Pediatric Nuclear Medicine and Radiation Dose S. Ted Treves, MD,*,† Anthony E. Falone, MS,† and Frederic H. Fahey, DSc† Nuclear medicine is a unique and valuable method that contributes to the diagnosis and assessment of many diseases in children. Radiation exposures in children undergoing diagnostic nuclear medicine studies are low. Although in the past there has been a rather large variation of pediatric radiopharmaceutical administered activities, adhering to recent standards for pediatric radiopharmaceutical administered doses can help assure that the lowest administered activity are employed and that the diagnostic value of the studies is preserved. Radiation exposures in children can be reduced further by optimizing routine protocols, application of advanced image processing and potentially with the use of advanced imaging systems. Semin Nucl Med 44:202-209 C 2014 Elsevier Inc. All rights reserved.

Pediatric Nuclear Medicine


uclear medicine contributes to the diagnosis and assessment of many diseases in children. Nuclear medicine studies are physiological, highly sensitive, and minimally invasive. Well-established nuclear medicine procedures reveal physiological processes in vivo, permit early detection of disease, help guide patient management and therapeutic decisions, as well as provide an important tool to follow the success of therapy or progression of disease. Nuclear medicine is ideally suited in the evaluation of children in practically all medical fields including urology, cardiology, neurology, surgery, endocrinology, orthopedics, and oncology. One of the reasons that nuclear medicine in pediatrics remains a successful technique is that nuclear medicine studies provide vital information about the patient's condition that cannot be obtained easily or, in some cases, not at all with other diagnostic methods, some of which may in fact be more invasive and riskier.1,2 In general, when performed appropriately, nuclear medicine procedures carry low radiation exposures and pose no demonstrable risk to patients. This article discusses the use of nuclear medicine in children, radiation risk,

*Division of Nuclear Medicine and Molecular Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, MA. †Division of Nuclear Medicine and Molecular Imaging, Boston Children's Hospital, Harvard Medical School, Boston, MA. Address reprint requests to S. Ted Treves, MD, Division of Nuclear Medicine and Molecular Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, MA. E-mail: [email protected]

202 0001-2998/& 2014 Elsevier Inc. All rights reserved.

pediatric radiopharmaceutical administered doses, and approaches to dose reduction and image-quality improvement.

Radiation Risk and Benefit In recent years, there has been a high level of interest and concern over the potential health risks to children from diagnostic studies utilizing ionizing radiation. For example, reported risks from CT in children include the development of cancers,3-5 and in the case of head CT radiation in early life, an effect on cognitive function.6 These concerns have been a source of extensive coverage in both the lay press and the scientific literature. Controversy still exists regarding what are considered real vs potential risks from low radiation exposures from diagnostic radionuclide imaging in children, and this topic remains a source of ongoing discussion and further research (see Adelstein in this issue).7 To date, there has not been documented evidence of cancer risk in patients from the low doses of radiation from nuclear medicine studies. Although radiation doses in pediatric nuclear medicine are low, it is important to consider the balance between potential risk from this radiation exposure and the benefit associated with these procedures. We do not really know if diagnostic doses are associated with an increased risk of developing cancer. The Society of Nuclear Medicine and Molecular Imaging (SNMMI) and the Society of Nuclear Medicine and Molecular Imaging Technologist Section (SNMMI-TS) have published a joint statement to address this issue, which states, “The right test with the right dose should be given to the right

Pediatric nuclear medicine and radiation dose patient for the right indication at the right time. When nuclear medicine and molecular imaging procedures are performed correctly on appropriate indications in patients, the real benefits of the procedure significantly outweigh the potential risks.”8 It is important to emphasize the great benefits of the use of radiation in medicine through the ability to diagnose and treat disease. This has without a doubt improved the quality of health care and longevity. Although, there has been concern about theoretical or potential risks from the use of low levels of radiation in diagnostic medicine, these concerns should be balanced by a greater emphasis on the benefits that are derived from diagnostic imaging. Therefore, there is the need for studies that aim to calculate the improvements in clinical outcomes, improving the quality of life and the numbers of lives saved by the use of diagnostic imaging.9

