63 Optimization of injected activities in 99m Tc- Sestamibi myocardial perfusion tomoscintigraphy

Abstracts / Physica Medica 56 (2018) 1–39

62 Kinetic data extraction from 18 F-FDOPA PET brain acquisition T. Zaragori a, L. Imbert a,b,c, J. Salvadori a,c, V. Roch a, G. Karcher a,c,d, P.Y. Marie a,c,d,e, A. Verger a,c,d a

CHRU-Nancy, Université de Lorraine, Plateforme Nancyclotep, Nancy, France b Institut de Cancérologie de Lorraine, Université de Lorraine, Nancy, France c Université de Lorraine, INSERM, UMR-947 IADI, Nancy, France d Faculty of Medicine, University of Lorraine, Nancy, France e INSERM, U1116, Nancy, France Introduction. The indications of Positron Emission Tomography (PET) using radiolabeled amino acids in neurology are growing especially for the diagnosis of brain tumors. The last classification ‘‘WHO 2016” (World Health Organization) concerning the gliomas implemented molecular parameters such as the IDH mutation and the 1p/19q co-deletion correlated with clinical observed outcomes. The aim of this study was to assess the diagnostic performance of the 18 F-FDOPA (L-3, 4-Dihydroxy-6-18 F-fluoro-phenyl-alanine) from dynamic PET recordings. Methods. Patients initially referred for newly diagnosed gliomas had been sorted according to the WHO classification into 3 distinct groups: oligodendrogliomas, astrocytomas IDH + and glioblastomas according to the anatomico-pathological results. Dynamic recordings were performed on a Biograph6 True Point (Siemens Healthcare) PET scanner after the injection of 3 MBq of 18F-FDOPA/kg. For each patient, a scan of 30 min was performed immediately after the intravenous injection. The data had been reconstructed in dynamic method with a 2D OSEM iterative algorithm (2 iterations, 21 subsets, Gaussian filtering with a FWMH of 4 mm) and an adapted temporal sampling, allowing a compromise between kinetic information and noise. A circular region of interest (ROI) with a diameter of 2 cm was centered on the pixel of the maximum tumor uptake on the static images (summed of the dynamic images). Then, this ROI was applied to the entire dynamic dataset in order to obtain the timeactivity curve (TAC) of the 18 F-FDOPA uptake in the tumor. The slope of the curve was obtained by fitting with a linear regression function the data recorded between 10 and 30 min post-injection. Results. Dynamic PET images were reconstructed into 30 timeframes of 1 min each. The TAC obtained with raw data were fitted with the following Eq. (1) SUV ðtÞ ¼ a0 þ ða1  a0 Þ 

A þ ðat2 Þp

B þ ðat2 Þq

and the mean correlation coefficient R2 was equal to 0,958. The time corresponding to the maximum of the tumor fixation was superior to 20 min after the injection for the oligodendrogliomas and astrocytomas IDH + whereas it was about 6 min for the glioblastomas. The slopes of the TAC were positive for the oligodendrogliomas (+0,3

35

SUV/h), negative for the astrocytomas IDH+ (-0,8 SUV/h) and more negative for the glioblastomas (-6 SUV/h). Conclusions. Dynamic 18 F-FDOPA PET recordings could be used to extract quantitative parameters allowing non-invasive staging of gliomas in patients referred for initial diagnosis. https://doi.org/10.1016/j.ejmp.2018.09.075

63 Optimization of injected activities in 99m Tc- Sestamibi myocardial perfusion tomoscintigraphy S. Joly a,b, J. Fontaine a, E. Verrecchia a, P. Retif a, S. Ben Mahmoud b a b

Unité de physique médicale, CHR Metz-Thionville, Metz, France Service de médecine nucléaire, CHR Metz-Thionville, Metz, France

Introduction. Optimization of radiopharmaceutical injected activities is an important issue for patient’s radioprotection in nuclear cardiology. This study aims to compare two gamma-cameras from different generations, the first one using a parallel hole collimator (PHC), and the second one using a converging collimator (CC) focused on the heart area, in myocardial tomoscintigraphy. It allows highlighting which factors impact the scintigraphic image quality, in order to optimize the injected activities, taking into account these factors and the better sensitivity obtained with the CC camera. Methods. Two groups of patients had myocardial perfusion imaging, respectively with a PHC camera (PHC group, n = 154) and a CC camera (CC group, n = 46). The average sensitivity was defined as the ratio between the average number of counts detected per voxel in left ventricle and the total number of counts emitted during the whole exam. For both groups and for each patient the average sensitivity was calculated and compared to the population characteristics (weight, size, BMI). In the same time, a qualitative visual analysis was conducted by four nuclear physicians, for a sub-group of 15 patients from the PHC group. The scintigraphic images were noted on a scale going from 1 to 5, in order to define the minimal image quality adequate for reliable interpretation. An average sensitivity threshold was defined from the visual analysis, and a minimal injected activity was calculated depending on the patients’ weight. Moreover, the sensitivity of each camera was experimentally measured on a phantom, and the sensitivity gain factor between the two devices was calculated. Results. The analysis realized on the PHC group showed a good correlation between the patients’ weight and the exam average sensitivity. The exponential fit correlation coefficient was 0.83  0.02. The same fit was also relevant for the CC group analysis, confirming the model reliability. The qualitative visual analysis helped to define an average sensitivity threshold of 4.82.1010. From this threshold, the injected

