Systematic literature review on the benefit of patient protection shielding during medical X-ray imaging: Towards a discontinuation of the current practice

Attitudes and awareness regarding the European consensus statement on the use of patient contact shielding

INTRODUCTION

Lead contact shielding has been an essential element of patient radiation protection since its introduction in the early 1900s. The European Consensus Statement (ECS) on Patient Contact Shielding argues that diagnostic radiation doses have decreased to negligible levels. Given the potential for lead shielding to be misaligned or displaced, the ECS recommends refraining from its use to prevent the occurrence of repeated radiation exposures. This study aims to describe the awareness of radiographers concerning the European Consensus Statement with emphasis dedicated to shielding outside the FOV or out-of-field shielding (OFS).

METHODS

An online survey was designed to assess radiographer's awareness and attitudes to the ECS. This survey incorporated quantitative and qualitative elements. The survey was distributed to a target population of registered radiographers.

RESULTS

There were 112 participants who registered as Irish radiographers. Seventy-nine (71 %) participants knew of the European Consensus publication on patient contact shielding. Eighty-one (72.3 %) participants agreed that the risk from ionising radiation in general radiography exams is negligible. Seventy-two (63.4 %) participants felt more training should be provided on OFS. Thirty-two (28.6 %) participants agreed that some patients are more sensitive to ionising radiation, and shielding may be the safest action.

CONCLUSION

The results of this study indicate that responding radiographers are aware of the European Consensus Statement and largely agree with its recommendations to discontinue the use of shielding during low-dose X-ray examinations. Additionally, the study reveals that most radiographers do not employ lead shielding in various common clinical practice scenarios.

IMPLICATIONS FOR PRACTICE

Further investigation is required to evaluate radiographer's attitudes toward contact shielding. Future research might explore the psychological impact on patients, infection concerns, departmental protocols, and discomfort related to contact shielding.

Evaluation of Male Gonadal Radiation Dose in Abdominal X-ray Examinations: The Impact of Radiographic Projections and Kilovoltage Peak (kVp)

In abdominal X-ray examinations, radiosensitive organs such as the gonads within or near the imaging region are at risk of radiation exposure. Minimizing the dose to these organs is crucial to reducing unnecessary radiation. This study utilized optically stimulated luminescence dosimeters (OSLDs) to measure the radiation dose to the male gonads at varying kilovoltage peak (kVp) settings while keeping the milliampere-seconds (mAs) constant across different radiographic projections. A Siemens Multix Top X-ray system (Siemens Healthcare Inc., Erlangen, Germany) was used for imaging, with three kVp settings (81, 83, and 85) and a fixed exposure of 32 mAs. The study employed a RANDO phantom (The Phantom Laboratory, Salem, New York, USA) to simulate human anatomy. The entrance surface dose (ESD) was recorded by placing an OSLD on the phantom's surface corresponding to the gonad location. In contrast, the absorbed dose was measured by positioning the OSLD at the gonadal region inside the phantom. Six abdominal projections were evaluated: anteroposterior (AP) supine, posteroanterior (PA) prone, lateral, AP erect, lateral decubitus, and dorsal decubitus. All imaging was conducted with a source-to-image distance of 100 cm. The dorsal and lateral decubitus positions resulted in relatively higher radiation doses. Conversely, the AP supine, PA prone, lateral, and AP erect positions exhibited lower ESD and absorbed doses. Statistical analysis revealed no significant differences in ESD and absorbed doses for male gonads across the projections. Additionally, an increase in kVp correlated with a reduction in both ESD and absorbed dose. This study emphasizes the critical importance of optimizing kVp settings to minimize radiation exposure to male gonads during abdominal X-ray examinations. It also emphasizes the significant influence of radiographic projections on radiation dose, advocating for careful selection of projections to enhance patient safety. These findings contribute to advancing radiological practices, reducing unnecessary radiation exposure, and improving patient care standards.

