Results for Effective Dose Equivalent

In a previous experimental study, Wphni and Stranden (1979) also investigated the relationships between the film badge response at the neck (located at the right-hand side of the thorax) and jF/e for various fluoroscopic conditions, including both over- and undertable x-ray tube orientations. The amount of scatter radiation observed from undertable orientation was less than from overtable orientation, while the distribution of the scatter radiation from undertable orientation was skewed towards the lower body, which can be shielded by protective devices located on the fluoroscopic system (Faulkner and Moores, 1982), 

From the Wphni and Stranden study, the increase in the ratio of to the film badge response for undertable orientation is observed to be fairly constant. For the combination of kVp and equivalent lead thickness of the apron that corresponds to the overtable limiting condition, the increase in this ratio is a factor of 1.6. A revised limiting minimum ratio that includes consideration of both underand overtable x-ray tube orientations would be 5.6 (i.e., the minimum value for the overtable case of 8.9 divided by 1.6). 

Webster (1989) proposed another approach for using the experimental findings for He (Faulkner and Harrison, 1988) that removes 

Hw and Hn are the values ofHp(lO) for the personal monitors worn at the waist and neck, respectively. The formula results in values between 0.97 to 1.07 He for 0.5 mm lead equivalent aprons and between 1.12 to 1.72 He for 0.3 mm lead equivalent aprons. Use of the formula is a simple and practical way to estimate He when both personal monitors are worn. 

---