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Thoracic tumors are a leading cause of cancer-related morbidity and mortality. In recent years, developments in oncologic treatments for these tumors have ushered in an era of targeted therapy, and, in many cases, these novel treatments have replaced conventional strategies to become standard therapeutic options, particularly in those with lung cancer. Targeted medical therapies for lung cancer now include angiogenesis inhibitors, tyrosine kinase inhibitors, and immunotherapeutic agents. Several novel ablative therapies have also gained widespread acceptance as alternatives to conventional surgical options in appropriately selected patients. Tumors treated with targeted medical therapies can respond to treatment differently when compared with conventional therapies. For example, pseudoprogression is a well-described phenomenon in patients receiving checkpoint inhibitor immunotherapy in which an initial increase in tumor burden is followed by a decrease in tumor burden and sometimes partial or complete response, while the frequent cavitating responses seen when antiangiogenic agents are used can be difficult to quantify using existing response assessment criteria. In some cases, novel response assessment criteria are needed to adequately capture response. In addition, numerous treatment-related side effects have been described, which are important to recognize, both to ensure appropriate treatment and to avoid misclassification as worsening tumor. Imaging plays a vital role in the assessment of patients receiving targeted medical therapy, and it is essential that thoracic radiologists are familiar with the rationale underpinning these treatments and the expected posttherapy findings.

Background: Animals exposed to sevoflurane during development sustain neuronal cell death in their developing brains. In vivo micro-positron emission tomography (PET)/computed tomography imaging has been utilized as a minimally invasive method to detect anesthetic-induced neuronal adverse effects in animal studies., Methods: Neonatal rhesus monkeys (postnatal day 5 or 6, 3 to 6 per group) were exposed for 8 h to 2.5% sevoflurane with or without acetyl-L-carnitine (ALC). Control monkeys were exposed to room air with or without ALC. Physiologic status was monitored throughout exposures. Depth of anesthesia was monitored using quantitative electroencephalography. After the exposure, microPET/computed tomography scans using F-labeled fluoroethoxybenzyl-N-(4-phenoxypyridin-3-yl) acetamide (FEPPA) were performed repeatedly on day 1, 1 and 3 weeks, and 2 and 6 months after exposure., Results: Critical physiologic metrics in neonatal monkeys remained within the normal range during anesthetic exposures. The uptake of [F]-FEPPA in the frontal and temporal lobes was increased significantly 1 day or 1 week after exposure, respectively. Analyses of microPET images recorded 1 day after exposure showed that sevoflurane exposure increased [F]-FEPPA uptake in the frontal lobe from 0.927 ± 0.04 to 1.146 ± 0.04, and in the temporal lobe from 0.859 ± 0.05 to 1.046 ± 0.04 (mean ± SE, P < 0.05). Coadministration of ALC effectively blocked the increase in FEPPA uptake. Sevoflurane-induced adverse effects were confirmed by histopathologic evidence as well., Conclusions: Sevoflurane-induced general anesthesia during development increases glial activation, which may serve as a surrogate for neurotoxicity in the nonhuman primate brain. ALC is a potential protective agent against some of the adverse effects associated with such exposures.