Nuclear Medicine

The nuclear medicine units at Karolinska perform diagnostic examinations with planar scintigraphy, SPECT/CT and PET/CT. We are also active in providing therapeutic treatments with radiopharmaceuticals. Research interests are broad and range from protocol optimization to statistical-based diagnosis, all focusing on improving patient care.

A selection of ongoing projects

Statistical algorithm based diagnosis in neurodegenerative disorders

Investigators:

Cathrine Jonsson (1, 2), Marco Pagani (1, 3), Johanna Öberg (1) and Lars-Olof Ronnevi (2)

Affiliations:

Karolinska University Hospital (1), Karolinska Institutet (2) and ISTC-CNR (Italy) (3)

The project is part of a continuing international collaboration aiming at improving diagnosis of conditions caused by Alzheimers' Disease to an unprecedented level, using PET imaging. Work carried out at the hospital includes the creation and implementation of dedicated scripts and easy-to-use-software for sophisticated statistical and image analyses, to allow an automatic and reliable diagnosis in clinical routine.  

Construction of a Monte Carlo model of a clinical PET camera for protocol optimisation studies

Investigators:

Agnetha Gustafsson, Maria Holstensson and Ulrika Dahlén

Affiliations:

Karolinska University Hospital

The Monte Carlo method is a valuable tool in medical imaging that can be used to assess and optimise image acquisition protocols. The objective of this study is to build and validate a model of a Siemens Biograph mCT PET-CT scanner within the GATE Monte Carlo code (the Geant4 Application for Tomographic Emission), to enable a wide variety of optimization studies. 

Reduction in the acquisition time for pulmonary embolism scintigraphy

Investigators:

Maria Holstensson, Agnetha Gustafsson, Ulrika Estenberg, Rimma Axelsson

Affiliations:

Karolinska University Hospital

For a subset of patients, ventilation-perfusion scintigraphy is the preferred choice for diagnosis of acute pulmonary thrombosis. Such patients are often critically ill and long scan times are not well tolerated. This study investigates whether the current protocol at the hospital is optimal, or whether alternative shorter acquisitions such as recommended by the European Association of Nuclear Medicine (EANM) can provide the necessary diagnostic information. The study adopts a simulation approach with a subsequent evaluation study of simulated images by physicians. 

Recent publications

Reduced acquisition times in whole body bone scintigraphy using a noise-reducing Pixon®-algorithm — a qualitative evaluation study

Investigators:

Oscar Ardenfors, Ulrika Svanholm, Hans Jacobsson, Patricia Sandqvist, Per Grybäck and Cathrine Jonsson

Affiliations:

Karolinska University Hospital

This patient study evaluated the commercial noise-reducing Pixon-algorithm applied to whole-body bone scintigraphy. It was investigated whether the use of Pixon on a scan with half the standard scan time could provide the same clinical information as the standard protocol. The results showed that 93% of the processed half-time images and 98% of the standard images were rated as sufficient or good with regard to lesion detectability. However, image quality (lesion detectability, image noise, and artifacts) was not fully compensated for with a halved scan-time, suggesting a less aggressive reduction is warranted. 

Metabolic spatial connectivity in amyotrophic lateral sclerosis as revealed by independent component analysis

Investigators:

Marco Pagani (1, 2), Johanna Öberg (2), Fabrizio De Carli (3), Andrea Calvo (4), Cristina Moglia (4), Antonio Canosa (4), Flavio Nobili (5), Silvia Morbelli (5), Piercarlo Fania (6), Angelina Cistaro (6) and Adriano Chiò (4, 1, 7)

Affiliations:

Institute of Cognitive Sciences and Technologies (Italy) (1), Karolinska University Hospital (2),  Institute of Molecular Bioimaging and Physiology (Italy) (3), University of Turin (Italy) (4), University of Genoa (Italy) (5), Euromedic Inc. (Italy) (6) and Neuroscience Institute of Turin (Italy) (7)

Positron emission tomography (PET) and volume of interest (VOI) analysis have recently shown high accuracy in distinguishing patients with amyotrophic lateral sclerosis (ALS) from controls. In this study it is demonstrated that spatial independent component analysis (ICA) performs better than univariate semi-quantification methods in identifying the neurodegenerative features of ALS, highlighting the further potential for PET in clinical trials and early diagnosis.

Repeatability of the Maximum Standard Uptake Value (SUVmax) in FDG PET

Investigators:

Henry Lindholm, Johan Staaf, Hans Jacobsson, Fredrik Brolin, Robert Hatherly and Alejandro Sanchez-Crespo

Affiliations:

Karolinska University Hospital

The maximum Standard Uptake Value standard or "SUVmax" is often calculated in FDG PET examinations, however, since SUVmax represents a very small portion of a lesion it may be questioned how statistically reliable the figure is as a measure of uptake. In this project the robustness of the statistic was studied by assessing the repeatability of SUVmax between two FDG acquisitions acquired immediately upon each other in 100 patients with chest lesions. Repeatability (mean difference) was found to be 1% indicating that SUVmax is a stable parameter.

Model-based correction for scatter and tailing effects in simultaneous 99mTc and 123I imaging for a CdZnTe cardiac SPECT camera

Investigators:

Maria Holstensson (1, 2), Kjell Erlandsson (1), Gavin Poludniowski (2), Simona Ben-Haim (3) and Brian F. Hutton (4)

Affiliations:

University College London (UK) (1), Karolinska University Hospital (2), Chaim Sheba Medical Center (IL) (3) and  University of Wollongong (AU) (4)

An advantage of semiconductor-based dedicated cardiac SPECT cameras compared to conventional gamma cameras is superior energy resolution, providing the potential for improved separation of the photopeaks in dual radionuclide imaging. There is, however, the added complexity of tailing effects in the detectors; this project developed a model-based correction algorithm to extract useful primary counts of (99m)Tc and (123)I from projection data.