Artificial sources of radiation account for approximately 14% of the annual radiation dose from all sources of radiation. Because of the increased lifetime risk per unit dose for children, radiographic procedures could lead to increase the radiogenic risk of cancer. This study intended to review the pediatric doses in planar radiography procedures and to assess different methods used to reduce the radiation dose for pediatric patients. Studies addressing pediatric dose optimization were identified from a search of the internet scientific databases. The search in literature was limited to journal articles that were written in English. The findings of the study illustrate that there are many available methods of dose reduction are available. The application of dose reduction methods will reduce the dose up to 75% of its current value. Training of staff is the cornerstone of patient dose optimization in pediatric radiology.
Planar radiograph (plain film or projection radiograph) is the practice of producing two-dimensional images using X-ray radiation. The radiographic images can be received on a film (screen film radiography (SFR)), special cassettes (computed radiography (CR)), or it may directly activate a matrix of solid-state detectors (digital radiography (DR)). SFR and CR systems utilize a cassette that houses the imaging receptor (film or imaging plate (IP)), while DR system captures the image directly onto a flat panel detector without the use of a cassette. Diagnostic radiology is vital for the health care, but due to the radiation risks, radiation protection of the patient becomes an important issue. Medical exposure is the largest source of man-made exposure to ionizing radiation accounting for nearly 96% of all man-made radiation exposure to human and continues to grow substantially [
An inclusive literature review was carried out in order to quantify the radiation dose in different pediatric planar radiography procedures. Therefore, other imaging modalities such as computed tomography (CT) and interventional radiology procedures were excluded. The research strategy for this particular review used the database PubMed, Sage and ScienceDirect in additional to the available data on the internet from international organizations. The search in literature was limited to the journal articles that were written in English and published after 2004 to ensure that the literature being reviewed was recent and up to date. There were no restrictions on the country of origin where the publications were produced, which help to provide a range of opinions and experiences. Articles identified from the refined search results were further reviewed on an individual basis for content.
The biological effects of ionizing radiation (photons or charged particles) due to the absorption of energy at molecular level directly or indirect oxidative damage produced by water radiolysis. The biological effects are classified into two categories: Tissue reactions (deterministic or non stochastic effects) and cancer/hereditary effects (stochastic effects) [
Deterministic effects (or tissue reactions) of ionizing radiation are related directly to the absorbed radiation dose and the severity of the effect increases as the dose increases. A deterministic effect typically has a threshold (of the order of magnitude of 0.1 Gy or higher) under which the effect does not occur. Deterministic effects are based on tissue damage. However, deterministic effects of ionizing radiation do not need to be considered as a health hazard at the low doses delivered during diagnostic radiography procedures [
Stochastic effects occur without specific threshold of radiation doses because ionizing radiation is carcinogenic factor since it can act to initiate, promote and progress cellular changes that lead to cancer. The dose of radiation received by an individual affects the probability of cancer, but not its aggressiveness. The probabilistic nature of this risk means that children have more time to accumulate exposures and damage, and more time after exposure to develop the disease as illustrated in (
Generally recommended measurable dose quantities are the entrance surface air kerma dose (ESAK) for individual radiographic projections and the kerma-area product (KAP) for complete X ray examinations. The ESAK can be directly measured with thermoluminescence dosimeters (TLDs), or it can be estimated on the basis of measured radiation output values for the X-ray tube. The total KAP from a complete examination, even when it involves both fluoroscopy and radiography, can be measured with a KAP meter and then compared directly against an appropriate reference level. Since the dose is critically dependent on patient size, it is recommended that measurements should be made for a representative sample of standard sized patients. The average dose of such a sample of each particular type of radiograph or examination would provide a good indication of the typical clinical practice in each room of an X ray department. The average doses should also be compared against national reference doses, in order to assess local performance [
The ESAK and the KAP are directly measurable quantities. They can be used for comparison against reference levels and for other quality assurance purposes, but they are not directly risk related quantities. Effective doses are needed in order to assess the population’s collective effective dose arising from the medical use of radiation. Organ doses and/or the effective dose cannot be measured but can be estimated on the basis of measured ESAK or KAP values.
