Pascau, J. (Javier)
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- A new workflow for image-guided intraoperative electron radiotherapy using projection-based pose tracking(IEEE, 2020) Ortuño, J.E. (Juan E.); Ledesma-Carbayo, M.J. (María J.); Santos, A. (Andrés); Gowami, S.S. (Subhra. S); Calvo, F.A. (Felipe A.); Pascau, J. (Javier)A new workflow is proposed to update the intraoperative electron radiotherapy (IOERT) planning refreshing the position and orientation (pose) of a virtual applicator with respect to the preoperative computed tomography (CT) with the actual pose during surgery. The workflow proposed relies on a robust registration of the preoperative CT and intraoperative projection radiographs acquired with a C-arm system. The workflow initially performs a geometric calibration of the C-arm using fiducials placed on the applicator. In the next step, a point-based 2D–3D registration based on fiducials positioned on the patient’s skin is performed, followed by an intensity-based registration that refines the point-based registration result. The performance of the workflow has been evaluated using a realistic physical phantom consisting of a pig lower limb and its corresponding CT and 7 C-arm projections at different poses. The accuracy has been measured with respect to the applicator origin and axis before and after the registration refinement process. A feasibility study with human data is also included. Error analysis revealed angular accuracy of 0.9 ± 0.7 degrees and translational accuracy of 1.9 ± 1 mm. Our experiments demonstrated that the proposed workflow can achieve subdegree angular accuracy in locating the applicator with respect to the preoperative CT to update and supervise the IOERT planning right before radiation delivery. The proposed workflow could be easily implementable in a routine, corresponding to a significant improvement in quality assurance during IOERT procedures.
- Practice-oriented solutions integrating intraoperative electron irradiation and personalized proton therapy for recurrent or unresectable cancers: Proof of concept and potential for dual FLASH effect(Frontiers, 2022) Aguilar, B. (Borja); Pedrero, D. (Diego); Aristu-Mendioroz, J.J. (José Javier); Ayestaran, A. (Adriana); Alonso, A. (Alberto); Meiriño, R. (Rosa); Palma, J. (Jacobo); Calvo, F.A. (Felipe A.); Lapuente, F. (Fernando); Chiva, L. (Luis); Pascau, J. (Javier); Cambeiro, M. (Mauricio); Morcillo, M.A. (Miguel Ángel); Prezado, Y. (Yolanda); Serrano-Andreu, J. (Javier); Azcona, J.D. (Juan Diego); Delgado, J.M. (José Miguel)Background: Oligo-recurrent disease has a consolidated evidence of long-term surviving patients due to the use of intense local cancer therapy. The latter combines real-time surgical exploration/resection with high-energy electron beam single dose of irradiation. This results in a very precise radiation dose deposit, which is an essential element of contemporary multidisciplinary individualized oncology. Methods: Patient candidates to proton therapy were evaluated in Multidisciplinary Tumor Board to consider improved treatment options based on the institutional resources and expertise. Proton therapy was delivered by a synchrotron-based pencil beam scanning technology with energy levels from 70.2 to 228.7 MeV, whereas intraoperative electrons were generated in a miniaturized linear accelerator with dose rates ranging from 22 to 36 Gy/min (at Dmax) and energies from 6 to 12 MeV. Results: In a period of 24 months, 327 patients were treated with proton therapy: 218 were adults, 97 had recurrent cancer, and 54 required re-irradiation. The specific radiation modalities selected in five cases included an integral strategy to optimize the local disease management by the combination of surgery, intraoperative electron boost, and external pencil beam proton therapy as components of the radiotherapy management. Recurrent cancer was present in four cases (cervix, sarcoma, melanoma, and rectum), and one patient had a primary unresectable locally advanced pancreatic adenocarcinoma. In re-irradiated patients (cervix and rectum), a tentative radical total dose was achieved by integrating beams of electrons (ranging from 10- to 20-Gy single dose) and protons (30 to 54-Gy Relative Biological Effectiveness (RBE), in 10–25 fractions). Conclusions: Individual case solution strategies combining intraoperative electron radiation therapy and proton therapy for patients with oligo-recurrent or unresectable localized cancer are feasible. The potential of this combination can be clinically explored with electron and proton FLASH beams.
