Monitoring for therapeutic effect after the initiation of dietary and/or pharmacological therapies for stone prevention allows clinicians to confirm that the therapies are achieving their intended effects, make dietary adjustments, or titrate dosing, frequency, or route of administration for medications. While the specific frequency of surveillance testing has not been established, the Panel recommends repeat metabolic testing within 3-6 months of initiating or modifying dietary and/or pharmacological therapy and repeat imaging every 6-12 months initially to assess for radiographic stone recurrence. Repeat testing to assess metabolic effect can guide additional dietary modification and/or medication dose titration. Testing intervals may be adjusted based on clinicians’ risk assessment and extended once stability is achieved. Patients with kidney stones should undergo periodic surveillance imaging, with the frequency and modality individualized according to patient-specific risk factors, stone characteristics, and clinical status. Shared decision-making is essential when developing an imaging plan, balancing the potential risks of radiation exposure and the benefits of detecting clinically meaningful stone activity, including growth of existing stones and formation of new stones. Available evidence demonstrates that asymptomatic stones frequently exhibit progression over time. A recent meta-analysis of 6 studies evaluating the natural history of asymptomatic renal stones in adults reported a pooled stone growth rate of 25% over a mean follow-up of approximately 43 months.242 These data underscore the importance of ongoing monitoring even in patients without symptoms. There is no universally accepted schedule for imaging surveillance because of the marked heterogeneity of stone disease and the absence of comparative studies on specific follow-up regimens. For patients in whom the aggressiveness of disease is not yet established, a shorter initial interval of 3-6 months is reasonable to assess early growth and recurrence. For clinically stable patients, a one-year imaging interval is generally appropriate and may be lengthened or shortened based on stone activity and additional indicators of risk, such as metabolic abnormalities, genetic conditions, or concerning laboratory findings. In patients with prolonged stability, surveillance may be transitioned to primary care and/or nephrology with re-referral to urology if recurrence is identified. Choice of imaging modality should reflect both diagnostic goals and patient safety. CT is widely available and provides the greatest diagnostic detail for kidney stones among imaging modalities. When obtaining a CT to assess stone recurrence, the Panel supports the routine use of low-dose CT protocols, which reduce exposure to ionizing radiation.243, 244 CT may also be prioritized in patients with morbid obesity (BMI >35), large body habitus, complex patient anatomy or stone burden limiting the diagnostic effectiveness of other modalities, or when surgical intervention is planned. Plain abdominal radiography is appropriate for adults with radiopaque stones because it is readily available and associated with minimal radiation exposure. Renal ultrasound is preferred for children, pregnant women, patients with substantial prior radiation exposure, and those with radiolucent stones.