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Create a Free AccountPapers from the SFPM 2021
A high-performance method of deep learning for prostate MR-only radiotherapy planning using an optimized Pix2Pix architecture
Computed tomography (CT) is commonly used as the reference imaging method for radiation therapy treatment planning [1]. Indeed, CT values can be directly converted to electron densities for radiation dose calculation [1]. However, CT images have several drawbacks, particularly the limited soft-tissue contrast and ionizing radiation to the patient [2,3].Highlights from the 59th scientific congress of the French Society of Medical Physics
The present focus issue of Physica Medica contains contributions presented in relation to the previous scientific congress of the French Society of Medical Physics (SFPM) that was organized in Rennes in the spring 2021. The SFPM congress, which occurs annually during 3 days, aims at bringing together physicists, dosimetrists, and other professionals involved in cancer therapy or in medical imaging to discuss current topics related to the three main fields of activity of the medical physicist i.e.Dose area product primary standards established by graphite calorimetry at the LNE-LNHB for small radiation fields in radiotherapy
Use of small fields is becoming standard in actual treatment modalities such as intensity-modulated radiotherapy (IMRT), volumetric-modulated arctherapy (VMAT) and stereotactic radiotherapy (SRT) thanks to the generalized availability of multileaf collimators (MLC). In particular, SRT is a widely used state-of-the-art technique combining high doses in small volumes accurately targeted, allowing a better sparing of surrounding healthy tissues. Initially developed to treat brain lesions [1,2], its use has been extended to all types of extra-cranial lesions (lung, liver, prostate, …) [3–5] with irradiation fields as small as 4 mm.Minimum non-isotropic and asymmetric margins for taking into account intrafraction prostate motion during moderately hypofractionated radiotherapy
Hypofractionated (HF) radiation therapy protocols have shown their effectiveness in treating prostate cancer patients [1,2]. However, these protocols require a high level of accuracy in dose delivery to allow reducing treatment margins because of an increased risk of toxicity to the surrounding organs at risk (OARs) [3]. The use of reduced clinical target volume to planning target volume (CTV-to-PTV) margins for HF versus conventional fractionated treatments has shown to lead to similar late effects between the 2 cohorts whereas early side effects were more pronounced for HF treatments [4].Proof-of-concept of DosiTest: A virtual multicentric clinical trial for assessing uncertainties in molecular radiotherapy dosimetry
Molecular radiotherapy (MRT) is a systemic use of radiolabelled vectors (radiopharmaceuticals) for the treatment of benign and malignant tumours. A radiopharmaceutical consisting of a radionuclide linked to a targeting molecule binds specifically to tumours to selectively irradiate the tumour cells while sparing healthy tissues. In clinical practice, patients are most often administered fixed activity (under the “radioactive chemotherapy” paradigm) [1]. However, significant variability in tumour uptake and radioactivity clearance from patient to patient can be observed.Fricke-Xylenol orange-Gelatin gel characterization with dual wavelength cone-beam optical CT scanner for applications in stereotactic and dynamic radiotherapy
In external radiotherapy, complex and sophisticated treatment techniques such as Intensity-Modulated Radiation Therapy (IMRT) and stereotactic radiotherapy are becoming widely used in clinics. These techniques are designed to fit tightly the target volumes and deliver complex and non-uniform dose distributions with steep dose gradients. However, the dosimeters currently available in clinics only measure point or planar dose distributions, or can be assembled in 2D or 3D arrays to provide 2D or sparse 3D dose distributions with a low spatial resolution.Implementation of volumetric-modulated arc therapy for locally advanced breast cancer patients: Dosimetric comparison with deliverability consideration of planning techniques and predictions of patient-specific QA results via supervised machine learning
Breast cancer is one of the most common cancers, but remains one of the most technically challenging to treat with radiation therapy. The shape and size diversity of the breast or chest wall, its superficial location, and its direct proximity to organs at risk (OARs) make this location particularly challenging. Conventional 3D conformal radiation therapy techniques (3D-CRT) can fail to provide appropriate target dose conformity and homogeneity while sparing OARs, in particular, for locally advanced breast cancers involving the internal mammary chain (IMC).Design and automation of specific geometric quality controls for cone-radiosurgery treatments
Stereotactic radiosurgery of very small intracranial lesions or functional disorders is mainly delivered using a Gamma-Knife system (Elekta AB, Sweden) specifically designed for these clinical indications, but a conventional linac is also highly indicated for those treatments, provided that a quality assurance (QA) program including robust geometric tests is implemented [1,2]. The success of this one-session irradiation technique primarily relies on the control of the geometric accuracy of the irradiation.Cardiac radioablation for ventricular tachycardia: Which approach for incorporating cardiorespiratory motions into the planning target volume?
Cardiac radioablation (CR) has recently emerged as a therapeutic option to treat cardiac arrhythmias in patients with recurrent ventricular tachycardia (VT) after being treated using the standard workflow, including antiarrhythmic drugs and/or catheter radiofrequency ablation [1]. CR involves the delivery of a single 25 Gy dose to the cardiac substrate identified as the source of abnormal electrical propagation. Both C-arm linear accelerators (linacs) (Elekta and Varian platforms) and the CyberKnife robotic system (Accuray), which are typically implemented for stereotactic body radiotherapy (SBRT), have been considered for CR of VT [2,3].
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