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Characterization of a MO Skin detector for in vivo skin dose measurements during interventional radiology procedures
Author(s) -
Safari M. J.,
Wong J. H. D.,
Ng K. H.,
Jong W. L.,
Cutajar D. L.,
Rosenfeld A. B.
Publication year - 2015
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4918576
Subject(s) - imaging phantom , detector , ionization chamber , nuclear medicine , reproducibility , dosimetry , dose profile , biomedical engineering , monitor unit , optics , field size , linear particle accelerator , materials science , radiation , beam (structure) , physics , medicine , ionization , mathematics , quantum mechanics , ion , statistics
Purpose: The MO Skin is a MOSFET detector designed especially for skin dose measurements. This detector has been characterized for various factors affecting its response for megavoltage photon beams and has been used for patient dose measurements during radiotherapy procedures. However, the characteristics of this detector in kilovoltage photon beams and low dose ranges have not been studied. The purpose of this study was to characterize the MO Skin detector to determine its suitability for in vivo entrance skin dose measurements during interventional radiology procedures. Methods: The calibration and reproducibility of the MO Skin detector and its dependency on different radiation beam qualities were carried out using RQR standard radiation qualities in free‐in‐air geometry. Studies of the other characterization parameters, such as the dose linearity and dependency on exposure angle, field size, frame rate, depth‐dose, and source‐to‐surface distance (SSD), were carried out using a solid water phantom under a clinical x‐ray unit. Results: The MO Skin detector showed good reproducibility (94%) and dose linearity (99%) for the dose range of 2 to 213 cGy. The sensitivity did not significantly change with the variation of SSD (±1%), field size (±1%), frame rate (±3%), or beam energy (±5%). The detector angular dependence was within ±5% over 360° and the dose recorded by the MO Skin detector in different depths of a solid water phantom was in good agreement with the Markus parallel plate ionization chamber to within ±3%. Conclusions: The MO Skin detector proved to be reliable when exposed to different field sizes, SSDs, depths in solid water, dose rates, frame rates, and radiation incident angles within a clinical x‐ray beam. The MO Skin detector with water equivalent depth equal to 0.07 mm is a suitable detector for in vivo skin dosimetry during interventional radiology procedures.