Radiation exposure in interventional procedures.

The aim of this study was to estimate radiation doses patients and staff are exposed to during interventional procedures (IPs), compare them with the international diagnostic reference levels and to develop initial National Diagnostic Reference Levels. The IP survey was undertaken as the initial task of which, retrospective data were collected from the only four Kenyan hospitals carrying out interventional radiology and cardiology procedures at the time of the study. Real-time measurement of radiation dose to patients and staff during these procedures was done. To the patients, kerma-area product (KAP) and fluoroscopy time measurements were done using an in-built KAP meter, while peak skin dose (PSD) was measured using slow Extended Dose Range (EDR2(®)) radiographic films. The staff occupational doses were measured using individual thermoluminescence dosemeters. The maximum and minimum KAP values were found to be 137.1 and 4.2 Gy cm(2), while the measured PSD values were 740 and 52 mGy, respectively. The fluoroscopic time range was between 3.3 and 70 min. The staff doses per procedure ranged between 0.05 and 1.41 mSv for medical doctors, 0.03 and 1.16 mSv for nurses, 0.04 and 0.78 mSv for radiographers and 0.04 and 0.88 mSv for clinical staff. The measured patient PSDs were within the threshold limit for skin injuries. However, with the current few IP specialists, an annual increase in workload as determined in the study will result in the International Commission on Radiation Protection annual eye lens dose limit being exceeded by 10 %. A concerted effort is required to contain these dose levels through use of protective gear, optimisation of practice and justification.

Optimisation of patient protection and image quality in diagnostic radiology.

OBJECTIVE: To determine the examination frequencies, quality of radiographic images and the entrance surface dose (ESD) in patients undergoing general radiographic examinations. DESIGN: Prospective study on the device performance, film reject rate, patient dose, and image quality during the use of standard and fast speed film screen combination. SETTING: Radiology Department of Kenyatta National Hospital, a referral, teaching and research hospital in Kenya. SUBJECTS: A total of 837 adult and 229 paediatric patients undergoing diagnostic examinations were assessed for patient dose and image quality. INTERVENTIONS: The X-ray tube output measurements and X-ray exposure parameters were determined. The patients ESD on standard 200 and fast 400 speed film screen combination was determined. The radiographic image quality was assessed. MAIN OUTCOME MEASURES: The findings were compared with the international diagnostic reference levels (DRL's) for determination of dose optimisation in diagnostic radiography. RESULTS: The relative frequency of examination was 80% and 20% for adults and paediatric patients respectively. The image quality improvement by 13% was achieved and patient dose reduction range of 31% to 77%. CONCLUSIONS: The patient dose reduction and image quality was achieved through a quantitative quality control (QC) assessment of processes involved in producing radiographs. The study leads to the introduction of the concept of plan- do-check-act on QC results and optimise with a view of patient dose reduction. The department appreciated the value of a quality assurance (QA) programme and continues to collect data for establishment of DRL's.