Simulation study of resistor networks applied to an array of 256 SiPMs

[EN] In this work we describe a procedure to reduce the number of signals detected by an array of 256 Silicon Photo-multipliers (SiPMs) using a resistor network to divide the signal charge into few readout channels. Several configurations were modeled, and the pulsed signal at the readout contacts were simulated. These simulation results were experimentally tested on a specifically designed and manufactured set of printed circuit boards. Three network configurations were modeled. The modeling provided encouraging results for all three configurations. The measurements on the prototypes constructed for this study, however, provided useful position-sensitivity for only one of the network configurations. The lack of input signal amplification into the networks, the SiPM dark current, as well as the complexity of an eight layers board with parasitic capacitances, could have caused the degradation of resolving the impact photon position. This is hard to overcome with external printed circuit boards and components.This work was supported by the Spanish Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (I+D+I) under Grant FIS2010-21216-CO2-01, the Valencian Local Government under Grant PROMETEO 2008/114 and through the JAE-Predoc grant from CSIC (BOE 29/01/2010).Gonzalez, A. J., Moreno, M., Barbera, J., Conde, P., Hernandez, L., Moliner, L., . . . Benlloch, J. M. (2013). Simulation study of resistor networks applied to an array of 256 SiPMs. IEEE Transactions on Nuclear Science, 60(2), 592-598. doi:10.1109/TNS.2012.2226051S59259860

EM tomographic image reconstruction using polarvoxels

[EN] The splitting of the field of view (FOV) in polar voxels is proposed in this work in order to obtain an efficient description of a cone-beam computed tomography (CT) scanner. The proposed symmetric-polar pixelation makes it possible to deal with the 3D iterative reconstruction considering a number of projections and voxel sizes typical in CT preclinical imaging. The performance comparison, between the filtered backprojection (FBP) and 3D maximum likelihood expectation maximization (MLEM) reconstruction algorithm for CT, is presented. It is feasible to achieve the hardware spatial resolution limit with the considered pixelation. The image quality achieved with MLEM and FBP have been analyzed. The results obtained with both algorithms in clinical images have been compared too. Although the polar-symmetric pixelation is presented in the context of CT imaging, it can be applied to any other tomographic technique as long as the scan comprises the measurement of an object under several projection angles.This work was supported by the Spanish Plan Nacional de Investigaci´on Cient´ıfica, Desarrollo e Innovaci´on Tecnol´ogica (I+D+I) under Grant No. FIS2010-21216-CO2-01 and Valencian Local Government under Grants PROMETEO/2008/114, ISIC/2012/013 and APOSTD/2010/012.Soriano Asensi, A.; Rodríguez Álvarez, MJ.; Iborra Carreres, A.; Sánchez Martínez, F.; Carles Fariña, M.; Conde Castellanos, PE.; González Martínez, AJ.... (2013). EM tomographic image reconstruction using polarvoxels. Journal of Instrumentation. 8(12):1-7. https://doi.org/10.1088/1748-0221/8/01/C01004S1781

Diseño e implementación de un SPECT pre-clínico basado en cristales continuos

El trabajo de esta tesis consiste en el desarrollo y puesta en marcha de dos prototipos SPECT para animales pequeños utilizando la mini gammacámara desarrollada previamente por nuestro grupo de Física Médica. Se realiza en primer lugar una primera prueba de concepto con el objetivo de comprobar la viabilidad del proyecto, dicho prototipo se diseña y desarrollolla en el Servicio de Medicina Nuclear del Hospital Clínico y Provincial de Barcelona. En el segundo prototipo se pretende ampliar la prueba de concepto y desarrollar un nuevo prototipo con el que se obtenga un mayor rendimiento del SPECT con la misma gammacámara. Para ello, este prototipo dispone de 2 detectores montadas opuestas en el sistema. En este prototipo se aplican distintas correcciones en la reconstrucción de la imagen e incorporará un colimador intercambiable entre pinhole y multipinhole con el fin de mejorar las prestaciones del SPECT. El diseño del nuevo colimador multipinhole se optimiza mediante simulación Monte Carlo con Geant4 (versión Geant 4.9.2). Finalmente se desarrolla un método de cuantificación de imagen, que permita relacionar las cuentas de la imagen reconstruida con la actividad del objeto o sujeto a estudio