An investigation into the knowledge, attitudes, and practice of radiation protection in interventional radiology and cardiac catheter-laboratories

BACKGROUND

According to current literature, there is a lack of information regarding the radiation protection (RP) practices of interventional radiology (IR) and cardiology catheter laboratory (CCL) staff. This study aims to determine the RP practices of staff within IR and CCLs internationally and to suggest areas for improvement.

METHODS

A cross-sectional study in the form of an online questionnaire was developed. Participation was advertised via online platforms and through email. Participants were included if they were healthcare professionals currently working in IR and CCLs internationally. Questionnaire design included Section 1 demographic data, Section 2 assessed RP training and protocols, Section 3 surveyed the use of different types of RP lead shields, both personal and co-worker use and Section 4 assessed other methods of minimising radiation dose within practice. Questions were a mix of open and closed ended, descriptive statistics were used for closed questions and thematic analysis was employed for open ended responses.

RESULTS

A total of 178 responses to the questionnaire were recorded with 130 (73 %) suitable for analysis. Most respondents were female (n = 94, 72 %) and were radiographers (n = 97, 75 %). Only 68 (53 %) had received training, the majority receiving this in-house (n = 54, 79 %). 118 (98 %) of respondents had departmental protocols in place for RP. Radiology managers (n = 106, 82 %) were most likely to contribute to such protocols. Multiple methods of dose minimisation exist, these include low-dose fluoroscopy, staff rotation, radiation dose audits and minimal time in the controlled areas. Respondents reported that lead apron shields were wore personally by 99 % of respondents and by co-workers in 95 % of cases.

CONCLUSION

The practices of RP by IR and CCL staff in this survey was variable and can be improved. The unavailability of basic radiation protection tools and RP specific training courses/modules were some of the reasons for sub-optimal self-protection against ionising radiation reported by respondents.

Multicentric characterization of organ-based tube current modulation in head computed tomography: A dosimetric and image quality study

PURPOSE

To evaluate the efficiency of organ-based tube current modulation (OBTCM) in head Computed Tomography (CT) for different radiology departments and manufacturers.

MATERIALS AND METHODS

Five CT scanners from four radiology departments were evaluated in this study. All scans were performed using a standard and a routine head protocol. A scintillating fiber optic detector was placed directly on the gantry to measure the tube exit kerma. Image quality was quantified on a 16-cm HEAD phantom by measuring the signal-to-noise ratio (SNR) and the standard deviation of the Hounsfield units (HU) of circular regions of interest placed in the phantom. The Noise Power Spectrum (NPS) was also studied. Measured values were compared on images with and without OBTCM.

RESULTS

The reduction rates in tube exit kerma, on the anterior part, vary between 11 % and 74 % depending on the CT scanner and the protocol used. The tube exit kerma on the posterior part remains unchanged in GE and Canon CT scanners. On the contrary, the tube exit kerma to the posterior part increases by up to 39 % in Siemens CT scanner. Image noise and SNR increase by up to 10 % in the five CT scanners. Nonetheless, the differences in noise and SNR are statistically significant (p-value < 0.05).The analysis of the NPS indicates that the noise texture remains unchanged.

CONCLUSION

OBTCM reduces the tube exit kerma to the anterior part of the gantry without reducing substantially image quality for head protocols.

Factors affecting radiographers' use of dose-reduction measures

This study investigates radiographers' views on implementing dose-reduction measures, with a focus on verifying patient identity and pregnancy status, practising gonad shielding in men and using compression. An electronic questionnaire was distributed to radiographers working in general radiography and/or computed tomography. The questionnaire was based on factors from a framework for analysing risk and safety in clinical medicine. Ordered logistic regressions were used to analyse associations among factors and use of dose-reduction measures. In total, 466 questionnaires were distributed and 170 radiographers (36%) completed them. Clear instructions and routines, support from colleagues, knowledge and experience, a strong safety culture, managerial support and access to proper equipment influence the likelihood of using dose-reduction measures. The strongest associations were found between support from colleagues and verifying pregnancy status (OR = 5.65,P= 0.026), safety culture and use of gonad shielding (OR = 2.36,P= 0.042), and having enough time and use of compression (OR = 2.11,P= 0.003). A strong safety culture and a supportive work environment appears to be essential for the use of dose-reduction measures, and education, training and stress management can improve utilisation of dose-reduction measures.

