Radiation dose estimation of pediatric upper extremity radiographs.

Background: Upper extremity radiographic exams have long been considered as a single category with one simplified low-dose estimate, despite covering a variety of body parts. There are limited tools currently available for the simulation/calculation of radiation dose from upper extremity exams.

Objective: This study aims to evaluate radiation dose (in terms of effective dose and organ doses) from various types of pediatric upper extremity radiographic exams as performed at a large tertiary care children's hospital using a new set of hybrid computational phantoms that incorporate the anatomy of upper extremities and cover varied patient sexes and ages.

Materials and methods: Technical acquisition parameters were collected for upper extremity exams at our institution according to the age-based categories as defined by clinical protocols. A relationship was established between radiographic acquisition parameters and dose-area product for each category using direct measurements. A new set of computational phantoms with posed upper extremities was introduced and used to run Monte Carlo simulations of patient effective dose and organ doses for all relevant projections.

Results: The calculated effective dose to upper extremities was found to range from 0.01 µSv for a hand/finger radiograph of a 3-6-year-old to 1.13 µSv for a humerus radiograph of a 1-3-year-old. The four tissues with the highest organ dose from all projections were the same: skin, muscle, endosteum, and red marrow. Doses to these organs as well as breast and thyroid were reported, and conversion coefficients to estimate effective dose and organ doses from dose-area product were calculated.

Conclusion: Simulations of pediatric upper extremity radiographs using a set of newly-modified computational phantoms present a wide range of effective and organ doses. The doses reported in this study can be adapted to site-specific practices for rough estimations.