For radiation treatments, the accurate measurement of an absorbed dose of radiation is essential to reduce side effects. Herein, we present a microfluidic chip calorimeter integrated with water medium and vanadium oxide (VOx) thermistor. Microfluidic chip calorimeter can be a novel candidate for absolute dosimetry, providing high spatial resolution with small detector size and self-calibration capability. VOx thermistor provides high temperature resolution of 42 μK. The device thermal insulation is enhanced with vacuum thermal insulation and the resulting thermal conductance was 23 μW/K.