Some concepts of radiation protection are not well understood and must be refreshed periodically. The basic knowledge that a vascular surgeon must have about radiation protection for patients and ...staff is summarised.
Diagnostic reference levels are a form of investigation into the medical exposure of patients during diagnostic and endovascular procedures that help to optimise them. Radiological quantities such as dose area product, also known as kerma area product and cumulative dose, are the most relevant to the patient. Equivalent dose, in mSv, determines the dose limits for staff. The effective dose (related to absorbed dose), also in mSv, represents the global risk of cancer and hereditary effects. For patient protection, the most important factors are fluoroscopy time, collimation, magnification, keeping the patient as near as possible to the image detector and as far as possible away from the tube, and trying to work in fluoroscope mode. Regarding occupational protection, distance, shielding, and dosimetry are the most important.
With the increased use of endovascular procedures, radiation protection is an issue that has grown in importance. Radiation protection is based on three principles: justification; optimisation; and dose limits. Every action focused on reducing a patient's radiation dose will also reduce the dose to staff. Basic principles such as “the further away the better”, “always use a lead apron, thyroid protector, and lead glasses”, and “do not forget to wear personal dosimeters” must be remembered at all times.
•Radiation protection focuses on healthcare staff and patients.•Diagnostic reference levels are essential in standard procedures.•Operators should know their personal dose and radiation limits.•Time, distance, and shielding are important.
Guidelines for patient radiation dose management Stecker, Michael S; Balter, Stephen; Towbin, Richard B ...
Journal of vascular and interventional radiology,
07/2009, Letnik:
20, Številka:
7 Suppl
Journal Article
Purpose
This study presents a prototype smartphone application for occupational dosimetry in interventional practices based on electronic personal dosimeters to assist in dose monitoring.
Methods
The ...prototype receives and records information from the occupational dose report containing the cumulative dose of electronic personal dosimeters worn over the apron at chest level and electronic area dosimeters located on C‐arms (reference dosimeters), for each fluoroscopy‐guided procedure. Using their smartphones, personnel involved in interventional practices can review and compare their occupational records with an investigation level, the dose limits, and their department colleagues (anonymously). The ratio between Hp(10) measured by the personal and the reference dosimeters at the C‐arm is presented as an indicator of consistent use of suspended operator shield. Some general results extracted from the first months of use are presented.
Results
The reference dosimeter located at the C‐arm (without lead protection and acting as an ambient dosimeter) recorded in one of the laboratories 217 mSv during 308 procedures over 5 months, showing an indication of the radiation risk present in an interventional laboratory. The ratio between the personal cumulative dose and the dose at a reference C‐arm dosimeter ranged from 0.2% to 1.67% (a factor of 8.5) for different interventionalists. These differences suggest different protection habits among interventional operators, as well as a target for dose reduction.
Conclusions
With this system, professionals have easy access to their occupational dosimetry records (including information on the workload) in the setting of their interventional departments, to thereby actively engage in the protection process.
Notwithstanding that 100 mSv is not a threshold for radiation effects, cumulative effective dose (CED) for patients of ≥100 mSv derived from recurrent imaging procedures with ionising radiation has ...been recently the topic of several publications. The International Commission on Radiological Protection has alerted on the problems to use effective dose for risk estimation in individual patients but has accepted to use this quantity for comparison the relative radiation risks between different imaging modalities. A new International Commission on Radiological Protection document on the use of effective dose (including medicine), is in preparation. Recently published data on the number of patients with CED ≥100 mSv ranged from 0.6 to 3.4% in CT and around 4% in interventional radiology. The challenges to manage the existing situation are summarised. The main aspects identified are: 1) New technology with dose reduction techniques. 2) Refinements in the application of the justification and optimisation for these groups of patients. 3) Patient dose management systems with alerts on the cumulative high doses. 4) Education on the proper use of cumulative effective dose for referrers and practitioners including information for patients. 5) Future research programmes in radiation biology and epidemiology may profit the patient dose data from the groups with high cumulative dose values.
It is relevant to estimate the uncertainties in the measurement of eye lens doses from a personal dosimeter over the protective apron without using additional dosimetry near the eyes. Additional ...dosimetry for interventionists represents a difficulty for routine clinical practice. This study analyses the estimated eye doses from dosimeter values taken at chest level over the apron and their uncertainties. Measurements of
(0.07) using optically stimulated luminescence dosimeters located on the chest over the apron and on the glasses (in the inner and outer part of the protection) were taken from ten interventionalists in a university hospital, in the period 2018-2019 during standard clinical practice. For a total sample of 133 interventional procedures included in our study, the ratio between the
(0.07) on the glasses (left-outer side) and on the chest over the apron had an average of 0.74, with quartiles of 0.47, 0.64, 0.88. Statistically significant differences were found among operators using the U-Mann-Whitney test. The average transmission factor for the glasses was 0.30, with quartiles of 0.21, 0.25, and 0.32. Different complexity in the procedures, in the quality of the scatter radiation and in the individual operational practices, involve a relevant dispersion in the results for lens dose estimations from the over apron dosimeter. Lens doses may be between a 64% and an 88% of the over apron dosimeter values (using median or 3rd quartile). The use of 88% may be a conservative approach.
Are the radiation doses we use in interventional procedures appropriate? Cardiologists should be able to answer this question, which is particularly important in pediatric patients. However, the ...answer matters not only to patients but also to the health professionals involved in these procedures. The occupational radiation doses received by health staff are associated with the doses received by patients, and "optimization" (keeping radiation doses to the minimum needed to achieve the clinical objective of the procedures involved) should be managed comprehensively for patients and professionals alike.1 The International Commission on Radiological Protection (ICRP) recommends using "diagnostic reference levels" (DRLs) to help in the optimization of imaging modalities with ionizing radiation (including interventional procedures).2 DRLs are indicative of "good clinical practice". It is recommended that they be established for specific clinical indications and can be estimated for the local, national, or regional level by using the third quartile of the distribution of the median values of the dose indicators for patients from various centers representative of these clinical practices.2 The term "achievable dose value" has been proposed in the United States for the 50th percentile instead of the third quartile. Although the ICRP has stated that the median could be used as an additional...
The primary goal of radiation management in interventional radiology is to minimize the unnecessary use of radiation. Clinical radiation management minimizes radiation risk to the patient without ...increasing other risks, such as procedural risks. A number of factors are considered when estimating the likelihood and severity of patient radiation effects. These include demographic factors, medical history factors, and procedure factors. Important aspects of the patient's medical history include coexisting diseases and genetic factors, medication use, radiation history, and pregnancy. As appropriate, these are evaluated as part of the preprocedure patient evaluation; radiation risk to the patient is considered along with other procedural risks. Dose optimization is possible through appropriate use of the basic features of interventional fluoroscopic equipment and intelligent use of dose-reducing technology. For all fluoroscopically guided interventional procedures, it is good practice to monitor radiation dose throughout the procedure and record it in the patient's medical record. Patients who have received a clinically significant radiation dose should be followed up after the procedure for possible deterministic effects. The authors recommend including radiation management as part of the departmental quality assurance program.
PDF
