Step back from the patient: Reduction of radiation dose to the operator by the systematic use of an automatic power injector for contrast media in an interventional angiography suite
ABSTRACT During arterial interventional procedures, power injectors allow the operator to step back from the patient or exit the angiography suite during digital subtraction angiography (DSA) acquisitions. Increasing the distance to the radiation source reduces exposure to the operator and staff.
To systematically investigate the effect of increasing the distance between the radiation source and the operator during DSA acquisitions in a daily clinical setting, regarding radiation exposure to the operator and patient, as well as the duration of the procedure using a power injector to deliver contrast media.
Patients scheduled for arterial interventional procedures in the pelvis or lower extremities were consecutively included. In phase one (duration 6 weeks, 44 patients) contrast media were injected manually. In phase two (duration until the total dose area product [DAP] was equal to phase 1, 41 patients) the operator used a power injector and exited the suite whenever possible. Patient, procedure, and examination data were recorded. Collective dose to the operator's collar, lead apron, and hands was recorded using thermo luminescent dosimetry (TLD).
Our results showed a dose reduction of 50% to the operator's hands, lead apron, and thyroid collar when using a power injector during DSA, with no significant increase in DAP or procedure time when performing pelvic procedures. For lower extremity procedures there was a small but significant increase in procedure time and DAP. Pelvic procedures yielded substantially higher DAP than lower extremity procedures during both phases.
Utilization of a power injector, thus allowing the operator to step back from the patient, facilitates a radiation dose reduction to the operator of approximately 50% with no significant increase in patient dose or procedure time during pelvic procedures.
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ABSTRACT: To characterize radiation exposure to patients and operating room personnel during fluoroscopic procedures. Patient dose information was collected from the imaging equipment. Real-time dosimetry was used to measure doses to the operators, scrub nurse, radiologic technologist (RT), and anesthesiologist in 39 cases of endovascular thoracoabdominal aortic aneurysm repair using fenestrated endografts. Overall equivalent doses and dose rates at time points of interest were noted and compared with the corresponding patient doses. The dosimeter on the anesthesia equipment received 143 μSv (38-247) more radiation per case than the average operator, and the scrub nurse and RT received 106 μSv (66-146) and 100 μSv (55-145) less, respectively. Adjusting for protective lead aprons by the Webster methodology, the average operator received an effective dose of 38 μSv. Except for the RT, personnel doses were well correlated with patient dose as measured by kerma area product (KAP) (r = .82 for average operator, r = .85 for scrub nurse, and r = .86 for anesthesia; all P < .001) but less well correlated with fluoroscopy time or cumulative air kerma (CAK). When preoperative cone beam computed tomography was performed, the equivalent dose to the RT was 1.1 μSv (0.6-1.5) when using shielding and 37 μSv (22-53) when unshielded. Digital subtraction acquisitions accounted for a large fraction of all individuals' doses. Decreasing field size (and thus, increasing magnification) was associated with decreased KAP (r = .47; P < .001) and increased CAK (r = -.56; P < .001). The square of the field size correlated strongly with the KAP/CAK ratio (r = .99; P < .001). Increased lateral angulation of the C-arm increased both CAK and KAP (at field size, 22 cm; r = .54 and r = .44; both P < .001) and the average dose rate to an operator was 1.78 (1.37-2.31) times as high in a lateral projection as in a posterior-anterior projection. Personnel doses were best correlated with KAP and less well correlated with fluoroscopy time or CAK. The dosimeter on the anesthesia equipment recorded the highest doses attributable to ineffective shielding. Operators can reduce the effective dose to themselves, the patient, and other personnel by minimizing the use of digital subtraction acquisitions, avoiding lateral angulation, using higher magnification levels when possible, and being diligent about the use of shielding during fluoroscopy cases.Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 06/2013; 58(3). DOI:10.1016/j.jvs.2013.02.032 · 2.98 Impact Factor