Prospective study of elective bilateral versus unilateral femoral arterial puncture for uterine artery embolization.

The purpose of this study was to assess the effect of elective bilateral femoral arterial punctures for uterine artery embolization (UAE) of symptomatic fibroids on fluoroscopy and procedural time, patient dose, and ease of procedure. We conducted a prospective study of UAE with either the intention to catheterize both uterine arteries using a single femoral puncture (n = 12) or elective bilateral arterial punctures from the outset (n = 12). The same two operators undertook each case. Main outcome measures were total procedure time, fluoroscopy time, dose-area product (DAP), and total skin dose. A simulation was then performed on an anthropomorphic phantom using the mean in vivo fluoroscopy parameters to estimate the ovarian dose. Bilateral UAE was achieved in all patients. None of the patients with initial unilateral arterial puncture required further contralateral arterial puncture. The mean fluoroscopy time in the group with elective bilateral punctures was 12.8 min, compared with a mean of 16.6 min in patients with unilateral puncture (p = 0.046). There was no significant difference in overall procedure time (p = 0.68). No puncture-site complications were found. Additional catheters were required only following unilateral puncture. The simulated dose was 25% higher with unilateral puncture. Although there was no significant difference in measured in vivo patient dose between the two groups (DAP, p = 0.32), this is likely to reflect the wide variation in other patient characteristics. Allowing for the small study size, our results show that the use of elective bilateral arterial punctures reduces fluoroscopy time, requires less catheter manipulation, and, according to the simulation model, has the potential to reduce patient dose. The overall procedure time, however, is not significantly reduced.

Key factors in the optimization of paediatric X-ray practice.

Justification of radiological requests, standardization of procedures and optimization of protection measures are key principles in the protection of individuals exposed to ionizing radiation for diagnostic purposes. Nowhere is this more pertinent than in the imaging of children and, following the recent introduction of the Ionising Radiation (Medical Exposure) Regulations, there is now a regulatory requirement for diagnostic radiology departments to demonstrate compliance with these principles. A study was undertaken to compare all aspects of paediatric radiological practice at two specialist and two non-specialist centres. An initial study involved analysis of nearly 3000 patient doses. The second phase of the project involved assessment of referral criteria, radiographic technique and approximately 100 radiographs at each centre by two consultant paediatric radiologists. While all radiographs were found to be diagnostically acceptable, major differences in technique were evident, reflecting the disparity in experience between staff at the specialist and non-specialist centres. The large number of sub-optimum films encountered at the latter suggests that there is a need for specific training of less experienced radiographic and clinical staff.

Rotational digital subtraction angiography of the renal arteries: technique and evaluation in the study of native and transplant renal arteries.

Rotational digital subtraction angiography (RDSA) allows multidirectional angiographic acquisitions with a single injection of contrast medium. The role of RDSA was evaluated in 60 patients referred over a 7-month period for diagnostic renal angiography and 12 patients referred for renal transplant studies. All angiograms were assessed for their diagnostic value, the presence of anomalies and the quantity of contrast medium used. The effective dose for native renal RDSA was determined. 41 (68.3%) native renal RDSA images and 8 (66.7%) transplant renal RDSA images were of diagnostic quality. Multiple renal arteries were identified in 9/41 (22%) native renal RDSA diagnostic images. The mean volume of contrast medium in the RDSA runs was 51.2 ml and 50 ml for native and transplant renal studies, respectively. The mean effective dose for 120 degrees native renal RDSA was 2.36 mSv, equivalent to 1 year's mean background radiation. Those RDSA images that were non-diagnostic allowed accurate prediction of the optimal angle for further static angiographic series, which is of great value in transplant renal vessels.

Radiation protection in interventional radiology.

There is growing concern regarding the radiation dose delivered during interventional procedures, particularly in view of the increasing frequency and complexity of these techniques. This paper reviews the radiation dose levels currently encountered in interventional procedures, the consequent risks to operators and patients and the dose reduction that may be achieved by employing a rigorous approach to radiation protection.

Effective dose at pneumatic reduction of paediatric intussusception.

AIM: The purpose of this study was to assess screening times and resulting dose implication at pneumatic reduction of intussusception in the paediatric age group and to examine the relationship with the outcome of the procedure. MATERIALS AND METHODS: We retrospectively reviewed the case notes and departmental records of 143 children who had undergone a total of 153 pneumatic reductions in our department over a 4-year period. Success rates, screening times and available dose-area products (DAP) were recorded. The DAPs were converted to effective dose (ED) for 77 procedures. RESULTS: A 76.5% (117/153) success rate was achieved with a recurrence rate of 6.5% and only one complication: a perforation. Screening times were recorded in 137 reductions and ranged from 15 s to 22.6 min. Although the longest screening time was associated with an unsuccessful outcome, the second longest time of 21 min was successful. This gave a DAP of 1278 cGy cm(2)and an ED of 12.73 mSv, which is equivalent to approximately 400 abdominal films for a 1-year-old. A lifetime risk of fatal cancer of one in 1000 was achieved, assuming the worst case, after a screening time of 30 min on our conventional fluoroscopy unit. CONCLUSION: Our success rate compares well with other centres. Our institution is a tertiary referral centre and the occasional long screening time may reflect the delay and complex nature of the patients referred. Persistence at air reduction may be successful and the success rate increases with delayed attempts but the risks of the increasing radiation burden must be weighed against the risks of emergency surgery and anaesthesia.Heenan, S. D. (2000). Clinical Radiology 55, 811-816.

A comparison of doses and techniques between specialist and non-specialist centres in the diagnostic X-ray imaging of children.

A dosimetric survey of 14 routine X-ray examinations in children was carried out between 1993 and 1995. Two children's hospitals and four general hospitals took part in the survey which involved the calculation and measurement of nearly 3000 doses. Entrance surface doses (ESD) were calculated from exposure factors for radiographic procedures, and dose-area products (DAP) were recorded for both radiographic and fluoroscopic procedures. Doses were in good agreement with earlier studies, but for some procedures were significantly lower than those reported from other European countries. The main dose influencing factors for radiographic procedures were found to be the speed of the film-screen system and the use of an antiscatter grid. For the main head/trunk examinations, specialist centres often delivered higher doses to the younger children as a result of widespread use of a grid. In fluoroscopy, where the main dose influencing factors were the use of a grid and the dose rate dependence of the image intensifier, the children's hospitals consistently delivered significantly lower doses. Both ESDs and DAPs were found to increase with patient age for the main head/trunk examinations, although in some cases (AP/PA chest) this relationship was weak. The dependence of dose on age necessitates the subdivision of the paediatric sample into a number of age categories. It is suggested that all authors use the same age groupings.