HUMAN ERRORS IN DATA TRANSFER DURING THE PREPARATION AND DELIVERY OF RADIATION TREATMENT AFFECTING THE FINAL RESULT - GARBAGE IN, GARBAGE OUT

Due to the large number of steps and the number of persons involved in the preparation of a radiation treatment, the transfer of information from one step to the next is a very critical point. Errors due to inadequate transfer of information will be reflected in every next step and can seriously affect the final result of the treatment. We studied the frequency and the sources of the transfer errors. A total number of 464 new treatments has been checked over a period of 9 months (January to October 1990). Erroneous data transfer has been detected in 139/24 128 (< 1%) of the transferred parameters; they affected 26% (119/464) of the checked treatments. Twenty-five of these deviations could have led to large geographical miss or important over- or underdosage (much more than 5%) of the organs in the irradiated volume, thus increasing the complications or decreasing the tumour control probability, if not corrected. Such major deviations, only occurring in 0.1% of the transferred parameters, affected 5% (25/464) of the new treatments. The sources of these large deviations were nearly always human mistakes, whereas a considerable number of the smaller deviations were, in fact, consciously taken decisions to deviate from the intended treatment. Nearly half of the major deviations were introduced during input of the data in the check-and-confirm system, demonstrating that a system aimed to prevent accidental errors, can lead to a considerable number of systematic errors if used as an uncontrolled set-up system. The results of this study show that human mistakes can seriously affect the outcome of patient treatments. Therefore, patient-related quality assurance procedures are highly recommended at the first treatment sessions to eliminate, at least, the systematic errors.