Accurate gain control of PET detectors is a prerequisite for quantitative accuracy. A shift in the 511 keV peak position can lead to errors in scatter correction, degrading quantitation. The PET detectors in a PET/MR scanner are subject to thermal transients due to eddy currents induced during gradient-intensive MRI sequences. Since the gain of silicon photomultiplier-based detectors changes with temperature, good gain control is particularly challenging. In this paper we describe a method that utilizes information from the entire singles spectrum to create a real-time gain control method that maintains gain of PET detectors stable within approximately ±0.5% (±2.5 keV) with varying levels of scatter and in the presence of significant thermal transients. We describe the methods used to combine information about multiple peaks and how this algorithm is implemented in a way that permits real-time processing on a field-programmable gate array. Simulations demonstrate rapid response time and stability. A method (“virtual scatter filter”) is also described that extracts unscattered photopeak events from phantom data and demonstrates the accuracy of the photopeak for various radionuclides that emit energies in addition to the pure 511 keV annihilation peak. Radionuclides ⁵² Mn, ⁵⁵ Co, ⁶⁴ Cu, ⁸⁹ Zr, ⁹⁰ Y, and ¹²⁴ I are included in the study for their various forms of spectral contamination.

中文翻译：

---

PET检测器的实时增益控制和具有挑战性的放射性核素的评估。

PET检测器的精确增益控制是定量精度的前提。511 keV峰值位置的偏移会导致散射校正中的错误，从而降低定量。PET / MR扫描仪中的PET检测器会受到热瞬态的影响，这是由于在梯度密集型MRI序列中产生的涡流引起的。由于基于硅光电倍增管的检测器的增益随温度变化，因此良好的增益控制尤其具有挑战性。在本文中，我们描述了一种方法，该方法利用来自整个单光谱的信息来创建实时增益控制方法，该方法可以将PET检测器的增益稳定在大约±0.5％（±2.5 keV）的范围内，并且具有不同的散射水平和存在重大的热瞬变。我们描述了用于组合有关多个峰的信息的方法，以及如何以允许在现场可编程门阵列上进行实时处理的方式来实现此算法。仿真显示了快速的响应时间和稳定性。还描述了一种方法（“虚拟散射过滤器”），该方法从幻像数据中提取未散射的光峰事件，并证明了除纯511 keV peak灭峰外，各种发出能量的放射性核素的光峰的准确性。放射性核素 还描述了一种方法（“虚拟散射过滤器”），该方法从幻像数据中提取未散射的光峰事件，并证明了除纯511 keV peak灭峰外，各种发出能量的放射性核素的光峰的准确性。放射性核素 还描述了一种方法（“虚拟散射过滤器”），该方法从幻像数据中提取未散射的光峰事件，并证明了除纯511 keV peak灭峰外，各种发出能量的放射性核素的光峰的准确性。放射性核素本研究中包括⁵² Mn，⁵⁵ Co，⁶⁴ Cu，⁸⁹ Zr，⁹⁰ Y和¹²⁴ I，因为它们具有各种形式的光谱污染。