Multimodale Bildgebung in der pädiatrischen Onkologie

The evaluation of multimodal imaging in paediatric oncology is the
main theme of this thesis. Both published studies evaluate
18F-fluorodesoxyglucose positron emission tomography (18FFDG-PET)
combined with an additional imaging modality in paediatric
oncological patients. 18F-FDG-PET is a functional imaging modality,
using radioactive glucose to demonstrate hypermetabolism in
malignant transformed cells. Therefore, it enables the
visualisation of the primary tumour, helps with the search for
metastases, and leads to exact tumour staging. The first study
focuses on combined 18F-FDG-PET/MR imaging in comparison to
18F-FDGPET or MR imaging alone for the detection of malignant
lesions in a non-selected patient collective. In patients suffering
from a variety of paediatric tumours, combined 18F-FDGPET/MR
imaging proofed its utility in the primary diagnostic work-up. In
the follow-up, 18FFDG-PET is recommended as single imaging modality
due to its high specificity unless the malignancy is located in
18F-FDG-PET inaccessible regions such as the urinary tract, where
unspecific radiotracer accumulation hides malignant transformed
tissue. The focus of the second study is on 18F-FDG-PET as a
diagnostic tool in children with peripheral neuroblastic tumours.
Neuroblastomas are commonly visualized on the
123I-metaiodobenzylguanidine(123I-MIBG)-scintigraphy/single photon
emission computer tomography (SPECT). However, a subgroup of
neuroblastomas fails to accumulate the specific radiotracer
123I-MIBG. In this study, the non-specific radiotracer 18F-FDG
demonstrated a high affinity to neuroblastoma and helped detecting
malignant disease. In case of a discrepancy between 123I-MIBG
scintigraphy/SPECT, MRI and clinical findings in patients with
neuroblastic tumours, 18F-FDG is recommended in the primary
diagnostic workup. In the follow-up of primary 123I-MIBG negative
neuroblastic tumours, 18F-FDG-PET is sufficient as single imaging
modality. To sum up, in both studies, 18F-FDG-PET combined with an
additional imaging modality demonstrated to be indispensable in
paediatric oncology for both the primary diagnostic work-up and the
follow-up.