Performance of a DOI-encoding small animal PET system with monolithic scintillators

PET systems designed for specific applications require high resolution and sensitivity instrumentation. In dedicated system design smaller ring diameters and deeper crystals are widely used in order to increase the system sensitivity. However, this design increases the parallax error, which degrades the spatial image resolution gradually from the center to the edge of the field-of-view (FOV). Our group has designed a depth of interaction(DOI)-encoding small animal PET system based on monolithic crystals. In this work we investigate the restoration of radial resolution for transaxially off-center sources using the DOI information provided by our system. For this purpose we have designed a support for point like sources adapted to our system geometry that allows a spatial compression and resolution response study. For different point source radial positions along vertical and horizontal axes of a FOV transaxial plane we compare the results obtained by three methods: without DOI information, with the DOI provided by our system and with the assumption that all the ¿-rays interact at half depth of the crystal thickness. Results show an improvement of the mean resolution of 10% with the half thickness assumption and a 16% achieved using the DOI provided by the system. Furthermore, a 10% restoration of the resolution uniformity is obtained using the half depth assumption and an 18% restoration using measured DOI. © 2011 Elsevier B.V.Carles Fariña, M.; Lerche, CW.; Sánchez Martínez, F.; Orero Palomares, A.; Moliner Martínez, L.; Soriano Asensi, A.; Benlloch Baviera, JM. (2012). Performance of a DOI-encoding small animal PET system with monolithic scintillators. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 695:317-321. doi:10.1016/j.nima.2011.11.02131732169

Minimization of parallax error in dedicated breast PET

[EN] The increase of the detector thickness and the incidence angle of impinging photons permits an enhancement of sensitivity in positron emission tomography (PET) scanners. But also increases the parallax error and leads to a worsening of spatial resolution. Instead of introducing hardware modifications in the readout electronics or in the detector, we propose in this work to model the photon penetration depth in the detector material and to account for this effect during the image reconstruction. The validation of the model was based on experimental measurements with the MAMMI breast dedicated PET. It consists of twelve detector modules of monolithic LYSO scintillators. A point-like source was acquired at several radial positions across the field of view. The performance of the model was analyzed in terms of position accuracy and spatial resolution. Full width at half maximum (FWHM) average improvement values of 1.0 mm (radial), 0.4 mm (tangential), and 0.3 mm (axial) have been measured when the photon penetration depth was taken into account. The use of the model proposed in this work allows us to design PET detectors with improved sensitivity while maintaining the spatial resolution of the scanner.This work was supported by the Spanish Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (I+D+I) under Grant FIS2010-21216-CO2-01 and Valencian Local Government under Grants PROMETEO 2008/114 and APOSTD 2010/012.Soriano Asensi, A.; González Martínez, AJ.; Sánchez Martínez, F.; Conde, P.; Moliner Martínez, L.; Orero Palomares, A.; Rodríguez Álvarez, MJ.... (2013). Minimization of parallax error in dedicated breast PET. IEEE Transactions on Nuclear Science. 60(2):739-745. doi:10.1109/TNS.2012.2226749S73974560

Attenuation correction without transmission scan for the MAMMI breast PET

[EN] Whole-body Positron Emission Tomography (PET) scanners are required in order to span large Fields of View (FOV). Therefore, reaching the sensitivity and spatial resolution required for early stage breast tumor detection is not straightforward. MAMMI is a dedicated breast PET scanner with a ring geometry designed to provide PET images with a spatial resolution as high as 1.5 mm, being able to detect small breast tumors ðo1 cmÞ. The patient lays down in prone position during the scan, thus making possible to image the whole breast, up to regions close to the base of the pectoral without the requirement of breast compression. Attenuation correction (AC) for PET data improves the image quality and the quantitative accuracy of radioactivity distribution determination. In dedicated, high resolution breast cancer scanners, this correction would enhance the proper diagnosis in early disease stages. In whole-body PET scanners, AC is usually taken into account with the use of transmission scans, either by external radioactive rod sources or by Computed Tomography (CT). This considerably increases the radiation dose administered to the patient and time needed for the exploration. In this work we propose a method for breast shape identification by means of PET image segmentation. The breast shape identification will be used for the determination of the AC. For the case of a specific breast PET scanner the procedure we propose should provide AC similar to that obtained by transmission scans as we take advantage of the breast anatomical simplicity. Experimental validation of the proposed approach with a dedicated breast PET prototype is also presented. The main advantage of this method is an important dose reduction since the transmission scan is not required.This study has been partially funded by the European Commission under the project "MAMmography with Molecular Imaging MAMMI, FP6-2005-LIFESCIHEALTH-7".Soriano Asensi, A.; González Martínez, AJ.; Orero Palomares, A.; Moliner Martínez, L.; Carles Fariña, M.; Sánchez Martínez, F.; Benlloch Baviera, JM.... (2011). Attenuation correction without transmission scan for the MAMMI breast PET. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 648:S75-S78. doi:10.1016/j.nima.2010.12.138SS75S7864