Pediatric Radiopharmaceutical Administered Doses Administered doses of radiopharmaceutical activities in the adult population have been standardized for the most part, with recommended doses available in radiopharmaceutical package inserts. Despite the longstanding use of nuclear medicine in pediatrics, standardization of pediatric administered radiopharmaceuticals doses have only recently been addressed. Further complicating this issue is the fact that most radiopharmaceutical package inserts do not provide guidance on pediatric doses. Therefore, administered activities or “doses” in pediatric nuclear medicine have been developed through clinical experience by taking into account the patient’s body mass, anticipated radiation exposure, type of examination, available photon flux, instrumentation, practitioner’s preference, examination time, and patient cooperation. Estimates of administered doses of activity for pediatric patients based on adult dose corrected for body weight or body surface area are generally acceptable guides for children older than 1 year. Premature infants and newborns require special consideration, and the concept of minimum total dose should be considered. Minimum dose can be defined as the minimum amount of administered radiopharmaceutical activity below which the study would likely be inadequate regardless of the patient’s body weight or surface area. The minimum dosage depends, in part, on the type of study: dynamic or static. Generally, dynamic studies require a higher dose of tracer compared with static studies as each frame of the study is typically acquired for a short time. It should be now well established that high doses of activity that do not result in improved diagnostic sensitivity or accuracy and, conversely, very low doses that may not permit adequate count statistics for a proper examination should be considered unnecessary radiation exposures. Owing to a lack of standardization, a rather large variation of recommended administered doses has been commonplace, even among specialized pediatric institutions. In 2008, a survey of 13 specialized pediatric hospitals confirmed the great variation of radiopharmaceutical administered doses among these institutions. In the survey, minimum dose for the smallest of children (o1 year) varied the

203 most, from a factor of 10, and in one case, by a factor of 20. The maximum administered activity and the activity per body mass in children older than 1 year varied on average by a factor of 3 and, in 1 instance, by as much as a factor of 10. The large variation in administered activities reported has been of concern, as the results indicate that a wide range of radiation exposure was given to patients even at these premier pediatric institutions.10

Consensus Guidelines Publication of the results of this survey elicited a great deal of interest, and the Image Gently Campaign of the Alliance for Radiation Safety in Pediatric Imaging encouraged the formation of a group of experts to evaluate such discrepancies in pediatric nuclear medicine to determine if a consensus toward standardization of doses could be achieved. Following 4 consensus workshops conducted with the partnerships of the Society of Nuclear Medicine (SNM, now SNMMI), the Society for Pediatric Radiology, and the American College of Radiology, the 2010 North American Consensus Guidelines for Pediatric Administered Radiopharmaceuticals were developed.11,12 These guidelines can be found in the Image Gently website. In addition, posters with the guidelines were widely disseminated by the Image Gently Campaign with support from the SNMMI. An analysis on the effectiveness of the guidelines across institutions is currently underway. In addition to the work being done in North America, the European Association of Nuclear Medicine has developed and published a dose chart. In general, the recommended pediatric doses by these 2 guidelines demonstrate some degree of consensus.13 In 2012 and 2013, these groups have made progress toward the harmonization of pediatric radiopharmaceutical administered doses across the Atlantic. Further work in this area is currently ongoing.

Dose Reduction Despite the low levels of radiation in nuclear medicine studies, it is considered prudent to perform such procedures with the lowest possible doses of activity that can assure a satisfactory examination that can address the clinical question at hand. Consequently, there has been a recent emphasis on the evaluation of methods leading to dose reduction. Dose reduction can be accomplished in a number of ways. Examples include appropriate utilization, use of new radiopharmaceutical dose guidelines, adjusting imaging protocols, use of advanced image processing, and the potential use of advanced imaging systems.

