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   Where and When P...
   Lymphomas
   Sarcomas
   Neuroblastoma
   Wilms' Tumor
   Langerhans Cell ...
   Brain Tumors
   Incorporation of...
   What are the Lon...
   How Should PET-C...
   What is the Way ...
   References

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Table of Contents
GUEST EDITORIAL
Year : 2010  |  Volume : 47  |  Issue : 4  |  Page : 355-359
 

PET-CT scan in pediatric oncology: Where, when, how and at what price?


1 Pediatric Oncology, Tata Memorial Hospital, Mumbai, India
2 Convener, Indian Cooperative Oncology Network, Mumbai, India

Date of Web Publication4-Dec-2010

Correspondence Address:
B Arora
Pediatric Oncology, Tata Memorial Hospital, Mumbai
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0019-509X.73546

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How to cite this article:
Arora B, Parikh P M. PET-CT scan in pediatric oncology: Where, when, how and at what price?. Indian J Cancer 2010;47:355-9

How to cite this URL:
Arora B, Parikh P M. PET-CT scan in pediatric oncology: Where, when, how and at what price?. Indian J Cancer [serial online] 2010 [cited 2019 Aug 24];47:355-9. Available from: http://www.indianjcancer.com/text.asp?2010/47/4/355/73546


The advent of combined positron emission tomography-computed tomography (PET-CT) has been an important innovation in the diagnosis, staging, monitoring of response to therapy, and disease surveillance in adult oncology. [1],[2] Combined morphological and functional information along with rapid, non-invasive whole-body tumor staging has proven to be a boon for treating oncologists. However, the role of PET-CT in the pediatric cancers is less clearly defined at present. In the recent times, the use of PET-CT imaging in pediatric cancer patients is growing rapidly and it is likely to become an important part of therapeutic decision tree in the near future. [3] In this issue of "The Indian Journal of cancer", Samuel et al. have given a comprehensive overview of PET-CT protocols and its clinical applications in children with cancer. The increasing use of serial PET-CT scans in the management of children raises the serious consideration of radiation exposure. Hence, it is imperative to weigh the risk-benefit ratio of this potentially harmful modality in this young and vulnerable population from the perspective of a clinician and precisely define the current role of this modality in the current practice.


  Where and When PET-CT Should Be Used? Top


PET-CT imaging is commonly performed after diagnosis for baseline staging, during or at therapy completion for monitoring disease response, and during follow-up for surveillance. For initial staging, imaging should always be performed before starting chemotherapy to minimize image misinterpretation caused by therapy related effects on tumors and other tissues. During therapy, for early response evaluation, imaging should be planned prior to initiation of the next course of therapy to avoid any "flare" response from chemotherapy. PET may be performed within 4 weeks after the completion of chemotherapy. In contrast, PET is generally not performed until 2-3 months after radiation or 1-2 months after surgery because acute inflammatory changes after radiation or surgery can result in false positive PET scans. [1] Currently, the most frequently requested indications for PET-CT imaging in pediatric oncology are lymphoma, sarcoma, neuroblastoma and brain tumors. Less frequent indications for PET imaging in pediatric oncology include evaluation of Langerhans cell histiocytosis (LCH), germ cell tumors, hepatoblastoma, Wilms' tumor, malignancy of unknown primary, and neurofibromatosis type 1. [4] The current application of this imaging in common cancers is detailed below.


  Lymphomas Top


In lymphomas, PET-CT is used for staging, evaluating response to therapy, restaging, assessment of residual masses after therapy and planning of radiation therapy. In the initial staging, PET-CT has been demonstrated to change staging and therapeutic management in 32-40% of pediatric patients. [5] It is significantly more accurate in distinguishing active disease from residual inactive masses, especially in nodular sclerosis subtype, after therapy. Also, PET-CT has a higher sensitivity, compared with CT alone, in evaluating patients for recurrent disease. A negative PET-CT scan at the end of therapy or during follow-up for lymphoma in children strongly suggests absence of disease but a positive PET-CT has low positive predictive value and should be interpreted with caution. [6],[7],[8] Pediatric Hodgkin's lymphoma (HL) patients with a negative PET in early response assessment have an excellent prognosis while PET-positive patients have an increased risk for relapse. [9] PET-CT is being evaluated for monitoring of early response to therapy and improving the outcome of disease and decreasing the long-term toxicities of treatment by using a response-adapted "risk-stratified" approach to the use of radiation therapy, anthracyclines, and alkylating agents. Herein, patients with complete morphological response on CT and negative PET scan do not receive additional chemotherapy or radiotherapy in order to reduce the risk of secondary malignancies and organ toxicities. [10]


