Survey of UK imaging practice for the investigation of pulmonary embolism in pregnancy.

AIM: To determine the utilisation of computed tomography pulmonary angiography (CTPA) and lung scintigraphy in the UK, and to assess their diagnostic qualities in the investigation of suspected pulmonary embolism (PE) in pregnancy. MATERIALS AND METHODS: Data were collected via electronic questionnaire in the UK from 24 sites. Data on the choice of imaging technique, radiation dose, technical adequacy, weeks' gestation, presenting symptoms, and further management of patients with indeterminate imaging were collected. RESULTS: The sample represented a population of 15.5 million and showed wide variation in the probability of investigation of suspected PE with rates per live birth of 0.06-2.2%. Nine hundred and ninety-one patients were imaged and there were 48 positive scans, an incidence of 0.038%. Of the 269 CTPAs performed, 5.9% were positive, 8.9% were technically inadequate. Of the 769 scintigraphy scans performed, 3.8% were positive and 9.1% were indeterminate; 63% of positive scans were in the third trimester. Most inadequate/indeterminate scans were in the third trimester. The calculated typical radiation dose to the breast and fetus from CTPA ranged from 14 to 2 mGy and 0.02 to 0.002mGy, respectively, and approximately 0.28 and 0.2 mGy, respectively, from scintigraphy. CONCLUSION: The incidence of PE in this population was extremely low and the number of indeterminate or inadequate scans was comparable. This suggests choice of imaging should be made based upon availability and radiation exposure.

Imaging the neonate in the incubator: an investigation of the technical, radiological and nursing issues.

Modern neonatal incubators incorporate an X-ray tray device into the mattress support structure to facilitate patient examination with minimal disturbance and distress. However, the usual method of examination is to place the image plate directly underneath the baby. Users often cite radiological reasons for not using X-ray trays but modern quantitative evidence is lacking. This work looks at the technical and clinical aspects of imaging neonates in incubators and the impact that these may have in determining the imaging protocol. A number of hospitals were surveyed to determine their current method of examination and the reasons for their preference. Experimental measurements of the radiological impact of using (or not using) the X-ray tray were performed for a range of neonatal incubators. The average dose to the image plate was 5.9 microGy (range 5.4-6.4 microGy) for the "plate on mattress" method and 3.0 microGy (2.0-3.8 microGy) when using the tray--a 49% reduction owing to the mattress support materials. However, when using a computed radiography (CR) imaging system, the image quality differences were marginal. Survey results indicated that nurses preferred to use the tray but that radiographers were reluctant. We conclude that incubator manufacturers could do much to improve the radiological performance of their equipment and we offer recommendations. We also conclude that, with appropriate nurse and radiographer training and the advent of CR imaging systems, use of X-ray tray facilities may optimize imaging of the neonate in the incubator.

Radiation exposure and the urologist: what are the risks?

PURPOSE: Endourology is established in urology practice with routine use of fluoroscopic guidance. Medical personnel are rarely exposed to direct radiation exposure but secondary exposure occurs via radiation scatter. There are few reports on scatter radiation exposure and the subsequent risk to medical personnel involved in urological fluoroscopic procedures. We review the risks of scatter radiation exposure to medical personnel with reference to the routine use of fluoroscopic imaging in urological practice. MATERIALS AND METHODS: We measured staff radiation exposure during a series of ureteral endourological procedures using LiF:Mg,Ti thermoluminescent dosimeters placed at the extremities of the operating surgeon, the assistant and the scrub nurse. Doses for percutaneous nephrolithotomy (PCNL) procedures were calculated by extrapolating from the ureteral procedure thermoluminescent dosimeter data. Theoretical scattered radiation dose rates were also calculated. RESULTS: The average ureteral procedure fluoroscopy time was 78 seconds with an exposure rate of 71 kV, 2.4 mA. The surgeon received the highest radiation exposure with the lower leg (11.6 +/- 2.7 microGy) and foot (6.4 +/- 1.8 microGy) receiving more radiation than the eyes (1.9 +/- 0.5 microGy) and hands (2.7 +/- 0.7 microGy). For a predicted annual caseload of 50 ureteral cases, the dose received does not exceed 0.12% of the Ionising Radiations Regulations 1999 annual dose limit for adult workers. Radiation exposure during PCNLs is higher but does not exceed 2% of the annual dose limits even if 50 PCNLs are performed annually. CONCLUSIONS: Fluoroscopic screening results in radiation exposure of medical personnel. The estimate of maximum scatter radiation exposure to the surgeon for 50 PCNL procedures a year did not exceed 10 mGy. This amount is less than 2% of permissible annual limits of equivalent dose to the extremities. Medical personnel should be aware of scatter radiation risks and minimize radiation exposure when involved in fluoroscopic screening procedures.

