Mancosu Pietro, Reggiori Giacomo, Stravato Antonella, Gaudino Anna, Lobefalo Francesca, Palumbo Valentina, Navarria Piera, Ascolese Anna, Picozzi Piero, Marinelli Marco, Verona-Rinati Gianluca, Tomatis Stefano, Scorsetti Marta
Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan 20098, Italy.
Radiation Oncology Department, Humanitas Clinical and Research Center, Rozzano, Milan 20089, Italy.
Med Phys. 2015 Sep;42(9):5035-41. doi: 10.1118/1.4927569.
To evaluate the new commercial PTW-60019 synthetic single-crystal microDiamond detector (PTW, Freiburg, Germany) for relative dosimetry measurements on a clinical Leksell Gamma Knife Perfexion radiosurgery system.
Detector output ratios (DORs) for 4 and 8 mm beams were measured using a microDiamond (PTW-60019), a stereotactic unshielded diode [IBA stereotactic field detector (SFD)], a shielded diode (IBA photon field detector), and GafChromic EBT3 films. Both parallel and transversal acquisition directions were considered for PTW-60019 measurements. Measured DORs were compared to the new output factor reference values for Gamma Knife Perfexion (0.814 and 0.900 for 4 and 8 mm, respectively). Profiles in the three directions were also measured for the 4 mm beam to evaluate full width at half maximum (FWHM) and penumbra and to compare them with the corresponding Leksell GammaPlan profiles.
FWHM and penumbra for PTW-60019 differed from the calculated values by less than 0.2 and 0.3 mm, for the parallel and transversal acquisitions, respectively. GafChromic films showed FWHM and penumbra within 0.1 mm. The output ratio obtained with the PTW-60019 for the 4 mm field was 1.6% greater in transverse direction compared to the nominal value. Comparable differences up to 0.8% and 1.0% for, respectively, GafChromic films and SFD were found.
The microDiamond PTW-60019 is a suitable detector for commissioning and routine use of Gamma Knife with good agreement of both DORs and profiles in the three directions.
评估新型商用PTW - 60019合成单晶微金刚石探测器（德国弗莱堡的PTW公司）在临床Leksell伽玛刀Perfexion放射外科系统上进行相对剂量测量的性能。
使用微金刚石探测器（PTW - 60019）、立体定向无屏蔽二极管[IBA立体定向场探测器（SFD）]、屏蔽二极管（IBA光子场探测器）和GafChromic EBT3胶片测量4毫米和8毫米射束的探测器输出比（DOR）。PTW - 60019测量考虑了平行和横向采集方向。将测量得到的DOR与伽玛刀Perfexion的新输出因子参考值（4毫米和8毫米射束分别为0.814和0.900）进行比较。还测量了4毫米射束在三个方向上的剂量分布曲线，以评估半高宽（FWHM）和半值层，并将其与相应的Leksell伽玛计划剂量分布曲线进行比较。
对于平行和横向采集，PTW - 60019的FWHM和半值层与计算值的差异分别小于0.2毫米和0.3毫米。GafChromic胶片显示FWHM和半值层在0.1毫米以内。PTW - 60019在横向方向上测得的4毫米射野的输出比与标称值相比大1.6%。GafChromic胶片和SFD分别发现了高达0.8%和1.0%的可比差异。
微金刚石探测器PTW - 60019是伽玛刀调试和常规使用的合适探测器，其DOR和三个方向上的剂量分布曲线都具有良好的一致性。
