[Implementation of the dematerialization of the patient file in the context of COVID in the ONCORAD radiotherapy units: Transition to "paperless"]. / Mise en place de la dématérialisation du dossier patient dans un contexte de COVID dans les services de radiothérapie de l'ONCORAD : passage « au sans papier ¼.

Paper patient file sharing has clearly been identified as a risk behavior for the COVID-19 virus transmission in radiotherapy units. In order to overcome this, the ONCORAD radiotherapy units worked on total dematerialization of the paper patient file, within 3 weeks. The methodology is based on a quality approch. This work has led to a convincing improvement in the management of risks a priori and a smoother patient care workflow.

18F-FDG brain PET hypometabolism in patients with long COVID.

PURPOSE: In the context of the worldwide outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), some patients report functional complaints after apparent recovery from COVID-19. This clinical presentation has been referred as "long COVID." We here present a retrospective analysis of 18F-FDG brain PET of long COVID patients from the same center with a biologically confirmed diagnosis of SARS-CoV-2 infection and persistent functional complaints at least 3 weeks after the initial infection. METHODS: PET scans of 35 patients with long COVID were compared using whole-brain voxel-based analysis to a local database of 44 healthy subjects controlled for age and sex to characterize cerebral hypometabolism. The individual relevance of this metabolic profile was evaluated to classify patients and healthy subjects. Finally, the PET abnormalities were exploratory compared with the patients' characteristics and functional complaints. RESULTS: In comparison to healthy subjects, patients with long COVID exhibited bilateral hypometabolism in the bilateral rectal/orbital gyrus, including the olfactory gyrus; the right temporal lobe, including the amygdala and the hippocampus, extending to the right thalamus; the bilateral pons/medulla brainstem; the bilateral cerebellum (p-voxel < 0.001 uncorrected, p-cluster < 0.05 FWE-corrected). These metabolic clusters were highly discriminant to distinguish patients and healthy subjects (100% correct classification). These clusters of hypometabolism were significantly associated with more numerous functional complaints (brainstem and cerebellar clusters), and all associated with the occurrence of certain symptoms (hyposmia/anosmia, memory/cognitive impairment, pain and insomnia) (p < 0.05). In a more preliminary analysis, the metabolism of the frontal cluster which included the olfactory gyrus was worse in the 7 patients treated by ACE drugs for high blood pressure (p = 0.032), and better in the 3 patients that had used nasal decongestant spray at the infectious stage (p < 0.001). CONCLUSION: This study demonstrates a profile of brain PET hypometabolism in long COVID patients with biologically confirmed SARS-CoV-2 and persistent functional complaints more than 3 weeks after the initial infection symptoms, involving the olfactory gyrus and connected limbic/paralimbic regions, extended to the brainstem and the cerebellum. These hypometabolisms are associated with patients' symptoms, with a biomarker value to identify and potentially follow these patients. The hypometabolism of the frontal cluster, which included the olfactory gyrus, seems to be linked to ACE drugs in patients with high blood pressure, with also a better metabolism of this olfactory region in patients using nasal decongestant spray, suggesting a possible role of ACE receptors as an olfactory gateway for this neurotropism.

18F-FDG brain PET hypometabolism in post-SARS-CoV-2 infection: substrate for persistent/delayed disorders?

PURPOSE: Several brain complications of SARS-CoV-2 infection have been reported. It has been moreover speculated that this neurotropism could potentially cause a delayed outbreak of neuropsychiatric and neurodegenerative diseases of neuroinflammatory origin. A propagation mechanism has been proposed across the cribriform plate of the ethmoid bone, from the nose to the olfactory epithelium, and possibly afterward to other limbic structures, and deeper parts of the brain including the brainstem. METHODS: Review of clinical examination, and whole-brain voxel-based analysis of 18F-FDG PET metabolism in comparison with healthy subjects (p voxel < 0.001, p-cluster < 0.05, uncorrected), of two patients with confirmed diagnosis of SARS-CoV-2 explored at the post-viral stage of the disease. RESULTS: Hypometabolism of the olfactory/rectus gyrus was found on the two patients, especially one with 4-week prolonged anosmia. Additional hypometabolisms were found within amygdala, hippocampus, parahippocampus, cingulate cortex, pre-/post-central gyrus, thalamus/hypothalamus, cerebellum, pons, and medulla in the other patient who complained of delayed onset of a painful syndrome. CONCLUSION: These preliminary findings reinforce the hypotheses of SARS-CoV-2 neurotropism through the olfactory bulb and the possible extension of this impairment to other brain structures. 18F-FDG PET hypometabolism could constitute a cerebral quantitative biomarker of this involvement. Post-viral cohort studies are required to specify the exact relationship between such hypometabolisms and the possible persistent disorders, especially involving cognitive or emotion disturbances, residual respiratory symptoms, or painful complaints.

