The concept of a miniaturized inorganic scintillator detector is demonstrated in the analysis of the small static photon fields used in external radiation therapy. Such a detector is constituted by a 0.25 mm diameter and 0.48 mm long inorganic scintillating cell (1.6 10⁻⁵ cm³ detection volume) efficiently coupled to a narrow 125 μm diameter silica optical fiber using a tiny photonic interface (an optical antenna). The response of our miniaturized scintillator detector (MSD) under 6 MV bremsstrahlung beam of various sizes (from 1 1 cm² to 4 4 cm²) is compared to that of two high resolution reference probes, namely, a micro-diamond detector and a dedicated silicon diode. The spurious Cerenkov signal transmitted through our bare detector is rejected with a basic spectral filtering. The MSD shows a linear response regarding the dose, a repeatability within 0.1% and a radial directional dependence of 0.36% (standard deviations). Beam profiling at 5 cm depth with the MSD and the micro-diamond detector shows a mismatch in the measurement of the full widths at 80% and 50% of the maximum which does not exceed 0.25 mm. The same difference range is found between the micro-diamond detector and a silicon diode. The deviation of the percentage depth dose between the MSD and micro-diamond detector remains below 2.3% within the first fifteen centimeters of the decay region for field sizes of 1 1 cm², 2 2 cm² and 3 3 cm² (0.76% between the silicon diode and the micro-diamond in the same field range). The 2D dose mapping of a 0.6 0.6 cm² photon field evidences the strong 3D character of the radiation-matter interaction in small photon field regime. From a beam-probe convolution theory, we predict that our probe overestimates the beam width by 0.06%, making our detector a right compromise between high resolution, compactness, flexibility and ease of use. The MSD overcomes problem of volume averaging, stem effects, and despite its water non-equivalence it is expected to minimize electron fluence perturbation due to its extreme compactness. Such a detector thus has the potential to become a valuable dose verification tool in small field radiation therapy, and by extension in Brachytherapy, FLASH-radiotherapy and microbeam radiation therapy.

小型化无机闪烁体探测器的概念在对外部放射治疗中使用的小静态光子场的分析中得到了证明。这种检测器由直径为 0.25 mm、长为 0.48 mm 的无机闪烁池（检测体积为 1.6 10 ^-5 cm ³ ）构成，该闪烁池使用微小的光子接口（光学天线）有效地耦合到直径为 125 μ m 的窄石英光纤。我们的微型闪烁体探测器 (MSD) 在各种尺寸（从 1 1 cm ²到 4 4 cm ^{2的 6 MV 轫致辐射光束下）的响应}) 与两个高分辨率参考探头（即微型金刚石探测器和专用硅二极管）进行比较。通过我们的裸探测器传输的杂散切伦科夫信号被基本的光谱过滤所拒绝。MSD 显示关于剂量的线性响应、0.1% 以内的重复性和 0.36% 的径向方向依赖性（标准偏差）。使用 MSD 和微型金刚石检测器在 5 厘米深度处进行的光束轮廓分析显示，在不超过 0.25 毫米的最大值的 80% 和 50% 处测量的全宽不匹配。在微金刚石探测器和硅二极管之间发现了相同的差异范围。对于 1 1 cm 的射野大小，MSD 和微金刚石探测器之间的百分比深度剂量偏差在衰减区域的前 15 厘米内保持在 2.3% 以下² , 2 2 cm ²和3 3 cm ²（同一场范围内硅二极管和微金刚石之间的0.76%）。0.6 0.6 cm ^{2的 2D 剂量映射}光子场证明了小光子场区域中辐射-物质相互作用的强 3D 特征。根据光束探针卷积理论，我们预测我们的探针高估了光束宽度 0.06%，使我们的探测器在高分辨率、紧凑性、灵活性和易用性之间取得了正确的折衷。MSD 克服了体积平均、茎效应的问题，尽管它与水不等价，但由于其极其紧凑，它有望最大限度地减少电子注量扰动。因此，这种检测器有可能成为小场放射治疗中有价值的剂量验证工具，并延伸到近距离放射治疗、FLASH 放射治疗和微束放射治疗中。