RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY

IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology RADIATION PROTECTION INDIAGNOSTIC ANDINTERVENTIONAL RADIOLOGY L 21: Optimization of Protection in Pediatric Radiology

Introduction • Good radiation protection policy in pediatric radiology is essential. • International guidelines are available to assist in optimization of image quality and radiation dose in pediatric imaging 21: Optimization of Protection in Pediatric Radiology

Topics • General recommendations • Quality criteria for radiographic images (EUR-16261 document) • Recommendations for X Ray equipment and rooms for pediatric radiology • References 21: Optimization of Protection in Pediatric Radiology

Overview • To become familiar with the principles of radiation protection in pediatric radiology, the X Ray systems to be used and the principles of optimization and quality control 21: Optimization of Protection in Pediatric Radiology

IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology Part 21: Optimization of Protection in Pediatric Radiology Topic 1: General recommendations for pediatric radiology

General recommendations for pediatric radiology • General, equipment and installation considerations • The generator should provide short exposure times (3 milliseconds) with sufficient power to obtain appropriate exposure • The generator should be high frequency to improve the accuracy and reproducibility of exposures • Automatic exposure control (AEC) devices should be used with caution in pediatrics • AEC should have specific technical requirements for pediatrics 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Careful manual selection of exposure factors usually results in lower doses • X Ray rooms for pediatrics should be designed for improving the child’s cooperation (control panel within easy reach, etc.) • Fast screen-film combinations or digital radiography have advantages (reduction of dose) and limitations • Low-absorbing materials in cassettes, table tops, etc. are important in pediatrics radiology 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Many examinations can be carried out without antiscatter grids (small volume irradiated, less scatter), thereby reducing the dose to the patient by a factor of two or more • Antiscatter grids for pediatrics should have specific technical requirements • Antiscatter grid should be removable in pediatric equipment, particularly fluoroscopic systems • Image intensifiers should have high conversion factors for reducing patient dose in fluoroscopic systems 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Specific kV-mA dose rate curves for automatic brightness control (ABC) should be used in fluoroscopic systems for pediatrics. • There should be a “floor” of 70 kV on fluoro • It is preferable not to use the ABC unless there is an automatic cut-off device. • Specific protocols should be used for pediatric patients in CT, e.g., lower mAs, lower kVp, etc. 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Consider the advantages and disadvantages of under-couch and over-couch fluoroscopy units • Pulsed fluoroscopy allows for significant patient dose reduction • Digital equipment and the use of frame-grab (Last image hold, or LIH) techniques will result pediatric dose reduction • The cine playback (digital) and video playback (digital or conventional fluoroscopy) in screening examinations may allow patient dose reductions • Additional tube filtration will reduce pediatric dose with no impact on image contrast 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Reduction of exposure • Repeat analysis should be carried out as part of the QC program. Feedback should be provided to the radiographers • Immobilization can reduce the repeat rate • Immobilization devices should be used. The role of simple aids such as tape, sponge wedges, and sand bags should also be considered. 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Short exposure times can improve image quality and reduce the number of repeat films • The use of mobile X Ray units for pediatrics should be restricted due to the difficulty in obtaining short exposure times • Radiographers should have specific training in pediatric radiology • Gonadal protection is important in pediatric radiology. Several sizes and types should be available 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Collimation is important. Every image should be collimated to the body part of interest. • The correct patient positioning and collimation is important in pediatrics, particularly for excluding the gonads from the direct beam • It is important to establish whether adolescent girls might be pregnant when abdominal examinations are contemplated 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Motion is a major problem in children and could require specific adjustment of radiographic techniques • Proper consultative relationship between the referring physician and the radiologist is especially important in pediatrics • Protocols and diagnostic pathways should be promoted 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Some radiological examinations are of questionable value in children (e.g., follow-up chest radiographs in simple pneumonia, abdominal radiographs in suspected constipation, etc.) • The repetition of a radiological examination in pediatrics should be at the discretion of the radiologist. 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Appropriate projections for minimizing dose in high risk tissues should be used (PA projections should replace AP where possible for spinal examinations) • Additional filters should be available to enable them to be easily changed (1 mm Al; 0.1 and 0.2 mm Cu should be available). • Shaped filters are available to reduce dose and improve image quality for full spine radiographs 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Dedicated pediatric room or complete sessions dedicated to pediatric radiography should be available • Experienced staff who can obtain the child’s confidence and cooperation in a secure and child-friendly environment are of paramount importance in reducing radiation doses in pediatrics • Specific referral criteria for pediatric radiology should be available, e.g., for head injury where the incidence of injury is low 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Referral criteria for all X Ray examinations of children should be established, especially those which may be age-related, e.g., scaphoid not ossified below age of 6 years; nasal bones cartilaginous below age of 3 years • Higher kV techniques should be used when possible in order to reduce pediatric doses. • Long focus patient distances could be used to minimize patient entrance dose (with the compromise of appropriate exposure times) 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Fluoroscopy should not be used for patient positioning. • Audit and quality control is essential for optimizing image quality and patient dose 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology Risk factors • Pediatric examinations require special consideration in the justification process since children are at greater risk of incurring stochastic effects, • The benefit of high dose, high risk examinations (e.g., computed tomography, IVU, etc.) should be carefully weighed against the increased risk 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology Risk factors • Longer life expectancy in children means a greater potential for manifestation of possible harmful effects of radiation • Radiation doses used to examine young children should generally be much lower than those employed in adults • Risk factors for cancer induction in children is between 2 and 3 times higher than for adults 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology Patient dosimetry – Diagnostic Reference Levels (DRLs) • Measuring patient doses in pediatrics presents special difficulties (small values) • Dosimetric techniques used in pediatrics should be specifically adapted • Patient doses are related to patient size 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • DRLs in pediatrics should be related to patient size, not age • DRLs presently available for pediatrics are limited (See EUR-16261 and NCRP Report on DRLs, available 2012) 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology Protection of personnel and parents • Parents can cooperate in the radiological examination of their children if they are duly informed and protected • Parents’ exposure in this situation can be considered as a medical exposure but optimization criteria must be applied 21: Optimization of Protection in Pediatric Radiology