  Sarcomas Top


The use of PET-CT in sarcoma (osteosarcoma, Ewing's sarcoma and soft tissue sarcoma, in particular, rhabdomyosarcoma) is mainly for staging, assessing response to therapy, especially chemotherapy, and restaging/detection of relapse of those sarcomas that demonstrate metabolic activity. For baseline staging, PET has been found equal or superior to bone scintigraphy in the detection of bone metastases of sarcomas and also for detecting other non-pulmonary metastases. For the depiction of small lesions, mainly represented by pulmonary metastases, PET is less sensitive than helical CT. [11],[12] Many recent studies have shown that pretreatment tumor SUVmax and change in SUVmax after neoadjuvant chemotherapy predict chemoresponsiveness and independently identify patients at high risk of tumor recurrence in both bone and soft tissue sarcomas. [13],[14] It is also useful in monitoring response to radiation therapy, and radiofrequency ablation and aids the postoperative evaluation of tumor resection sites. Importantly, FDG-PET scan has been particularly helpful in sarcomas treated with radiation to differentiate scarring or fibrosis from persistent or recurrent disease. [11],[12],[13],[14],[15] FDG-PET has been found useful in differentiating between benign and malignant bone tumors. However, significant false positivity or negativity has been observed and caution must be used when basing an imaging diagnosis on SUVs. [16] It may also be valuable in the identification of unknown primary or recurrent rhabdomyosarcoma.[11] Finally, PET-CT has been found very useful in differentiating benign neurofibromas from malignant peripheral nerve sheath tumors in patients with neurofibromatosis, which are unreliably evaluated by conventional imaging modalities. [17] Overall, PET-CT with contrast-enhanced standard dose chest CT is preferred in sarcoma patients, and magnetic resonance imaging (MRI) is used for imaging of the primary tumor site.


  Neuroblastoma Top


Limited information is currently available regarding the utility of PET-CT imaging in neuroblastoma and associated diseases. [15],[18],[19],[20] (18)F-FDG is avidly concentrated by primary and metastatic sites of disease at diagnosis, but this uptake varies after therapy. At diagnosis, (18)F-FDG is superior in depicting stage 1 and 2 neuroblastoma, although (123)I-metaiodobenzylguanidine (MIBG) is required sometimes to exclude higher-stage disease. (18)F-FDG PET is very useful for patients with tumors that weakly accumulate (123)I-MIBG and for decision making during therapy (i.e., before stem cell transplantation or surgery). (18)F-FDG can also better characterize disease extent in the chest, abdomen, and pelvis, whereas (123)I-MIBG is significantly better in the evaluation of stage 4 neuroblastoma, primarily because of the better detection of bone or marrow metastases. [15],[18],[19] The value of PET-CT to distinguish between neuroblastoma, ganglioneuroblastoma, and ganglioneuroma is unclear. After completion of therapy, PET-CT and bone marrow studies suffice for following high-risk neuroblastoma patients. However, MIBG scan is significantly more sensitive for individual lesion detection in relapsed neuroblastoma than FDG-PET, though FDG-PET may play a complementary role, particularly in soft tissue lesions. [19],[20] Finally, novel sympathetic nervous system specific PET tracers, such as C-11-hydroxyephedrine (HED), are being evaluated for detection of disease, staging, and monitoring therapy in neuroblastoma, which might be useful in future. [21]


  Wilms' Tumor Top


PET-CT may be considered for confirming metastatic disease, identifying biopsy sites, helping with surgical planning, and differentiating nephroblastomatosis from Wilms' tumor. [22],[23] PET-CT imaging may help in distinguishing benign nephrogenic rests from nephroblastomatosis and to identify their potential evolution into Wilms' tumor. [15],[22] A recent study has shown that FDG-PET does not provide any supplementary information to the standard imaging for staging, preoperative response assessment evaluation and for predicting clinical outcome. However, FDG-PET was advantageous in ruling out residual disease after completion of first line treatment and in pretreatment staging of relapse patients. Furthermore, there was good correlation between initial SUV and histological differentiation. [22],[23] Overall, the impact of this modality on staging, treatment response assessment, and ultimate patient outcome in Wilms' tumor is yet to be fully determined and should await large studies.


