Cancer Staging and Assessment of Spread: PET/CT is successfully used in many cancer types to determine the extent of the disease (staging) after a cancer diagnosis. It especially guides the accurate planning of regional treatment approaches in patients with metastatic disease.

Determination of Treatment Strategy: PET/CT has the potential to change the treatment plan in approximately one-third of patients. This allows for a shift towards drug therapies instead of unnecessary major surgical interventions, while in some cases, by showing no spread in patients suspected of distant metastases, it enables the decision for surgical resection.

Early Assessment of Drug Treatment Response: Since cancer drugs can have serious side effects, it is critical to determine the efficacy of the correct drug early on. PET/CT provides early information on drug effectiveness after the first or second course of treatment, preventing unnecessary side effects and allowing ineffective treatments to be quickly changed to a more suitable one.

Monitoring Post-Treatment Response: PET/CT quantitatively assesses the response to cancer treatment based on both structural changes and levels of cellular metabolic activity. By detecting the presence of viable cancer cells after treatment is completed, treatment efficacy can be determined. This is the earliest imaging method to show response to treatment.

Radiotherapy Planning: In radiotherapy applications, PET/CT precisely maps areas containing viable tumor cells, ensuring that radiation is concentrated on the targeted regions. This increases treatment efficacy while protecting surrounding healthy tissues from radiation.

Early Diagnosis of Disease Recurrence: When suspicious findings are detected through methods like ultrasound, tomography, and blood tests during post-treatment follow-up, PET/CT is an effective method that can definitively determine whether viable cancer cells have recurred and their extent.