Estimation of effective dose and radiation risk in pediatric barium studies procedures

A Tutorial on Diagnostic Benefit and Radiation Risk in Videofluoroscopic Swallowing Studies

The videofluoroscopic swallowing study (VFSS) is a key tool in assessing swallowing function. As with any diagnostic procedure, the probable benefits of the study must be weighed against possible risks. The probable benefit of VFSS is an accurate assessment of swallowing function, enabling patient management decisions potentially leading to improved patient health status and quality of life. A possible (though highly unlikely) risk in VFSS is carcinogenesis, arising from the use of ionizing radiation. Clinicians performing videofluoroscopic swallowing studies should be familiar with both sides of the risk benefit equation in order to determine whether the study is medically justified. The intent of this article is to provide the necessary background for conversations about benefit and risk in videofluoroscopic swallowing studies.

Harmonisation of imaging protocols, radiation doses and image quality in gastrointestinal fluoroscopy examinations - multicentre study

BACKGROUND

Paediatric gastrointestinal fluoroscopy examinations can impart varying amounts of radiation for the same patient size and exam type.

OBJECTIVE

To investigate the variability of imaging protocol, radiation dose and image quality in paediatric fluoroscopy examinations in order to provide recommendations for the harmonisation and optimisation of local practices.

MATERIALS AND METHODS

Five paediatric radiology departments performing fluoroscopically-guided contrast enema, micturating cystourethrography and upper gastrointestinal tract examinations participated in this study. Information on imaging protocols and radiation doses was retrospectively collected for more than 2,400 examinations. Image quality was analysed on clinical and phantom images.

RESULTS

Patient doses showed great variability among centers with up to a factor of 5 for similar fluoroscopy times. The five departments had imaging protocols with major differences in fluoroscopy dose regulation curves and additional filtration. Image quality analysis on phantoms and patients images showed no major improvement in contrast, spatial resolution or noise when increasing the radiation dose. Age-based diagnostic reference levels using both dose area product and fluoroscopy time were proposed per procedure type.

CONCLUSION

Disparities between centers and no correlation of radiation dose with image quality criteria create margins for optimisation. These results highlight the need for guidelines on fluoroscopy image quality and dose reference levels in paediatric gastrointestinal examinations to harmonise practices and optimise patient dose.

Evaluation of effective dose and entrance skin dose in digital radiology

Background: Ionizing radiation has an indispensable role in diagnostic radiology and clinical treatments. Apparently, medical exposure in diagnostic radiology pertains to be the preeminent man-made source of radiation.

Objective: The aim of the present scientific study is to calculate the Entrance Surface Dose (ESD) and Effective Dose (ED) in digital radiography in Mazandaran province.

Materials and methods: The study was performed on 3600 patients in digital X-ray rooms 15 hospitals and the required data were collected from two age groups (10>15 years and adults) in each projection. Based on the results of this study, ESD and ED were calculated for skull (PA), skull (lateral), cervical spine (AP), cervical spine (lateral), chest (PA), chest (lateral), abdomen (AP), lumbar spine (AP), lumbar spine (lateral), pelvis (AP), thoracic spine (AP) and thoracic spine (lateral) examinations. It was calculated using PCXMC software (version 2.0).

Results: In this study, mean ESDs for the 10-15 year group varied from 0.97±0.21 mGy to 3.62±1.38 mGy for chest (PA) and lumbar spine (lateral), respectively. For the adult group varied from 1.05±0.31 to 3.85±1.44 for cervical spine (AP) and lumbar spine (lateral), respectively. And also ED value was from in the range of 10.40 µSv to 378.46 µSv for skull (PA) 10-15 year group and abdomen adults, respectively

Conclusion: This survey revealed a significant variation in the radiation dose of digital radiology examinations among hospitals in Mazandaran province. Application of a dose reference level (DRL) could be an optimization procedure for reducing the patient’s dose in Mazandaran province.