Correction algorithms for signal reduction in insensitive areas of a small gamma camera

The radiation sensitive part of the wide-field, small gamma camera Sentinella 108 consists of a monolithic, 102 x 102 mm2 wide CsI(Na) crystal coupled to four position-sensitive photomultipliers. These are read out via a resistor mesh reducing the 256 PMT channels to four digitized values which allow for a simple image reconstruction, based on polynomials, with high spatial resolution. The sensor areas between neighboring PMTs suffer from reduced detection efficiency for scintillation light. The corresponding lack of signal amplitude translates to a poor uniformity and additional image compression in the border regions of the images after the first step of reconstruction. These effects cannot be completely eliminated by a global calibration procedure alone. We have developed and evaluated two classes of algorithms to compensate for this reduction of signal amplitude. Corrections are applied for each detected event separately, maintaining the real-time capability of the gamma camera. Algorithm 1 is based on a four-parameter, geometric calculation of the four output signals. This model aims to attack the underlying lack of detection efficiency without further assumptions on the true event distribution, preserving the global polynomial image decompression. Algorithm 2, to the contrary, starts from measured reference distributions of point sources which are used to model local deformations and energy loss without further information on the underlying detector geometry. Here too, a good image quality has been obtained after application of the deduced corrections. These algorithms are applied in the first step of event reconstruction. Within an energy interval of +-0.2 E_p around the photopeak position of 99m-Tc, E_p = 140.5 keV, and comparing several cameras, global uniformities around 5-8% have been obtained with both models. Measured energy resolutions are about 9-14%.Project funded by the Centre for Industrial Technological Development (CDTI) through the Science Industry Subprogramme under Grant No. IDC-20101144.Seimetz, M.; Orero Palomares, A.; Morera Ballester, C.; Abellan Castillo, AI.; Polo Collado, R.; Hernández Hernández, L.; Vidal San Sebastián, LF.... (2014). Correction algorithms for signal reduction in insensitive areas of a small gamma camera. Journal of Instrumentation. 9(C05042):1-10. https://doi.org/10.1088/1748-0221/9/05/C05042S1109C0504

Small animal PET scanner based on monolithic LYSO crystals: Performance evaluation

