[SPECT/CT for staging and treatment monitoring in oncology. Applications in differentiated thyroid cancer and liver tumors].
OBJECTIVE
Hybrid imaging of function and morphology has gained significant importance for lesion detection and treatment monitoring in oncology. In patients with differentiated thyroid carcinoma (DTC) a planar whole body scan is carried out after radioiodine therapy (RIT) for staging. However, due to limited spatial resolution the diagnostic accuracy of this scintigraphy method is impaired.                         Radioembolization utilizing (90)Yttrium loaded micro-spheres by selective internal radiotherapy (SIRT) allows a minor invasive therapy of primary and secondary liver tumors. In order to avoid side effects of the micro-spheres caused by an outflow into intestines, stomach or lungs, imaging the arteries supplying the liver has to be performed by means of technetium-99m macroaggregated albumin ((99m)Tc-MAA) and scintigraphy. The limited morphological information supplied by scintigraphy is again a challenge in treatment monitoring.                                               STANDARD RADIOLOGICAL/NUCLEAR MEDICAL METHODS:                                                      (131)Iodine whole body scanning is used for staging in patients with DTC 3-4 days after ablation. Monitoring of the tumor marker thyroglobulin and selective radioiodine whole body scans are available for patients with a high risk profile in the further follow-up with imaging of the arteries supplying the liver by means of (99m)Tc-MAA scintigraphy in preparation of SIRT.


METHODS
Single photon emission computed tomography/computed tomography (SPECT/CT) of the neck and thorax with a therapeutic activity of radioiodine for staging after ablation. Techniques include imaging of arteries supplying the liver by means of (99m)Tc-MAA SPECT/CT before SIRT and evaluation and quantification of the uptake of liver tumors, especially in comparison to the uptake of liver parenchyma by means of SPECT/CT.


METHODS
Due to the integration of combined functional and morphological information SPECT/CT can be used to characterize the morphology and iodine uptake of lesions more accurately, resulting in optimized staging in patients with DTC in comparison to whole body iodine scans and SPECT/CT provides more accurate imaging of the arterial supply of the liver and of potential outflows of micro-spheres into other organs. SPECT/CT allows evaluation and quantification of the uptake of liver tumors.


RESULTS
Improved postablative staging in patients with differentiated thyroid cancer by SPECT/CT in comparison to radioiodine whole body scans can be achieved. Improved planning and monitoring of SIRT therapies utilizing SPECT/CT leads to optimized therapeutic doses within liver lesions.


CONCLUSIONS
Integration of SPECT/CT into the clinical standard for postablative staging in patients with DTC is recommended as well as utilization of SPECT/CT during the planning process, for dose calculation and treatment monitoring of SIRT therapies.
Institut für Klinische Radiologie, Klinikum der Ludwig-Maximilians-Universität München, Campus Innenstadt, München, Deutschland.
K
K
Weber
F
F
Berger
M
M
Mustafa
M F
MF
Reiser
P
P
Bartenstein
A
A
Haug
D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008113:Liver Neoplasms / Q000473:pathology*; D064847:Multimodal Imaging / Q000379:methods*; D009367:Neoplasm Staging / Q000379:methods; D049268:Positron-Emission Tomography; D013964:Thyroid Neoplasms / Q000473:pathology*; D014057:Tomography, X-Ray Computed