[Impact of dynamic IMRT and tomotherapy in pelvic cancers: a prospective dosimetric study with 51 patients]. / Apport de la RCMI rotationnelle et de la tomothérapie hélicoïdale dans les cancers pelviens : étude dosimétrique prospective sur 51 patients.

PURPOSE: To compare the dosimetric results of different techniques of dynamic intensity modulated radiation therapy (IMRT) in patients treated for a pelvic cancer with nodal irradiation. PATIENTS AND METHODS: Data of 51 patients included prospectively in the Artpelvis study were analyzed. Thirty-six patients were treated for a high-risk prostate cancer (13 with helical tomotherapy, and 23 with Rapid'Arc(®)) and 15 patients were treated for a localized anal cancer (nine with helical tomotherapy and six with Rapid'Arc(®)). Plan quality was assessed according to several different dosimetric indexes of coverage of planning target volume and sparing of organs at risk. RESULTS: Although some dosimetric differences were statistically significant, helical tomotherapy and Rapid'Arc provided very similar and highly conformal plans. Regarding organs at risk, Rapid'Arc(®) provided better pelvic bone sparing with a lower non-tumoral integral dose. CONCLUSION: In pelvis cancer with nodal irradiation, Rapid'Arc and helical tomotherapy provided very similar plans. The clinical evaluation of Artpelvis study will verify this equivalence hypothesis.

Clinical results of an EPID-based in-vivo dosimetry method for pelvic cancers treated by intensity-modulated radiation therapy.

The purpose of our work was to investigate the feasibility of using an EPID-based in-vivo dosimetry method initially designed for conformal fields on pelvic dynamic IMRT fields. The method enables a point dose delivered to the patient to be calculated from the transit signal acquired with an electronic portal imaging device (EPID). After defining a set of correction factors allowing EPID pixel values to be converted into absolute doses, several tests on homogeneous water-equivalent phantoms were performed to estimate the validity of the method in reference conditions. The effects of different treatment parameters, such as delivered dose, field size dependence and patient thickness were also studied. The model was first evaluated on a group of 53 patients treated by 3D conformal radiotherapy (3DCRT) and then on 92 patients treated by IMRT, both for pelvic cancers. For each measurement, the dose was reconstructed at the isocenter (DREC) and compared with the dose calculated by our treatment planning system (DTPS). Excellent agreement was found between DREC and DTPS for both techniques. For 3DCRT treatments, the mean deviation between DREC and DTPS for the 211 in-vivo dose verifications was equal to -1.0  ±  2.2% (1SD). Concerning IMRT treatments, the averaged deviation for the 418 fields verified was equal to -0.3 ± 2.6% (1SD) proving that the method is able to reconstruct a dose for dynamic IMRT pelvic fields. Based on these results, tolerance criteria and action levels were established before its implementation in clinical routine.

[Prospective economic evaluation of image-guided radiation therapy for prostate cancer in the framework of the national programme for innovative and costly therapies assessment]. / Évaluation économique prospective de la radiothérapie guidée par l'image des cancers de la prostate dans le cadre du programme national de soutien aux thérapeutiques innovantes et coûteuses.

PURPOSE: The main objective of the economical study was to prospectively and randomly assess the additional costs of daily versus weekly patient positioning quality control in image-guided radiotherapy (IGRT), taking into account the modalities of the 3D-imaging: tomography (CBCT) or gold seeds implants. A secondary objective was to prospectively assess the additional costs of 3D versus 2D imaging with portal imaging for patient positioning controls. PATIENTS AND METHODS: Economics data are issued from a multicenter randomized medico-economics trial comparing the two frequencies of patient positioning control during prostate IGRT. A prospective cohort with patient positioning control with PI (control group) was constituted for the cost comparison between 3D (IGRT) versus 2D imaging. The economical evaluation was focused to the radiotherapy direct costs, adopting the hospital's point of view and using a microcosting method applied to the parameters that may lead to cost differences between evaluated strategies. RESULTS: The economical analysis included a total of 241 patients enrolled between 2007 and 2011 in seven centres, 183 in the randomized study (128 with CBCT and 55 with fiducial markers) and 58 in the control group. Compared to weekly controls, the average additional cost per patient of daily controls was €847 (CBCT) and €179 (markers). Compared to PI, the average additional cost per patient was €1392 (CBCT) and €997 (fiducial markers) for daily controls; €545 (CBCT) and €818 (markers) in case of weekly controls. CONCLUSION: A daily frequency for image control in IGRT and 3D images patient positioning control (IGRT) for prostate cancer lead to significant additional cost compared to weekly control and 2D imaging (PI). Long-term clinical assessment will permit to assess the medico-economical ratio of these innovative radiotherapy modalities.