Management of pregnant or potentially pregnant patients undergoing diagnostic and interventional radiology procedures: Investigation of clinical routine practice

It is well known that foetuses are highly sensitive to ionising radiation and special attention to justification and optimisation of radiological procedures involving a pregnant patient is required. A task to review, validate and compare different approaches to managing the pregnant patient and to estimating the associated foetal doses arising from a diagnostic or interventional radiology (DIR) procedure was designed in the framework of EURADOS working group 12. As a first step, a survey of radiation protection practice including dosimetry considerations among EURADOS members was performed using online questionnaire. Then, to evaluate the possible differences in the estimated foetal doses, a comparison of assessed dose values was made for three cases of pregnant patients that underwent different CT procedures. More than 120 professionals from 108 institutions and 17 countries that are involved in managing pregnant patients undergoing DIR procedures answered the questionnaire. Most of the respondents use national or hospital guidelines on the management of pregnant patients undergoing DIR procedures. However, the guidelines differ considerably among respondents. Comparison of foetal dose assessments performed by dosimetry experts showed the variety of methods used as well as large variability of estimated foetal doses in all three cases. Although European and International commission on radiation protection guidelines already exist, they are more than 20 years old and, in some aspects, they are obsolete. This paper shows that there is a need to revise and update these guidelines.

The effect of contact radiation shielding on breast dose during CT abdomen-pelvis: a phantom study

This study aims to investigate if contact shielding reduces breast radiation dose during computed tomography (CT) abdomen-pelvis examinations using automatic tube current modulation to protect one of the four most radiosensitive organs during CT examinations. Dose measurements were taken with and without contact shielding across the anterior and lateral aspects of the breasts and with and without organ dose modulation (ODM) to quantify achievable dose reductions. Although there are no statistically significant findings, when comparing with and without shielding, the mean breast surface dose was reduced by 0.01 μSv without ODM (1.92-1.91 μSv, p = 0.49) and increased by 0.03 μSv with ODM (1.53-1.56 μSv, p = 0.44). Comparing with and without ODM, the mean breast surface dose was reduced by 0.35 μSv with shielding (1.91-1.56 μSv, p = 0.24) and by 0.39 μSv without shielding (1.92-1.53 μSv, p = 0.17). The addition of contact shielding does not provide significant breast surface radiation dose reduction during CT abdomen-pelvis.

Exploring radiographers' perceptions and knowledge about patient lead shielding: a cross-sectional study in Greece and Cyprus

The present study aimed to explore radiographers' knowledge, clinical practice and perceptions regarding the use of patient lead shielding in Greece and Cyprus. Qualitative data were analyzed using conceptual content analysis and through the classification of findings into themes and categories. A total of 216 valid responses were received. Most respondents reported not being aware of the patient shielding recommendations issued by the American Association of Physicists in Medicine (67%) or the guidance issued by the British Institute of Radiology (69%). Shielding-related training was generally not provided by radiography departments (74%). Most of them (85%) reported that they need specific guidance on lead shielding practices. Also, 82% of the respondents said that lead shielding should continue to be used outside the pelvic area when imaging pregnant patients. Pediatric patients are the most common patient category to which lead shielding was applied. Significant gaps in relevant training have been identified among radiographers in Greece and Cyprus, highlighting the need for new protocols and provision of adequate training on lead shielding practices. Radiography departments should invest in appropriate shielding equipment and adequately train their staff.

European survey on the use of patient contact shielding during radiological examinations

OBJECTIVES

Contact shielding (CS) of patients during X-ray studies has been used for decades to protect radiosensitive organs. This practice has not changed much despite increasing evidence that CS is not useful in many cases. The Gonad And Patient Shielding (GAPS) group-founded by representatives of the main European bodies involved in radiology-promoted this survey to assess the current practice of CS among European radiology departments and the attitude towards a non-shielding policy.

METHODS

Over a four-month period (15 May-15th September 2021) European Society of Radiology and European Society of Paediatric Radiology radiologist members were invited to respond to a web-based questionnaire consisting of 59 questions.

