Rhodes C G, Hughes J M
MRC Cyclotron Unit, Hammersmith Hospital, London, UK.
Eur Respir J. 1995 Jun;8(6):1001-17.
The detailed investigation of regional differences in lung function at a local level began when suitable gamma-ray emitting isotopes and focused external radiation detectors (especially the Anger gamma-camera) became available. A major recent advance has been the development of positron emission tomography (PET), which provides a powerful combination of highly accurate tomographic reconstruction of radioisotope concentration with a potentially unlimited list of biological compounds to be labelled with the positron emitting isotopes of oxygen, carbon and fluorine. Early studies using PET focused on the inhalation of 11CO (or C15O) and 19Ne gases and the intravenous injection of 13N in saline and H215O for the measurement of relatively simple aspects of regional lung function, such as tissue, blood and gas volumes, blood flow, ventilation and ventilation/perfusion (V'A/Q'). More recent work has been directed towards the more challenging areas of regional endothelial permeability, carbohydrate utilization, enzyme and receptor binding assays, and in vivo pharmacokinetics. The short physical half-lives of the isotopes (17 s to 2 h) and the noninvasive nature of PET allows serial measurements to be made on patients (within the constraints of permitted radiation doses) to assess the effect of physiological and therapeutic interventions.
当合适的发射伽马射线的同位素和聚焦外部辐射探测器（特别是安格伽马相机）问世后，对局部肺功能区域差异的详细研究便开始了。近期的一项重大进展是正电子发射断层扫描（PET）技术的发展，它将放射性同位素浓度的高精度断层重建与一系列可用氧、碳和氟的正电子发射同位素标记的生物化合物相结合，具有强大的功能。早期使用PET的研究集中于吸入11CO（或C15O）和19Ne气体，以及静脉注射盐水中的13N和H215O，以测量区域肺功能的相对简单方面，如组织、血液和气体容量、血流、通气和通气/灌注（V'A/Q'）。最近的工作则针对区域内皮通透性、碳水化合物利用、酶和受体结合测定以及体内药代动力学等更具挑战性的领域。这些同位素的物理半衰期较短（17秒至2小时），且PET具有非侵入性，这使得能够在患者身上进行系列测量（在允许的辐射剂量范围内），以评估生理和治疗干预的效果。