[Benefit of intensity modulated and image-guided radiotherapy in prostate cancer]. / Apports de la radiothérapie avec modulation d'intensité guidée par l'image dans les cancers prostatiques.

External beam radiotherapy (RT) is used to treat all stages of localized prostate cancer. Using a 3D conformal RT (3DCRT) without any androgen deprivation, a clear dose-effect relationship has been shown in terms of both biochemical control and also unfortunately of rectal and urinary toxicity. Compared to a "standard" 3DCRT, intensity modulated RT (IMRT) improves the dose distribution by mainly providing concave dose distribution and tight dose gradients. Based on large clinical experiences for at least one decade, IMRT is widely used to increase the dose in the prostate and therefore local control, without increasing toxicity. Indeed, toxicity rates observed after high dose delivered in the prostate (80Gy) with IMRT appear no different than those observed after a standard dose (70Gy) delivered by a standard 3DCRT. Arc IMRT appears a new promising IMRT modality, decreasing dramatically treatment duration. However, this IMRT-based dosimetric benefit may not be translated into a full clinical benefit, if intra-pelvic prostate motion is not taken in account. Image-guided radiotherapy (IGRT) should be therefore associated with IMRT for a maximal clinical benefit. This article is a literature review showing the interest of both combined approaches.

[On board imaging with cone beam CBCT kV VARIAN: Montauban's radiation therapy department experience]. / Système d'imagerie par tomographie conique de basse énergie (kV)de Varian : expérience de Montauban.

PURPOSE: To describe our practice day to day with a VARIAN linac "Clinac 2100" fully equipped with an On Board Imager (OBI) for patients with prostate cancer. MATERIALS AND METHODS: A volumetric and dosimetric study was performed in 2006 using ARTIVIEW software (AQUILAB) for nine patients and 76 Cone Beam CT kV (CBCT kV). We have contoured targets and organs at risk from CBCT kV slides acquisitions. Second, we achieved a dose-volume histogram (DVH) study for a patient treated in 2007 with IMRT technique in comparison with the 2006 study. RESULTS: 2006 analysis: The study showed a very important variability of organ measurements. Seminal vesicles were strongly influenced by adjacent organs; observed differences for prostate could be explained by contouring uncertainty on the apex. Inter-sessions motions could be observed for bladder, rectum and seminal vesicles (SV). Part of prostate volume not encompassed by PTV is about 2.5%; VS volume outside PTV is about 35%. Tumoral conformation index (TCI) is inferior to 97.5% in 22% of all cases. Anteroposterior displacements of the prostate barycentre is superior to 5mm. From this analysis, we recommended the strict respect of hygienodietetic rules, and we have adapted the system settings for better immobilization, which were applied for the 2007 study. For the 2007 analysis, since April 2007, most of patients are treated with IMRT for prostate cancer, at the second part of the radiation therapy to encompass only the prostate volume. Dose-volume histograms showed a great spreading out for 2006 patients, and not for the 2007 patient. CONCLUSIONS: IMRT and IGRT should permit a margin reduction for PTV. Strict respect of hygienodietetics rules is necessary to avoid rectal distension and local recurrence.

Trans-rectal ultrasonography (TRUS) with lipiodol injection for localization of the prostatic apex before radiotherapy planning.

PURPOSE: To evaluate reliability of Trans-rectal ultra-sonography (TRUS) guidance with lipiodol injection for prostate localization before radiotherapy planning. MATERIAL AND METHODS: From October 1997 to March 2000, 31 patients with prostatic adenocarcinoma and six patients with anastomotic recurrence after radical prostatectomy had TRUS-guided injection of lipiodol. Two milliliters of lipiodol were injected into each side of the prostate and 1 ml into both seminal vesicles with a 22 Gauge CHIBA needle and US probe guide before radiotherapy planning. We had established a contrast quality index (0 for no prostate enhancement to 5 for efficient pacification without any diffusion). On simulation films, we had performed anatomic measurements for comparison with other anatomic studies. RESULTS: For all 37 patients, TRUS-guided injection was well tolerated. Among 31 patients with the prostate in situ, three had no apex opacification and 15 had no vesicle enhancement or peri-vesicle space diffusion. However, in 19 patients there was good contrast quality with an index score of > or =3. The majority of patients had prostatic apex between 1.5 and 3.5 cm from ischial tuberosities ligne (27 from 28 evaluable for apex). Among 19 evaluable patients, 15 had seminal vesicles 2-4 cm above the top of pubis. For six patients with anastomotic recurrence after radical prostatectomy, lipiodol was precious aid to locate it. We had only one failure because of a precocious bladder absorption relating to a delay which is too long between rectal probe locating and portal films. CONCLUSION: TRUS injection of lipiodol is a simple, inexpensive, relatively safe technique for localization of prostatic apex, but not appropriate for seminal vesicles enhancement. This is also an interesting method to locate anastomotic recurrence.