9+/-3.4)% baseline value to (70.4+/-3.2)% at the end of the second week, and averaged THC exhibits a continuous decrease from pretreatment value of (80.7+/-7.0) [microM] to (73.3+/-8.3) [microM] at the end of the second week and to (63.0+/-8.1) [microM] at the end of the fourth week of therapy. These preliminary results suggest daily diffuse-optics-based therapy monitoring is feasible during the first two weeks and may have clinical promise.

Near-infrared diffuse correlation spectroscopy in cancer diagnosis and therapy monitoring

“…[25][26][27] DCS can be easily and continually applied at the bedside in clinical rooms. [28][29][30][31][32][33][34] 35 and has been used less in the "cancer" context than in other scenarios such as brain and muscle. Therefore, a review of potential for cancer applications of DCS is valuable at this time for both optical and cancer communities.…”

“…This review is not intended to discuss every detail about DCS; rather it provides a flavor for the DCS method and a snapshot of its recent progress in cancer research. For example, DCS has been utilized in the monitoring of tumor-to-normal flow contrasts 25,30 and early hemodynamic/metabolic responses to chemotherapy 30 in human breast cancers, physiological effects of chemoradiation therapy on human head and neck cancers, 29,53 hemodynamic responses to photodynamic therapy (PDT) in human prostate cancers, 28,51 and efficacies of PDT in murine tumor models. 5,35,[55][56][57] In some of these studies, DCS was combined with NIRS in hybrid instruments for accurately extracting tumor blood flow 21 and for calculating tumor metabolic rate of oxygen consumption (TMRO 2 ) from the measured flow and oxygenation data.…”

“…In practice, however, the diffusion model, i.e., hΔr 2 ðτÞi ¼ 6D B τ, fits the autocorrelation curves rather well over a broad range of tissue types, ranging from rat brain, 43,45 and mouse tumor, 5,35 to piglet brain, 39 adult human skeletal muscle, 23,26 premature brain, 34,38 adult brain, 20,27,33,41 and adult tumors. 21,29,30 Here D B is the effective Brownian diffusion coefficient. Therefore the combined term, αD B , has been referred to as the blood flow index in biological tissues and has been commonly used to calculate relative blood flow (rBF) compared to the baseline flow index before physiological changes.…”

“…1(b)) with straight or 90-deg bent fibers is used in studies of tumors close to the body surface (e.g., breast tumor, head and neck tumor). 21,25,29,30 The second probe [see Fig. 1(c)] is a noncontact probe mounted on the imaging plane of a mechanical camera which is fixed at a certain distance (e.g., 15 cm) from the tumor surface.…”

“…Practically all innovations from the design of NIRS probes can be taken and adapted for DCS use, and hybrid probes for both NIRS and DCS can be easily built by adding extra source and detector fibers. 21,25,[28][29][30] 3 Diagnostic Applications DCS/NIRS has been previously tested for use in diagnosis of cancers where tumor blood flow, oxygenation, and oxygen metabolism (TMRO 2 ) were measured. 25,30 One such example is in the detection of tumor-to-normal flow contrast in breast tumors.…”