36

Abstracts / Physica Medica 56 (2018) 1–39

activities could be optimized depending on the patients’ weight (Fig. 1). The CC camera sensitivity was measured 5 times greater than the PHC camera sensitivity. This sensitivity gap was taken into account to calculate the optimized average sensitivity on the CC camera. Finally, the global sensitivity gain factor was calculated depending on the patients’ weight, up to 10 for the lowest weight patients. Conclusions. The CC camera brings an important sensitivity gain, allowing consequent reduction of injected activities. This preliminary study is a first step for the methodical optimization of injected activities, for the patients requiring a myocardial perfusion imaging. https://doi.org/10.1016/j.ejmp.2018.09.076

Conclusions. Concurrently to the acquisition of basic skills of the medical physicist, the objective of the 22 months of internship is to transform the DQPRM students in a young professional in a progressive and supervised way by teaching them the teamwork, the empowerment and time management thanks to clinical activities and projects. https://doi.org/10.1016/j.ejmp.2018.09.077

65 DQPRM trainees welcome in EAP: APHM experience B. Farman, S. Gempp Raucoules APHM, Department of Medical Physics, Marseille, France

Education/research in Medical Physics Session 64 Management of the medical physics students in internship: Feedback of Centre Eugène Marquis (Regional Cancer Center of Rennes/France) C. Lafond, S. Laffont, J. Bellec, O. Henry, M. Perdrieux, F. Jouyaux, N. Perichon, N. Delaby, C. Hervé Centre Eugène Marquis, Rennes, France Introduction. The Regional Cancer Center of Rennes (Centre Eugène Marquis, CEM) is one of 31 French institutions hosting students preparing the final diploma of medical physicist (DQPRM) for 22-month internship in the three area of medical physics: radiotherapy (RT), nuclear medicine (NM) and radiology (RX). The CEM is accredited by the National Institute for Nuclear Science and Technology (INSTN) to train two students in the first year and two students in the second year. The objective is to share the feedback from the CEM on the management of students during these 22 months of internship. Methods. During the first week of the internship, a meeting of the entire physics team is organized to introduce the DQPRM students to all the members of the team, to plan the weeks dedicated to each field and to define the reference physicist for each activity to be acquired. During this meeting the general organization of the team and the specific organization for the DQPRM students are presented. The scientific work of the second year is defined among the list of projects of the team in dialogue between the student and the referent physicist of the training center. The study is managed by a senior physicist specialized in the area of the work. Some parts of the document presenting the functional schedule of the team are dedicated to the DQPRM students to reveal clearly their participation in the clinical activities. The students are invited to all meetings in which the medical physicists participate. A bi-monthly point of 30 min is organized between the students and the referent physicist of the training center. Results. During the first month, the students have to define with the referent physicist for every activity the annual organization to acquire the expected skills. Regarding to functional schedule of 2017, the students of 1st year spent 49% of days in RT, 20% in NM and 10 in RX. These percentage were 51%, 16% and 11% respectively for the students of 2nd year. A delegation of some functional tasks are possible after validation of specific skills base. Depending of the subject of the scientific work performed during 2nd year of training, writing of the report is encouraged in English in order to facilitate the submission in an international journal.

Introduction. DQPRM (Qualification diploma in Radiological and Medical Physics) students have theoretical courses at INSTN (National Institute of Nuclear Sciences and Technologies) for 6 months and complete their training with a 22-months hospital internship in an institution named Principal Home (EAP), in order to learn and validate the skills required for their future career of medical physicist. The internship duration is divided into different branches of activity that are mainly radiotherapy, radiology and nuclear medicine. Trainees are supervised by experimented medical physicists in each domain. Methods. Before their arrival, students are invited to contact the person in charge of their reception at the EAP, and organize a first visit of the center. Upon arrival, after having completed the administrative steps (medical approval for work, blouses, meal card, computer access, . . .), trainees are invited to participate to a full meeting, letting them meet the whole physics team. At this time, the welcome book, previously sent, is detailed. It describes the Physics unit, organization of as well as the radiotherapy and medical imaging departments. During this meeting, the organization of the internship is explained and an annual planning is defined on the different parts. This organization allows a fair time distribution between participation in clinical routine and the completion of activity sheets supervised by different members of the team. This assignment allows optimal preparation and completion of the activities with the designated referent. Each supervisor sets with the trainees, the moment of the realization and validation of the skills. The students prepare the measurements to be done and the working method, and have the referent process validated. The measurements are made with or under supervision of the supervisor. This will validate the level of mastery of skills (not acquired, being acquired or acquired). Trainees also participate in the clinical routine. It’s important that they integrate perfectly the routine organization of the service (for example to participate in the morning staff, to integrate the planning of quality assurance of linear accelerators, to carry out pre-treatment checks, to carry out controls in medicine nuclear or estimate fetal exposure in radiology). This is a key step in learning the profession of medical physicists. Conclusions. Effective and respectful management of DQPRMs is essential for the training in the field to be optimal, both humanly and scientifically. It’s meaningful that the two years of internship, which for many, are their first steps in medical physics, become a success. https://doi.org/10.1016/j.ejmp.2018.09.078