RESULTS

225 centres from 35 countries responded to this survey. CS was routinely applied in at least one radiological modality in 49.2% of centres performing studies in adults, 57.5% of centres performing studies in children, and 47.8% of centres performing studies on pregnant women. CS was most frequently used in conventional radiography, where the most frequently shielded organs were the gonads, followed by thyroid, female breasts, and eye lens. 83.6% respondents would follow European recommendations on the use of CS when provided by the main European bodies involved in radiology.

CONCLUSIONS

This review shows that CS is still largely used across Europe. However, a non-shielding policy could be adopted in most departments if European professional societies provided recommendations. In this regard, a strong commitment by European and national professional societies to educate and inform practitioners, patients and carers is paramount.

CLINICAL RELEVANCE STATEMENT

According to this survey expectations of patients and carers, and skepticism among professionals about the limited benefits of CS are the most important obstacles to the application of a no-shielding policy. A strong commitment from European and national professional societies to inform practitioners, patients and carers is fundamental.

The effect of breast shielding outside the field of view on breast entrance surface dose in axial X-ray examinations: a phantom study

PURPOSE

The purpose of this study was to evaluate the effect of outside-field-of-view (FOV) lead shielding on the entrance surface dose (ESD) of the breast on an anthropomorphic X-ray phantom for a variety of axial skeleton X-ray examinations.

METHODS

Using an anthropomorphic phantom and radiation dosimeter, the ESD of the breast was measured with and without outside-FOV shielding in anterior-posterior (AP) abdomen, AP cervical spine, occipitomental 30° (OM30) facial bones, AP lumbar spine, and lateral lumbar spine radiography. The effect of several exposure parameters, including a low milliampere-seconds technique, grid use, automatic exposure control use, wraparound lead (WAL) use, trolley use, and X-ray table use, on the ESD of the breast with and without outside-FOV shielding was investigated. The mean ESD (μSv) and standard deviation for each radiographic protocol were calculated. A one-tailed Student's t-test was carried out to evaluate whether ESD to the breast was reduced with the use of outside-FOV shielding.

RESULTS

A total of 920 breast ESD measurements were recorded across the different protocol parameters. The largest decrease in mean ESD of the breast with outside-FOV shielding was 0.002 μSv (P = 0.084), recorded in the AP abdomen on the table with a grid, OM30 on the table with a grid, OM30 standard protocol on the trolley, and OM30 on the trolley with WAL protocols. This decrease was found to be statistically non-significant.

CONCLUSION

This study found no significant decrease in the ESD of the breast with the use of outside-FOV shielding for the AP abdomen, AP cervical spine, OM30 facial bones, AP lumbar spine, or lateral lumbar spine radiography across a range of protocols.

[Use of patient radiation shielding in diagnostic and interventional radiology]

The use of patient contact shielding provides an opportunity to reduce patient radiation exposure. Recently, the use has been the subject of controversy. The Radiation Protection Committee has published a recommendation on the use of patient radiation shields by considering the recent findings on dose savings but also the risks of incorrect use. In this article, a specification for the more frequently used types of X‑ray examination is given, which describes whether and which radiation contact shielding should be used. This is accompanied by a rationale for the use or non-use of patient radiation protection agents. Problems and possible errors are explained, as well as how to deal with special situations such as pregnant women and children.

Evaluation of silicone rubber-lead shield's effectiveness in protecting the breast during thoracic CT

