Estimated cumulative radiation dose received by diagnostic imaging during staging and treatment of operable Ewing sarcoma 2005-2012.

BACKGROUND: Patients with Ewing sarcoma are subject to various diagnostic procedures that incur exposure to ionising radiation. OBJECTIVE: To estimate the radiation doses received from all radiologic and nuclear imaging episodes during diagnosis and treatment, and to determine whether 18F-fluorodeoxyglucose positron emission tomography - computed tomography (18F-FDG PET-CT) is a major contributor of radiation. MATERIALS AND METHODS: Twenty Ewing sarcoma patients diagnosed in Norway in 2005-2012 met the inclusion criteria (age <30 years, operable disease, uncomplicated chemotherapy and surgery, no metastasis or residual disease within a year of diagnosis). Radiation doses from all imaging during the first year were calculated for each patient. RESULTS: The mean estimated cumulative radiation dose for all patients was 34 mSv (range: 6-70), radiography accounting for 3 mSv (range: 0.2-12), CT for 13 mSv (range: 2-28) and nuclear medicine for 18 mSv (range: 2-47). For the patients examined with PET-CT, the mean estimated cumulative effective dose was 38 mSv, of which PET-CT accounted for 14 mSv (37%). CONCLUSION: There was large variation in number and type of examinations performed and also in estimated cumulative radiation dose. The mean radiation dose for patients examined with PET-CT was 23% higher than for patients not examined with PET-CT.

Introduction of positron emission tomography into the Western Norwegian Health Region: Regional balance in resource utilization from 2009 to 2014.

BACKGROUND: The aim was to compare resource utilization across the four health trusts within the Western Norway Regional Health Authority since the establishment of positron emission tomography (PET) at Haukeland University Hospital in Bergen in 2009. METHODS: Metadata from all PET examinations from 2009 to 2014 were automatically imported from the PET centre's central production database into a custom-developed database system, MDCake. A PET examination was defined as a procedure based on a single injection of radioactive tracer. The patients' place of residence and tentative diagnosis were coded based on the available clinical information. RESULTS: The total number of PET examinations increased from 293 in 2009 to 1616 in 2014. The number of PET examinations per year increased across all diagnostic groups, but plateaued for lung cancer, gastrointestinal cancer and malignant melanoma since 2013. The number of examinations per capita was evenly distributed between the three northern health trusts with an average of 1260 PET studies per million inhabitants in 2014. However, patients residing in the most southerly health trust received between 44% (2010) and 27% (2014; P<0·001, repeated measures ANOVA) fewer examinations per capita per year. CONCLUSION: Centralized PET in the Western Norwegian health region meets the current clinical demand for patients residing in the three northern health trusts while patients from the most southern health trust receive approximately 30% fewer PET examinations. Access to specialized health care should be monitored routinely in order to identify inequalities in referral patterns and resource utilization.

F-18-FDG PET-CT in children and young adults with Ewing sarcoma diagnosed in Norway during 2005-2012: a national population-based study.

BACKGROUND: To examine national imaging strategies regarding the use of F-18-FDG PET-CT in patients with Ewing sarcoma and study factors that might influence the use of PET-CT, such as tumour biology (Picci grade of operation specimen), clinical disease stage and age. METHODS: We examined the medical records including pathology and imaging of all patients below 30 years diagnosed with Ewing sarcoma in Norway in 2005-2012. RESULTS: Of 61 patients treated at one of the two national sarcoma treatment service centres (Oslo: 35, Bergen: 26), 29 patients had localized disease, 8 had tumour extending to organs nearby and 24 had metastases. Among 35 operated patients with neoadjuvant chemotherapy, 15 had Picci grades II and III (good responders) and 20 grade I (poor responders). We found a significant difference in the use of PET-CT (Oslo/Bergen 0·9 versus 2·0 scans per patient, P = 0·010) and in the use of MRI (Oslo/Bergen: eight versus 13, P = 0·006). No differences were proven for ultrasound, radiography, CT or skeletal scintigraphy. The number of PET-CTs was associated with clinical disease stage at diagnosis (P = 0·041) but not with Picci grade or age. The number of PET studies was not correlated to the number of MR studies. CONCLUSIONS: The use of PET-CT in children and young adults diagnosed with Ewing sarcoma in Norway during 2005-2012 at the two national sarcoma treatment service centres differed significantly. The use of PET-CT imaging was related to the clinical disease stage at diagnosis but unrelated to patient age and tumour biology (Picci grade).

Is there a role for PET-CT and SPECT-CT in pediatric oncology?

During the last decade, hybrid imaging has revolutionized nuclear medicine. Multimodal camera systems, integrating positron emission tomography (PET) or single photon emission computed tomography (SPECT) with computed tomography (CT) now combine the contrast provided by tumor-avid radioactive drugs with the anatomic precision of CT. While PET-CT to a great extent has replaced single-modality PET in adult oncology, the use of PET-CT in children has been controversial, since even the lowest dose CT protocols adds approximately 2 mSv to the radiation dose of about 4 mSv from the PET-study with F-18-fluorodeoxyglucose (F-18-FDG). The article describes the current techniques used, discusses radiation doses and gives an overview of current indications for PET-CT and SPECT-CT in children. Hybrid imaging with a tumor-avid radioactive drug provides extremely high contrast between tumor and background tissues, while the CT component helps to locate the lesion anatomically. Currently both PET-CT and SPECT-CT play a role in pediatric oncology; PET-CT using F-18-FDG particularly for staging and follow-up of lymphoma and brain cancer, bone and soft tissue sarcomas; SPECT-CT with I-123-metaiodobenzylguanidine (MIBG) for tumors of the sympathetic nervous system such as neuroblastoma and pheochromocytoma while the remaining neuroendocrine tumors are imaged with radioactively labeled somatostatin analogues. To reduce radiation dose, a low-dose CT in combination with ultrasound and/or magnetic resonance imaging for the assessment of anatomy is often preferred.

[Positron emission tomography in neuroendocrine tumours]. / Positronemisjonstomografi ved nevroendokrine svulster.

BACKGROUND: Neuroendocrine tumours constitute a small group of malignancies; about 200 new patients are diagnosed in Norway annually. This article discusses problems associated with use of deoxyfluoroglucose (FDG) Positron Emission Tomography (PET) and other available options in patients with these conditions, as well as challenges related to introduction of new radiopharmaceutical agents. MATERIAL AND METHODS: The article is based on review of literature in connection with development of new guidelines for nuclear medicine examinations, supplemented with literature identified through a non-systematic search of Pubmed. RESULTS: A large proportion of these tumours grow slowly, and recent data show that 5-year survival is about 50 %. Neuroendocrine tumours are characterised by specific biochemical processes that enable tailoring of radiopharmaceutical agents for PET and consequently a more accurate diagnosis and improved follow-up of these patients. INTERPRETATION: As for other cancer types, diagnostics and detection of metastases are an important factor for correct treatment of neuroendocrine tumours. PET with FDG is of limited use for patients with this condition. New specific radiopharmaceutical agents for PET may imply detection of 90 % of all such tumours.