A photon spectrometric dose-rate constant determination for the Advantage Pd-103 brachytherapy source.
A photon spectrometric dose-rate constant determination for the Advantage Pd-103 brachytherapy source.
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DOI：
10.1118/1.3298011
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发表时间：
2010-02
期刊：
影响因子：
3.8
通讯作者：
Zhe Chen;P. Bongiorni;R. Nath
中科院分区：
文献类型：
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作者：
Zhe Chen;P. Bongiorni;R. Nath
虽然已经报道了新的Advantage Pd-103放射源（IsoAid，LLC，里奇港，FL）使用Monte Carlo模拟和热释光剂量测定法（Thermoluminescent dosemetry，EAI）进行的几种剂量测定表征，但尚未确定放射源剂量测定参数的AAPM共识值。这项工作的目的是执行一个额外的剂量率常数（λ）的测定，使用最近建立的光子光谱技术（PST），是独立于已公布的电子束和蒙特卡罗技术。方法采用IAPD-103 A型AdvantagePd-103放射源。使用为低能光子设计的高分辨率锗光谱仪测量由每个源沿着横轴发射的相对光子能谱。对于每个源，剂量率常数是从其发射的能谱确定的。PST确定的剂量率常数（PST λ），然后进行了比较，由ESTA（ESTA λ）和蒙特卡罗（MC λ）技术确定的。一个可能的共识λ值估计为平均λ值的算术平均值确定的三种不同的技术。结果发现三种优势源的平均PST λ值为（0.676 ± 0.001）。0.026）cGyh（-1）U（-1）。PST λ的源间变异小于0.01%。PST λ在PTRAN、EGSnrc和MCNP 5代码确定的报告MC λ值的2%以内。比报道的λ值低3.4%。一个可能的共识λ值估计为（0.688 +/- 0.026）cGyh（-1）U（-1），与目前推荐用于Theragenics的AAPM共识值相似（Buford，GA）200型（0.686 +/- 0.033）cGyh（-1）U（-1），NASI（查茨沃斯，CA）型号MED 3633（0.688 +/- 0.033）cGyh（-1）U（-1），以及Best Medical（Springfield，VA）型号2335（0.685 +/- 0.033）cGyh（-1）U（-1）103 Pd源。结论：对Advantage Pd-103源进行了独立的λ测定。在这项工作中获得的PST λ提供了额外的信息，需要建立一个更准确的共识λ值的优势Pd-103源。
PURPOSE Although several dosimetric characterizations using Monte Carlo simulation and thermoluminescent dosimetry (TLD) have been reported for the new Advantage Pd-103 source (IsoAid, LLC, Port Richey, FL), no AAPM consensus value has been established for the dosimetric parameters of the source. The aim of this work was to perform an additional dose-rate constant (lamda) determination using a recently established photon spectrometry technique (PST) that is independent of the published TLD and Monte Carlo techniques. METHODS Three Model IAPD-103A Advantage Pd-103 sources were used in this study. The relative photon energy spectrum emitted by each source along the transverse axis was measured using a high-resolution germanium spectrometer designed for low-energy photons. For each source, the dose-rate constant was determined from its emitted energy spectrum. The PST-determined dose-rate constant (PST lamda) was then compared to those determined by TLD (TLD lamda) and Monte Carlo (MC lamda) techniques. A likely consensus lamda value was estimated as the arithmetic mean of the average lamda values determined by each of three different techniques. RESULTS The average PST lamda value for the three Advantage sources was found to be (0.676 +.- 0.026) cGyh(-1) U(-1). Intersource variation in PST lamda was less than 0.01%. The PST lamda was within 2% of the reported MC lamda values determined by PTRAN, EGSnrc, and MCNP5 codes. It was 3.4% lower than the reported TLD lamda. A likely consensus lamda value was estimated to be (0.688 +/- 0.026) cGyh(-1) U(-1), similar to the AAPM consensus values recommended currently for the Theragenics (Buford, GA) Model 200 (0.686 +/- 0.033) cGyh(-1) U(-1), the NASI (Chatsworth, CA) Model MED3633 (0.688 +/- 0.033) cGyh(-1) U(-1), and the Best Medical (Springfield, VA) Model 2335 (0.685 +/- 0.033) cGyh(-1) U(-1) 103Pd sources. CONCLUSIONS An independent lamda determination has been performed for the Advantage Pd-103 source. The PST lamda obtained in this work provides additional information needed for establishing a more accurate consensus lamda value for the Advantage Pd-103 source.