Page 18 - Effects of radiotherapy and hyperbaric oxygen therapy on oral microcirculation Renee Helmers

Chapter 1
of the microcirculation in the tissue. The absorption of LED lights in hemoglobin of the erythrocytes provides an image of RBCs in the microcirculation contrasted by a light background.13 SDF imaging also improved in clinical applicability by using low-power LED lights so that with the use of a battery pack the device is more mobile for ambulant use. Braedius Scientific introduced the third- generation device, the CytoCam (CC) Microscope System (Braedius Medical, Huizen, The Netherlands), a computer-controlled video microscopy imaging system with even higher image resolution and larger field of view.1,17,25 With a controllable focal depth it is easier to obtain images of different regions of interest by maintaining the right focus margin.25 Additionally, the hardware of the CC offers online analyzing which brings diagnostics and analysis one step closer to realizing practical bedside application and therefore its clinical use. HVM techniques have previously been applied in oral and maxillofacial research.20,26
HVM was able to enhance evaluation and examination of microcirculation heterogeneity in perfusion, microvascular density, flow and angiomorphology. These parameters collectively represent the microcirculatory state and can indicate perfusion (dys-)function. It has been proposed that heterogeneity in flow compromises O2 distribution and therefore is less tolerated by tissues than diminished homogeneous flow in which extraction of O2 from the blood supply is still possible.12 For assessment of these parameters several methods were developed and validated for which consensus guidelines were established.2
OUTLINE OF THE THESIS
The aim of this thesis was to elucidate the effects of RT and HBOT independently on oral microcirculation in preclinical and clinical studies. In clinical studies the objective was to clarify aspects of LRTI in the oral microcirculation of HNCP and the subsequent resuscitating potential of HBOT. Furthermore, the feasibility of HVM (SDF and CC) in detecting RT and HBOT induced changes in the microcirculation was examined. It was hypothesized that RT elicits detectable microcirculatory derangement corresponding with a disturbed hemodynamic function and a hypovascular state. Furthermore, it was hypothesized that HBOT promotes compromised microvascular tissue towards healing or healthy microvascular tissue state.
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