Skin Entrance Radiation Dose in an Interventional Radiology Procedure

Abstract

Monitoring of skin entrance radiation exposure in lengthy interventional procedures has been recommended because of the potential for skin injury. Fluoroscopy duration and dose-area product (DAP) are readily available real-time measurements. It would be of interest to study the correlation of these parameters and skin entrance radiation. Twenty neurological interventional procedures performed through the aortic arch were monitored. Two pieces of GafChromic XR Type R film were placed between the patient and the examination table. An observer recorded the fluoroscopy duration and DAP for each phase of the procedure. Each film was scanned post-procedure in RBG mode, and then the image was analyzed for peak skin entrance radiation dose (in air kerma). All DAP values were corrected according to a calibration with an ion chamber. With the DAP values for the respective phases of a procedure, the effective dose in a Reference Man was calculated. For these twenty cases, the means and standard deviations were 17.2+/-6.4 min for x ray on-time, 256+/-65 Gy cm (-2) for DAP, 94+/-34 cGy for peak skin entrance dose in air kerma, and 19.2+/-5.0 mSv for effective dose, respectively. The peak skin entrance dose was correlated to fluoroscopy duration, DAP, and effective dose with the r(2)-values of 0.48, 0.46, and 0.09, respectively. The correlation with DAP or fluoroscopy duration was not sufficiently strong to infer skin entrance dose from either of these parameters. Therefore, skin entrance dose should be determined directly.

DNA Double-Strand Breaks after Percutaneous Transluminal Angioplasty

“…To date, radiation exposure from interventional radiologic procedures has been monitored by using physical or chemical dosimeters. Current approaches to monitoring the ef- fects of interventional radiologic procedures include estimating the effective dose by using Monte Carlo calculations and measuring the skin entrance dose (23)(24)(25)(26). Analyses of chromosomal alterations in lymphocytes are limited because of the low yield of these alterations at low doses of ionizing radiation (27).…”

Radiochromic film for verification of superficial x-ray backscatter factors

“…Its optical density to absorbed dose response differs by less than 3-5% over the energy range 50kVp to 150kVp [8], is only approximately 0.3 mm thick and could be easily used in a layered method to extrapolate to zero thickness. This film would also be useful for measurement of doses in x-ray guided interventional procedures due to its low energy dependence [9]. Using these characteristics, this note investigates the ability of GAFCHROMIC TM EBT film model to measure BSF's for x-ray qualities typically used for superficial radiotherapy.…”

How to set up and apply reference levels in fluoroscopy at a national level

“…Since the dose-intensive examinations involving fluoroscopy may result in a significant risk of deterministic effects, notably to the skin, it is recommended that the entrance surface doses be monitored for preventing skin injuries. Some authors claim that the DAP is not a suitable quantity for such a monitoring task because of the weak correlation between the DAP and the entrance surface dose [29], and that the latter should be measured directly on the patient. But in the absence of a direct measurement, conversion factors published in the literature [19,[30][31][32][33] may be used to establish the maximum (peak) skin dose from the DAP.…”