Radiation Sensibilities
Quantification of Increased Patient Radiation Dose When Gonadal Shielding Is Used With Automatic Exposure Control

https://doi.org/10.1016/j.jacr.2020.05.027Get rights and content

Introduction

Gonadal shields consisting of lead-equivalent material have been used in radiography since the early 1950s [1,2]. When this practice began, radiography used entrance air kerma values 25 times greater than current values [3,4] for both adult and pediatric patients. The current era of reduced patient doses and an improved understanding of radiation effects have raised questions about the effectiveness of gonadal shielding [5, 6, 7]. One of these questions concerns the use of gonadal shielding with the management of the patient’s radiation dose by the x-ray machine’s automatic exposure control (AEC).

In the early 1950s, a patient’s radiation dose was determined by manual radiographic techniques set before exposure. AEC was adapted by radiology soon thereafter [8] and is ubiquitous today in controlling radiation dose. AEC uses radiation sensors at the image receptor to sum the detector dose and terminate the x-ray exposure at a predetermined threshold. For pelvic radiography, a properly positioned female gonadal shield is at the same location as the central AEC sensor. Shielding of the AEC sensor should increase the radiation output of the machine to reach the required dose threshold, thus increasing the dose to organs outside the shielded area, such as colon, bone marrow, stomach, liver, and even female gonads [5,9, 10, 11, 12]. Paradoxically, this likely increases the patient’s risk. In a phantom model, radiation to the stomach increased 100% in an adult and 44% in a child when female gonadal shielding was used with AEC [13].

AEC and gonadal shielding are commonly used together in clinical practice despite technologist guidelines that caution against this practice [14]. In this study, we test the hypothesis that gonadal shielding used in clinical practice for both female and male subjects with the x-ray unit’s AEC feature increases the radiation output of the machine and the patient’s radiation dose.

Section snippets

Materials and Methods

This retrospective review was approved by our institutional review board.

Results

Our search algorithm and exclusion criteria resulted in 899 examinations for analysis, including 428 female and 471 male examinations. Female subjects ranged in age from 6.0 to 20.7 years, and male subjects ranged in age from 6.1 to 20.8 years. The mean age for female subjects was 12.8 ± 3.8 years and the median was also 12.8 years. For male subjects, the mean age was 12.9 ± 3.5 years with a median of 13.1 years. Neither patient age nor use of grid statistically affected results between the

Discussion

Our study indicated that gonadal shielding in clinical practice increased patient radiation dose 23% to 24%, except for lateral view shielding in male subjects, which increased only 13%. We also found a 62% increase when a female shield was optimally positioned, but no significant increase when the shield was suboptimally positioned. These results support Policy Statement PP 32-A from the American Association of Physicists in Medicine, which recommends against the use of gonadal shielding.

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      Citation Excerpt :

      Moreover, “anecdotal evidence suggests that patients feel more secure and less anxious when they are shielded, and it is a demonstration that the radiology professional is concerned for their safety” [3]. Nevertheless, in recent years, it has been argued that the amount of radiation needed to perform an X-ray procedure is about one-twenty-fifth of what it was in the 1950s [4]. Besides, the gonads are now assumed to be less radiosensitive than previously thought [5], raising the question as to whether GCS is still needed [6].

    The authors state that they have no conflict of interest related to the material discussed in this article. All authors are non-partner/non-partnership track/employees.

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