Short-lived positron emitters in beam-on PET imaging during proton therapy
Short-lived positron emitters in beam-on PET imaging during proton therapy
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DOI：
10.1088/0031-9155/60/23/8923
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发表时间：
2015-12-07
影响因子：
3.5
通讯作者：
Brandenburg, S.
中科院分区：
文献类型：
--
作者：
Dendooven, P.;Buitenhuis, H. J. T.;Brandenburg, S.
目前临床使用的质子束放射治疗体内剂量输送验证的唯一方法是对患者在照射过程中产生的正电子发射体进行正电子发射断层扫描 (PET)。光束打开时的 PET 成像（所谓的光束 PET）是一种有吸引力的选择，可提供最大数量的计数、最少的生物冲刷和最快的反馈。在此实施中，所有核素，无论其半衰期如何，都将做出贡献。作为评估短寿命核素（半衰期短于 C-10，T-1/2 = 19 s）与使用射束 PET 进行体内剂量输送验证的相关性的第一步，我们测量了它们在水、碳、磷和钙中停止 55 MeV 质子时的产生量。产生最多的短寿命核素及其相对于相关长寿命核素的生产率为： N-12 (T-1/2 = 11 ms) 对碳（C-11 的 9%）、P-29 (T-1/2 = 4.1 s) 对磷（20% P-30）和 K-38m (T-1/2 = 0.92 s) 对钙（K-38g 的 113%）。氧气不会产生短寿命核素。在 PMMA 和 4 种组织材料的照射过程中，从照射开始积分的衰减数作为时间的函数已被确定。对于（富含碳的）脂肪组织，N-12 占主导地位长达 70 秒。在骨组织中，在前 8-15 秒内，N-12 优于 O-15（取决于碳氧比）。在 70 秒的照射过程中，磷和钙产生的短寿命核素提供的光束 PET 计数是这些元素产生的长寿命核素的 2.5 倍。根据 N-12 PET 计数的估计数量，我们得出结论，对于任何组织，与使用优化的刀口狭缝相机进行即时伽玛成像相比，N-12 PET 成像可能提供相同或更好的质子范围信息。讨论了 N-12 PET 成像的实际实施。
The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of C-10, T-1/2 = 19 s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: N-12 (T-1/2 = 11 ms) on carbon (9% of C-11), P-29 (T-1/2 = 4.1 s) on phosphorus (20% of P-30) and K-38m (T-1/2 = 0.92 s) on calcium (113% of K-38g). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, N-12 dominates up to 70 s. On bone tissue, N-12 dominates over O-15 during the first 8-15 s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70 s irradiation. From the estimated number of N-12 PET counts, we conclude that, for any tissue, N-12 PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of N-12 PET imaging is discussed.