  Langerhans Cell Histiocytosis Top


Currently, identification of disease sites and evaluation of response to therapy, especially bone lesions with conventional imaging (radiography and bone scanning), is a major challenge in the management of LCH. PET-CT's ability to exhibit lesional activity in addition to lesion localization is crucial for the diagnosis and follow-up of LCH. [15],[24],[25] A recent study has shown that PET-CT can detect disease activity and early response to therapy with greater precision than other conventional imaging modalities in patients with LCH lesions in the bones and soft tissues. [25]


  Brain Tumors Top


PET-CT scan may be used in CNS tumours for grading, prognostic stratification, planning biopsy or surgery, assessing response to therapy, detection of recurrence and radiation therapy planning. [26],[27],[28],[29],[30] Novel PET tracers are commonly used in brain tumors, e.g., labeled amino acids. Many recent studies have shown that PET has a significant impact on the surgical decisions and procedures for managing pediatric brain tumors. MET-PET guidance could help to improve the number of total resections and the amount of tumor removed in infiltrative gliomas in children. [26],[27] PET guidance also improves the diagnostic yield of stereotactic biopsy sampling and allows the practitioner to reduce the number of sampling procedures, especially in patients with infiltrative brainstem lesions. [28] FDG-PET of the brain with MRI coregistration can be used to obtain a more specific diagnosis with respect to malignancy grading. Furthermore, MET-PET appears be a useful tool to differentiate tumorous from non-tumorous lesions in children, compared to routine structural imaging. [29] PET along with proliferation index has also been found to be a useful measure in the identification of high-risk, low-grade gliomas. Lastly, its ability to identify a subset of aggressive low-grade glioma early helps in planning further therapy including resurgery or aggressive adjuvant treatment. [30]


  Incorporation of PET-CT Information into Surgery or Radiation Therapy Planning Top


PET-CT with diagnostic CT may be utilized for planning local therapy such as surgery or radiotherapy. Radiation planning incorporating PET-CT information can be particularly beneficial in minimizing treatment toxicities through reduction of radiation therapy dose or volume. This treatment targeting is based on an established (18)F-FDG threshold of activity in addition to size and contrast uptake, as shown by CT or MRI. [31] PET imaging is able to demarcate areas not previously identified or of unknown value when evaluated by anatomical imaging. [32] For brain tumors, initial PET-CT with radiolabeled amino acids may be easily integrated into the simulation and planning of radiotherapy (commonly with MRI coregistration). [31] In patients requiring definitive radiation after induction chemotherapy, such as those with Hodgkin's disease, Ewing tumors, soft tissue sarcomas or neuroblastomas, a response-adapted PET-CT approach to plan the irradiation dose and volume may be used. In these patients, use of PET-CT after chemotherapy completion also helps save one additional radiotherapy planning CT. [10],[15]


  What are the Long-Term Costs of PET-CT? Top


Rapidly rising use of PET-CT along with serial CT and plain-film radiography in the management of children with cancer for prolonged periods ranging from 3 to 5 years raises the important issue of radiation exposure. Children have an increased risk of developing secondary malignancies from radiation exposure compared with adults as confirmed by extrapolating data from atomic bomb survivors, in which increased risk is by an order of magnitude much greater than that of adults. This risk may be explained by greater life span and a greater proportion of actively dividing cells in children, making them more susceptible to radiation-related damage. Also, organ doses for children from radiation exposure due to CT scan are clearly higher than those for adults. [33],[34]

The greatest contributor to overall radiation exposure in PET-CT is the whole-body diagnostic CT. The average total radiation dose of 25 mSv from one adult whole-body PET-CT is roughly equivalent to an exposure of 7 years of background radiation in an adult. [35],[36] In pediatrics, the radiation exposure from a standard PET-CT with diagnostic contrast-enhanced CT ranges from 15 to 20 mSv depending upon the age and weight. Using combined FDG-PET/low-dose CT, the radiation exposure is roughly reduced by 50%. [37] Overall, imaging related radiation exposure assumes greater relevance in children because most children achieve long-term cure of disease.