The ICRP [
Examination | ESAK (µGy) | ||||
---|---|---|---|---|---|
Age | |||||
0 | 1 | 5 | 10 | 15 | |
Abdomen AP | 110 | 340 | 590 | 860 | 2010 |
Chest PA/AP* | 60 | 80 | 110 | 70 | 110 |
Pelvis AP | 170 | 350 | 510 | 650 | 1300 |
Skull AP | / | 600 | 1250 | / | / |
Skull LAT | / | 340 | 580 | / | / |
*PA: Postero-anterior; AP: Antero-posterior.
group, it would be difficult to interpret whether the observed value of the sample is higher or lower than the diagnostic reference level. A diagnostic reference level does not apply to individual patients.
Lead apron will reduce the testicular absorbed dose by up to 95% [
Pediatric procedures required lower exposure factors than adults to obtain an acceptable diagnostic radiograph due to their thinner body. Therefore, the X-ray machines should be capable to provide the necessary short exposure times with sufficient consistency, even with low target thicknesses [
Referral criteria or justification of the procedures should base on clear clinical indications for pediatric patients. If the procedure is justified by a qualified medical practitioner, the techniques should be specifically tailored for pediatric patients, necessitating improvement in both equipment and staff training; and patient preparation guidelines, exposure factors, diagnostic guidance (reference) levels and image quality criteria should be developed. From a radiological protection perspective, clear justification of radiological examinations for children and young adults is essential. In addition, dose protocols and techniques have to be adapted to children and young adult patients while providing the required diagnostic information, thus optimizing protection.
Parameters | Effects | Patient Dose |
---|---|---|
High frequency generator | Improve the accuracy and reproducibility of exposures | Reduce patient dose |
Mobile X Ray | Long exposure time | Increase patient dose |
Protective shield | Protection of gonads | Reduce patient dose |
Additional filtration | Absorption of soft radiation | Reduce patient dose |
Automatic exposure control (AEC) | Manual selection of exposure factors | Reduce patient dose |
X-ray rooms | Improve patient cooptation | Avoid repetition |
Fast screen-film combinations | Short exposure time | Motion reduction |
Digital radiography | Short exposure time | Avoid motion |
Radiation field collimation | Reduction of scatter radiation | Improve image quality |
Reject analysis | Image quality improvement | Reduce the repetition rate |
Patient immobilization | Image quality improvement | Reduce the repetition rate |
Pulsed mode fluoroscopy | Mobile/suspended screen | ALARA principles (As Low As Reasonably Achievable) |
A recommended dose for a radiologic study is usually expressed in DRL. This reference value is set to provide the lowest possible radiation dose that can produce images of sufficient diagnostic value. It is usually the third quartile value of the overall distribution of radiation doses to be applied in real practice [
Development of pediatric radiology comes with many challenges. Unlike adults, children cannot always understand a change of environment. Therefore, staff is usually required to wear colorful uniforms as opposed to a normal hospital uniform. It is also important to recognize that when a child is unwell, they follow their instincts, which is usually to cry and stay close to their parents. This presents a huge challenge for the radiography specialist, who must try to gain the child’s trust and gain their cooperation. Once co-operation has been achieved there is another big challenge of keeping the child still for their imaging test. This can be very difficult for children in a lot of pain. Coercion and support from parents is usually enough to achieve this, however, in some extreme cases (such as MRI and CT), it may be necessary to sedate the child [
Another challenge faced is the radiation difference between an adult and child. Operators must use different equipment, setting for pediatric patients in order to reduce patient doses. Collaboration by several radiology, medical physics, pediatrics, and governmental organizations are essential to increase awareness of radiation safety issues in children and to provide education to all stakeholders caring for children on ways to decrease the ionizing radiation exposure in children [
Pediatric radiography has been steadily improved over the last years. Imaging and dose reduction are improved in order to assure that the patient will receive the lowest radiation dose without impairing image quality. Although there are many dose reduction measures helping in dose reduction in the literature, it is important to recognize that pediatric patients still receive a higher dose from unnecessary radiation. To successfully diagnose a pediatric condition, high quality images are needed to give a diagnosis. To achieve this requires creating an environment where a child is comfortable. This is one of the most essential elements to pediatric radiology. For imaging departments which specialize in pediatric radiology, this is very easy as rooms can be tailored to suit a child’s needs. There is no standard protocol for this procedure in all hospitals; thus, children receive a high dose of radiation in some causes.