General recommendations for pediatric radiology • Parents or helpers should be duly informed and should know exactly what is required of them • Pregnant women should not be allowed to help during pediatric examinations • Lead aprons and lead gloves (if the hands are near the direct radiation field) should be used 21: Optimization of Protection in Pediatric Radiology

ICRP-ISR “smart” message for pediatrics 21: Optimization of Protection in Pediatric Radiology

IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology Part 21: Optimization of protection in Pediatric Radiology Topic 2: Quality criteria for radiographic images (EUR document)

European Guidelines on Quality Criteria for Diagnostic Radiographic Images in Paediatrics, July 1996. EUR 16261 EN Free PDF version available at: http://www.cordis.lu/fp5-euratom/src/lib_docs.htm 21: Optimization of Protection in Pediatric Radiology

21: Optimization of Protection in Pediatric Radiology

Criteria related to images • The Image Criteria for pediatric patients presented for a particular type of radiograph are those deemed necessary to produce an image of standard quality • No attempt has been made to define acceptability for particular clinical indications • The image criteria allow an immediate evaluation of the image quality of the respective radiograph. They are appropriate for the most frequent requirements of radiographic imaging of pediatric patients 21: Optimization of Protection in Pediatric Radiology

Criteria related to images • The anatomical features and body proportions vary due to the developmental process in infancy, childhood and adolescence • They are different in the respective age groups and are distinct from those of a mature patient • The Guidelines presuppose knowledge of the changing radiographic anatomy of the developing child. • The term “consistent with age” indicates that the respective image criteria essentially depend on the age of the patient 21: Optimization of Protection in Pediatric Radiology

Criteria related to images • The smaller body size • The age dependent body composition • The lack of co-operation and many functional differences (e.g., higher heart rate, faster respiration, inability to stop breathing on command, increased intestinal gas, etc.) • Prevent the production of radiographic images in pediatric patients to which standard adult image criteria can be applied 21: Optimization of Protection in Pediatric Radiology

Criteria related to images • Correct positioning of pediatric patients will be more difficult than in co-operative adult patients • Use of auxiliary devices is essential for effective immobilization • Sufficient skill and experience of the imaging staff, and ample time for the particular examination, are necessary to obtain quality images in infants and younger children 21: Optimization of Protection in Pediatric Radiology