  How Should PET-CT Be Used in Pediatric Oncology Top


It is imperative to strictly follow ALARA (as low as is reasonably achievable) principle in the radiation exposure of PET-CT, without losing the diagnostic information.[38] The major contributor to overall radiation exposure in PET-CT is the whole-body diagnostic CT and this can be reduced significantly by decreasing the tube current (mA) value and by following the pediatric protocols.

Combined PET-CT with diagnostic CT should be avoided if the desired information can be gained by other safer imaging techniques without radiation exposure (e.g., ultrasound or MRI). MRI is the modality of choice for morphological tumor imaging in most regions of the pediatric patient's body, except thorax. Hence, except for pulmonary lesions, PET should be performed using PET-CT with low-dose CT. [3],[12],[15]

PET-CT may be necessary initially for planning surgery and biopsy of FDG-avid lesions, since morphological imaging (CT scan) is essential. However, for monitoring early response and follow-up, PET alone may be sufficient, especially if no abnormal FDG uptake is observed. Furthermore, instead of using whole-body PET-CT at each point in management, CT or PET-CT limited to the area of interest or area of PET avidity may be considered, whenever appropriate. Each institution should have clear guidelines for the optimal interval, number, and frequency of PET-CT scans for each pediatric malignancy, to minimize its misuse. [3],[4],[15]

In conclusion, PET-CT with a so-called diagnostic whole-body, contrast-enhanced CT scan should not be routinely performed in pediatric oncology. Instead, FDG-PET alone or PET-CT with ultralow-dose plain CT scan should be combined with diagnostic breath-hold CT of the thorax, if necessary.


  What is the Way Forward from PET-CT to Perfect-CT Top


It is likely that PET-CT would play a crucial part in correct diagnosis, staging, therapy monitoring and risk-adapted, individualized treatment in the near future. There is a serious need for evidence-based guidelines on frequency, interval and number of PET-CT scans in the management of pediatric malignancies. This can be fulfilled by conducting prospective scientific studies to confirm the overall benefit of PET-CT in improving patient care and to explore whether PET-CT can be used as "one stop shop" for staging and follow-up in cancer patients instead of employing multiple imaging tools.

Also, combined PET/MRI may be a superior option to reduce radiation exposure in the future, except for evaluation of lung metastases. However, this may be challenging because children would require sedation for the long duration of an MRI. The scope and utility of PET-CT in pediatric oncology is likely to expand further through use of novel PET tracers targeting biological functions such as apoptosis, hypoxia or angiogenesis. Till such time, PET-CT in children should be used very judiciously on a case-by-case basis with particular thrust on the assessment of risk-benefit and cumulative radiation dose to children.

 
  References Top

1.Juweid ME, Cheson BD. Positron-emission tomography and assessment of cancertherapy. N Engl J Med 2006;354:496-507.   Back to cited text no. 1
[PUBMED]  [FULLTEXT]  
2.Czernin J, Schelbert HR. PET/CT imaging: Facts, opinions, hopes, and questions. J Nucl Med 2004;45:1S-3.  Back to cited text no. 2
    
3.Franzius C, Juergens KU. PET/CT in paediatric oncology: Indications and pitfalls. Pediatr Radiol 2009;39:446-9.  Back to cited text no. 3
[PUBMED]  [FULLTEXT]  
4.Stauss J, Franzius C, Pfluger T, Juergens KU, Biassoni L, Begent J, et al. Guidelines for 18F-FDG PET and PET-CT imaging in paediatric oncology. Eur J Nucl Med Mol Imag 2008;35:1581-8.  Back to cited text no. 4
    
5.Riad R, Omar W, Kotb M, Hafez M, Sidhom I, Zamzam M, et al. Role of PET/CT in malignant pediatric lymphoma. Eur J Nucl Med Mol Imag 2010;37:319-29.   Back to cited text no. 5
    
