Student thesis: Doctoral thesis


Breast cancer is the first cause of cancer death among women. Early diagnosis is widely

acknowledged 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 Award27 Jun 2014
Original languageEnglish
SupervisorMokhtar Chmeissani (Director) & Enrique Fernandez Sanchez (Tutor)

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