Pattern and experience with cancers treated with the Chinese GWGP80 cobalt unit at Mulago Hospital, Kampala

To review the pattern of cancers treated at Mulago hospital with the new Chinese GWGP80 Cobalt-60 unit and to analyse its breakdowns, downtime and attempts at repairs during its first two years of operation and to assess its reliability and safety.

A retrospective cross-sectional study.

This involved analysing data from the radiotherapy records book, the patient's case notes and a "fault's Log book" which was opened on the day the machine was commissioned. All causes of non-performance were documented in this book and an assessment of the severity of breakdowns, period of downtime and repairs carried out was done. Faults requiring only a few minutes maintenance work or non-performance due to general power failure were however excluded. All patients who had been treated earlier on the orthovoltage machine and were re-treated on the cobalt unit were also excluded from the analysis.

Department of Radiotherapy, Mulago Hospital, Kampala, Uganda.

One thousand and forty eight new patients were treated during this period. Three hundred and fifty nine were males and 689 were females. Cancer of the cervix was by far the commonest cancer seen (37.2%) followed by head and neck cancers (16.0%), breast cancers (13.8%) and Kaposi's sarcoma (10.5%). There were 47 machine faults. Most of these were relatively minor requiring only a few hours of maintenance work. Two of these faults were however major with downtime of more than a week. These were due to a failure of the "force back system" of the radioactive source necessitating it to be hammered back into the safe position.

The Chinese GWGP80 Cobalt unit has effectively treated a large number of cancer patients but the failures of the "force back system" of its radioactive source compromise its radiation safety and ideally would require a change in the engineering design to decrease on the associated radiation hazards.