CT Scan

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

1. Diagnosis / Detection
   • Identifies primary tumors and suspicious lesions.
   • Often first-line imaging for many solid tumors.
2. Staging
   • Assesses local invasion, lymph node involvement, and distant metastases.
   • Helps determine treatment eligibility (surgery, chemotherapy, radiation).
3. Treatment Planning
   • Guides surgical resection or radiotherapy target volumes.
   • Baseline imaging before systemic therapy initiation.
4. Response Assessment
   • Measures tumor response to chemotherapy, targeted therapy, or immunotherapy.
   • Uses RECIST criteria (Response Evaluation Criteria in Solid Tumors).
5. 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.