Appropriate Use An important factor toward achieving dose reduction requires good communication among the nuclear medicine team and their referring physicians who will ultimately use results from nuclear medicine studies to help guide medical decisions for their patients. Appropriate clinical use refers to the physician’s initial selection of the safest, fastest, and most effective imaging test

204 that will most likely yield the diagnostic information desired. This approach takes little additional time to implement and can produce significant benefit. Using sound clinical judgment and sufficient clinical information, selecting the most appropriate imaging test can facilitate an early diagnosis and allow prompt initiation of therapy, as well as reduce the number of total examinations that need to be performed. Avoiding the use of less sensitive imaging methods can reduce patient waiting and anxiety and also result in cost savings. Initially selecting the most appropriate diagnostic test could also lead to increased patient comfort, cooperation, and satisfaction. For instance, some physicians rely more frequently on serial ultrasonography for the evaluation of cortical renal integrity and differential renal function in acute or chronic pyelonephritis. Unfortunately, the sensitivity of conventional ultrasound for the detection of acute pyelonephritis or renal scarring is very low. On the contrary, 99mTc-dimercaptosuccinic acid (99mTc-DMSA) imaging has a very high sensitivity of 495%. It would seem that this approach should be considered early, as it easily and rapidly evaluates cortical renal integrity and differential renal function. Localization of a skeletal cause of back or extremity pain in young children can be challenging. Patient or parent reporting of the location of pain may be unreliable, as pain may be referred away from the causative lesion. Frequently, these patients initially undergo plain radiography or even CT to the region suspected of being the origin of pain, which may in some instances be the wrong region of the body to be imaged. In this setting, one advantage of skeletal scintigraphy is that a large area of the body can be evaluated in a single imaging session, thus providing increased ability for early detection of the causative lesion, and the prompt establishment of therapy. In 1 example, a mother reported that her young child had developed ankle pain following a fall. Radiographic findings of the area were normal, and the orthopedic surgeon prescribed “high-top” sneakers in an attempt to provide support to the patient’s ankle. As the patient did not improve, the surgeon indicated a bone scan. The scan revealed a spiral fracture of the tibia that was later confirmed by a plain radiograph. In retrospect, the diagnosis of tibial injury could have been obtained with an early bone scan that would have directed the therapy quickly and more precisely. In the evaluation of a patient with lymphoma for the assessment of effectiveness of therapy, a PET scan using FDG (or perhaps other PET agents such as 18F-labeled fluorothymidine [[18F]-FLT]) could rapidly determine if the chemotherapeutic regime is effective, and could suggest the need for a change in therapy. Purely relying on the size of the tumor by serial anatomical imaging will likely take much longer to assess the effectiveness of therapy, and thus, changes in the therapy would likely be delayed. Certain oncology protocols require multiple CT examinations over the course of therapy. Importantly, reduction in the uptake of FDG in tumors has been shown to reflect early effectiveness of therapy even though tumor size may not have shown a concomitant decrease on CT, as is frequently seen in patients with lymphoma. Therefore, through physiological or molecular imaging and more timely use of PET with FDG and other PET agents as biomarkers, there

S.T. Treves et al. is a potential to reduce the number of CT examinations needed to follow up the effect of therapy, and as a result, significantly reduce radiation exposure. In another example, if the clinical question is vesicoureteral reflux, in many cases, it is most appropriate to obtain an initial radionuclide cystogram rather than a conventional radiographic voiding cystogram. The radionuclide cystogram not only possess a higher sensitivity but also a much lower radiation exposure, roughly 20-100 times less than a conventional radiographic voiding cystogram. In the case of pulmonary aspiration, a radionuclide salivagram should be preferred, as it is highly physiological and needs only a drop of radiopharmaceutical administered orally—a much less administered volume is needed compared with the standard barium swallow. The salivagram is highly sensitive, as it can detect aspiration as little as 0.2 mL and carries very low radiation exposure. These are just a few examples that demonstrate the clinical, emotional, and economic benefits that accompany selection of appropriate diagnostic studies. It is obvious that proper selection of diagnostic scans is dependent on physician education and knowledge of nuclear medicine and other techniques.