6.Rhodes MM, Delbeke D, Whitlock JA, Martin W, Kuttesch JF, Frangoul HA, et al. Utility of FDG-PET/CT in follow-up of children treated for Hodgkin and non-Hodgkin lymphoma. J Pediatr Hematol Oncol 2006;28:300-6.   Back to cited text no. 6
[PUBMED]  [FULLTEXT]  
7.Mody RJ, Bui C, Hutchinson RJ, Frey KA, Shulkin BL. Comparison of (18)F Flurodeoxyglucose PET with Ga-67 scintigraphy and conventional imaging modalities in pediatric lymphoma. Leuk Lymphoma 2007;48:699-707.  Back to cited text no. 7
[PUBMED]  [FULLTEXT]  
8.Riad R, Omar W, Sidhom I, Zamzam M, Zaky I, Hafez M, et al. False-positive F-18 FDG uptake in PET/CT studies in pediatric patients with abdominal Burkitt's lymphoma. Nucl Med Commun 2010;31:232-8.  Back to cited text no. 8
[PUBMED]  [FULLTEXT]  
9.Furth C, Steffen IG, Amthauer H, Ruf J, Misch D, Schφnberger S, et al. Early and late therapy response assessment with [18F]fluorodeoxyglucose positron emission tomography in pediatric Hodgkin's lymphoma: Analysis of a prospective multicenter trial. J Clin Oncol 2009;27:4385-91.   Back to cited text no. 9
    
10.Kφrholz D, Clavies A, Hasenclever D, Kluge R, Hirsch W, Kamprad F, et al. The concept of the GPOH-HD 2003 therapy study for pediatric Hodgkin's disease: Evolution in the tradition of DAL/GPOH studies. Klin Pδdiatr 2004;216:150-6.  Back to cited text no. 10
    
11.McCarville MB, Christie R, Daw NC. PET/CT in the evaluation of childhood sarcomas. AJR Am J Roentgenol 2005;184:1293-304.   Back to cited text no. 11
    
12.Franzius C, Daldrup-Link HE, Sciuk J, Rummeny EJ, Bielack S, Jόrgens H, et al. FDG-PET for the detection of pulmonary metastases from malignant primary bone tumors: Comparison with spiral CT. Ann Oncol 2001;12:479-86.   Back to cited text no. 12
    
13.Schuetze SM, Rubin BP, Vernon C, Hawkins DS, Bruckner JD, Conrad EU, et al. Use of positron emission tomography in localized extremity soft tissue sarcoma treated with neoadjuvant chemotherapy. Cancer 2005;103:339-48.  Back to cited text no. 13
    
14.Hawkins DS, Schuetze SM, Butrynski JE, Rajendran JG, Vernon CB, Conrad EU, et al. [18F]Fluorodeoxyglucose positron emission tomography predicts outcome for Ewing sarcoma family of tumors. J Clin Oncol 2005;23:8828-34.  Back to cited text no. 14
    
15.Kaste SC. 18F-PET-CT in extracranial paediatric oncology: When and for whom is it useful? Pediatr Radiol 2008;38:S459-66.  Back to cited text no. 15
    
16.Shin DS, Shon OJ, Han DS, Choi JH, Chun KA, Cho IH. The clinical efficacy of (18)F-FDG-PET/CT in benign and malignant musculoskeletal tumors. Ann Nucl Med 2008;22:603-9.   Back to cited text no. 16
    
17.Ferner RE, Golding JF, Smith M, Calonje E, Jan W, Sanjayanathan V, et al. [18F]2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) as a diagnostic tool for neurofibromatosis 1 (NF1) associated malignant peripheral nerve sheath tumours (MPNSTs): A long-term clinical study. Ann Oncol 2008;19:390-4.   Back to cited text no. 17
    
18.Sharp SE, Shulkin BL, Gelfand MJ, Salisbury S, Furman WL. 123I-MIBG scintigraphy and 18F-FDG PET in neuroblastoma. J Nucl Med 2009;50:1237-43.   Back to cited text no. 18
    
19.Kushner BH, Yeung HW, Larson SM. Extending positron emission tomography scan utility to high-risk neuroblastoma: Fluorine-18 fluorodeoxyglucose positron emission tomography as sole imaging modality in follow-up of patients. J Clin Oncol 2001;19:3397-405.  Back to cited text no. 19
    
20.Taggart DR, Han MM, Quach A, Groshen S, Ye W, Villablanca JG, et al. Comparison of iodine-123 metaiodobenzylguanidine (MIBG) scan and [18F]fluorodeoxyglucose positron emission tomography to evaluate response after iodine-131 MIBG therapy for relapsed neuroblastoma. J Clin Oncol 2009;27:5343-9.  Back to cited text no. 20
    
21.Franzius C, Lang K, Vormoor J. Whole body PET-CT with C-11-meta-hydroxyephedrine (C-11-HED) in tumors of the sympathetic nervous system: Comparison with I-123-mIBG SPECT. Eur J Nucl Med Mol Imag 2005;1:54.  Back to cited text no. 21
    
