Cardiovascular Journal of Africa: Vol 32 No 5 (SEPTEMBER/OCTOBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 5, September/October 2021 274 AFRICA that was consistently worn throughout all the procedures. No staff member could give an estimation of the doses he/she had received in the past. Most staff (91%) wore the dosimeter under the apron, either in the scrubs pocket or hanging at pelvis level. Discussion The floor nurse’s duties were executed at approximately 3 m from the tube (Table 3), and therefore the dosimeter readings for the floor nurse were reported as zero. The cardiologist and nurse, as a rule closest to the patient, received doses to the eye, thyroid, hands and feet, with the highest dose to the feet. This could be attributed to the absence of table screens. The nurse received higher dose readings than the cardiologist, except for the hand. The dose recorded to the thyroid of the cardiologist, nurse and radiographer was noteworthy, since all were consistently wearing the dosimeter underneath the thyroid shield. The thyroid shield could be experienced as too tight, especially during long cases or long theatre lists, during which staff tended to loosen the shield. Although the doses were low, one could argue that even if 100 procedures were done, the accumulative dose would never reach the annual limit of 20 mSv. Nevertheless, radiation exposure should adhere to the ALARA principle because there is no threshold for the occurrence of the stochastic effect of ionising radiation. The distance of the radiographer’s feet from the X-ray tube was 150 cm in most cases. The cardiologist and nurse, however, had a mean distance of 59.7 and 58.5 cm, respectively. The foot pedal was closer than 15 cm to the X-ray tube in 90% of the procedures. When the cardiologist used the foot pedal, he/she was near the tube, with a mean distance of 6.5 cm. In most cases, the radiographer was further from the X-ray tube. The foot pedal can be moved to double the distance, while the cardiologist will still maintain comfortable access to the catheter insertion area. Another option is to let the radiographer use the foot pedal at a further distance from the X-ray tube to exercise the habit of increasing the distance from the source. The cardiologist’s hand was never in the beam, and yet doses to the hands were recorded for all staff. This could be because no ceiling-suspended screens were used. During the mechanical injection of contrast media, the acquisition of images is linked to higher doses, and the cardiologist and nurse can move slightly further from the patient and X-ray source. Other observers should be informed to step away because the dose is higher than during fluoroscopy. The elbow in the beam was observed when the cardiologist either concentrated to place the tip of the catheter or when applying force to inject the contrast media manually. Closing the theatre door is a team responsibility that can become a habit in order to comply with the principle to keep unauthorised persons out of the room. The constant movement of the nurse and cardiologist around the table made it impractical to measure one exact distance from the patient or X-ray tube. Throughout the data collection, the researcher measured the distance as soon as the first run of acquiring images commenced, in the sequence of cardiologist, radiographer, scrub nurse and then the floor nurse. The fluoroscopy time ranged from 0.24 to 25.53 minutes, depending on the complexity of the procedure. Due to the difference in procedures, the fluoroscopy times are not compared to other studies but noted as a reference for future procedures for this site. The operator of the foot pedal can optimise radiation time by making use of intermittent screening and avoid continuous fluoroscopy by giving preference to pulsed fluoroscopy, selecting the lowest possible fluoroscopy dose. A reduction of 67% in radiation exposure is possible by lowering the fluoroscopic pulse rate from 15 to 7.5 f/s. 21 It is important that the recommended table screens and ceiling-suspended screens are acquired and used. A re-audit could then investigate its effectiveness. No doses were recorded for the floor nurses, but it was observed that most wore a lead apron that was open at the back. This could be problematic when the nurse performs tasks with the back towards the X-ray source and the dosimeter is therefore not between the operator and the X-ray source. During the procedure, the researcher had to ascertain that the foot dosimeters stayed in place. On two occasions the foot dosimeters were seen next to the shoe of the wearer, on the floor, and had to be re-attached. The type of plaster was changed to ensure that the meters stayed in place for the entire procedure. The hand dosimeters were successfully attached with a sheet of Tegaderm so that the nurse and the cardiologist could scrub. The sterile glove was then used over the Tegaderm so as not to compromise the normal sterility protocol. All radiation workers at this site were issued with one dosimeter and its consistent wearing was commendable. No staff member had an idea of the doses they had received in the past. By providing the staff with dosimeters and consequently creating awareness of radiation exposure could improve the radiation safety culture. The recommendation from the South African Department of Health is to wear the dosimeter outside the lead apron at the collar level when no eye protection is worn. Technically, only the cardiologist with lead eye glasses may wear the dosimeter underneath the lead apron. 22 Radiographers and nurses are supposed to wear the dosimeters above the lead apron at the collar level. The ICRP recommends that two personal dosimeters are used for occupational dose monitoring, one inside the chest of the apron and the other outside the apron at the level of the collar. 16 When only one dosimeter is available, it must be worn outside on the collar at all times. The dosimeter outside the apron estimates the dose to the unshielded parts of the body. A personal dosimeter worn outside a protective apron is a good screening device for doses to the eyes and fingers, as well as for effective dose, even though the effective dose is grossly overestimated. Relatively high doses to the fingers and eyes remain undetected by a dosimeter worn underneath the apron. 23 Consistent monitoring of the eye dose remains a challenge (due to availability and hindrance of vision) and could be more reliable for shorter periods of time. The main consideration is that quality control should ensure that screens and lead glasses are used. 8 A study by Bordy concluded that it is impossible to accurately rely on the results of whole-body dosimeters to estimate the eye lens exposure. 24 Although research programmes should pursue the development of computational technologies (not requiring dosimeters) with personnel position sensing to assess personnel doses, including eye doses, the finger meters ordered from the SABS seemed to be a practical solution. 8 The measurements may