Pediatric Administered Radiopharmaceutical Dose Guidelines Implementing guidelines for pediatric radiopharmaceutical administered doses is a readily available resource to help optimize doses and, even in some cases, reduce pediatric administered radiotracer activities. As discussed previously, before the establishment of pediatric guidelines, doses varied over a wide range among institutions. Therefore, it is safe to assume that children were exposed to varying levels of radiation from one institution to another for the same nuclear medicine procedure. With the publication of the North American guidelines, many institutions have altered their dosing protocols to reflect the current dosing scheme recommended by the guidelines. A more detailed analysis to determine the effect of new guidelines on the practice of pediatric nuclear medicine should be conducted. It is vital for all institutions that offer pediatric nuclear imaging to become aware of updates on dose-reduction initiatives, as well as methods for image optimization.

Adjusting Routine Acquisition and Display Protocols Adjusting existing protocols based on the diagnostic task at hand could significantly reduce the administered doses in a straightforward and efficient way. One way to reduce pediatric administered doses is to consider the type of study, dynamic or static, and the diagnostic goal or task. For example in 99mTcmercaptoacetyltriglycine (99mTc-MAG3) renography, some centers, have been routinely acquiring a rapid 60-second dynamic renal study [radionuclide angiography] at a rapid framing rate (0.5-1:00 second/frame), following by a 20-30 minute acquisition at a slower framing rate (0.25-0.30 per second frames). However, in most cases, these studies

Pediatric nuclear medicine and radiation dose are routinely viewed and evaluated in series of approximately 1.0-minute frames. This is because the information gathered by the radionuclide angiogram very rarely adds to the interpretation of the study. Therefore, in most cases, there is no need to administer radiotracer doses of activity to optimize the radionuclide angiogram. A smaller dose of activity is sufficient to provide a diagnostic study only at the slower framing times just mentioned. This method can also be applied to other dynamic studies such as hepatobiliary scintigraphy.

Advanced Image Processing Using advanced image processing and reconstruction techniques in both planar scintigraphy and single-photon emission computed tomography (SPECT), it is possible to achieve significant reductions in radiopharmaceutical administered doses and therefore radiation exposures, without any loss of diagnostic information. The use of spatially adaptive filtering software helps reduce either the radiopharmaceutical administered dose or the imaging time required to complete the scan.14 In planar imaging, this approach can be useful in static and dynamic studies.15 This software approach aims to decrease the random noise in the image without degrading the spatial resolution by varying the degree of filtration, depending on the image content of the local image region. In static imaging, adaptive filtering allows for a reduction in the amount of activity administered to the patient given the same acquisition time, or alternatively, while using the standard administered activity, significantly reducing the imaging time. For example, a whole-body bone scan that would normally take approximately 20-30 minutes (depending on scan speed) to acquire could be completed in half the time or in

Figure 1 99mTc-MDP planar whole-body scintigraphy. Use of enhanced planar processing (EPP) to facilitate reduction in imaging time while preserving diagnostic information. Left panel: Whole-body scan in a 3-year-old boy who received 3.7 mCi [136.9 MBq] of 99m Tc-MDP. The total imaging time was 14 minutes. Right panel: With EPP, the total imaging time was only 3.5 minutes. Alternatively, the patient could receive 25% of the original amount of tracer and be imaged for 14 minutes.

