EFFECTIVE DOSE IN PEDIATRIC INTERVENTIONAL CARDIOLOGY.

The aim of this study was to estimate the effective doses (EDs) to children undergoing pediatric interventional cardiology examinations in hospitals of St.-Petersburg, to calculate associated dose conversion coefficients (DCCs) and to investigate their dependence of different parameters of the various procedures. Basic parameters of pediatric cardiology examinations and patient doses were studied in three main pediatric city hospitals. More than 300 examinations were under consideration. The technical, geometrical and dosimetric parameters, as well as patients' parameters, for each individual procedure were collected. All cardiac examinations were divided into five age groups (newborn, 1, 5, 10 and 15 y old). The EDs and the corresponding DCCs from the dose-area product to ED were calculated using PCXMC 2.0 software and based on the collected data. The study included the evaluation of the relations between the DCCs, patient age and parameters of examinations. The results of the study indicated significant dependence of the DCCs on the patients' age and the beam quality. The DCCs for the newborns and 15-year old groups differed by a factor of 10. The maximum estimated ED of 26 mSv was found in the newborn age group.

Patient doses from medical examinations in Russia: 2009-2015.

The aim of this study was to evaluate adult patient doses in Russia in the context of patient protection. Effective doses from x-ray and nuclear medicine examinations were assessed using two approaches. The first was based on data collection performed by the authors in hospitals in St. Petersburg and other 17 Russian regions. The second approach was to assess mean doses through the collective dose estimated annually within the federal data bank ESKID. In 2015, 203 million examinations were conducted in Russia, i.e. 1.4 examinations per capita. The number of examinations has increased by 35% over the last 10 years. Patient doses from x-ray examinations are strongly dependent on the imaging modality. Mean dose increases by an order of magnitude with each x-ray modality from dental examinations (0.01-0.1 mSv) to radiography (0.1-1 mSv), fluoroscopy and CT (1-10 mSv) and to interventional examinations (more than 10 mSv). Mean doses for x-ray examinations are comparable with that of foreign countries. Scintigraphy examinations with 99mTc are associated with mean doses of 1-5 mSv. Mean doses from PET/CT whole body examinations are 15-25 mSv with similar contributions from CT and radiopharmaceuticals. In nuclear medicine, patient doses are lower compared to other countries. According to ESKID data the collective dose from medical exposure in Russia has decreased from 140 000 man-Sv in 2000 to 77 000 man-Sv in 2015. Medical exposure contributes about 13% into a total collective dose. The maximum contribution was from CT examinations, i.e. 45% in 2015. A range of mean doses between different hospitals was up to two orders of magnitude for radiography and one order of magnitude for CT. In interventional studies, the scatter of individual doses was significant. Significant variations in doses between hospitals and some regions indicate the potential for optimization with the focus on interventional examinations, CT and nuclear medicine examinations combined with CT.

Russian practical guidance on radiological support for justification of X-ray and nuclear medicine examinations.

An important part of the justification process is assessment of the radiation risks caused by exposure of a patient during examination. The authors developed official national methodology both for medical doctors and sanitary inspectors called 'assessment of radiation risks of patients undergoing diagnostic examinations with the use of ionizing radiation'. The document addresses patients of various age groups and a wide spectrum of modern X-ray and nuclear medicine examinations. International scale of risk categorisation was implemented by the use of effective dose with account for age dependence of radiation risk. The survey of effective doses in radiology, including CT, mammography, and intervention radiology, and nuclear medicine, including single-photon emission tomography and positron emission tomography, for patients of various age groups from several regions of Russia was used for the risk assessment. The output of the methodology is a series of tables for each diagnostic technology with lists of examinations for three age groups (children/adolescents, adults and seniors) corresponding to various radiation risk categories.