Purpose: The authors have developed a small animal Positron emission tomography(PET)scanner based on monolithic LYSO crystals coupled to multi-anode photomultiplier tubes (MA-PMTs). In this study, the authors report on the design, calibration procedure, and performance evaluation of a PET system that the authors have developed using this innovative nonpixelated detector design. Methods : The scanner is made up of eight compact modules forming an octagon with an axial field of view (FOV) of 40 mm and a transaxial FOV of 80 mm diameter. In order to fully determine its performance, a recently issued National Electrical Manufacturers Association (NEMA) NU-4 protocol, specifically developed for small animal PETscanners, has been followed. By measuring the width of light distribution collected in the MA-PMT the authors are able to determine depth of interaction (DOI), thus making the proper identification of lines of response (LORs) with large incidence angles possible. PET performances are compared with those obtained with currently commercially available small animal PETscanners. Results : At axial center when the point-like source is located at 5 mm from the radial center, the spatial resolution measured was 1.65, 1.80, and 1.86 mm full width at half maximum (FWHM) for radial, tangential, and axial image profiles, respectively. A system scatter fraction of 7.5% (mouse-like phantom) and 13% (rat-like phantom) was obtained, while the maximum noise equivalent count rate (NECR) was 16.9 kcps at 12.7 MBq (0.37 MBq/ml) for mouse-like phantom and 12.8 kcps at 12.4 MBq (0.042 MBq/ml) for rat-like phantom The peak absolute sensitivity in the center of the FOV is 2% for a 30% peak energy window. Several animal images are also presented. Conclusions: The overall performance of our small animal PET is comparable to that obtained with much more complex crystal pixelated PET systems. Moreover, the new proposed PET produces high-quality images suitable for studies with small animals.This work was supported by the Spanish Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica (I+D+I) under Grant No. FIS2010-21216-CO2-01 and Valencian Local Government under Grant No. PROMETEO 2008/114. The authors would like to thank Andrew Duncan for checking and correcting the text.Sánchez Martínez, F.; Moliner Martínez, L.; Correcher, C.; González Martínez, AJ.; Orero Palomares, A.; Carles Fariña, M.; Soriano Asensi, A.... (2012). Small animal PET scanner based on monolithic LYSO crystals: Performance evaluation. Medical Physics. 39(4):643-653. https://doi.org/10.1118/1.3673771S643653394Myers, R. (2001). The biological application of small animal PET imaging. Nuclear Medicine and Biology, 28(5), 585-593. doi:10.1016/s0969-8051(01)00213-xChatziioannou, A. F. (2002). Molecular imaging of small animals with dedicated PET tomographs. European Journal of Nuclear Medicine and Molecular Imaging, 29(1), 98-114. doi:10.1007/s00259-001-0683-3Cherry, S. R. (2001). Fundamentals of Positron Emission Tomography and Applications in Preclinical Drug Development. The Journal of Clinical Pharmacology, 41(5), 482-491. doi:10.1177/00912700122010357Myers, R. (2002). Small animal PET. European Neuropsychopharmacology, 12(6), 545-555. doi:10.1016/s0924-977x(02)00103-7Hume, S., & Myers, R. (2002). Dedicated Small Animal Scanners: A New Tool for Drug Development? Current Pharmaceutical Design, 8(16), 1497-1511. doi:10.2174/1381612023394412Gu, Y., Matteson, J. L., Skelton, R. T., Deal, A. C., Stephan, E. A., Duttweiler, F., … Levin, C. S. (2011). Study of a high-resolution, 3D positioning cadmium zinc telluride detector for PET. Physics in Medicine and Biology, 56(6), 1563-1584. doi:10.1088/0031-9155/56/6/004Lage, E., Vaquero, J. J., Sisniega, A., España, S., Tapias, G., Abella, M., … Desco, M. (2009). Design and performance evaluation of a coplanar multimodality scanner for rodent imaging. Physics in Medicine and Biology, 54(18), 5427-5441. doi:10.1088/0031-9155/54/18/005S. A. Kis I. Lajtos M. Emri L. Tron G. Opposits T. Bükki Gy. Hegyesi J. Imrek I. Valastyán J. Molnár D. Novák L. Balkay Performance test of the MiniPET-II small animal scanner according to the NEMA NU-4 standard IEEE Nuclear Science Symposium Conference Record 3185 3189 2009Bao, Q., Newport, D., Chen, M., Stout, D. B., & Chatziioannou, A. F. (2009). Performance Evaluation of the Inveon