Patient shielding was used from the last 70 years, however, recent literature revealed new approaches. Shielding can be constituted by different materials with diverse atomic number. Lead is the most traditional, nevertheless bismuth and barium had been widely used on the last decades.
According to the use, patient shielding can be divided taking into account the acquisition plane (in-plane and out-of-plane) and the patient contact (with and without). Some particular shielding is more frequently used in specific modalities or examinations with the aim of dose reduction in radiosensitive organs.
On the last 40 years, no hereditary effects from ionising radiation of medical imaging procedures have been observed, examination doses reduced and consequently the gonads exposure reduced significantly. And the radiological equipment technical evolution also provided modern systems that strongly decreased the radiation levels outside the Field of View (FOV).
The use of shielding can also be controversial considering that in-plane shielding can block anatomical information and increase the radiation dose levels if the automatic exposure control (AEC) is used. Out-of-plane shielding impact is described as irrelevant by some authors, taking into account that most of the radiation comes from the scatter inside body.
The chances of repeat the exposure are also described as a concern. However, this fact also depends on patient collaboration and radiographer training. Exclusively paediatric radiographers are more trained to use shielding than the ones that works in a mix centre, with adult and paediatric patients.
Conventionally paediatric procedures involved patient shielding, however in 2015 Eurosafe Imaging recommended to avoid the use of gonadal shielding, for female paediatric patients, considering the ovaries positioning out of shielding area and the dose increase caused by AEC use. On this “Ask Eurosafe Imaging tips and tricks” document is suggested that out-of-plane shielding can be used for male paediatric patients.
More recently, in 2020, Eurosafe Imaging presented a review of patient shielding use recommendations on the European countries. Some countries do not recommend the use of bismuth shielding, as for example Norway. German Commission on Radiological Protection indicates that some computed tomography procedures may include out-of-plane shielding.
Some countries already provide documents to guide the use of patient shielding for diagnostic radiology applications. In the majority of situations shielding is not recommended. A list of a few exceptions is presented: particular patient care pathway, number of repeat examinations, high examination frequency in paediatric patients and a multidisciplinary decision after a patient request.
Image Wisely Campaign, from United States of America, provided some frequently ask questions (FAQs) about gonadal and foetal shielding in order to help professionals decisions and avoid the shielding use.
In our days new studies about patient shielding are still presented, however, more research is needed mainly about out-plane shielding without patient contact.
Actually, a large variation of procedures is present across the countries. Despite some countries presenting different guidance, a few countries don’t have new recommendations and the lack of norms harmonisation and guidelines hinders radiographers’ decisions.
According to Basic Safety Standards, radiographers are involved on benefits and risk patient communication, associated with radiation dose from medical exposure. Radiographers are in direct contact with the patients and the majority of them considering that the use of shielding in each procedure is a radiographer’s decision, must be to lower patient risk.
Is also relevant to be aware, that patients are used to the shielding, especially in paediatric procedures. Based on this, strategies to promote patient/tutor engagement to change the practices are crucial, in order to decrease the patient risk and maintain the confidence on radiography professionals.
The radiographer’s education and training guidelines, presented on “Radiation Protection Report nº 175, from European Commission” and on “European Qualification Framework (EQF), Level 6 Benchmarking Document: Radiographer” from, European Federation of Radiographer Societies, include patient shielding on the learning outcomes (described in knowledge, skills and competences). During the graduation course all the European radiographers learned how to use shielding and a large percentage increased their training on the daily practice or in specific continuing professional development (CPD).
The decision of shield, or not shield, is based in optimised procedures. However, worldwide different levels of radiation exposure optimisation are present. Dose reduction strongly depends on the examination device, the examination technique and the patient situation.
Recommendations must be harmonised in order to change undergraduate radiographer’s education and training, and radiographers CPD, to adapt the practices according to the norms and best practices.
If the technological devices evolve, the practices should be adapted in order to promote patient comfort and engagement without increasing risk.
Dr Joana Santos
This article appears in the latest issue of Omnia Health Magazine. Read the full issue online today.