Increasing radiation exposure by medical examinations is getting more concerns. For optimal medical imaging, reducing radiation exposure with preservation image quality is important. One of the solutions is use of iterative recontruction of CT examination. In this study, the investigators aimed to investigate the clinical feasibility of ultralow dose abdominopelvic CT with iterative reconstruction in patients with intraabdominal abscess. Patients with intrabdominal abscess usually undergo multiple CT examinations to evaluate treatment response. Therefore, ultralow dose CT can reduce unnecessary radiation exposure in these patients.

Inclusion Criteria:

1. patients who underwent standard dose CT for suspected intraabdominal abscess
2. patients who need follow-up CT to evaluate treatment response of abscess 3) Adult patient, 4) patients who agreed this study protocol

Exclusion Criteria:

1. pregnancy
2. patients with poor renal function (GFR < 30 mL/min/1/73m2)
3. Patients who have allergy to CT contrast media
4. Patients who are not cooperative (e.g., dementia)

Patients with suspected abdominal abscess from a tertiary care clinic.