Abstract
ntroduction: PET imaging is increasingly used in prostate
cancer diagnostics as it enables sensitive lesion detection and
molecular characterisation of cancer lesions in vivo. For accurate
PET interpretation and cancer staging, understanding of healthy
tissue uptake is important, as the uptake of suspected tumours
is compared to background activity (surrounding healthy tissue
or a reference organ). Hence, high variability in healthy tissue
uptake could impair reliable PET reading, both between patients and within patients at different time points during treatment. The aim of this study was to quantify the variability of [68Ga]Prostate Specific Membrane Antigen ([68Ga]PSMA), [18F]fluoromethylcholine ([18F]FCH) and [18F]dihydrotestosterone ([18F]FDHT) uptake in healthy tissues, in order to evaluate their appropriateness as reference region. Additionally, reference ranges
for standardized uptake values (SUV) will be provided, which are
applicable as image-derived Quality Control (QC) for future PET
acquisitions. Materials and Methods: N=201 PET scans from
multiple hospitals were analysed, including n=87 [
68Ga]PSMA;n=87 [18F]FCH and n=27 [18F]FDHT PET/CT scans. Tracer uptake
in the aortic blood pool, lung, liver, bone marrow and muscle
was assessed, using several SUV metrics (i.e. SUVmax, SUVpeak, SUVmean). Variability in uptake was analysed using Coefficients of Variations (COV %). For image-derived QC purposes, SUV reference ranges (mean ± 1.96*SD) were provided for all healthy tissues, for each radiotracer. Results: For [68Ga]PSMA, lowest variability was observed for blood pool SUVpeak (COV 19.0%; reference range 0.8 - 1.7). All other tissues displayed considerable
variability (range COV 27.6 - 32.0%). For [18F]FCH, liver SUVpeak
was most stable (COV 16.8%; reference range 7.3 - 14.4). Reliable
uptake was also observed in the blood pool and bone marrow
(COV 19.1 - 19.5%). For [18F]FDHT, stable uptake was observed
in the liver, blood pool, and bone marrow (COV 14.0 - 18.3%;
reference range liver SUVpeak 3.3 - 5.8). Acquisition efficiency
rates (i.e. total image-detected Bq / injected dose at start scan)
were stable for all tracers (COV 6.2 - 10.7%). Conclusion: Only
blood pool provide a reliable reference region for [68Ga]PSMA
PET scans. For [18F]FCH and [18F]FDHT PET, either liver, blood pool
or bone marrow could be used as reference regions. Reference
ranges for healthy tissue uptake and scanner efficiency per tracer are proposed as image-derived QC measures.
cancer diagnostics as it enables sensitive lesion detection and
molecular characterisation of cancer lesions in vivo. For accurate
PET interpretation and cancer staging, understanding of healthy
tissue uptake is important, as the uptake of suspected tumours
is compared to background activity (surrounding healthy tissue
or a reference organ). Hence, high variability in healthy tissue
uptake could impair reliable PET reading, both between patients and within patients at different time points during treatment. The aim of this study was to quantify the variability of [68Ga]Prostate Specific Membrane Antigen ([68Ga]PSMA), [18F]fluoromethylcholine ([18F]FCH) and [18F]dihydrotestosterone ([18F]FDHT) uptake in healthy tissues, in order to evaluate their appropriateness as reference region. Additionally, reference ranges
for standardized uptake values (SUV) will be provided, which are
applicable as image-derived Quality Control (QC) for future PET
acquisitions. Materials and Methods: N=201 PET scans from
multiple hospitals were analysed, including n=87 [
68Ga]PSMA;n=87 [18F]FCH and n=27 [18F]FDHT PET/CT scans. Tracer uptake
in the aortic blood pool, lung, liver, bone marrow and muscle
was assessed, using several SUV metrics (i.e. SUVmax, SUVpeak, SUVmean). Variability in uptake was analysed using Coefficients of Variations (COV %). For image-derived QC purposes, SUV reference ranges (mean ± 1.96*SD) were provided for all healthy tissues, for each radiotracer. Results: For [68Ga]PSMA, lowest variability was observed for blood pool SUVpeak (COV 19.0%; reference range 0.8 - 1.7). All other tissues displayed considerable
variability (range COV 27.6 - 32.0%). For [18F]FCH, liver SUVpeak
was most stable (COV 16.8%; reference range 7.3 - 14.4). Reliable
uptake was also observed in the blood pool and bone marrow
(COV 19.1 - 19.5%). For [18F]FDHT, stable uptake was observed
in the liver, blood pool, and bone marrow (COV 14.0 - 18.3%;
reference range liver SUVpeak 3.3 - 5.8). Acquisition efficiency
rates (i.e. total image-detected Bq / injected dose at start scan)
were stable for all tracers (COV 6.2 - 10.7%). Conclusion: Only
blood pool provide a reliable reference region for [68Ga]PSMA
PET scans. For [18F]FCH and [18F]FDHT PET, either liver, blood pool
or bone marrow could be used as reference regions. Reference
ranges for healthy tissue uptake and scanner efficiency per tracer are proposed as image-derived QC measures.
| Original language | English |
|---|---|
| Pages (from-to) | S539-+ |
| Journal | European Journal of Nuclear Medicine and Molecular Imaging |
| Volume | 45 |
| Issue number | S1 |
| Publication status | Published - Oct 2018 |