Veselsky T, Novotny J, Pastykova V, Koniarova I
Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Department of Dosimetry and Application of Ionizing Radiation, Prague, Brehova 78/7, 110 00, Czech Republic; Na Homolce Hospital, Medical Physics Department, Prague, Roentgenova 2/37, 150 30, Czech Republic; Motol University Hospital, Oncology Clinic, Prague, V Uvalu 84, 150 00, Czech Republic.
Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Department of Dosimetry and Application of Ionizing Radiation, Prague, Brehova 78/7, 110 00, Czech Republic; Na Homolce Hospital, Medical Physics Department, Prague, Roentgenova 2/37, 150 30, Czech Republic; Motol University Hospital, Oncology Clinic, Prague, V Uvalu 84, 150 00, Czech Republic.
Phys Med. 2017 Dec;44:66-71. doi: 10.1016/j.ejmp.2017.11.010. Epub 2017 Nov 20.
The aim of this study was to determine small field correction factors for a synthetic single-crystal diamond detector (PTW microDiamond) for routine use in clinical dosimetric measurements.
Correction factors following small field Alfonso formalism were calculated by comparison of PTW microDiamond measured ratio M/M with Monte Carlo (MC) based field output factors Ω determined using Dosimetry Diode E or with MC simulation itself. Diode measurements were used for the CyberKnife and Varian Clinac 2100C/D linear accelerator. PTW microDiamond correction factors for Leksell Gamma Knife (LGK) were derived using MC simulated reference values from the manufacturer.
PTW microDiamond correction factors for CyberKnife field sizes 25-5 mm were mostly smaller than 1% (except for 2.9% for 5 mm Iris field and 1.4% for 7.5 mm fixed cone field). The correction of 0.1% and 2.0% for 8 mm and 4 mm collimators, respectively, needed to be applied to PTW microDiamond measurements for LGK Perfexion. Finally, PTW microDiamond M/M for the linear accelerator varied from MC corrected Dosimetry Diode data by less than 0.5% (except for 1 × 1 cm field size with 1.3% deviation).
Regarding low resulting correction factor values, the PTW microDiamond detector may be considered an almost ideal tool for relative small field dosimetry in a large variety of stereotactic and radiosurgery treatment devices.
本研究的目的是确定用于临床剂量测量常规使用的合成单晶金刚石探测器（PTW 微型金刚石）的小射野校正因子。
通过将 PTW 微型金刚石测量的比值 M/M 与使用剂量学二极管 E 确定的基于蒙特卡罗（MC）的射野输出因子Ω或与 MC 模拟本身进行比较，计算遵循小射野阿方索形式的校正因子。二极管测量用于射波刀和瓦里安 Clinac 2100C/D 直线加速器。Leksell 伽玛刀（LGK）的 PTW 微型金刚石校正因子使用制造商的 MC 模拟参考值得出。
射波刀射野尺寸 25 - 5 毫米的 PTW 微型金刚石校正因子大多小于 1%（5 毫米虹膜射野为 2.9%，7.5 毫米固定准直器射野为 1.4%除外）。对于 LGK Perfexion，分别需要对 PTW 微型金刚石测量值应用 8 毫米和 4 毫米准直器 0.1%和 2.0%的校正。最后，直线加速器的 PTW 微型金刚石 M/M 与 MC 校正的剂量学二极管数据的差异小于 0.5%（1×1 厘米射野尺寸偏差为 1.3%除外）。
鉴于所得校正因子值较低，PTW 微型金刚石探测器可被视为在各种立体定向和放射外科治疗设备中进行相对小射野剂量测定的几乎理想工具。