- Surface scanning for 3D dose calculation in intraoperative electron radiation therapy(BioMed Central, 2018) Vaquero, J.J. (Juan J.); Desco, M. (Manuel); García-Vázquez, V. (Verónica); Calvo, F.A. (Felipe A.); Sesé-Lucio, B. (Begoña); Pascau, J. (Javier)Background: Dose calculations in intraoperative electron radiation therapy (IOERT) rely on the conventional assumption of water-equivalent tissues at the applicator end, which defines a flat irradiation surface. However, the shape of the irradiation surface modifies the dose distribution. Our study explores, for the first time, the use of surface scanning methods for three-dimensional dose calculation of IOERT. Methods: Two different three-dimensional scanning technologies were evaluated in a simulated IOERT scenario: a tracked conoscopic holography sensor (ConoProbe) and a structured-light three-dimensional scanner (Artec). Dose distributions obtained from computed tomography studies of the surgical field (gold standard) were compared with those calculated under the conventional assumption or from pseudocomputed tomography studies based on surfaces. Results: In the simulated IOERT scenario, the conventional assumption led to an average gamma pass rate of 39.9% for dose values greater than 10% (two configurations, with and without blood in the surgical field). Results improved when considering surfaces in the dose calculation (88.5% for ConoProbe and 92.9% for Artec). Conclusions: More accurate three-dimensional dose distributions were obtained when considering surfaces in the dose calculation of the simulated surgical field. The structured-light three-dimensional scanner provided the best results in terms of dose distributions. The findings obtained in this specific experimental setup warrant further research on surface scanning in the IOERT context owing to the clinical interest of improving the documentation of the actual IOERT scenario.
- Intraoperative computed tomography imaging for dose calculation in intraoperative electron radiation therapy: Initial clinical observations(2020) Calvo-Haro, J. (José); Ledesma-Carbayo, M.J. (María J.); Desco, M. (Manuel); García-Vázquez, V. (Verónica); Calvo, F.A. (Felipe A.); Pascau, J. (Javier); Solé, C. (Claudio)In intraoperative electron radiation therapy (IOERT) the energy of the electron beam is selected under the conventional assumption of water-equivalent tissues at the applicator end. However, the treatment field can deviate from the theoretic flat irradiation surface, thus altering dose profiles. This patient-based study explored the feasibility of acquiring intraoperative computed tomography (CT) studies for calculating three-dimensional dose distributions with two factors not included in the conventional assumption, namely the air gap from the applicator end to the irradiation surface and tissue heterogeneity. In addition, dose distributions under the conventional assumption and from preoperative CT studies (both also updated with intraoperative data) were calculated to explore whether there are other alternatives to intraoperative CT studies that can provide similar dose distributions. The IOERT protocol was modified to incorporate the acquisition of intraoperative CT studies before radiation delivery in six patients. Three studies were not valid to calculate dose distributions due to the presence of metal artefacts. For the remaining three cases, the average gamma pass rates between the doses calculated from intraoperative CT studies and those obtained assuming water-equivalent tissues or from preoperative CT studies were 73.4% and 74.0% respectively. The agreement increased when the air gap was included in the conventional assumption (98.1%) or in the preoperative CT images (98.4%). Therefore, this factor was the one mostly influencing the dose distributions of this study. Our experience has shown that intraoperative CT studies are not recommended when the procedure includes the use of shielding discs or surgical retractors unless metal artefacts are removed. IOERT dose distributions calculated under the conventional assumption or from preoperative CT studies may be inaccurate unless the air gap (which depends on the surface irregularities of the irradiated volume and on the applicator pose) is included in the calculations.
- Clinical feasibility of combining intraoperative electron radiation therapy with minimally invasive surgery: a potential for electron-FLASH clinical development(Springer, 2022) Asencio, J.M. (José Manuel); García-Sabrido, J.L. (José Luis); Aristu-Mendioroz, J.J. (José Javier); Miñana-López, B. (Bernardino); Palma, J. (Jacobo); Lapuente, F. (Fernando); Cuesta, M.A. (Miguel Ángel); Pascau, J. (Javier); Cambeiro, M. (Mauricio); Morcillo, M.A. (Miguel Ángel); Valle, E. (Emilio) del; Serrano-Andreu, J. (Javier); Calvo-Manuel, F.Á. (Felipe Ángel); Solé, C. (Claudio)Background Local cancer therapy by combining real-time surgical exploration and resection with delivery of a single dose of high-energy electron irradiation entails a very precise and efective local therapeutic approach. Integrating the benefts from minimally invasive surgical techniques with the very precise delivery of intraoperative electron irradiation results in an efcient combined modality therapy. Methods Patients with locally advanced disease, who are candidates for laparoscopic and/or thoracoscopic surgery, received an integrated multimodal management. Preoperative treatment included induction chemotherapy and/or chemoradiation, followed by laparoscopic surgery and intraoperative electron radiation therapy. Results In a period of 5 consecutive years, 125 rectal cancer patients were treated, of which 35% underwent a laparoscopic approach. We found no diferences in cancer outcomes and tolerance between the open and laparoscopic groups. Two esophageal cancer patients were treated with IOeRT during thoracoscopic resection, with the resection specimens showing intense downstaging efects. Two oligo-recurrent prostatic cancer patients (isolated nodal progression) had a robotic-assisted surgical resection and post-lymphadenectomy electron boost on the vascular and lateral pelvic wall. Conclusions Minimally invasive and robotic-assisted surgery is feasible to combine with intraoperative electron radiation therapy and ofers a new model explored with electron-FLASH beams.