intracranial hyperthermia through local photothermal heating with a fiberoptic microneedle device background and objectives the fiberoptic microneedle device fmd seeks to leverage advantages of both laserinduced thermal therapy litt and convectionenhanced delivery ced to increase volumetric dispersal of locally infused chemotherapeutics through sublethal photothermal heat generation this study focused on determination of photothermal damage thresholds with 1064nm light delivered through the fmd into in vivo rat modelsmaterials and methods fmds capable of codelivering laser energy and fluid agents were fabricated through a novel offcenter splicing technique involving fusion of a multimode fiberoptic to lightguiding capillary tubing fmds were positioned at a depth of 25mm within the cerebrum of male rats with fluoroptic temperature probes placed within 1mm of the fmd tip irradiation without fluid infusion was conducted at laser powers of 0 sham 100 200 500 or 750mw evans blueserum albumin conjugated complex solution eba and laser energy codelivery were performed in a second set of preliminary experimentsresults maximum steadystate temperatures of 38716 and 42009 c were measured for the 100 and 200mw experimental groups respectively histological investigation demonstrated needle insertion damage alone for sham and 100mw irradiations photothermal damage was detected at 200mw although observable thermal damage was limited to a small penumbra of cerebral cortical microcavitation and necrosis that immediately surrounded the region of fmd insertion codelivery of eba and laser energy presented increased volumetric dispersal relative to infusiononly controlsconclusion fluoroptic temperature sensing and histopathological assessments demonstrated that a laser power of 100mw results in sublethal brain hyperthermia and the optimum sublethal target energy range is likely 100200mw the preliminary fmdced experiments confirmed the feasibility of augmenting fluid dispersal using slight photothermal heat generation demonstrating the fmds potential as a way to increase the efficacy of ced in treating mg