205 some cases, a quarter of the time, using the standard administered activity (Fig. 1). Reduction of imaging time can increase patient comfort, reduce immobilization time, and reduce the need for sedation. Obviously, in dynamic studies, adaptive filtering software cannot help reduce imaging time, as acquisition time is governed by organ function and radiopharmaceutical kinetics. However, this software allows for a reduction of administered activity without loss of diagnostic information. Research has shown that image quality of 99mTc-MAG3 renal studies as well as 99mTc-Disofenin hepatobiliary studies can be retained with a 50%-60% reduction of radiopharmaceutical administered activity (Figs. 2 and 3).16,17 In SPECT, the Filtered Back Projection (FBP) has been the standard method of reconstruction. However, in the past few years, iterative reconstruction methods with resolution recovery in 3-dimensional (3D) have shown promising results. Unlike FBP, these methods can compensate for both the noise properties of the projection data as well as other physical parameters such as how the collimator resolution varies with distance, leading to a more accurate reconstruction. Importantly, iterative reconstruction techniques have been shown to provide at least similar, but most often, improved image quality with significantly less counts needed to achieve the diagnostic task. As mentioned before, high-quality studies can be obtained with much lower radiation exposure to the patient, shorter imaging times, or a combination of both. Ordered Subset Expectation Maximization (OSEM-3D) with resolution recovery software has been shown to achieve this goal.18,19 Research has successfully demonstrated the benefits of OSEM-3D with resolution recovery in renal (99mTc-DMSA) and skeletal 99mTc-methyl diphosphonate (99mTc-MDP) SPECT. Application of OSEM-3D on SPECT data in both imaging studies showed that administered doses of the radiopharmaceuticals can be reduced to at least 50% with a significant improvement in image resolution (Figs. 4 and 5).20,21 With this approach, it is possible to reduce administered doses using the same acquisition times or reduce imaging time by an estimated 50%, or a combination of these 2 advantages. For example, a clinic can easily reduce the administered dose by 25% and the imaging time also by 25%, thus decreasing radiation exposure and improving patient comfort and cooperation. Another example of OSEM-3D application can be observed in 123I-metaiodobenzylguanidine (123I-MIBG) SPECT. These studies are known to contain inherent noise, which is clearly reduced using OSEM-3D compared with conventional FBP (Fig. 6). This SPECT reconstruction algorithm provides great hope in making SPECT more feasible in small patients through improved resolution or shortened imaging times or both.

Instrumentation Recent advances in nuclear medicine instrumentation, through both optimization of conventional systems as well as newly developed systems, have the potential to contribute toward a reduction of radiopharmaceutical administered doses while maintaining diagnostic image quality in children.

S.T. Treves et al.


Figure 2 Dose reduction in 99mTc-MAG3. All images represent the same 60-120 second portion of a dynamic renal study also known as the parenchymal phase of the renogram. (A) Original image with the full standard tracer dose. (B) Subsampled images at 50% count reduction without and with EPP. (C) Subsampled images at 70% lower counts without and with EPP. (D) Counts are lowered by 90% of the original. Note that it is possible to reduce the administered radiopharmaceutical dose by 50%-70% of the standard administered dose. These images were obtained with an ultrahighresolution collimator (UHRC). Using a high-resolution collimator will produce twice the counts of an UHRC.

For example, most studies in pediatric nuclear medicine are obtained using conventional gamma cameras with a high-resolution collimator. Through optimization of the conventional gamma camera, it is now considered routine to use dual-detector systems instead of single-detector systems, which helps reduce the administered dose with the same image acquisition time. Another method of reducing radiopharmaceutical administered doses through conventional system optimization is selecting the most appropriate collimator in relation to the patient size and the clinical task. An ultrahigh-resolution (UHR) collimator has a sensitivity of 100 counts per minute per microcurie, whereas a high-resolution (HR) collimator is twice as sensitive at

200 counts per minute per microcurie. A high-sensitivity (HS) collimator has a sensitivity of 1000 counts per minute per microcurie. The spatial resolutions expressed as full width at half maximum are 6.0, 7.4, and 15.6 mm at 10 cm for UHR, HR, and HS collimators, respectively. At closer distances between the face of the collimator and the object being imaged, the difference between the system spatial resolution for the UHR and HR collimators is less pronounced. Thus, it may be possible to effectively use a collimator with higher sensitivity for patients with rather small body cross section, especially babies, than in a patient with a relatively large cross section. For example, it is possible to use a HS collimator for a baby undergoing a hepatobiliary scan, if the objective of the study is simply to

Figure 3 99mTc-Disofenin hepatobiliary scintigraphy preserving image quality while significantly reducing radiopharmaceutical administered dose. Selected frame from a 99mTc-Disofenin hepatobiliary scan in an infant. (A) Selected frame from the study at 15 minutes after the administration of 0.5 mCi (18.5 MBq). (B) Same frame after subsampling to a 75% reduction in counts equivalent to 0.125 mCi (4.6 MBq). (C) Same image at 75% in counts after the application of enhanced planar processing (EPP). The image is very similar to that obtained with the original number of counts in (A).

