1.
Safety Guide SSG-46
The IAEA published in 2018 a new Safety Guide on Radiation Protection and Safety in Medical Uses of Ionizing Radiation,
SSG-46 [4] which recommends how medical uses of ionizing radiation should be carried out safely within the framework of GSR Part 3.
The documents gives additional recommendations on setting and using DRLs,
in line with the ICRP Publication 135 [2].
There are several steps to the establishment of DRLs:
- Establish working group; appoint coordinator and administrator of the database;
- Decide for which imaging procedures DRLs to be established - priority to more frequent and higher dose procedures; simply defined in terms of the anatomical region being imaged or including the clinical purpose of the examination (e.g.
indication based protocols).
- Decide which dose quantities (modality specific,
measurable)
- Decide on the methodology - preferably using sample of patients,
or phantoms (in the absence of adequate patient data)
- Decide on definition of groups of patients,
especialy for pediatrics,
and minimum sample size
- Prepare standardised data collection forms (electronic or paper-based)
- In a particular contributing X-ray room - perform data collection and perform statistical data analysis - set typical dose (median is recomended)
- In a big hospital or set of hospitals: collect data from different X-ray rooms,
performing the same procedure and establish local DRLs
- At country/ region level: collect data from different X-ray rooms,
performing the same procedure (representative sample)
- Perform statistical analysis and set DRL,
usually at 3rd Q (75th percentile)
Once DRLs are established,
they should be known and used by the medical facilities for benchmarking and optimization.
The results of the surveys used to determine typical doses at the radiology facility should be used as part of the ongoing review of the optimization of protection and safety at the facility,
and should be used for comparison with established DRLs.
The results should also be submitted to the organization in the State or region that is responsible for establishing and reviewing national or regional DRLs.
Patient dosimetry surveys,
required by GSR Part 3 [3],
should take place at intervals of no more than five years and preferably no more than three years.
Another trigger for a survey would be the introduction of new equipment or technology into the radiology facility or when significant changes have been made to the protocols or the equipment.
2.
Guidance in the Radiation Protection of Patients website
The Radiation Protection of Patients website is the leading resource for health professionals,
patients and public on the safe and effective use of radiation in medicine.
It has almost 900 000 views,
with annual increase of 40% in audience in last 3 years.
The website part with information for health professional gives answers to a number of frequently asked questions related to Diagnostic Reference Levels in radiology,
structured in in three sections:
-
About DRLs - describes what is the purpose of DRLs,
how to set DRLs,
who is responsible,
do DRLs apply to individual patients; what is the difference between national and local DRLs,
are DRLs effective in improving patient radiation protection
-
DRLs in medical imaging - why do we need DRLs,
which dose quantities are used for setting DRLs,
how DRLs are used,
what can be done for individual patients,
which examination should have DRLs,
how shoud we account for patient size, Where should I start in the absence of well-established national and local support for DRLs; what are the potential pitfalls in comparing your typical dose values (medians) with published DRLs?
-
DRLs in paediatric radiology - which dose quantities are used for setting DRLs for paediatric radiology,
how should we account for patient size,
where should I start in the absence of well-established national and local support for DRLs,
what are the potential pitfalls in comparing local median values with published values?
3.
IAEA Technical Meeting on Patient Dose Monitoring and the Use of Diagnostic Reference Levels for the Optimization of Protection in Medical Imaging
A technical meeting on patient dose monitoring and the use of diagnostic reference levels for the optimization of protection in medical imaging was held at the IAEA headquarters in 2016.
More than 60 professionals from 35 different countries and 8 international organizations and professional bodies participated in this meeting.
The meeting aimed to understand the current situation,
identify strengths and weaknesses in using DRLs for optimization of patient safety and improving medical practice.
Good examples have been demonstrated of well-organized dose surveys,
coordinated either by the national authorities or by the initiative of professionals (“champions”).
Some countries already established dose index registries,
for automatic or web-based data collection,
many others still use paper-based data collection approach.
Research and efforts are going on to make the best use of dose management systems already available in many hospitals and countries.
