Impact of adjuvant radiotherapy on biological and clinical parameters in right-sided breast cancer.

PURPOSE: In patients with right-sided breast cancer (BC) the liver might be partially irradiated during adjuvant radiotherapy (RT). Thus, we performed a prospective observational study to evaluate the dose delivered to the liver, and its potential biological impact. PATIENTS AND METHODS: We enrolled 34 patients with right-sided BC treated with adjuvant RT. The RT schedules were either the Canadian (42.5Gy in 16 fx) or standard fractionated (50Gy in 25 fx) regimen respectively with 9 (26.5%) and 25 (73.5%) patients each, ± a boost of 10-16Gy. Each patient had a complete blood count and liver enzymes analysis, before starting and during the last week of treatment. RESULTS: A significant decrease in white blood cells and thrombocytes counts was observed during RT. We observed a significant correlation between certain hepatic parameters and the volume of the irradiated liver and/or the mean liver dose. A significant correlation between the volume of the right lung and the liver mean dose was found (P=0.008). In the bivariate analysis, a significant correlation between fatigue and the white blood cell count's evolution was observed (P<0.025). CONCLUSION: With the standard RT technique, incidental irradiation of the liver was documented in a large number of patients, and some significant hepatic parameters alterations were observed, without an apparent clinical impact, but this study cannot exclude them. The liver mean dose was correlated with the right lung volume suggesting that deep inspiration breath hold (DIBH) techniques may represent a way to decrease the liver dose. These findings need to be evaluated in further larger studies.

An efficient procedure for tomotherapy treatment plan verification using the on-board detector.

In this work, a fast and simple procedure for tomotherapy treatment plan verification using the on-board detector (OBD) has been developed. This procedure allows verification of plans with static and dynamic jaws (TomoEDGE). A convolution-based calculation model has been derived in order to link the leaf control sinogram from the treatment planning system to the data acquired by the OBD during a static couch procedure. The convolution kernel has been optimized using simple plans calculated in the Tomotherapy Cheese phantom. The optimal kernel has been found to be a lorentzian function, whose parameter Γ is 0.186 for the 1 cm jaw opening, 0.232 for the 2.5 cm jaw opening and 0.373 for the 5 cm jaw opening. The evaluation has been performed with a γ-index analysis. The dose criterion was 3% of the 95th percentile of the dose distribution and the distance-to-agreement criterion is 2 mm. In order to validate the procedure, it has been applied to around 50 clinical treatment plans, which had already been validated by the Delta4 phantom (Scandidos, Sweden). 96% of the tested plans have passed the criteria. Concerning the other 4%, significant discrepancies between the leaf pattern in the leaf control sinogram and the OBD data have been shown, which might be due to differences in the leaf open time. This corresponds also to a higher sensitivity of this method over the Delta4, adding the possibility of better monitoring the treatment delivery.

The exchange of radiotherapy data as part of an electronic patient-referral system.

PURPOSE: To describe the implementation and use of an electronic patient-referral system as an aid to the efficient referral of patients to a remote and specialized treatment center. METHODS AND MATERIALS: A system for the exchange of radiotherapy data between different commercial planning systems and a specially developed planning system for proton therapy has been developed through the use of the PAPYRUS diagnostic image standard as an intermediate format. To ensure the cooperation of the different TPS manufacturers, the number of data sets defined for transfer has been restricted to the three core data sets of CT, VOIs, and three-dimensional dose distributions. As a complement to the exchange of data, network-wide application-sharing (video-conferencing) technologies have been adopted to provide methods for the interactive discussion and assessment of treatments plans with one or more partner clinics. RESULTS: Through the use of evaluation plans based on the exchanged data, referring clinics can accurately assess the advantages offered by proton therapy on a patient-by-patient basis, while the practicality or otherwise of the proposed treatments can simultaneously be assessed by the proton therapy center. Such a system, along with the interactive capabilities provided by video-conferencing methods, has been found to be an efficient solution to the problem of patient assessment and selection at a specialized treatment center, and is a necessary first step toward the full electronic integration of such centers with their remotely situated referral centers.

A treatment planning inter-comparison of proton and intensity modulated photon radiotherapy.

