Recommandations pour le contrôle de qualité en curiethérapie

Brachytherapy consists of sealed radioactive source implantation. The diversity in the nature of radioelements, in their energy and activity requires strict implantation and utilization rules. These rules include radioactive source physical parameters check, after-loading machine and treatment planning system quality assurance and safe and reproducible dosimetric systems. Patient and medical workers information guarantee radioprotection and prevention of accidental exposures.     

Radiothérapie guidée par l’image pour les petits animaux : une nouvelle ère pour les études précliniques

Preclinical external beam radiotherapy irradiations used to be delivered with a static broad beam. To promote the transfer from animal to man, the preclinical treatment techniques dedicated to the animal have been optimized to be similar to those delivered to patients in clinical practice. In this context, preclinical irradiators have been developed. Due to the small sizes of the animals, and the irradiation beams, the scaling to the small animal dimensions involves specific problems. Reducing the size and energy of the irradiation beams require very high technical performance, especially for the mechanical stability of the irradiator and the spatial resolution of the imaging system. In addition, the determination of the reference absorbed dose rate must be conducted with a specific methodology and suitable detectors. To date, three systems are used for preclinical studies in France. The aim of this article is to present these new irradiators dedicated to small animals from a physicist point of view, including the commissioning and the quality control.     

Sécurité de l’information en centre de radiothérapie : contrôler ses risques pour mieux y faire face

The dematerialization of data, the multiplication of sharing and exchanges between professionals, the increase of business software offer (patient files, human resources management, financial management, document management, etc.) question us about the security of information systems. This protection contributes to the quality of the care of patients in respect of their rights, to ensure the confidentiality, traceability and sustainability of digital personal health data and to strengthen the confidence of professionals in the system and its uses. But what security procedures are currently being undertaken in the radiotherapy centres?     

Complément de dose de protons pour les cancers du nasopharynx localement évolués : une expérience de l’institut Curie

PurposeThe aim of this study was to assess the treatment outcome and toxicity for patients with locally advanced nasopharyngeal carcinoma treated with a complementary dose with proton.Patients and methodsBetween November 1999 and September 2016, 17 patients have been treated for a stage III–IVa nasopharyngeal carcinoma in the proton therapy centre of Curie Institute. Bilateral lymph node in the neck (I–V levels) received from 40 to 54 Gy with photon beam. The primary tumor volume including microscopically extensions received a complementary dose with proton in order to reach the dose of 70 to 78 Gy. All the patients received a concomitant chemotherapy. The end-points of the study were loco-regional control, survival, and treatment-related toxicity.ResultsPatients characteristics were: median age 49, 71 % male, 88% stage IVa, with a majority (82%) of T4N0M0. The median follow-up was 99 months. The 2-, 5- and 10-year actuarial locoregional free survival and overall survival were 94% and 88%, 86% and 74%, and 86% and 66%, respectively. The grade ≥ 3 late adverse events were sphenoid bone radionecrosis (5.9%) and hearing loss (23.5%).ConclusionThis study showed that a complementary dose with proton seems to be a good option for the treatment of locally advanced nasopharyngeal carcinoma, particularly for T4N0M0.     

Comparaison des contrôles de position de patients atteints de cancer ORL entre médecin et manipulateurs en vue d’une délégation partielle

PurposeThe aim of this prospective study was to evaluate daily set-up by a radiation oncologist and by radiation therapists using on-board imaging of patients with head and neck cancer in order to calculate margin to PTV (planning target volume) and intent partial delegation of positioning images control.Patients and methodsThe files of 11 patients with head and neck cancer treated on a Synergy™ (Elekta™) accelerator with on-board imaging system were evaluated. Daily kV-kV images were double-blind reviewed by radiation therapists (7 participants) and by one radiation oncologist. The radiation oncologist's measures were used for margin calculation from CTV to PTV. The difference of measures and the concordance of decisions between radiation therapists and the radiation oncologist were calculated.ResultsThe 325 measures made by the radiation oncologist resulted in a margin of 5 mm to be applied to the CTV in each direction. Nine hundred seventy-seven measures were made by the radiation oncologist and radiation therapists with a difference of 3 mm or less in 98.46%. The concordance of decision for a 4 mm difference or less to the isocenter was 96.7%.ConclusionThis study confirms the 5 mm PTV margin mostly used in ORL. The small gap between the radiation oncologist's and therapists’ measures allows a partial delegation of positioning images control.     

Place de la radiothérapie pour les lymphomes du mucosa-associated lymphoid tissue gastriques : résultats d’une étude rétrospective

Purpose

We aimed to evaluate therapeutic results of radiotherapy for gastric mucosa-associated lymphoid tissue (MALT) lymphomas.

L’accompagnement des traitements adjuvants : les soins de support pour la phase adjuvante

To better support women with breast cancer during their treatment phase, supportive care offer and organization were modified. This is the result of new needs and the new organization of the patient’s follow-up between hospital and general practice care. Patient–doctor dialog involved especially in the development of therapeutic education. Also, patient’s abilities are motivated to manage for the best an illness which became chronic. Progressively, to fulfill the patient’s wishes to be leaded to a more global medical care, the offer in supportive care has changed to a wider concept of “self care”.     