A radiation perspective for treating loin pain in pregnancy by double-pigtail stents.

OBJECTIVE: To review the risks of placing double-pigtail stents during pregnancy in women presenting with loin pain associated with hydronephrosis. PATIENTS AND METHODS: A consecutive series of women presenting with loin pain and hydronephrosis in pregnancy were treated with double-pigtail ureteric stents. A flexible cystoscope was used to identify the ureteric orifice and to pass a guidewire into the renal pelvis under fluoroscopic guidance. Stents were placed using the exchange technique over a stiff guidewire. Procedures were carried out under none or limited sedoanalgesia. Screening times and radiation dose were recorded. Data were collected for the average uterine radiation dose from a variety of radiological procedures. Previous publications were reviewed to determine the lethal, teratogenic and carcinogenic risk to the developing fetus from radiation exposure. RESULTS: Seven patients referred with symptomatic hydronephrosis during pregnancy were treated. The screening time during placement was minimized. The mean (range) uterus (i.e. fetal) dose was 0.40 (0.03-0.79) mGy. Most radiological procedures involve uterine doses of < 20 mGy, far below the 100 mGy that may result in fetal damage during periods of maximum radiosensitivity. CONCLUSION: Minimized radiation exposure from a range of uroradiological procedures in pregnant women has limited fetal risk. The use of fluoroscopy for symptomatic hydronephrosis during pregnancy allows ureteric stents to be placed safely and reliably. The average excess risk to the fetus from this procedure is 1 in 43 000 of cancer induction and 1 in 100 000 of heritable disease, i.e. very small when compared with the natural incidence. Pregnancy should not exclude the use of appropriate diagnostic radiation exposure and urologists may conduct appropriate diagnostic and therapeutic procedures, taking care to limit X-ray exposure without fear of risk to the developing fetus.

Calibration frequency of dose--area product meters.

Calibration of patient dose monitoring devices in diagnostic radiology has become increasingly important in the light of new legislation that requires monitoring of patient dose against local and national diagnostic reference levels. An investigation was conducted into the long-term stability of 41 dose-area product (DAP) meters over a period of approximately 5 years, to assess the suitability of an annual calibration regimen. For DAP meters fitted to overcouch X-ray tubes, 77% of calibrations were within 10%, whilst for undercouch tubes only 50% of calibrations were within 10%. These findings suggest that annual calibration may be too infrequent. Suitable calibration frequencies for different clinical workloads are discussed.

Psychiatric hospitalization of children in Florida. Legal aspects.

The hospitalization of children in psychiatric hospitals and their associated rights or lack thereof remains an important issue. Much attention has been focused on children's rights in Florida, most recently with the cases of Gregory K. and Kimberly Mays. On a national level, Hillary Rodham Clinton has drawn attention to children's rights through her advocacy for children. The commitment of children to mental health facilities in Florida deserves examination. This is an important issue, not only to the psychiatrist who tests youths, but also to the family practitioner, internist, or any other referring physician who is involved in the case of the child and the family. It is imperative that the primary care physician as well as the psychiatrist know and understand the limitations and requirements for civil commitment of a child in a psychiatric setting.