Pozitron Emisyon Tomografisinin Uzun Dönem Yan Etkileri
Özet
Pozitron Emisyon Tomografisi/Bilgisayarlı Tomografi (PET/BT), onkolojide tanı, evreleme ve tedavi yanıtını değerlendirmede yaygın olarak kullanılan hibrit bir moleküler görüntüleme yöntemidir. En sık kullanılan Flor-18 florodeoksiglukoz (18F-FDG) ajanı, kanserli hücrelerdeki yüksek glukoz metabolizması sayesinde lezyonların morfolojik ve fonksiyonel olarak tespitini sağlar. Ancak PET/BT tetkiki, hem radyonüklid bozunumundan hem de BT bileşeninden kaynaklanan iyonize radyasyon nedeniyle hastalar için ciddi bir maruziyet kaynağıdır. Takip süreçlerinde tekrarlayan çekimler, özellikle yaşam beklentisi uzun olan genç ve pediatrik hastalarda hematolojik ve solid malignite riskini artıran kümülatif dozlara ulaşabilmektedir. Bu nedenle çekimlerde ALARA (mümkün olan en düşük radyasyon) prensibi benimsenmeli ve radyofarmasötik veya BT dozları optimize edilmelidir. En çok maruz kalan mesane ve kalp gibi organlarda uzun dönemli patoloji bildirilmemiş olsa da, bu tetkikin kesin endikasyonlarla ve dikkatle planlanması kritik önem taşır.
Positron Emission Tomography/Computed Tomography (PET/CT) is a hybrid molecular imaging modality widely utilized in oncology for diagnosis, staging, and treatment response evaluation. The most commonly preferred agent, Fluorine-18 fluorodeoxyglucose (18F-FDG), enables the morphological and functional detection of lesions due to the increased glucose metabolism in cancer cells. However, PET/CT scans cause significant radiation exposure derived from both radionuclide decay and the concurrent CT component. Repeated scans during follow-up can lead to high cumulative doses that increase the risk of hematologic and solid malignancies, particularly in pediatric and young patients with long life expectancies. Therefore, the ALARA (as low as reasonably achievable) principle must be adopted by optimizing radiopharmaceutical or CT acquisition parameters. Although no long-term benign or malignant pathologies have been reported in the most exposed organs, such as the bladder and heart, planning these scans with accurate clinical indications remains critically vital.
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