Impact of the calibration conditions of XR-RV3 films on peak skin dose measurements in interventional radiology

Abstract

In this study, the impact of radiochromic films' (XR-RV3) calibration on PSD measurements was investigated under various peak kilovoltage (kVp) and additional filtration conditions. Films were calibrated free-in-air for six beam qualities with Allura Xper FD20 system (Philips). Six calibration curves (CCs) were constructed. Each beam quality was characterized in terms of mean energy (ME) in the air, with table, with table and water phantom using Monte Carlo simulations. A cohort of 155 patient films from cardiology (37) and vascular (118) procedures were read with each CC. Routine calibration beam quality was taken as reference (DoseNorm). Overall, it was observed that for a wider ME difference between the exposed film and the CC used, a larger deviation (from -28% to +41%) was observed. The choice of beam quality for the calibration is a key point when additional filtration and kVp are automatically controlled in clinical conditions.

Validation of a dose tracking software for skin dose map calculation in interventional radiology

“…The films were scanned 24 h after the irradiation with an Epson Expression 11000XL scanner (Epson, Nagano, Japan) (resolution: 72 dpi corresponding to 0.35 mm, pixel depth: 48 bit) in reflection mode over a black panel [46,47]. The red color channel was read because it shows higher sensitivity and better differentiation in low dose regions [47][48].…”

Calibration of Gafchromic XR-RV3 film under interventional radiology conditions

“…Moreover, dose metrics, which are routinely recorded during the procedure, do not constitute the peak skin dose (PSD) on the patient's skin, because they are an indicator of the tube output and cannot be readily used for estimating the patient skin dose. 1,2 PSD is responsible for the appearance of the deterministic effects of ionizing radiation. One of these indicators is kerma at the reference point (Kair,ref), as defined by the IEC 60601-2-43 standard.…”

“…The verification of doses received by patients undergoing interventional radiology procedures is a time-consuming process depending on some factors (low dose rate compare to radiotherapeutic units to establish a calibration curve, the need for passive dosimeter processing, and data analysis). [2][3][4] The basis for this is the use of appropriate dosimetry systems and their proper calibration. Among the methods used for dose measurement in clinical practice, radiochromic films are commonly used in radiation therapy for dosimetric verification of treatment plans, [5][6][7]8 whereas in interventional radiology, they are used to assess the surface dose on the patient's skin(peak skin dose).…”

“…11 Since this dosimetric method is a relative one, the proper calibration curve needs to be determined prior to its use for dose assessment. 2,3,4,[10][11][12][13][14] In the literature there is still an insufficient number of detailed descriptions of the calibration curve fitting analysis for XR-RV3 films. Due to the relatively low dose rate of ionizing radiation of X-ray units used in interventional radiology compared to radiotherapeutic units, this process performed in clinical conditions is somewhat time-consuming.…”

“…4 These films are self-developing and provide 2D dose mapping. 2,15,16 To obtain dose information, however, it is necessary to read them, i.e. to quantify the optical density changed as a result of dose deposition, using a scanner and determine the calibration curve.…”