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Use of a Longer Extension Tube Reduces Operator Radiation Exposure During Vertebroplasty 2003

Ortiz O, Gregorius D, Koehler V, Natarajan V
Department of Radiology
Winthrop-University Hospital
Mineola, NY 11501

Purpose:
To assess the effect upon operator radiation exposure by increasing the length of the injection tube of a vertebroplasty injection device.

Method:
Vertebroplasty was performed in two patients, each with two osteoporotic vertebral compression fractures. An experienced operator used a bilateral transpedicular approach, utilizing biplane fluoroscopy in all of the procedures. Two different lengths of extension tubing were used in combination with an injection device (EZ Flow CDS, ArthroCare Corporation). A short or 29cm tube (EZ Flow CDS, ArthroCare Corporation) or a long or 80-cm tube (Namic clearaCIL) were used. The combined length of each tube attached to the injection device was 44 cm and 95 cm, respectively. The average distance from fluoroscopic isocenter on the patient’s back to the operator was 60cm and 100cm with the short and long tube, respectively. The short tube was used for cement delivery in 2 vertebral levels and the long tube was used for cement delivery in two vertebral levels. Radiation exposure to the operator was measured with an electronic pocket dosimeter (Aloka Co., Ltd.). These measurements were also compared to predicted dose measurements that were calculated with the inverse square law.

Results:
Radiation dose to the operator, measured in micro-Sieverts/minute, averaged 1.62 micro-Sieverts/minute with the long tube and 2.67 micro-Sieverts/minute with the short tube. The predicted exposure using mathematical modeling with the inverse square law was 2.5 micro-Sieverts/minute and 3.3 micro-Sieverts/minute, respectively.

Conclusion:
Radiation exposure to the operator was significantly reduced by attaching a longer extension tube to the injection device, thus allowing the operator to increase his distance from the fluoroscopy unit. This observation reflects the protective benefit of applying the inverse square law in order to minimize radiation exposure to the operator.

References:

1. Bushberg JT, Seibert JA, Leidholdt EM, Boone JM. The Essential Physics of Medical Imaging. 2ed. Lippincott Williams & Wilkins, Philadelphia, 2002
2. Marx MV. Interventional procedures: risks to patients and personnel. Radiation Risk: A Primer. American College of Radiology, Reston, VA 1996:23-26