Abstract
Breast cancer is the first cause of cancer death among women. Early diagnosis is widelyacknowledged as being crucial in the successful treatment of the disease.
Positron emission mammography (PEM) is a diagnostic technique of positron emission
tomography (PET) dedicated to the breast. By placing the detectors close to the breast, the
PEM geometry subtends more solid angle around the breast than a whole body PET scanner
which allows to detect smaller breast cancers. Additional advantages are lower necessary dose,
costing much less and enhanced device portability. Over the past few years, crystal PEMs have
dramatically increased their importance in the diagnosis and treatment of early stage breast
cancer. Nevertheless, design based on scintillators are characterized by an intrinsic deficiency
of the depth of interaction information from relatively thick crystals constraining the size of
the smallest detectable tumor. This work shows how to overcome such intrinsic limitation by
substituting scintillating crystals with pixilated CdTe detectors.
The proposed high resolution design is developed within the Voxel Imaging PET (VIP)
Pathfinder project and evaluated via Monte Carlo simulation. The system is simulated following
the prescription of the NEMA NU-4 2008 protocol for the evaluation of small animal PET
devices. Several tests are performed to assess the counting and the imaging performance of
the VIP PEM scanner with the accurate modeling of the required experimental conditions.
The volumetric spatial resolution of the VIP PEM is expected to be up to 8 times better than
standard commercial devices and with a point spread function of 1 mm full width at half
maximum (FWHM) in all directions. Pixelated CdTe detectors can also provide an energy
resolution as low as 1.57% FWHM at 511 keV for a virtually pure signal with negligible
contribution from scattered events. The VIP collects virtually noise-free data leading to
excellent quality images. The results show the potential of the novel design for providing high
specificity metabolic images for very small lesions and low TNR.
This thesis consists of 7 chapters. Chapter 1 is a review of the theoretical and historical
background of PET. Chapter 2 defines breast cancer detection in nuclear medicine and state
of the art scanners for PEM. Chapter 3 is the VIP PEM geometry and its distinctive features.
Chapter 4 describes the system simulation and image reconstruction. Chapter 5 describes
the study of the counting performance of the VIP PEM design. Chapter 6 is dedicated to the
assessment of the image quality and the testing of the VIP in pseudo-clinical conditions. Finally,
the conclusions are discussed in the chapter 7.
| Date of Award | 27 Jun 2014 |
|---|---|
| Original language | English |
| Supervisor | Mokhtar Chmeissani (Director) & Enrique Fernandez Sanchez (Tutor) |