Comparison between silicon photomultiplier-based and conventional PET/CT in patients with suspected lung cancer-a pilot study

Johan Economou Lundeberg; Jenny Oddstig; Ulrika Bitzén; Elin Trägårdh

doi:10.1186/s13550-019-0504-y

Comparison between silicon photomultiplier-based and conventional PET/CT in patients with suspected lung cancer-a pilot study

EJNMMI Res. 2019 Sep 9;9(1):35. doi: 10.1186/s13550-019-0504-y.

Authors

Johan Economou Lundeberg¹, Jenny Oddstig², Ulrika Bitzén³, Elin Trägårdh^{3

4}

Affiliations

¹ Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital, 221 85, Lund, Sweden. Johan.economoulundeberg@skane.se.
² Radiation Physics, Skåne University Hospital, Lund, Sweden.
³ Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital, 221 85, Lund, Sweden.
⁴ Wallenberg Center for Molecular Medicine, Lund University, Lund, Sweden.

Abstract

Background: Lung cancer is one of the most common cancers in the world. Early detection and correct staging are fundamental for treatment and prognosis. Positron emission tomography with computed tomography (PET/CT) is recommended clinically. Silicon (Si) photomultiplier (PM)-based PET technology and new reconstruction algorithms are hoped to increase the detection of small lesions and enable earlier detection of pathologies including metastatic spread. The aim of this study was to compare the diagnostic performance of a SiPM-based PET/CT (including a new block-sequential regularization expectation maximization (BSREM) reconstruction algorithm) with a conventional PM-based PET/CT including a conventional ordered subset expectation maximization (OSEM) reconstruction algorithm. The focus was patients admitted for ¹⁸F-fluorodeoxyglucose (FDG) PET/CT for initial diagnosis and staging of suspected lung cancer. Patients were scanned on both a SiPM-based PET/CT (Discovery MI; GE Healthcare, Milwaukee, MI, USA) and a PM-based PET/CT (Discovery 690; GE Healthcare, Milwaukee, MI, USA). Standardized uptake values (SUV) and image interpretation were compared between the two systems. Image interpretations were further compared with histopathology when available.

Results: Seventeen patients referred for suspected lung cancer were included in our single injection, dual imaging study. No statically significant differences in SUV_max of suspected malignant primary tumours were found between the two PET/CT systems. SUV_max in suspected malignant intrathoracic lymph nodes was 10% higher on the SiPM-based system (p = 0.026). Good consistency (14/17 cases) between the PET/CT systems were found when comparing simplified TNM staging. The available histology results did not find any obvious differences between the systems.

Conclusion: In a clinical setting, the new SiPM-based PET/CT system with a new BSREM reconstruction algorithm provided a higher SUV_max for suspected lymph node metastases compared to the PM-based system. However, no improvement in lung cancer detection was seen.

Keywords: Analogue PET; BSREM; Digital PET; Lung cancer; TNM stage.