Positron emission tomography/computed tomography (PET/CT) is a cornerstone of oncologic imaging, but two concerns persist: whether diagnostic ionizing radiation could perturb tumor dormancy and whether cumulative exposure poses a meaningful stochastic risk. Infrared thermography (IRT) has also re-emerged as a potential radiation-free adjunct. This perspective article incorporates a narrative literature review. A structured PubMed search was performed using combinations of terms including PET/CT, tumor dormancy, low-dose radiation, DNA damage, angiogenesis, epidemiological risk, and IRT. Approximately 110 records were screened by title and abstract, and 68 full-text articles were reviewed. Studies were selected based on relevance to oncologic imaging, low-dose radiation biology, and translational applicability. No formal systematic review protocol or meta-analysis was applied because of heterogeneity in study design, populations, and outcomes. Experimental studies suggest that sub-Gray exposures may promote angiogenesis and dormant-to-active tumor transition; however, murine models indicate that PET-equivalent doses (~10 mGy) do not increase cancer incidence. PET/CT can induce measurable DNA damage markers, but substantial repair occurs within 24 h. Epidemiological data suggest that cumulative lymphoma surveillance exposure (~80–100 mSv) confers an incremental lifetime risk of ~0.5%, mainly from CT. IRT correlates with PET in brown adipose tissue assessment and may assist superficial tumor monitoring, but its diagnostic accuracy is lower than that of PET/CT or mammography. Overall, optimized PET/CT remains clinically indispensable, whereas artificial intelligence-enabled PET/CT–IRT integration may help guide scan timing and reduce cumulative radiation exposure.