Pediatric nuclear medicine and radiation dose

Figure 4 Dose reduction with image improvement in renal imaging. 99m Tc-DMSA SPECT. Left panel: SPECT reconstruction using filtered back projection (FBP). Right panel: same study reconstructed using half the counts and reconstructed with iterative reconstruction with resolution recovery in 3D (OSEM-3D). The image shows significant improvement in resolution with only half the counts. Alternatively, OSEM-3D allows a 50% reduction in imaging time at the original dose of tracer.

identify if tracer migrates to the bowel. For some patients, using a HR collimator can reduce the dose by half compared with an UHR collimator. Therefore, radiopharmaceutical administered doses can be adapted to the diagnostic task under consideration of the appropriate choice of collimator, so that the desired diagnostic information can be obtained at a very low radiopharmaceutical administered activity. Advances in new imaging equipment can also contribute to a reduction of administered dose in pediatrics. For instance, 3D-PET, which has largely replaced 2D-PET, allows for the acquisition of a larger number of photons per unit of time owing to the larger field of view, while enabling more rapid imaging times compared with 2D-PET. Even with the increased susceptibility to scatter with 3D acquisition, this is not an important factor in imaging children. Thus, less

Figure 5 Dose reduction with image improvement in 99mTc-MDP skeletal SPECT. Left panel: A MIP image reconstructed with filtered back projection (FBP). Right panel: same study subsampled to 50% lower counts before reconstruction using OSEM-3D. The difference in image quality is strikingly better with OSEM-3D.


Figure 6 Image improvement of 123I-MIBG SPECT using OSEM-3D SPECT reconstruction. Top panel: selected slices after reconstruction using filtered back projection (FBP). Bottom panel: same study with the same dose of tracer reconstructed using OSEM-3D. Note the increased image sharpening with improved definition of the internal structures noted in all slices. For example, the transverse image on the right shows a sharper definition of the myocardial uptake and the lack of radial artifacts with OSEM-3D compared with FBP. This is helpful also for image fusion with MRI.

administered activity can be given to patients without adverse effect on clinical result. In addition, some scanners have been designed with an extended axial field that further increases the sensitivity significantly. During the past few years, new systems have been designed specifically to optimize myocardial perfusion SPECT. Some designs are equipped with newer detectors such as cadmium zinc telluride which provide improved energy resolution and geometric efficiency leading to faster acquisition times or reduced administered activity. For example, they can complete myocardial perfusion studies in one-fourth of the time as conventional gamma camera systems, in addition to imaging at lower administered radiopharmaceutical doses. With the obvious advantages of higher sensitivity and resolution, these systems could potentially be adapted for imaging children. In addition, with the wider availability of hybrid imaging (PET/CT and SPECT/CT), the radiation dose from the CT also needs to be considered as an important factor contributing to patient radiation exposure.22 Some investigators have developed approaches that can result in significant reduction of CT radiation exposure in hybrid imaging to avoid redundant or unnecessary CT studies. Currently, there has been no uniform agreement about the most appropriate approach to address this issue. It is possible to obtain appropriate attenuation correction with CT at doses much lower than diagnostic levels. If attenuation correction is all that is needed, a low-dose CT will be sufficient, which may also be adequate in many cases for anatomical localization of PET lesions. If the patient needs both the PET and the CT in a single imaging session, this can be done with diagnostic levels of CT that also can be used for both attenuation correction and CT.23,24 For example, if a patient with Hodgkin’s disease is referred for an FDG PET/CT who had a diagnostic CT a few days earlier, it is unnecessary to obtain another high-quality CT. If the quality of the previously obtained CT is adequate, it can be fused electronically with the PET, avoiding additional diagnostic CT exposure to the patient.

S.T. Treves et al.

