Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology
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To assess family physicians' views on common indications for palliative radiotherapy and to determine whether this influences patient referral. ⋯ Many of the family physicians surveyed were unaware of the effectiveness of radiotherapy in a variety of common palliative situations, and radiotherapy referral was correlated with knowledge about the indications for palliative radiotherapy. This was not surprising given the limited education they received in this area and the limited contact they have had with radiation oncologists. Strategies need to be developed to improve continuing medical education opportunities for family physicians and to facilitate more interaction between these physicians and radiation oncologists.
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To evaluate the treatment outcome in patients with locally recurrent nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). ⋯ Our preliminary results showed that good control of rT1-3 NPC can be achieved using IMRT with a dose between 50 and 60 Gy, whereas the outcome for r T4 tumor remained poor. Late toxicities were common but incidence of severe toxicities was relatively low.
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Clinical Trial
Automated selection of beam orientations and segmented intensity-modulated radiotherapy (IMRT) for treatment of oesophagus tumors.
For some treatment sites, there is evidence in the literature that five to nine equi-angular input beam directions are enough for generating IMRT plans. For oesophagus cancer, there is a report showing that going from four to nine beams may even result in lower quality plans. In this paper, our previously published algorithm for automated beam angle selection (Cycle) has been extended to include segmented IMRT. For oesophagus cancer patients, we have investigated whether automated orientation selection from a large number of equi-angular input beam directions (up to thirty-six) for IMRT optimisation can result in improved lung sparing. ⋯ For the studied oesophagus cancer patients the best plans for IMRT were obtained with Cycle, using automated beam orientation selection from thirty-six input beam directions. The lowest mean lung doses could be obtained with, on average, a selection of only seven beams with non-zero weight.
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Multicenter Study Comparative Study
Observer variation in target volume delineation of lung cancer related to radiation oncologist-computer interaction: a 'Big Brother' evaluation.
To evaluate the process of target volume delineation in lung cancer for optimization of imaging, delineation protocol and delineation software. ⋯ With the 'Big Brother' tool a method was developed to trace the delineation process. The differences between observers concerning the delineation style were large. This study led to recommendations on how to improve delineation accuracy by adapting the delineation protocol (guidelines for L/W use) and delineation software (double window with lung and mediastinum L/W settings at the same time, enforced use of coronal and sagittal views) and including FDG-PET information (lymph nodes and atelectasis).
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Comparative Study
Normal tissue complication probability modeling for acute esophagitis in patients treated with conformal radiation therapy for non-small cell lung cancer.
To evaluate the ability of a well-known normal tissue complication probability (NTCP) model to predict radiation esophagitis by determining updated model parameters and then comparing these results with the predictive value of other dosimetric parameters. ⋯ New values of TD50, n and m offer a good description of the esophagitis distribution in our population. Compared to the use of this model with previously published parameters (associated with late toxicity) predictions of the model for acute esophagitis using the new parameters would indicate that, for a population of patients, the distribution of events as a function of uniform dose would occur with a lower mean uniform dose value (smaller TD50), over a wider range of uniform doses (larger m), while also exhibiting a bigger volume effect (larger n). These new parameter values are supported in essence by the correlations found for the dose/volume threshold parameters.