Dedicated PET Preclinical Tomograph Based on the NEMA NU-4 Standards. Journal of Nuclear Medicine, 50(3), 401-408. doi:10.2967/jnumed.108.056374Prasad, R., Ratib, O., & Zaidi, H. (2010). Performance Evaluation of the FLEX Triumph X-PET Scanner Using the National Electrical Manufacturers Association NU-4 Standards. Journal of Nuclear Medicine, 51(10), 1608-1615. doi:10.2967/jnumed.110.076125Huisman, M. C., Reder, S., Weber, A. W., Ziegler, S. I., & Schwaiger, M. (2006). Performance evaluation of the Philips MOSAIC small animal PET scanner. European Journal of Nuclear Medicine and Molecular Imaging, 34(4), 532-540. doi:10.1007/s00259-006-0271-7Belcari, N., Guerra, A. D., Bartoli, A., Bianchi, D., Lazzarotti, M., Sensi, L., … Sgadò, P. (2007). Evaluation of the performance of the YAP-(S)PET scanner and its application in neuroscience. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 571(1-2), 18-21. doi:10.1016/j.nima.2006.10.021Zhang, H., Bao, Q., Vu, N. T., Silverman, R. W., Taschereau, R., Berry-Pusey, B. N., … Chatziioannou, A. F. (2010). Performance Evaluation of PETbox: A Low Cost Bench Top Preclinical PET Scanner. Molecular Imaging and Biology, 13(5), 949-961. doi:10.1007/s11307-010-0413-yKim, J. S., Lee, J. S., Im, K. C., Kim, S. J., Kim, S.-Y., Lee, D. S., & Moon, D. H. (2007). Performance Measurement of the microPET Focus 120 Scanner. Journal of Nuclear Medicine, 48(9), 1527-1535. doi:10.2967/jnumed.107.040550Canadas, M., Embid, M., Lage, E., Desco, M., Vaquero, J. J., & Perez, J. M. (2011). NEMA NU 4-2008 Performance Measurements of Two Commercial Small-Animal PET Scanners: ClearPET and rPET-1. IEEE Transactions on Nuclear Science, 58(1), 58-65. doi:10.1109/tns.2010.2072935Prasad, R., Ratib, O., & Zaidi, H. (2011). NEMA NU-04-based performance characteristics of the LabPET-8™ small animal PET scanner. Physics in Medicine and Biology, 56(20), 6649-6664. doi:10.1088/0031-9155/56/20/009Benlloch, J. M., Carrilero, V., González, A. J., Catret, J., Lerche, C. W., Abellán, D., … Sebastiá, A. (2007). Scanner calibration of a small animal PET camera based on continuous LSO crystals and flat panel PSPMTs. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 571(1-2), 26-29. doi:10.1016/j.nima.2006.10.020Smith, R. J., Karp, J. S., & Muehllehner, G. (1994). The countrate performance of the volume imaging PENN-PET scanner. IEEE Transactions on Medical Imaging, 13(4), 610-618. doi:10.1109/42.363107Sánchez, F., Benlloch, J. M., Escat, B., Pavón, N., Porras, E., Kadi-Hanifi, D., … Sebastià, A. (2004). Design and tests of a portable mini gamma camera. Medical Physics, 31(6), 1384-1397. doi:10.1118/1.1755570Ling, T., Lewellen, T. K., & Miyaoka, R. S. (2007). Depth of interaction decoding of a continuous crystal detector module. Physics in Medicine and Biology, 52(8), 2213-2228. doi:10.1088/0031-9155/52/8/012Vaska, P., Krishnamoorthy, S., Stoll, S., Woody, C. L., O’Connor, P., Purschke, M., … Villanueva, A. (s. f.). An improved anger detector approach for PET with high resolution and sensitivity. IEEE Symposium Conference Record Nuclear Science 2004. doi:10.1109/nssmic.2004.1466632Antich, P., Malakhov, N., Parkey, R., Slavin, N., & Tsyganov, E. (2002). 3D position readout from thick scintillators. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 480(2-3), 782-787. doi:10.1016/s0168-9002(01)01214-1Lerche, C. W., Döring, M., Ros, A., Herrero, V., Gadea, R., Aliaga, R. J., … Benlloch, J. M. (2009). Depth of interaction detection for -ray imaging. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 600(3), 624-634. doi:10.1016/j.nima.2008.11.151Lerche, C. W., Ros, A., Herrero, V., Esteve, R., Monzo, J. M., Sebastia, A., … Benlloch, J. M. (2008). Dependency of Energy-, Position- and Depth of Interaction Resolution on Scintillation Crystal Coating and Geometry. IEEE Transactions on Nuclear Science, 55(3), 1344-1351. doi:10.1109/tns.2008.920254Siegel, S., Silverman, R. W., Yiping Shao, & Cherry, S. R. (1996). Simple charge division readouts for imaging scintillator arrays using a multi-channel PMT. IEEE Transactions on Nuclear Science, 43(3), 1634-1641. doi:10.1109/23.507162Performance measurements for small animal positron emission tomographs (PETs) 2008Cherry, S. R., & Gambhir, S. S. (2001). Use of Positron Emission Tomography in Animal Research. ILAR Journal, 42(3), 219-232. doi:10.1093/ilar.42.3.21