208 It is evident that multiple steps can be taken to improve pediatric nuclear medicine to achieve dose reduction. Decreasing the radiation exposure to patients will provide 2 significant benefits. The potential risk of exposure to patients will be drastically reduced, making nuclear medicine studies even safer and more convenient. In addition, the volume of referrals for nuclear medicine studies may increase as physicians may be more apt to ordering these scans knowing that the benefit of early detection of disease greatly outweighs the very low potential risk of radiation exposure.

Education and Communication Perception about radiation risk varies widely among the public, as well as physicians, scientists, and other members of care teams. The word “nuclear” has traditionally elicited concern; it is essential that members of the nuclear medicine team be able to communicate effectively with referring physicians, patients, parents, and other members of the patient’s care team about nuclear medicine and radiation exposures within the context of the examination at hand. It is no longer sufficient to merely indicate that nuclear medicine procedures are safe. It is useful to prepare procedure-specific brochures or pamphlets that can also be posted on the internet to provide information to patients and families. These informational tools should contain explanations about the procedures and radiation exposures, as well as the clinical question being asked. Moreover, patients and families should be assured that every precaution has been taken to ensure that the appropriate test is being selected to provide the information desired at the lowest possible radiation exposure. As new information about advances in pediatric nuclear medicine, radiation exposures, and potential risks becomes available, it is important that such information is shared and communicated among professionals, patients, and the public.25-27 Members of the nuclear medicine community should advise clinicians about the best test or imaging strategy available to study the clinical problem. Given the low radiation doses in pediatric nuclear medicine, any potential risks have to be balanced with the real benefits to the patient along with the kind of imaging methodology and their cost.28 The Image Gently Campaign of the Alliance for Radiation Safety in Pediatric Imaging is a very a useful source of information. Image Gently seeks to increase awareness about lowering radiation exposures from imaging studies and to provide information to patients, families, and caregivers (

Summary Pediatric nuclear medicine provides invaluable information in many clinical settings with characteristic high sensitivity and the ability to provide early diagnoses. This is achieved with a low radiation exposure to the patient. When properly applied, the numerous benefits, most notably early detection of disease, associated with this imaging modality far exceed any potential risk that accompanies low-dose radiation exposure. Members of the pediatric nuclear medicine community including scientists, physicians, and technologists are working diligently

to address these concerns through dose reduction and image optimization, improved instrumentation, and general education and communication.

