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This work reports the results of the application of a practical method to determine the in vivo dose at the isocenter point, D(iso), of brain thorax and pelvic treatments using a transit signal S(t). The use of a stable detector for the measurement of the signal S(t) (obtained by the x-ray beam transmitted through the patient) reduces many of the disadvantages associated with the use of solid-state detectors positioned on the patient as their periodic recalibration, and their positioning is time consuming. The method makes use of a set of correlation functions, obtained by the ratio between S(t) and the mid-plane dose value, D(m), in standard water-equivalent phantoms, both determined along the beam central axis. The in vivo measurement of D(iso) required the determination of the water-equivalent thickness of the patient along the beam central axis by the treatment planning system that uses the electron densities supplied by calibrated Hounsfield numbers of the computed tomography scanner. This way it is, therefore, possible to compare D(iso) with the stated doses, D(iso,TPS), generally used by the treatment planning system for the determination of the monitor units. The method was applied in five Italian centers that used beams of 6 MV, 10 MV, 15 MV x-rays and (60)Co gamma-rays. In particular, in four centers small ion-chambers were positioned below the patient and used for the S(t) measurement. In only one center, the S(t) signals were obtained directly by the central pixels of an EPID (electronic portal imaging device) equipped with commercial software that enabled its use as a stable detector. In the four centers where an ion-chamber was positioned on the EPID, 60 pelvic treatments were followed for two fields, an anterior-posterior or a posterior-anterior irradiation and a lateral-lateral irradiation. Moreover, ten brain tumors were checked for a lateral-lateral irradiation, and five lung tumors carried out with three irradiations with different gantry angles were followed. One center used the EPID as a detector for the S(t) measurement and five pelvic treatments with six fields (many with oblique incidence) were followed. These last results are reported together with those obtained in the same center during a pilot study on ten pelvic treatments carried out by four orthogonal fields. The tolerance/action levels for every radiotherapy fraction were 4% and 5% for the brain (symmetric inhomogeneities) and thorax/pelvic (asymmetric inhomogeneities) irradiations, respectively. This way the variations between the total measured and prescribed doses at the isocenter point in five fractions were well within 2% for the brain treatment, and 4% for thorax/pelvic treatments. Only 4 out of 90 patients needed new replanning, 2 patients of which needed a new CT scan.

OBJECTIVE:To investigate the pattern of care and outcomes for newly diagnosed glioblastoma in Italy and compare our results with the previous Italian Patterns of Care study to determine whether significant changes occurred in clinical practice during the past 10 years. METHODS: Clinical, pathological, therapeutic, and survival data regarding 1059 patients treated in 18 radiotherapy centers between 2002 and 2007 were collected and retrospectively reviewed. RESULTS: Most patients underwent both computed tomography and magnetic resonance imaging either preoperatively (62.7%) or postoperatively (35.5%). Only 123 patients (11.6%) underwent a biopsy. Radiochemotherapy with temozolomide was the most frequent adjuvant treatment (70.7%). Most patients (88.2%) received 3-dimensional conformal radiotherapy. Median survival was 9.5 months. Two-and 5-year survival rates were 24.8% and 3.9%, respectively. Multivariate analysis showed the statistical significance of age, postoperative Karnofsky Performance Status scale score, surgical extent, use of 3-dimensional conformal radiotherapy, and use of chemotherapy. Use of a more aggressive approach was associated with longer survival in elderly patients. Comparing our results with those of the subgroup of patients included in our previous study who were treated between 1997 and 2001, relevant differences were found: more frequent use of magnetic resonance imaging, surgical removal more common than biopsy, and widespread use of 3-dimensional conformal radiotherapy + temozolomide. Furthermore, a significant improvement in terms of survival was noted (P < .001). CONCLUSION: Changes in the care of glioblastoma over the past few years are documented. Prognosis of glioblastoma patients has slightly but significantly improved with a small but noteworthy number of relatively long-term survivors.