Abstract Background: We studied the relationship between trismus (maximum interincisor opening [MIO] ≤35 mm) and the dose to the ipsilateral masseter muscle (iMM) and ipsilateral medial pterygoid muscle (iMPM). Methods: Pretreatment and post-treatment measurement of MIO at 13 weeks revealed 17% of trismus cases in 83 patients treated with chemoradiation and intensity-modulated radiation therapy. Logistic regression models were fitted with dose parameters of the iMM and iMPM and baseline MIO (bMIO). A risk classification tree was generated to obtain optimal cut-off values and risk groups. Results: Dose levels of iMM and iMPM were highly correlated due to proximity. Both iMPM and iMM dose parameters were predictive for trismus, especially mean dose and intermediate dose volume parameters. Adding bMIO, significantly improved Normal Tissue Complication Probability (NTCP) models. Optimal cutoffs were 58 Gy (mean dose iMPM), 22 Gy (mean dose iMM) and 46 mm (bMIO). Conclusions: Both iMPM and iMM doses, as well as bMIO, are clinically relevant parameters for trismus prediction.
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Atherosclerosis is the development of lipid-laden plaques in arteries and is nowadays considered as an inflammatory disease. It has been shown that high doses of ionizing radiation, as used in radiotherapy, can increase the risk of development or progression of atherosclerosis. To elucidate the effects of radiation on atherosclerosis, we propose a mathematical model to describe radiation-promoted plaque evelopment. This model distinguishes itself from other models by combining plaque initiation and plaque growth, and by incorporating information from biological experiments. It is based on two consecutive processes: a probabilistic dose-dependent plaque initiation process, followed by deterministic plaque growth.
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Abstract—A survey was conducted among 20 Dutch hospitals about radiation protection for interventional fluoroscopy. This was a follow-up of a previous study in 2007 that led to several recommendations for radiation protection for interventional fluoroscopy. The results indicate that most recommendations have been followed. However, radiation-induced complications from interventional procedures are still often not recorded in the appropriate register. Furthermore, even though professionals with appropriate training in radiation protection are usually involved in interventional procedures, this often is not the case when these procedures are carried out outside the radiology department. Although this involvement is not required by Dutch law, it is recommended to have radiation protection professionals present more often at interventional procedures. Further improvements in radiation protection for interventional fluoroscopy may come from a comparison of dose-reducing practices among hospitals, the introduction of diagnostic reference levels for interventional procedures, and a more thorough form of screening and follow-up of patients
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