Design and first results of an innovative and dedicated for hanging breast imaging PET

In this work the design and preliminary clinical results obtained with an innovative and dedicated breast PET is presented. A geometrical study clearly pointed out the advantages of the prone position and the technique of hanging breast in comparison to the supine, conventionally used for other imaging modalities. Occult, multifocal and also lesions close to the pectoral muscle were depicted by means of the prone method. The measured diameters of the hanging breasts allowed us to define an optimum transaxial FOV of up to 170 mm. This was achieved by means of 12 detector heads mounted on ring geometry, each using a monolithic LYSO crystal a position sensitive photomultiplier, among other components. The detector showed up an extrinsic spatial resolution as high as 1.4 mm in the center of the FOV with a physical sensitivity of 1.2 %. A clinical trial is undergoing at the Netherlands Cancer Institute in terms of a clinical validation of the dedicated breast PET. An adequate image matching between this device and the whole-body PET was observed, even for deep chest lesions. A preliminary quantitative comparison also shows a good agreement between both systems. However, a tiny deviation to higher Standard Uptake Values is observed for the prototype.González Martínez, AJ.; S Aukema, T.; Barbera Ballester, J.; Benlloch Baviera, JM.; Correcher Salvador, C.; Orero Palomares, A.; Soriano Asensi, A.... (2012). Design and first results of an innovative and dedicated for hanging breast imaging PET. Current Medical Imaging Reviews. 8(2):144-150. doi:10.2174/157340512800672199S1441508

Design and evaluation of the MAMMI dedicated breast PET

Purpose: A breast dedicated positron emission tomography (PET) scanner has been developed based on monolithic LYSO crystals coupled to position sensitive photomultiplier tubes (PSPMTs). In this study, we describe the design of the PET system and report on its performance evaluation. Methods: MAMMI is a breast PET scanner based on monolithic LYSO crystals. It consists of 12 compact modules with a transaxial field of view (FOV) of 170 mm in diameter and 40 mm axial FOV that translates to cover up to 170 mm. The patient lies down in a prone position that facilitates maximum breast elongation. Quantitative performance analysis of the calculated method for the attenuation correction specifically developed for MAMMI, and based on PET image segmentation, has also been conducted in this evaluation. In order to fully determine the MAMMI prototype’s performance, we have adapted the measurements suggested for National Electrical Manufacturers Association (NEMA) NU 2-2007 and NU 4-2008 protocol tests, as they are defined for whole-body and small animal PET scanners, respectively. Results: Spatial resolutions of 1.6, 1.8, and 1.9 mm were measured in the axial, radial, and tangential directions, respectively. A scatter fraction of 20.8% was obtained and the maximum NEC was determined to be 25 kcps at 44 MBq. The average sensitivity of the system was observed to be 1% for an energy window of (250 keV–750 keV) and a maximum absolute sensitivity of 1.8% was measured at the FOV center. Conclusions: The overall performance of the MAMMI reported on this evaluation quantifies its ability to produce high quality PET images. Spatial resolution values below 3 mm were measured in most of the FOV. Only the radial component of spatial resolution exceeds the 3 mm at radial positions larger than 60 mm. This study emphasizes the need for standardized testing methodologies for dedicated breast PET systems similar to NEMA standards for whole-body and small animal PET scannersThis work was supported by the Spanish Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica (I+D+I) under Grant No. FIS2010-21216-CO2-01 and Valencian Local Government under Grant Nos. PROMETEO 2008/114 and APOSTD 2010/012. The authors would like to thank Teodor Dima and Brennan Holt for checking and correcting the text.Moliner Martínez, L.; González Martínez, AJ.; Soriano Asensi, A.; Sánchez Martínez, F.; Correcher Salvador, C.; Orero Palomares, A.; Carles Fariña, M.... (2012). Design and evaluation of the MAMMI dedicated breast PET. Medical Physics. 39(9):5393-5405. https://doi.org/10.1118/1.4742850S5393540539