Le contrôle de la respiration en radiothérapie

Background and purpose

The use of centimetric margins to cover the target movements influenced by the breathing create an important irradiation. Some radiotherapies may be improved applying a breathing control.

Material and methods

Breathing control essentially involves any of three techniques and two methods. Breath hold or synchronization have to be implemented regarding to the expected improvements.

Clinical objectives

Lung, liver and breast sites have specific constraints. Lung radiotherapy is optimized when sparing healthy parenchyma with inspiration. Left breast radiotherapy often needs to protect the heart pushed out of the irradiation fields with inspiration. The liver is the most complex site where all methods have the same low precision.

Conclusions

Breathing control during radiotherapy brings important dosimetric improvements. The results of current clinical trials will help to confirm the potential benefit.     

Curiethérapie prostatique de rattrapage : solution pour les rechutes localisées après irradiation ?

Salvage brachytherapy after a first prostate radiation therapy is an emerging technique, which has to be considered in the therapeutic armamentarium in the clinically challenging context of patients with isolated local failure from prostate cancer who may still be considered for cure. These occult failures are more and more frequently diagnosed at an early stage, thanks to targeted biopsies and advances in imaging modalities, such as multiparametric MRI and PET-CT. Salvage brachytherapy benefits from the implantation accuracy of brachytherapy procedures using 3D dosimetry and has resulted in more than 50% tumour control rates with long-term. Incontinence rates are always below those of other salvage treatments such as radical prostatectomy, HIFU or cryotherapy. Today, a consensus has been reached to better define good candidates for salvage brachytherapy with respect to disease characteristics at baseline and at failure. No consensus has been clearly defined yet regarding the choice of the technique (low or high dose rate), the total dose to be delivered, or the volume to be implanted (whole gland or focal). While we await robust data from recently completed phase II studies and given the heterogeneous results in the literature, this technique (although already included in the last 2016 NCCN guidelines) remains to be precisely evaluated, optimally within the frame of controlled trials.     

De la construction du bunker à la prise en charge du patient : contrôles qualité des techniques modernes de radiothérapie

Installation and use of a new radiotherapy device require an adequate quality and safety policy. The process leading to the commissioning of an accelerator following the construction of a bunker includes, among other tasks, the installation of the accelerator, the verification of compliance with the specifications, the signature of the acceptance specification as well as the process of characterization and modeling of the accelerator before its clinical use. The emergence of modern radiotherapy techniques, such as intensity modulated conformational radiotherapy and stereotactic radiotherapy, has resulted in more complex quality controls. The purpose of this article is to explain the different stages of the implementation of innovative radiotherapy techniques and to specify their features.     

Développement d’une procédure de contrôle de qualité externe des faisceaux du CyberKnife : étude préliminaire multicentrique

PurposeTo develop an external quality control procedure for CyberKnife^® beams. This work conducted in Nancy, has included a test protocol initially drawn by the medical physicist of Nancy and Lille in collaboration with Equal-Estro Laboratory.Materials and methodsA head and neck anthropomorphic phantom and a water-equivalent homogeneous cubic plastic test-object, so-called “MiniCube”, have been used. Powder and solid thermoluminescent dosimeters as well as radiochromic films have been used to perform absolute and relative dose studies, respectively. The comparison between doses calculated by Multiplan treatment planning system and measured doses have been studied in absolute dose. The dose distributions measured with films and treatment planning system calculations have been compared via the gamma function, configured with different tolerance criteria.ResultsThis work allowed, via solid thermoluminescent dosimeter measurements, verifying the beam reliability with a reproducibility of 1.7 %. The absolute dose measured in the phantom irradiated by the seven participating centres has shown an error inferior to the standard tolerance limits (±5 %), for most of participating centres. The relative dose measurements performed at Nancy and by the Equal-Estro laboratory allowed defining the most adequate parameters for gamma index (5 %/2 mm – with at least 95 % of pixels satisfying acceptability criteria: γ < 1). These parameters should be independent of the film analysis software.ConclusionThis work allowed defining a dosimetric external quality control for CyberKnife^® systems, based on a reproducible irradiation plan through measurements performed with thermoluminescent dosimeters and radiochromic films. This protocol should be validated by a new series of measurement and taking into account the lessons of this work.     

Prise en charge adjuvante des cancers invasifs du sein : les techniques de radiothérapie modifient-elles les taux de contrôle local et de survie ?

Conventional radiotherapy (RT) in breast cancer treatment includes a total dose of 50 Gy with a 16 Gy-boost in a smaller volume. After mastectomy, radiotherapy of all node-positive patients seems to be applied whatever the positive node number. Modulation of RT technique uses the fraction dose, namely through accelerated hypofractionation regimen in a constant volume. A group of patient with a low risk of recurrence may benefit from this technique. In a smaller irradiated volume, accelerated hypofractionation still belongs to intensive clinical research evaluating intraoperative RT, brachytherapy, Mammosite, and external partial breast irradiation. Intensity-modulated radiotherapy decreases the risk of moist desquamation. The development of the gating offers greater protection of certain critical organs including lung, heart, and chest/ribs. Finally, predictive tests identifying patients at high risk of developing late effects led us to adapt RT technique to some of them and therefore increase long term therapeutic ratio.