Ahmadi Ganjeh Zahra, Zapien-Campos Brian, Traneus Erik, Both Stefan, Dendooven Peter
Particle Therapy Research Center (PARTREC), Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
RaySearch Laboratories AB, Stockholm, Sweden.
Phys Med Biol. 2024 Sep 27;69(19). doi: 10.1088/1361-6560/ad7d5c.
.N, having a half-life of 11 ms, is a highly effective positron emitter that can potentially provide near real-time feedback in proton therapy. There is currently no framework for comparing and validating positron emission imaging ofN. This work describes the development and validation of a Monte Carlo (MC) framework to calculate the images ofN, as well as long-lived isotopes, originating from activation by protons.. The available dual-panel Biograph mCT PET scanner was modeled in GATE and validated by comparing the simulated sensitivity map with the measured one. The distributions ofN and long-lived isotopes were calculated by RayStation and used as the input of GATE simulations. The RayStation/GATE combination was verified using proton beam irradiations of homogeneous phantoms. A 120 MeV pulsed pencil beam with 10protons per pulse was used. Two-dimensional images were created from the GATE output and compared with the images based on the measurements and the 1D longitudinal projection of the full 2D image was used to calculate theN activity range.. The simulated sensitivity in the center of the FoV (5.44%) agrees well with the measured one (5.41%). The simulated and measured 2D sensitivity maps agree in good detail. The relative difference between the measured and simulated positron activity range for bothN and long-lived isotopes is less than 1%. The broadening of theN images relative to those of the longer-lived isotopes can be understood in terms of the large positron range ofN.. We developed and validated a MC framework based on RayStation/GATE to support the in-beam PET method for quality assurance of proton therapy. The inclusion of the very short-lived isotopeN makes the framework useful for developing near real-time verification. This represents a significant step towards translatingN real-time in vivo verification to the clinic.
半衰期为11毫秒的氮-13是一种高效正电子发射体，有可能在质子治疗中提供近实时反馈。目前没有用于比较和验证氮-13正电子发射成像的框架。这项工作描述了一个蒙特卡罗（MC）框架的开发和验证，该框架用于计算源自质子活化的氮-13以及长寿命同位素的图像。现有的双面板Biograph mCT PET扫描仪在GATE中进行了建模，并通过将模拟灵敏度图与测量灵敏度图进行比较进行了验证。氮-13和长寿命同位素的分布由RayStation计算，并用作GATE模拟的输入。RayStation/GATE组合通过均匀体模的质子束照射进行了验证。使用了每脉冲10个质子的120 MeV脉冲笔形束。从GATE输出创建二维图像，并与基于测量的图像进行比较，使用完整二维图像的一维纵向投影来计算氮-13活度范围。视野中心的模拟灵敏度（5.44%）与测量灵敏度（5.41%）吻合良好。模拟和测量的二维灵敏度图在细节上吻合良好。氮-13和长寿命同位素的测量和模拟正电子活度范围之间的相对差异小于1%。相对于长寿命同位素，氮-13图像的展宽可以根据氮-13较大的正电子射程来理解。我们开发并验证了一个基于RayStation/GATE的MC框架，以支持用于质子治疗质量保证的束内PET方法。包含极短寿命的同位素氮-13使该框架有助于开发近实时验证。这代表了将氮-13实时体内验证转化为临床应用的重要一步。
