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Advances in Radiotherapy
& Nuclear Medicine PET and Compton Camera CZT based system

A

B

Figure 11. Normalized activity profiles of Figure 8 with Gaussian fits after 3500 iterations of MLEM. (A) Top row, normalized activity profiles in the x, y,
and z directions of positron emission tomography MLEM. (B) Bottom row, normalized activity profiles in the x, y, and z directions of Compton camera
MLEM.
Abbreviation: MLEM: Maximum likelihood expectation maximization.

Table 3. Summary of full width at tenth‑maximum results from normalized activity profiles
Iteration FWHM (mm)
20 800 3500
x y z x y z x y z
Profile
PET 12.156 18.858 12.025 11.463 8.183 11.113 11.478 7.137 11.102
CC 1.786 2.790 1.763 4.558 9.708 4.405 2.150 4.522 2.126
Abbreviations: CC: Compton camera; FWTM: Full width at tenth-maximum; PET: Positron emission tomography.

Future work must be carried out in the implementation future work in random rejection. With growing interest in
of existing concepts in the joint reconstruction of LOR the experimental validation of quantum entanglement of
and COR data or the development of system-specific joint annihilation photons, 57-61 there’s potential for substantial
reconstruction. 16,25 It’s important to note that the resolution advancements in rejecting random, particularly when
for both PET and CC was degraded in the y direction of dealing with non-pure β emitters like As, which emit
72
+
our scanner. This degradation in the y direction is typical high-energy gammas that contaminate the 511 keV PET
for a dual-panel scanner and is a limitation for overcoming energy window.
positron range corrections in this dimension. Either a
56
cylindrical geometry must be used in place of a dual-panel 5. Conclusion
geometry or progress in limited-angle artifact correction We conclude that our dual-panel CZT system is a
must be made for implementation in joint PET-CC simple and cost-effective detector with the ability to
reconstructions. leverage prompt gamma for hybrid PET and CC imaging
Furthermore, the system’s capability to detect Compton applications. This functionality opens avenues for positron
scattering not only from prompt gammas but also from range correction, random rejection, and multi-isotope
annihilation photons holds significant implications for imaging, underscoring the potential impact of our device.

Volume 2 Issue 2 (2024) 10 doi: 10.36922/arnm.3330