References 1. Treves ST: Pediatric Nuclear Medicine/PET. 3rd ed. New York: Springer; 2006 2. Treves ST, Baker A, Fahey FH, et al.: Nuclear medicine in the first year of life. J Nucl Med 2011;52(6):905-925 3. Ernst M, Freed ME, Zametkin AJ: Health hazards of radiation exposure in the context of brain imaging research: Special consideration for children. J Nucl Med 1998;39(4):689-698 4. Pearce SP, Salotti JA, Little MP, et al.: Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumors: A retrospective cohort study. Lancet 2012. ctscanrad.pdf 5. Brenner D, Elliston C, Hall E, et al.: Estimated risks of radiation-induced fatal cancer from pediatric CT. AJR Am J Roentgenol 2001;176:289-296 6. Hall P, Olov Adami H, et al.: Effect of low doses of ionising radiation in infancy on cognitive function in adulthood: Swedish population based cohort study. Br Med J 2004;328(3):1-5 7. Adelstein SJ: Radiation Risk in Nuclear Medicine. Semin Nucl Med 2014;44:187-192 8. SNM position statement on dose optimization for nuclear medicine and molecular imaging procedures. Society of Nuclear Medicine and Molecular Imaging. Reston, VA. Statement_on_Dose_Optimization_FINAL_June_2012.pdf 9. Zanzonico,P, Stabin M: Benefits of medical radiation exposures. Health Physics Society, 2009. Available at: articles/Benefitsofmedradexposures.html 10. Treves ST, Davis RT, Fahey FH: Administered radiopharmaceutical doses in children: A survey of 13 pediatric hospitals in North America. J Nucl Med 2008;49(6):1024-1027 11. Gelfand MJ, Parisi MT, Treves ST: Pediatric radiopharmaceutical administered doses: 2010 North American consensus guidelines. J Nucl Med 2011;52(2):318-322 12. Treves ST, Parisi MT, Gelfand MJ: Pediatric radiopharmaceutical doses: New guidelines. Radiology 2011;261(2):347-349 13. Lassmann M, Biassoni L, Monsieurs M, et al.: The new EANM paediatric dosage card: Additional notes with respect to F-18. Eur J Nucl Med Mol Imaging 2008;35(9):1666 14. Mawlawi O, Yahil A, Vija H, et al.: Reduction in scan duration or injected dose in planar bone scintigraphy enabled by pixon post-processing. J Nucl Med 2007;48(suppl 2):13P 15. Gelfand MJ: Dose reduction in pediatric hybrid and planar imaging. Q J Nucl Med Mol Imaging 2010;54:379-388 16. Hsiao EM, Cao X, Zurakowski D, et al.: Reduction in radiation dose in mercaptoacetyltriglycerine renography with enhanced planar processing. Radiology 2011;261:907-915 17. Fahey FH, Zukotynski K, Zurakowski D, et al.: Beyond dose guidelines: Reduction in radiation dose with preserved image quality in pediatric hepatobiliary scintigraphy, submitted for publication 18. Romer W, Reichel N, Vija HA, et al.: Isotropic reconstruction of SPECT data using OSEM3D: Correlation with CT. Acad Radiol 2006;13:496-502 19. Vija AH, Yahil A, Hawman EG: Adaptive noise reduction and sharpening of OSEM-reconstructed data. In: IEEE Nuclear Science Symposium Conference Record; 23-29 Oct 2005, 2583-2587 20. Sheehy N, Tetrault TA, Zurakowski D, et al.: Pediatric 99mTc-DMSA SPECT performed by using iterative reconstruction with isotropic resolution recovery: Improved image quality and reduced radiopharmaceutical activity. Radiology 2009;251(2):511-516 21. Caamano Stansfield E, Sheehy N, Zurakowski D, et al.: Pediatric 99mTcMDP bone SPECT with ordered subset expectation maximization iterative reconstruction with isotropic 3D resolution recovery. Radiology 2010;257 (3):793-801 22. McCollough CH, Primak AN, Braun N, et al.: Strategies for reducing radiation dose in CT. Radiol Clin North Am 2009;47:27-40

Pediatric nuclear medicine and radiation dose 23. Chawla SC, Federman N, Zhang D, et al.: Estimated cumulative radiation dose from PET/CT in children with malignancies: A 5-year retrospective review. Pediatr Radiol 2010;40:681-686 24. Alessio AM, Kinahan PE, Manchanda V, et al.: Weight-based, low-dose pediatric whole-body PET/CT protocols. J Nucl Med 2009;50:1570-1577 25. Goske MJ, Applegate KE, Boylan J: Image gently (SM): A national education and communication campaign in radiology using the science of social marketing. J Am Coll Radiol 2008;5:1200-1205 26. Fahey FH, Treves ST, Adelstein SJ: Minimizing and communicating radiation risk in pediatric nuclear medicine. J Nucl Med 2011;52(8): 1240-1251

209 27. Goske MJ, Applegate KE, Bulas D, et al.: Approaches to promotion and implementation of action on radiation protection for children. Radiat Prot Dosimetry 2011;147(1-2):137-141 28. Roca-Bielsa I, Vlajković M: Pediatric nuclear medicine and pediatric radiology modalities, image quality, dosimetry and correlative imaging: New strategies. Pediatr Radiol 2013;43:391-392 29. What you should know about pediatric nuclear medicine and radiation safety. Web site of the alliance for radiation safety in pediatric imaging. Available at: 204pgNucMed14.8.2010.pdf

Pediatric nuclear medicine and radiation dose.

Nuclear medicine is a unique and valuable method that contributes to the diagnosis and assessment of many diseases in children. Radiation exposures in...
626KB Sizes 0 Downloads 3 Views