In Russia, especially in big cities like St. Petersburg, the annual number of interventional radiological (IR) examinations for both diagnostic and treatment purposes is increasing continuously. However, IR examinations might involve high patient doses and even the risk of skin injures that should be prevented. In this study, the exposure of patients caused by these examinations was analysed. Methods for the estimation of the effective dose (risk reduction of stochastic effects) were proposed. Thresholds for kerma-area product values that correspond to the occurrence of skin injury are also given.

служба по надзору в сфере защиты прав потребителей и благополучия человека, Москва, Россия 3 Санкт-Петербургский научно-исследовательский институт радиационной гигиены имени профессора П.В. Рамзаева Федеральной службы по надзору в сфере защиты прав потребителей и благополучия человека, Санкт-Петербург, Россия 4 Управление Федеральной службы по надзору в сфере защиты прав потребителей и благополучия человека по городу Санкт-Петербургу, Санкт-Петербург, Россия 5 Управление Федеральной службы по надзору в сфере защиты прав потребителей и благополучия человека по Ленинградской области,

The current study was aimed at the justification and proposal of the supplements and corrections that are planned for the implementation in the updated version of the Methodical guidelines “Control of the effective doses of the patients from the X-ray examinations” (MU 2.6.1.2944-11). This study included estimation and/ or update of the values of the conversion coefficients from measurable dose characteristics (entrance-surface dose, dose-area product) to the effective dose for various X-ray examinations. Estimation of the updated conversion coefficients was based both on the home analytical and experimental studies based on the modern protocols of the X-ray examinations, and the results of the published data. Updated values of the conversion coefficients were presented for: fluoroscopic examinations of the gastro-intestinal tract with barium media for adult and pediatric patients; interventional examinations of the adult patients; computed tomography examinations for adult and pediatric patients; dental intraoral examinations. For the first time, the methods of the estimation of the effective dose and corresponding conversion coefficients were presented for: computed tomography of the extremities, whole body, scan of several anatomic regions; angiographic examinations of the heart vessels of the pediatric patients of different age categories; slot-scanning X-ray examinations; bone densitometry.

The study is devoted to the assessment of dose parameters determine the probability of deterministic effects in the skin for patients undergoing high-dose interventional radiological examinations. Particular attention is paid to the analysis of the geometry of the absorbed dose distribution over the patient’s skin for the main types of interventional examinations. The aim of this study was to clarify the methodology for assessment of the maximum absorbed dose in the patients’ skin, taking into account new data. The data collection was carried out in nine city hospitals from Sankt-Petersburg; detailed information about more than 400 procedures was obtained. The data about operation technique for the main types of interventional examinations, physical, technical, geometric and dosimetric parameters for each procedure were registered. Based on the statistical data on distribution of geometric procedure parameters (fields size and projections) possible localizations and values of the absorbed dose in certain areas of the patients’ skin were determined. An updated methodology for skin dose assessment based on the recorded dosimetric value of dose area product considering the radiation fields size was presented. As an alternative, an estimation of the maximum skin dose based on the cumulative air kerma at the patient’s reference point – «representative» point for the patient’s skin considering the tube rotation was proposed. This method does not require the information on used field size. The conservative conversion coefficients from the measured dosimetric values to the peak skin dose and trigger values to prevent deterministic effects in the patients’ skin were calculated.

Interventional procedures are accompanied with high levels of patient exposure and even with the possibility of radiation skin damage. That’s why any actions leading to reduction of patients’ exposure levels are of utmost importance. Implementation of diagnostic reference levels is considered to be one of the most successful actions to reduce patient exposure levels. However the basic concept of diagnostic reference levels cannot be used for interventional radiology due to fact that procedures are not standardized. The article studies the main difficulties in applying the standard concept of diagnostic reference levels for interventional radiology procedures and proposes a new concept, taking into account the specifics of these procedures; the domestic and international documents are analyzed. The list of interventional procedures for diagnostic reference levels establishment is suggested based on the statistical data on performed procedures in the Russian Federation. The results of this study were used for the new Russian guidelines “Optimization of radiation protection of patients undergoing medical radiation diagnostic examinations through the use of diagnostic reference levels”.