Networking globally provides effective support.
IAEA actions and support were identified as critical for many less resourced countries in establishment of a methodology and starting with dose data collection and evaluation.
Good practice was demonstrated on establishing cooperation between authorities and professional societies or clinical experts for surveys and DRL setting and periodic stakeholder DRL reviews.
Regulatory inspections were also identified as having role in proper use of DRLs.
Based on the analysis of weaknesses and challenges,
the meeting identified possible solutions and actions needed,
grouped around six main points:
o Human resources: Actions are needed to guarantee sufficient involvement of medical physicists in diagnostic imaging and their recognition; to improve availability and knowledge on radiation protection of radiologists and nuclear medicine specialists; strengthen the motivation and involvement of radiographers in patient dose monitoring.
o Training of medical staff is critical in understanding the use of dose monitoring and DRLs,
the role and responsibilities of each profession on dose reduction technics,
image quality assessment and interpretation,
risks and benefits.
Specialised training is needed of regulatory officers on the concept of optimization using dose monitoring and DRLs.
o Safety and quality culture: Actions are needed to improve awareness on importance of justification and optimization and recognition of the value of team work and holistic strategy,
to increase the contribution of professional societies; encourage accountability,
improve motivation of health professionals,
develop and use means of collaboration.
There is a need to improve government’s and leaders’ awareness on importance of radiation protection in medicine; to increase competence and increase coordination between authorities.
Providing public communication is important.
o Regulations: There is a need to establish or improve legislation and build up infrastructure for radiation protection,
including optimization; enforce employment of medical physicists in diagnostic radiology facilities; increase resources/staff of authorities; increase human capacity.
Patient dosimetry,
DRLs and quality assurance should be mandatory.
o Funding: Lobbying and giving motivation to governments for funding; inrease micro funding.
o Tools and methods have been identified: Establish national program for DRLs,
from setting DRLs to implementation; establish sustainable system to enable frequent updating of DRLs; establish mechanisms for dose collection and reporting; improve standardization of classification systems for medical procedures; provide dosimetry equipment and improve calibration and quality control; improve strategy of DRLs,
specificity to indications and patient size; develop image quality analysis techniques and implementation.
Big data is a challenge,
needs improved patient exposure data management by using electronic automatic systems,
preferably integrated with general electronic health record systems; data validation systems have to be introduced and maintained.
Hospital based local actions in some countries need to be translated to nationwide actions.
Cooperation across countries should be promoted.
The meeting discussed also advanced concepts for optimization,
promoting moving from reactive optimization to proactive optimization actions.
Special focused sessions presented and discussed the role of international organizations,
national professional societies and the role of manufacturers of medical equipment and software.
The meeting findings and recomendations were publised in two papers in scientific journals [5,
6].
4.
IAEA technical support to Member States
The Technical cooperation (TC) program of the IAEA is a powerful instrument for providing assistance to less developed countries.
The TC programme operates in four geographic regions: Africa,
Asia and the Pacific,
Europe and Latin America and the Caribbean.
Within each region,
it helps Member States to address their specific needs,
taking into consideration existing capacities and different operational conditions. Technical cooperation projects can be national,
regional or interregional.
Several projects in each 2-years TC cycle are focusing on improving safety and quality in diagnostic imaging.
As identified above,
there are many issues in implementation of the concept of DRL and optimization,
and when requested by MS,
the IAEA provides expert advice and training to help address these issues.
Data collection forms and guidelines for setting facilities typical doses and DRLs have been developed for different modalities - radiography,
fluoroscopy,
mammography,
hybrid imaging,
CBCT.
These forms have been widely used by the projects counterparts to perform their local surveys and set national DRLs.
A recent example is the published survey from Egypt on setting DRLs in CT [7].
The counterparts are joining efforts in performing multi-national surveys,
an example of which is the survey of pediatric CT doses in 40 countries,
from which international DRLs have been proposed [8,
9,
10].
Many other IAEA supported national and international studies are under way,
aiming to provide an objective information of patient doses and improve optimization of patient protection.