Nuclear medicine research is one of the main pillars of the Belgian Nuclear Research Centre (SCK CEN). Our research focuses on several areas of radiopharmaceutical development like radioisotope research and development, chelator development and radiolabeling, biological and preclinical evaluation, evaluation and prediction of radiation doses and metrology for nuclear medicine. Our current isotope portfolio includes Ac-225, Lu-177, Tb-161, Re-188, and Sm-153. Nuclear medicine research activities are carried out in our newly commissioned hot animal facility and radiochemistry labs.
To ensure the safe and secure implementation of these radiopharmaceuticals we dedicate considerable efforts in accurately quantifying the activity of each isotope of interest. However, metrological aspects of activity quantification during the preclinical evaluation of radiopharmaceuticals present numerous challenges. Among these challenges we have lack of traceability and standardization, as well as issues related to the nature of the devices used for activity quantification, like detector efficiency, attenuation and scatter.
Specifically, in imaging devices like Single Photon Emission Computed Tomography (SPECT), the acquired data are in counts units, not activity, necessitating absolute quantification. To perform quantitative imaging, calibration factors (CF) must be derived to convert voxel intensity (counts) to MBq/ml. This can be achieved by imaging an object with known activity. Additionally, we must account for several factors that affect quantification, including photon attenuation, scatter correction, partial volume effects, collimator resolution and septal penetration
As part of our dosimetry and calibration tasks, we perform cross calibrations of all imaging and non-imaging devices for each isotope of interest against a common higher reference standard. In our hot animal facility these devices include various types of radionuclide calibrators, gamma counter, autoradiography system and micro SPECT-CT, which are calibrated against our secondary standard chamber Fidelis.
The objective of this project is to contribute to the cross calibration activities. The aim will be to optimize the image acquisition and reconstruction protocols for Lu177 and Tb161 in micro SPECT-CT. For this, the student will analyze a set of phantom images that have already been acquired. From the analysis, we will derive image quality metrics and recovery coefficients for Lu-177 and Tb-161. Based on the results we will established optimized settings for activity quantification of these isotopes via SPECT images. A correct quantification is crucial to be able to perform dosimetry calculations using longitudinal in vivo SPECT studies.
Het vereiste minimumdiploma van de kandidaat
- Academic bachelor
De vereiste achtergrondkennis van de kandidaat
- Physics