Criteria related to images • Incorrect positioning is the most frequent cause of inadequate image quality in pediatric radiographs • Image criteria for the assessment of adequate positioning (symmetry and absence of tilting etc) are much more important in pediatric imaging than in adults • A lower level of image quality than in adults may be acceptable for certain clinical indications 21: Optimization of Protection in Pediatric Radiology

Criteria related to images • A lower quality image cannot be justified unless this has been part of optimization and is associated with a lower radiation dose • The fact that the X Ray was taken from of non-cooperative pediatric patient (anxious, crying, heavily resisting) is not an excuse for producing an inferior quality image which is often associated with excessive dose 21: Optimization of Protection in Pediatric Radiology

Criteria for Radiation Dose to the Patient • DRLs are expressed as the entrance surface dose for a “standard sized” pediatric patient • DRLs are only available for the most frequently performed types of examinations for which sufficient data is available 21: Optimization of Protection in Pediatric Radiology

Criteria for Radiation Dose to the Patient • Some form of dose measurement is required in order to audit patient doses • This requires representative sampling of the patient population • A number of dose measurement methods are described in the European Guidelines 21: Optimization of Protection in Pediatric Radiology

General principles associated with good imaging performance Image Annotation • The patient identification, date of examination, position markers, and name of the facility must be present and legible on the image • These annotations should not obscure the diagnostically relevant regions of the image • Identification of the individual carrying out the examination should be on the film 21: Optimization of Protection in Pediatric Radiology

General principles associated with good imaging performance Quality Control of X Ray Imaging Equipment • Quality control programs should be in use in every medical X Ray facility and should monitor image quality and patient dose • Operating levels and control limits should be established by a medical physicist 21: Optimization of Protection in Pediatric Radiology

General principles associated with good imaging performance Low Attenuation Materials • Recent developments in materials for cassettes, grids, tabletops and front plates of film-changers using carbon fiber and some new plastics enable significant reduction in patient doses • This reduction is most significant in the radiographic voltage range recommended in pediatric patients and may reach 40%. Use of these materials should be encouraged 21: Optimization of Protection in Pediatric Radiology

General principles associated with good imaging performance Patient Positioning and Immobilization • Patient positioning must be exact whether or not the patient co-operates. • For infants, toddlers, and younger children immobilization devices, will help to assure that: • the patient does not move • the beam can be centered correctly • the film is obtained in the proper projection • accurate collimation limits the field size exclusively to the required area • shielding of the remainder of the body is possible. 21: Optimization of Protection in Pediatric Radiology

General principles associated with good imaging performance Patient Positioning and Immobilization 21: Optimization of Protection in Pediatric Radiology

General principles associated with good imaging performance Patient Positioning and Immobilization • Immobilization devices must be easy to use, and their application atraumatic to the patient. • Their usefulness should be explained to the accompanying parent(s). • Radiological staff members should only hold a patient under exceptional circumstances • Examination time allocation must include the time to explain the procedure not only to the parents but also to the child 21: Optimization of Protection in Pediatric Radiology

General principles associated with good imaging performance Field Size and X Ray Beam Limitation • Inappropriate field size is the most important fault in pediatric imaging • A field which is too small will exclude potentially important information • A field which is too large will not only reduce image contrast by increasing the amount of scattered radiation but also result in unnecessary radiation exposure outside the area of interest 21: Optimization of Protection in Pediatric Radiology

General principles associated with good imaging performance Field Size and X Ray Beam Limitation • Correct beam limitation requires proper knowledge of the external anatomical landmarks by the radiographer • These differ with the age of the patient according to the varying proportions of the developing body. • In addition, the size of the field of interest depends much more on the nature of the underlying disease in infants and younger children than in adults 21: Optimization of Protection in Pediatric Radiology

General principles associated with good imaging performance Field Size and X Ray Beam Limitation • A basic knowledge of pediatric pathology is required for radiographers to assure proper beam limitation • The acceptable minimal field size is set by the recognizable anatomical landmarks for specific examinations 21: Optimization of Protection in Pediatric Radiology

RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY