Publications by authors named "Marie Claude Biston"
Purpose: To retrospectively assess the differences between planned and delivered dose during ultra-hypofractionated (UHF) prostate cancer treatments, by evaluating the dosimetric impact of daily anatomical variations alone, and in combination with prostate intrafraction motion.
Methods: Prostate intrafraction motion was recorded with a transperineal ultrasound probe in 15 patients treated by UHF radiotherapy (36.25 Gy/5 fractions).
Purpose: To investigate the performance of 4 atlas-based (multi-ABAS) and 2 deep learning (DL) solutions for head-and-neck (HN) elective nodes (CTVn) automatic segmentation (AS) on CT images.
Material And Methods: Bilateral CTVn levels of 69 HN cancer patients were delineated on contrast-enhanced planning CT. Ten and 49 patients were used for atlas library and for training a mono-centric DL model, respectively.
Purpose: To determine whether SBRT of spinal metastasis using a dedicated treatment planning system (TPS) and delivered with a gantry-based LINAC could provide plans of similar quality to the Cyberknife technology. Additional comparison was also done with other commercial TPS used for volumetric modulated arc therapy (VMAT) planning.
Materials And Methods: Thirty Spine SBRT patients, previously treated in our institution with CyberKnife (Accuray, Sunnyvale) using Multiplan TPS, were replanned in VMAT with an dedicated TPS (Elements Spine SRS, Brainlab, Munich) and our clinical TPS (Monaco, Elekta LTD, Stockholm), using exactly the same arc geometry.
Anatomical variations occur during head and neck (H&N) radiotherapy (RT) treatment. These variations may result in underdosage to the target volume or overdosage to the organ at risk. Replanning during the treatment course can be triggered to overcome this issue.
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- - The study aimed to evaluate the effectiveness of both four atlas-based and two deep learning methods for automatically segmenting organs-at-risk in head-and-neck treatments.
- - Results showed that deep learning algorithms generally outperformed atlas-based methods in accuracy, although one hybrid atlas-based approach sometimes matched the best performance of the deep learning algorithms.
- - While deep learning methods were faster and more efficient for manual corrections, significant dose differences were mostly noticed when organs were close to treatment targets, indicating careful consideration needed in contour placement.
Article Synopsis
- Stereotactic body radiotherapy (SBRT) is emerging as a treatment option for localized prostate cancer, but research supporting its effectiveness is still developing.
- Many clinical studies have been conducted, but there is a lack of standardization in treatment methods, target areas, and dosage limits across these studies.
- The French Genito-Urinary Group (GETUG) provides recommendations based on the existing research, acknowledging the need for more consistent evidence in SBRT for prostate cancer.
Purpose: To investigate the impact on dose distribution of intrafraction motion during moderate hypofractionated prostate cancer treatments and to estimate minimum non-isotropic and asymmetric (NI-AS) treatment margins taking motion into account.
Methods: Prostate intrafraction 3D displacements were recorded with a transperineal ultrasound probe and were evaluated in 46 prostate cancer patients (876 fractions) treated by moderate hypofractionated radiation therapy (60 Gy in 20 fractions). For 18 patients (346 fractions), treatment plans were recomputed increasing CTV-to-PTV margins from 0 to 6 mm with an auto-planning optimization algorithm.
Purpose: Automated planning techniques aim to reduce manual planning time and inter-operator variability without compromising the plan quality which is particularly challenging for head-and-neck (HN) cancer radiotherapy. The objective of this study was to evaluate the performance of an a priori-multicriteria plan optimization algorithm on a cohort of HN patients.
Methods: A total of 14 nasopharyngeal carcinoma (upper-HN) and 14 "middle-lower indications" (lower-HN) previously treated in our institution were enrolled in this study.
Purpose: To evaluate the repositioning accuracy of 4 immobilization devices (ID) used for whole breast Helical Tomotherapy treatments: arm float with VacFix® (Par Scientific, Denmark), all-in-one® (AIO®) system (Orfit, Belgium), MacroCast thermoplastic mask (Macromedics, The Netherlands) and BlueBag® system with Arm-Shuttle (Elekta, Sweden).
Materials And Methods: Twenty four women with breast cancer with PTV including the breast/chest wall and lymph nodes were involved in this study (6 women per group). Pretreatment registration results were first collected using automatic bone registration + manual adjustment on the vertebra followed by independent registrations on different ROIs representing each treated area (axillary, mammary chain, clavicular, breast/chest wall).
Article Synopsis
- The study compares two prostate radiotherapy monitoring devices: intra-prostatic electromagnetic transmitters (EM-T) and transperineal ultrasound imaging (TP-US), both tested on phantoms and patients for accuracy.* -
- Phantom tests showed minimal interference between the devices, with less than 0.5 mm deviation during translations, but larger systematic shifts were noted during rotations (up to 6.9 mm for TP-US and 3.8 mm for EM-T).* -
- Overall, both devices demonstrated strong correlation in measurements for most patients, making them viable options for monitoring prostate cancer treatment, despite some discrepancies mainly linked to prostate movement and gas presence.*
Article Synopsis
- The study investigates how Linear Energy Transfer (LET) affects the behavior of ATM (Ataxia Telangiectasia Mutated) protein in response to different types of radiation, particularly focusing on its movement from the cytoplasm to the nucleus for DNA repair.
- Researchers used immunofluorescence techniques to measure the recognition and repair of DNA double-strand breaks (DSBs) in fibroblast cells exposed to various radiation types, including x-rays and high-energy particles.
- Results indicate that ATM's nucleo-shuttling rate is specific to each radiation type and enhancing nuclear membrane permeability can protect cells by promoting this shuttling, ultimately contributing to our understanding of how different radiation affects DNA repair mechanisms in human cells.
Iodine-containing contrast media (ICM) are extensively used to improve image quality and information content in x-ray-based examinations, particularly in computed tomography (CT). In parallel, there is increasing evidence that the use of ICM during CT sessions is associated with deoxyribonucleic acid (DNA) breaks that may influence the estimation of the risks linked to x-ray exposure. Why has iodine been preferred to any other heavy elements to enhance contrast in radiodiagnostics? How to understand such DNA breaks effect? We searched for the answers in the early times of x-ray medical use.
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- The study examines the link between post-radiation therapy overreactions (OR) in patients and their clinical radiosensitivity, highlighting the lack of consensus on effective prediction methods since 2003.
- Researchers collected skin biopsy samples from patients with varying degrees of OR, focusing on skin fibroblasts from different sensitivity groups and analyzing their DNA damage response after radiation.
- Findings suggest that OR patients experience a delay in the ATM protein's activity rather than a complete repair defect, leading to a proposed classification of human radiosensitivity into three groups based on their reaction severity.
Purpose: The aim of this study was to evaluate a new system based on transperineal ultrasound (TP-US) acquisitions for prostate and post-prostatectomy pre-treatment positioning by comparing this device to cone-beam computed tomography (CBCT).
Methods: The differences between CBCT/CT and TP-US/TP-US registrations were analyzed on 427 and 453 sessions for 13 prostate and 14 post-prostatectomy patients, respectively. The inter-operator variability (IOV) of the registration process, and the impact and variability of the probe pressure were also evaluated.
Purpose: To evaluate the accuracy of an intra-modality trans-abdominal ultrasound (TA-US) device against soft-tissue based Cone-Beam Computed tomography (CBCT) registration for prostate and post-prostatectomy pre-treatment positioning.
Methods: The differences between CBCT and US shifts were calculated on 25 prostate cancer patients (cohort A) and 11 post-prostatectomy patients (cohort B), resulting in 284 and 106 paired shifts for cohorts A and B, respectively. As a second step, a corrective method was applied to the US registration results to decrease the systematic shifts observed between TA-US and CBCT results.
Purpose: The aim of the present work is to propose and evaluate registration algorithms of three-dimensional (3D) transabdominal (TA) ultrasound (US) images to setup postprostatectomy patients during radiation therapy.
Methods: Three registration methods have been developed and evaluated to register a reference 3D-TA-US image acquired during the planning CT session and a 3D-TA-US image acquired before each treatment session. The first method (method A) uses only gray value information, whereas the second one (method B) uses only gradient information.
Purpose: To evaluate the impact of transabdominal probe pressure on prostate positioning with an intramodality ultrasound (US) image-guided-radiotherapy system and to quantify pressure variability over the treatment course.
Material And Methods: 8 prostate cancer patients (group A) and 17 healthy volunteers underwent 3 consecutive US images with increasing probe pressure levels, and 1 CT acquisition for the group A only. Prostate positions were compared after manual registration of the first US image contour projected on 2 others.
Article Synopsis
- - The study compared two treatment planning systems (Monaco and Pinnacle) for VMAT in prostate cancer patients, focusing on dose distributions, treatment delivery, and quality control results.
- - Results indicated that Monaco showed better homogeneity and lower doses to certain critical tissues, but Pinnacle had advantages for the rectal wall, with both systems providing clinically acceptable treatments overall.
- - The findings suggest that while both TPS perform well for prostate cancer, further research is needed to explore their effectiveness on more complex treatment volumes.
We report on a 71-year-old woman with parapharyngeal sarcoma. Surgery could not be performed because of the size and location of the tumor. After failure of four cycles of chemotherapy, intensity-modulated radiation therapy (IMRT) achieved complete clinical response and partial magnetic resonance imaging response (80%) at 24 months of follow-up.
View Article and Find Full Text PDFFor the past 5 years, a radio-chemotherapy approach based on the photoactivation of platinum atoms (PAT-Plat) consisting of treating tumors with platinated compounds and irradiating them above the platinum K edge (78.4 keV) has been developed at the European Synchrotron Radiation Facility (Grenoble, France). Compared to other preclinical modalities, PAT-Plat provides the highest survivals of rats bearing the rodent F98 glioma.
View Article and Find Full Text PDFPurpose: Heavy-atom-enhanced synchrotron stereotactic radiotherapy (SSR) is a treatment that involves selective accumulation of high-Z elements in tumors followed by stereotactic irradiation with X-rays from a synchrotron source. The purpose of this study was to determine whether the efficacy of iodine-enhanced SSR could be further improved in the F98 rodent glioma model, by using a concomitant injection of an iodinated contrast agent and a transient blood-brain barrier opener (mannitol) during irradiation.
Methods And Materials: Fourteen days after intracerebral inoculations of F98 cells, the rats were irradiated with 50-keV X-rays while receiving an infusion of hyperosmotic mannitol with iodine, either intravenously or via the carotid (9 to 15 rats per group, 117 rats total).
Purpose: To date, iodinated contrast agents (ICA) are commonly used in medical imaging to improve tumor visualization by attenuating scanners X-rays. However, some adverse reactions to ICAs are still reported, and their molecular origin remains unclear. In 1983, it was proposed to visualize and treat ICA-loaded tumors by using scanners as therapy machines to enhance X-rays absorption at the iodine atoms.
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