Influence of radiation dose reduction gloves on exposure parameters, entrance dose rates and eye doses of interventionalists during mobile C-arm fluoroscopic procedures: A phantom study

INTRODUCTION

During fluoroscopic examinations, radiation dose reduction gloves (RRGs) protect the hands of the interventionalist against ionising scattered radiation from the patient. Some fluoroscopic procedures may require the hands of the interventionalist in the path of the primary X-ray beam. This study investigates the influence of RRGs in the field of view (FOV) on exposure parameters, entrance dose rates and eye doses of interventionalists during mobile C-arm fluoroscopic procedures.

METHOD

Polymethylmethacrylate (PMMA) slabs were stacked on each other to simulate patient thicknesses. The abdomen protocol of the unit was selected for the study. The entrance dose rates to the surface of the PMMA slabs and the scattered radiation were measured for an undercouch configuration with and without RRGs in the FOV. The exposure parameters were noted. The scattered radiation for an overcouch configuration was measured.

RESULTS

The entrance dose rate increases as the FOV decreases for a fixed thickness of PMMA. The presence of RRGs in the FOV increases the exposure parameters, entrance dose rates and the scattered radiation to the eyes of the interventionalist. For the first level of RRG coverage, percentage increases in entrance dose rates and eye doses for the 23 cm FOV for all thicknesses of PMMA slabs ranged from 1.0% to 17.0% and 20.0%-30.0%, respectively; for the second level of RRG coverage, the entrance dose rates ranged from 17.0% to 45.0% and the eye doses from 50.0% to 60.0%. Percentage increases depend on the FOV, the patient's thickness, and the size and orientation of the RRGs in the FOV. Scattered radiation to the eyes of the interventionalist increases with an overcouch configuration compared to an undercouch configuration.

CONCLUSION

Sterile RRGs protects the hands of the interventionalist against scattered radiation. But in the FOV, they increase the scattered radiation to the personnel and the patient entrance dose rate.

IMPLICATIONS FOR PRACTICE

For best practice in C-arm fluoroscopy-guided procedures, appropriate FOV and C-arm orientation should be selected, whilst RRGs should not be in the path of the primary beam unless necessary.

Context dependence of head bobs in gerbils and potential neural contributions

Headbobs are up-down movements of the cranium associated with the use of motion parallax for depth perception. Mongolian gerbils (aka jirds; Meriones unguiculatus) often execute a series of headbobs prior to jumping between surfaces. Gerbils were tested in a jumping stand task and headbobs videotaped under three light levels approximating low daylight, dawn/dusk, and moonlight across a range of distances to target. Headbobs per trial increased linearly with increasing distance to the target platform, whereas headbob frequency (rate of headbobbing pre-jump on the start platform) increased with gap distance up to an intermediate level and then decreased. Overall, gerbils made the most headbobs per trial under the darkest conditions, whereas their headbobbing rate was highest for medium illumination, especially for medium-long gap distances. There was a positive correlation between headbob frequency and volume of the superior colliculus (SC), but no relationship between headbobs and relative size of the temporo-posterior (TP) visual cortex. The results suggest that gerbils employ a specific visuomotor strategy for depth perception differentially under different conditions. We suggest that the deployment of headbobs under specific conditions may be part of an SC-driven vigilant state, of which more rapid sampling of the visual environment using headbobs for depth estimation is one component. Moreover, the findings highlight the importance of considering ecological factors in designing studies of visual behavior and its underpinnings in rodents.

Remote and rapid pathological diagnosis in a resource challenged unit

Malawi is one of the world's poorest countries, but despite this, has a dedicated paediatric oncology service. The service has been hampered by the inability to make a timely cytological diagnosis in the majority of patients. A telemedicine programme was commenced to help overcome this problem, and the results for the first 197 consecutive patients are described. The results are compared with the local reports where available. Most samples were fine needle aspirates (104/197-53%), but others included bone marrow aspirates, peripheral blood films and other fluid collections. A diagnosis was arrived at in 52% of the samples; there were 46 discordant results, 38 were when one or other of the local or distant teams were unable to make a diagnosis, and only 8 where the diagnoses of the 2 teams differed. Diagnoses were made and reports were compiled by the 'distant' team within 24 h and sent to the centre in Malawi. This simple telepathology initiative has had a positive impact on clinical management, and could be used in other less resourced centres twinned with better resourced ones.

Spectrum and presentation of pediatric malignancies in the HIV era: experience from Blantyre, Malawi, 1998-2003

BACKGROUND

Data on childhood cancers in Africa are sparse, particularly since the spread of HIV. We aimed to document the frequency of pediatric cancers presenting to a large central hospital in Malawi, detailing the presenting features, initial investigations, and HIV status of these children.

PROCEDURE

A retrospective audit of the spectrum and clinical presentation of cancers among children (<16 years) seen at Queen Elizabeth's Central Hospital (QECH), between 1998 and 2003.

RESULTS

Seven hundred seven children with cancer were seen, the number of cases per year increased over the time period; 50% (351) had Burkitt lymphoma, 13% (89) had retinoblastoma, and 9% (61) had Kaposi sarcoma, with a variety of other tumors comprising the remainder. Kaposi sarcoma markedly increased in frequency over time. Histological verification of diagnosis was available for 49% (348). The proportion of children with cancer who were tested for HIV increased over time, but varied by cancer type. Amongst those tested, the seroprevalence was 93% (52/56) for children with Kaposi sarcoma, 4% (11/289) for those with Burkitt lymphoma, 31% (8/26) for those with other non-Hodgkin lymphomas, 7% (1/15) for those with Hodgkin disease, and 5% (5/103) for those with other cancers.

CONCLUSIONS

The number of cases seen per year has increased over the study period for almost all cancers, but in particular for Kaposi sarcoma. Burkitt lymphoma remains the commonest pediatric tumor in Malawi. In the case of Burkitt lymphoma, non-Hodgkin lymphoma, and Kaposi sarcoma there is a significant difference in the presentation of HIV-seropositive and -seronegative children.