Radiation of thoracic computed tomography (CT) involves the breast although it is not considered an organ of interest. According to the International Commission on Radiological Protection (ICRP) No. 103, the breast is an organ with a high level of sensitivity when interacting with x-rays, increasing the potential risk of breast cancer. Therefore, the radiation dose must be optimized while maintaining image quality. The dose optimization can be accomplished using a radiation shield. This study aims to determine the effect of silicone rubber (SR)-lead (Pb) in various thicknesses as an alternative protective material limiting dose and preserving the image quality of the breast in thoracic CT. SR-Pb was made from SR and Pb by a simple method. The SR-Pb had thicknesses of 3, 6, 9, and 12 mm. The breast dose was measured using a CT dose profiler on the surface of the breast phantom. The CT number and the noise level of the resulting image were determined quantitatively. The dose without the radiation shield was 5.4 mGy. The doses measured using shielding with thicknesses of 3, 6, 9, and 12 mm were 5.2, 4.5, 4.3, and 3.3 mGy, respectively. Radiation shielding with a thickness of 12 mm reduced breast surface dose by up to 38%. The CT numbers and noise levels for the left and right breast phantom images were almost the same as those ​​without radiation shields indicating there were only slight artifacts in the image. Therefore, SR-Pb is considered a good shielding material which can be pplied in a clinical setting by placing it directly on the breast surface for dose optimization.

Using barium as an internal radioprotective shield for pregnant patients undergoing CT pulmonary angiography: A retrospective study

PURPOSE

The purpose of our retrospective study was to assess the effect of barium sulfate contrast medium on radiation dose and diagnostic quality of CT Pulmonary Angiography (CTPA) in an in-vivo study of pregnant patients.

METHODS

Our retrospective study included 33 pregnant patients who underwent CTPA to exclude pulmonary embolism. The patients received oral 40% w/v barium solution just prior to the acquisition of their planning radiograph. All CTPA were performed on 64-slice, single-source CT scanners with AEC with noise index = 28.62-31.64 and the allowed mA range of 100-450. However, only 5/33 patients had mA modulation (AEC 100-450 mA range), while 28/33 patients had mA maxed out at the set maximum mA of 450 over the entire scan range. We recorded CTDIvol (mGy), DLP (mGy.cm) and scan length. The same information was recorded in weight-and scanner-matched, non-pregnant patients. Statistical tests included descriptive data (median and interquartile range) and Mann-Whitney test.

RESULTS

There were no significant differences in CTDIvol and DLP between the barium and control group patients (p > 0.1). The median mA below the diaphragm was significantly higher in each patient with barium compared to the weight and scanner-matched patient without barium. Evaluation of lung and subsegmental lower lobe pulmonary arteries was limited in 85% barium group. Due to thin prospective section thickness (1.25 mm), most patients were scanned at maximum allowed mA for AEC.

CONCLUSION

Use of AEC with thick barium in pregnant patients undergoing CTPA as an internal radioprotective shield produces counterproductive artifacts and tube current increments.

Evaluation of thyroid radiation dose during abdominal Computed Tomography procedures and dose reduction effectiveness of thyroid shielding

INTRODUCTION

During abdominal Computed Tomography (CT) studies, vicinity organs receive a dose from scatter radiation. The thyroid is considered an organ at greater risk due to high radiosensitivity.

METHODS

The primary objective of this study was to determine the entrances surface dose (ESD) to the thyroid during abdominal CT studies and to evaluate the efficiency of dose reduction by lead shielding. The calibrated thermoluminescence dosimeter (TLD) chips were used to measure the ESD during 180 contrast-enhanced (CE) and non-contrast-enhanced (NC) abdominal CT studies in the presence and absence of lead shielding.

RESULTS

Thyroid shielding reduces the ESD by 72.3% (0.55 mGy), 86.5% (2.95 mGy) and 64.0% (2.24 mGy) during NC, 3-phase and 4-phase abdominal CT scans. Also, the patient height was identified as a parameter that inversely influenced the thyroid dose, proving that the taller patients receive less dose to the thyroid. Regardless, the scan parameters such as time and display field of view (DFOV) positively impact the thyroid dose.

CONCLUSION

Lead shielding can prevent the external scatter reaching the thyroid region by 64%-87% during the non-vicinity scans such as abdomen CT. However, the actual dose saving lies between 0.2% and 0.4%, compared to the total effective dose of the whole CT procedure.

IMPLICATIONS FOR PRACTICE

The thyroid shield can effectively reduce external scatter radiation during abdominal CT procedures. However, the dose saving is insignificant compared to the total effective dose from the whole examination. Therefore, the use of thyroid shielding should be carefully evaluated during CT abdomen procedures.