22.Kaste SC, Dome JS. PET/PET-CT imaging of Wilms tumor. In: Charron M, editor. Practical pediatric PET imaging. New York: Springer; 2006.  Back to cited text no. 22
    
23.Misch D, Steffen IG, Schφnberger S, Voelker T, Furth C, Stφver B, et al. Use of positron emission tomography for staging, preoperative response assessment and posttherapeutic evaluation in children with Wilms tumour. Eur J Nucl Med Mol Imag 2008;35:1642-50.   Back to cited text no. 23
    
24.Kaste SC, Rodriguez-Galindo C, McCarville ME. PET-CT in pediatric Langerhans cell histiocytosis. Pediatr Radiol 2007;37:615-22.  Back to cited text no. 24
    
25.Phillips M, Allen C, Gerson P, McClain K. Comparison of FDG-PET scans to conventional radiography and bone scans in management of Langerhans cell histiocytosis. Pediatr Blood Cancer 2009;52:97-101.  Back to cited text no. 25
    
26.Pirotte BJ, Lubansu A, Massager N, Wikler D, Van Bogaert P, Levivier M. Clinical impact of integrating positron emission tomography during surgery in 85 children with brain tumors. J Neurosurg Pediatr 2010;5:486-99.  Back to cited text no. 26
    
27.Pirotte B, Goldman S, Van Bogaert P, David P, Wikler D, Rorive S. Integration of [11C]methionine-positron emission tomographic and magnetic resonance imaging for image-guided surgical resection of infiltrative low-grade brain tumors in children. Neurosurgery 2005;57:128-39.  Back to cited text no. 27
    
28.Pirotte BJ, Lubansu A, Massager N, Wikler D, Goldman S, Levivier M. Results of positron emission tomography guidance and reassessment of the utility of and indications for stereotactic biopsy in children with infiltrative brainstem tumors. J Neurosurg 2007;107:392-9.  Back to cited text no. 28
    
29.Galldiks N, Kracht LW, Berthold F, Miletic H, Klein JC, Herholz K, et al. [11C]-L-ethionine positron emission tomography in the management of children and young adults with brain tumors. J Neurooncol 2010;96:231-9.   Back to cited text no. 29
    
30.Kruer MC, Kaplan AM, Etzl MM Jr, Carpentieri DF, Dickman PS, Chen K, et al. The value of positron emission tomography and proliferation index in predicting progression in low-grade astrocytomas of childhood. J Neurooncol 2009;95:239-45.  Back to cited text no. 30
    
31.Krasin MJ, Hudson MM, Kaste SC. Positron emission tomography in pediatric radiation oncology: Integration in the treatment-planning process. Pediatr Radiol 2004;34:214-21.  Back to cited text no. 31
    
32.Mah K, Caldwell CB, Ung YC. The impact of (18)FDGPET on target and critical organs in CT-based treatment planning of patients with poorly defined non-small-cell lung carcinoma: A prospective study. Int J Radiat Oncol Biol Phys 2002;52:339-50.  Back to cited text no. 32
    
33.Pierce DA, Shimizu Y, Preston DL. Studies of the mortality of atomic bomb survivors: Report 12, Part 1-Cancer: 1950-1990. Radiat Res 1996;146:1-27.   Back to cited text no. 33
    
34.Brenner DJ, Elliston CD, Hall EJ. Estimating cancer risks from pediatric CT: Going from the qualitative to the quantitative. Pediatr Radiol 2002;32:228-31.   Back to cited text no. 34
    
35.Brix G, Lechel U, Glatting G. Radiation exposure of patients undergoing whole-body dual-modality 18F-FDG PET/CT examinations. J Nucl Med 2005;46:608-13.   Back to cited text no. 35
    
36.Frush DP, Donnelly LF, Rosen NS. Computed tomography and radiation risks: What pediatric health care providers should know. Pediatrics 2003;112:951-7.   Back to cited text no. 36
    
37.Byrne A, Nadel H. Whole body low dose 18F-FDG PET/CT in pediatric oncology [abstract]. J Nucl Med 2007;48:118.  Back to cited text no. 37
    
38.Slovis TL. Conference on the ALARA (as low as reasonably achievable) concept in pediatric CT: Intelligent dose reduction. Pediatr Radiol 2002;32:217-8.  Back to cited text no. 38
    




 

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