Investigating the adjacent patient radiation dose received during a simulated ward chest X-ray examination

Introduction: A patient having a chest X-ray will inevitably be exposed to radiation from the primary beam. Using a light beam diaphragm (LBD) on the X-ray tube reduces scattered radiation at the X-ray tube through longitudinal and horizontal collimation. But not scattered secondary radiation resulting from interactions of the primary beam. This study aimed to investigate whether lead protection on simulated hospital ward inpatients (opposite and adjacent to a simulated chest X-ray examination) would change the secondary scattered radiation dose received.

Method: Two rando phantoms (simulated patients) were positioned at different distances from the simulated patient receiving the chest X-ray. The phantoms were positioned one metre adjacent (either side of the phantom being X-rayed) and two metres opposite. The scattered radiation dose to radiosensitive organs (thyroid, breast, and gonads) was recorded using Thermoluminescent Dosimeters (TLDs). Six exposures were conducted, three with lead protection and three without. The mean radiation dose and standard deviation were compared using a paired two-sample t-test for statistical significance (p>0.05).

Results: The lead protection reduced the radiation dose to the radiosensitive organs by 64%-100% (p=0.51-0.18) one metre adjacent and 65%-100% (p=0.65-0.18) two metres opposite. Noticeably the phantom two metres opposite had substantial individual organ dose reductions due to the distance from the primary beam.

Conclusion: Lead aprons, thyroid collars, and distance reduced the radiation dose to the radiosensitive organs of the surrounding phantoms (simulated patients) from an adjacent chest X-ray examination and present opportunities for dose reduction techniques during ward chest X-ray examinations.

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