Investigation of the Occurrence of Human Errors in Treatment of Cancer Patients with External Beam Radiotherapy

The main objective of clinical radiotherapy procedures is to deliver accurate doses to cancer patients. However, human errors can occur during the treatment planning and dose delivery that may result in under- or overexposure to the patient. Therefore the aim of the present study was to detect and quantify different types of errors that may occur during radiation treatment at the Nuclear Medicine, Oncology and Radiotherapy Institute (NORI) in Islamabad, Pakistan. In this context, systematic studies were carried out over an 18-month period at NORI, for which 800 patients were selected. Eight different types of human errors were detected and corrected before or during the first five radiation therapy fractions. Errors detected during the dose calculation and patient setup steps were ∼22% and ∼14% of the total incidents, respectively. Wedge/shielding blocks placement and field size settings-related errors were ∼10% and 19%, whereas source-surface distance/source-axis distance settings-related errors were ∼8%. Errors observed during treatment time/monitor unit, gantry/collimator angle settings, and counting fraction were about 7%, 9%, and 11%, respectively. Of the 105 errors detected, 28 were major errors (deviation from the prescribed daily dose ≥5%) and 77 were minor errors. The occurrence of minor and major error rates were 9.6% and 3.5%, respectively.