Definition
- Computed Tomography (CT) is an imaging technique that uses X-rays and computer processing to create cross-sectional images of the body.
- Provides detailed information about tumor size, location, and involvement of surrounding structures.
Clinical Uses in Oncology
- Diagnosis / Detection
- Staging
- Assesses local invasion, lymph node involvement, and distant metastases.
- Helps determine treatment eligibility (surgery, chemotherapy, radiation).
- Treatment Planning
- Guides surgical resection or radiotherapy target volumes.
- Baseline imaging before systemic therapy initiation.
- Response Assessment
- Measures tumor response to chemotherapy, targeted therapy, or immunotherapy.
- Uses RECIST criteria (Response Evaluation Criteria in Solid Tumors).
- Surveillance / Recurrence Detection
- Post-treatment imaging for early detection of recurrence.
Pharmacist Considerations
- Contrast agents:
- Iodinated IV contrast improves visualization of vasculature and lesions.
- Caution: nephrotoxicity risk in patients with renal impairment.
- Hydration often required with high-risk patients.
- Monitor for allergic reactions (pre-medication in patients with contrast allergy).
- Radiation exposure: Cumulative exposure is a concern in long-term surveillance.
- Drug timing / interference: Certain drugs (e.g., metformin) require temporary discontinuation around contrast administration due to risk of lactic acidosis.
- Interpretation context: Changes in tumor density or cavitation can occur with targeted therapy or immunotherapy, not always representing progression.
Summary
CT scan in oncology is a key imaging tool for diagnosis, staging, treatment planning, response assessment, and surveillance. Pharmacists focus on contrast safety, renal function monitoring, drug interactions, and patient counseling on procedure-related risks.