Radiation Safety in Videofluoroscopic Swallowing Study: Systematic Review

Videofluoroscopic swallowing study (VFSS) is generally used to diagnose dysphagia and oropharyngeal aspiration during swallowing movement. Patients and bolus-feeding operators (such as occupational therapist and speech language pathologist) may undergo multiple VFSS procedure, placing them at risk for more radiation exposure due to increased scan time. The present study investigated the dose-area product, effective dose of various protocols, and summarized dose reports from various studies of VFSS. The PubMed database searched for relevant publications reporting radiation dose in the VFSS procedure. 13 articles were selected to be reviewed. This systematic review involved 13 peer-reviewed articles that reported the specific dose of the VFSS procedure. The articles were categorized into three types: operator radiation dose, adult patient radiation dose, and pediatric radiation dose. The operator dose reports showed that the operators' scattering exposure, equivalent dose (across the whole body, eyes, and hands), and annual effective dose were significantly lower than the annual dose limit of 20 mSv. Both adult and pediatric patient dose reports showed that the effective dose, which was estimated from recorded dose-area product, was significantly lower than the annual background exposure of 2.4 mSv in various protocols. The present literature review suggested that the radiation dose of VFSS by modified barium swallowing is acceptable in both operators and patients. However, various radiation protection strategies should be conducted during the procedure to reduce the risk of stochastic effect.

A Scalable Database of Organ Doses for Common Diagnostic Fluoroscopy Procedures of Children: Procedures of Historical Practice for Use in Radiation Epidemiology Studies

Assessment of health effects from low-dose radiation exposures in patients undergoing diagnostic imaging is an active area of research. High-quality dosimetry information pertaining to these medical exposures is generally not readily available to clinicians or epidemiologists studying radiation-related health risks. The purpose of this study was to provide methods for organ dose estimation in pediatric patients undergoing four common diagnostic fluoroscopy procedures: the upper gastrointestinal (UGI) series, the lower gastrointestinal (LGI) series, the voiding cystourethrogram (VCUG) and the modified barium swallow (MBS). Abstracted X-ray film data and physician interviews were combined to generate procedure outlines detailing X-ray beam projections, imaged anatomy, length of X-ray exposure, and presence and amount of contrast within imaged anatomy. Monte Carlo radiation transport simulations were completed for each of the four diagnostic fluoroscopy procedures across the 162-member (87 males and 75 females) University of Florida/National Cancer Institute pediatric phantom library, which covers variations in both subject height and weight. Absorbed doses to 28 organs, including the active marrow and bone endosteum, were assigned for all 162 phantoms by procedure. Additionally, we provide dose coefficients (DCs) in a series of supplementary tables. The DCs give organ doses normalized to procedure-specific dose metrics, including: air kerma-area product (µGy/mGy · cm2), air kerma at the reference point (µGy/µGy), number of spot films (SF) (µGy/number of SFs) and total fluoroscopy time (µGy/s). Organs accumulating the highest absorbed doses per procedure were as follows: kidneys between 0.9-25.4 mGy, 1.1-16.6 mGy and 1.1-9.7 mGy for the UGI, LGI and VCUG procedures, respectively, and salivary glands between 0.2-3.7 mGy for the MBS procedure. Average values of detriment-weighted dose, a phantom-specific surrogate for the effective dose based on ICRP Publication 103 tissue-weighting factors, were 0.98 mSv, 1.16 mSv, 0.83 mSv and 0.15 mSv for the UGI, LGI, VCUG and MBS procedures, respectively. Scalable database of organ dose coefficients by patient sex, height and weight, and by procedure exposure time, reference point air kerma, kerma-area product or number of spot films, allows clinicians and researchers to compute organ absorbed doses based on their institution-specific and patient-specific dose metrics. In addition to informing on patient dosimetry, this work has the potential to facilitate exposure assessments in epidemiological studies designed to investigate radiation-related risks.