PURPOSE: A comparative treatment planning study has been undertaken between standard photon delivery techniques,b intensity modulated photon methods and spot scanned protons in order to investigate the merits and limitations of each of these treatment approaches. METHODS: Plans for each modality were performed using CT scans and planning information for nine patients with varying indications and lesion sites and the results have been analysed using a variety of dose and volume based parameters. RESULTS: Over all cases, it is predicted that the use of protons could lead to a reduction of the total integral dose by a factor three compared to standard photon techniques and a factor two compared to IM photon plans. In addition, in all but one Organ at Risk (OAR) for one case, protons are predicted to reduce both mean OAR dose and the irradiated volume at the 50% mean target dose level compared to both photon methods. However, when considering the volume of an OAR irradiated to 70% or more of the target dose, little difference could be shown between proton and intensity modulated photon plans. On comparing the magnitude of dose hot spots in OARs resulting from the proton and IM photon plans, more variation was observed, and the ranking of the plans was then found to be case and OAR dependent. CONCLUSIONS: The use of protons has been found to reduce the medium to low dose load (below about 70% of the target dose) to OARs and all non-target tissues compared to both standard and inversely planned photons, but that the use of intensity modulated photons can result in similar levels of high dose conformation to that afforded by protons. However, the introduction of inverse planning methods for protons is necessary before general conclusions on the relative efficacy of photons and protons can be drawn.

Quality assurance of the EORTC radiotherapy trial 22931 for head and neck carcinomas: the dummy run.

PURPOSE: A dummy run was organized to test the compliance of participating centres with the guidelines of EORTC protocol 22931, which compares high dose radiotherapy with concomitant radiochemotherapy in a postoperative setting for patients presenting with locally advanced head and neck carcinomas. METHODS: In a first step the participants (seven centres, six replies) were asked to define the planning target volume (PTV) in a given patient on the basis of clinical, surgical and radiological (CT-images) data-sets and according to the protocol guidelines. In a second phase a series of CT-reconstructed slices with on- and off-axis PTV outlines were sent to 11 centres (10 replies), which were asked to plan a treatment following the recommendations made in the frame of the trial. RESULTS: The first step of this dummy run emphasized wide intercentre variations in PTV extensions. This fact raises the question of the reproducibility when pooling patients in multicentric trials. The second step indicated a large variability in the field arrangements which was left to the discretion of the investigators. Only three out of 10 of the institutions followed the ICRU 50 recommendations for dose reporting. Moreover, protocol requirements were not met for dose distribution homogeneity in any centre. CONCLUSIONS: In order to reduce intercentre treatment heterogeneities, several actions have been taken by the EORTC Radiotherapy Group, e.g. amendments have been brought to protocol 22931 regarding a better definition of clinical and planning target volumes. Furthermore, a stricter application of the ICRU 50 recommendations for dose reporting has been sought.

Transfer of information between angiographic films and CT images: a technique to control the drawing of target volumes.

BACKGROUND AND PURPOSE: This work was undertaken to improve the definition of target volumes for radiosurgery using the angiographic and CT data. MATERIALS AND METHODS: The basis of this new method is to combine both imaging modalities and to compare them in each representation, i.e. to plot the volume obtained by angiography on CT images and also the contours defined by the CT on angiographic films. To obtain the angiographic volume, the radiographs are taken at several incidence angles. The X-ray sources position and the position of the films are determined using rectangular markers, then the intersection of all the loci of the target volume are calculated. RESULTS: Verifications with a phantom show the accuracy of the procedure and the benefit obtained by increasing the number of angles of incidence in the angiographic imaging. The centre of gravity of the experimental target could be localized to an accuracy of better than 0.4 mm. The method was used in 11 clinical cases with excellent clinical results. CONCLUSIONS: The method can be easily applied and improves the delineation of target volumes in radiosurgery. CT data counterbalances the relative weakness of angiography concerning the three-dimensional geometry. Angiography adds useful information on the blood flow that is not shown in CT. Almost all the presented clinical cases benefit from the technique described here.

[Stereotaxic radiotherapy of brain metastases: experiences in Lausanne]. / Radiothérapie stéréotaxique des métastases cérébrales: expérience lausannoise.

We report the first series of patients treated by stereotactic radiation therapy for brain metastases in Switzerland. From August 1993 to December 1994, 19 patients were treated using a linear accelerator adapted for stereotactic treatment set-up. Most of the patients received combined treatment including external irradiation. The crude overall control rate for brain metastases was 79%. Median survival was 12.2 months. Overall survival at one year was 50 +/- 12%. These data compare reasonably well with the reported median survival of 3-6 months using external cranial irradiation alone. There was no "late toxicity". The data thus indicate that stereotactic radiation therapy combined with external whole brain irradiation appears to increase life expectancy and quality of life in a selected cohort of patients.