Description
Purpose: Hypoxia in colorectal cancer (CRC) and gastroesophageal cancer (GEC) decreases
tumour responsiveness to radio and chemotherapy leading to cancer progression and poor
prognosis. This is the first study to utilise [18F]FAZA hypoxia radiotracer in patients with
CRC and GEC.
Methods: Six patients (mean age 68±8 years, 2 males and 4 females) with CRC and 4 patients
diagnosed with GEC (mean age 65 years, 3 males and 1 female) were included in the study.
[18F]FAZA was synthesised at the John Mallard Scottish PET Centre. After injection with
370 MBq of [18F]FAZA, PET/CT images with 60 min dynamic scan were acquired. In
addition, 15 min static scans 2 hr post injection were performed. 3D PET images were
reconstructed iteratively using an ordered subset expectation maximization (OSEM) method
and fused to the corresponding low-dose CT images. [18F]FAZA uptake parameters including
maximum standard uptake value (SUVmax), tumour-to-muscle ratio (T/M), tumour-to-bowel
ratio (T/B) and volume of interest (VOI) were measured.
Results: 4 out 6 patients with CRC (66%) showed clear uptake of [18F]FAZA in the primary
tumour. The mean tumour SUVmax was 2.2±0.91 (range 1.12 - 3.71). The tumour SUVmax
was significantly higher compared with muscle and bowel (t(5) =3.11, P=0.03), (t(5) =3.08,
P=0.03), respectively. However, tumour SUVmean didn’t differ significantly compared with
muscle and bowel (t(5) =2.41 , P=0.06), (t(5) =2.46 , P=0.06) respectively. The mean tumour
to muscle ratio (T/M) ratio was 1.89±0.64 (range 1.10 - 2.87), while the mean tumour to
normal bowel (T/B) was 1.92±0.64 (range 1.08 - 2.74). However, [18F]FAZA did not
accumulate in any of the tumours found in patients with GEC.
Conclusions: [18F]FAZA PET/CT imaging is suitable and feasible for detecting CRC hypoxic
tumour regions with image quality that can be used in clinical practice.
| Technical Track | Nuclear Applications and Radiation Processing |
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