Quasi-VMAT in high-grade glioma radiation therapy.

PURPOSE: To compare a quasi-volumetric modulated arc therapy (qVMAT) with three-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT) for the treatment of high-grade gliomas. The qVMAT technique is a fast method of radiation therapy in which multiple equispaced beams analogous to those in rotation therapy are radiated in succession. PATIENTS AND METHODS: This study included 12 patients with a planning target volume (PTV) that overlapped at least one organ at risk (OAR). 3D-CRT was planned using 2-3 non-coplanar beams, whereby the field-in-field technique (FIF) was used to divide each field into 1-3 subfields to shield the OAR. The qVMAT strategy was planned with 15 equispaced beams and IMRT was planned using 9 beams with a total of 80 segments. Inverse planning for qVMAT and IMRT was performed by direct machine parameter optimization (DMPO) to deliver a homogenous dose distribution of 60 Gy within the PTV and simultaneously limit the dose received by the OARs to the recommended values. Finally, the effect of introducing a maximum dose objective (max. dose < 54 Gy) for a virtual OAR in the form of a 0.5 cm ring around the PTV was investigated. RESULTS: The qVMAT method gave rise to significantly improved PTV95% and conformity index (CI) values in comparison to 3D-CRT (PTV95% = 90.7 % vs. 82.0 %; CI = 0.79 vs. 0.74, respectively). A further improvement was achieved by IMRT (PTV95% = 94.4 %, CI = 0.78). In qVMAT and IMRT, the addition of a 0.5 cm ring around the PTV produced a significant increase in CI (0.87 and 0.88, respectively), but dosage homogeneity within the PTV was considerably reduced (PTV95% = 88.5 % and 92.3 %, respectively). The time required for qVMAT dose delivery was similar to that required using 3D-CRT. CONCLUSION: These findings suggest that qVMAT should be preferred to 3D-CRT for the treatment of high-grade gliomas. The qVMAT method could be applied in hospitals, for example, which have limited departmental resources and are not equipped with systems capable of VMAT delivery.

[Exclusive intra-operative radiation therapy (IORT) for early stage breast cancer: pilot study of feasibility]. / Radioterapia intraoperatoria (IORT) esclusiva nel carcinoma iniziale della mammella: studio pilota di fattibilità.

AIM: To evaluate feasibility, tolerability and cosmetic outcome of intra-operative radiation therapy (IORT) as an exclusive post-surgery treatment of early stage breast cancer. PATIENTS AND METHODS: From October 2008 to October 2009 30 patients underwent wide breast cancer excision or quadrantectomy followed by IORT on tumor bed with accelerated electrons at the dose of 21Gy. The characteristics of the patients were: ductal breast cancer or invasive lobular cT1, cT2 ≤ 2,5 cm, cN0, G1-2, age over 35 years, M0. RESULTS: The average age was 51.7 (range 38 - 75) with an average follow up of 11.7 months (range 6 - 18). The pathologic stage of the lesions resulted pT1 in 29 cases (96,6%), in particular: one case pT1a (3,3%), 21 cases pT1b (70,0%) and 7 cases pT1c (23,3%). One case (3,3%) was pT2 with a diameter of 2.5 cm. The grading was G2 in 20 cases (66,6%) and G1 in 10 cases (33,3%). The toxicity, evaluated according to the EORTC-RTOG criteria, was G0 (33.3%) in 10 cases, G1 (63,3%) in 19 cases, G2 in one case (3,4%); there was no G3 toxicity. The time needed for a complete healing of the wound was less than 10 days in 96,7% of the cases, with one case of limphocele (3,3%). There were no infections of the surgical wound nor any mastitis, neither in the treated quadrant nor in the other ones. We observed a light fibrosis in 5 cases (16,6%), moderate in 2 cases (6,6%) but never severe. Cosmetics, evaluated in four levels, according to Danoff et al., was excellent in 3 cases (43,3%), good in 15 cases (50%), sufficient in 2 cases (6,7%), never insufficient. As regards local control, there was no local relapse. The global survival was 100%. CONCLUSIONS: The IORT in early breast cancer, at the doses used in this study, proved itself as a secure technique, repeatable, with limited complications. The advantages of its use are the possibility of a direct control, by the surgeon and the radiotherapist, of the structures to treat and those to protect; the absence of time needed for cellular repopulation between surgery and radiotherapy; a good cosmetic outcome; and logistic advantages. It is necessary to have a long term follow up to evaluate the efficacy in terms of long term cosmetic and local control.

Study of cerebral flow with radionuclide: 99mTc-pertechnetate transit times and curves.

The transit of intravenously injected 99mTc-pertechnetate in the cerebrovascular tree can be monitored in patients in a supine position by means of a computer-assisted gamma-camera. When programmed properly, time-activity curves of the tracer in the region to be studied can be displayed, i.e. internal carotid arteries, brain hemispheres, etc. The application of the modified gamma function to these curves is employed in order to more accurately define the transit and transfer times in this region. Thirtyseven patients with cerebrovascular disturbances were examined. In most cases asymmetrical cerebral perfusion and a significant difference between right and left transit and/or transfer times were noted.

[Current trends in the treatment of Graves' disease]. / Attuali orientamenti nel trattamento del morbo di Basedow.

Between 1973 and 1992 153 patients with Graves' disease were observed at the Surgery and Oncology Institute-Cagliari University. 103 underwent subtotal (70) or total (33) thyroidectomy, while 50(after 1985) were submitted to radioactive-iodine therapy. Surgical indications were failure of antithyroid drug therapy, signs of compression and large size goitre. Until 1988, all patients were submitted to subtotal thyroidectomy with thyroid remnant of about 8 g. From 1988 the choice of total thyroidectomy came out from: similar complications (paralysis of recurrent nerve and hypoparathyroidism), lack of relapse and suppression of risk of occult carcinoma. After subtotal thyroidectomy definitive hypoparathyroidism in 1 patient (1.8%), transitory hypoparathyroidism in 5 (9.4%), clinical hypothyroidism in 17 (31.5%), recidive hyperthyroidism in 3 patients (5.5%) were observed. After total thyroidectomy 1 patient presented definitive paralysis of recurrent nerve (3%), 1 definitive hypoparathyroidism (3%), 8 transitory hypoparathyroidism (24%): small (44 patients) or large goitre (3 patients) or relapse (3 patients) were indications to radioactive-iodine therapy. At median follow-up of 16 months no relapses of hyperthyroidism were observed, while clinical signs of hypothyroidism were present in 33% of patients. Authors stress that, after a first attempt with antithyroid drugs therapy, radioiodine treatment is elective in Graves' disease. Surgery still remains the treatment of choice during pregnancy, in patients with large goitres, signs of compression or in presence of scintigraphic "cold" area.

Modifications induced in phosphatidylcholine multilayers by Co-60 gamma-rays.

Using differential scanning calorimetry it was observed that gamma-radiation induced modifications in dimyristoyl phosphatidylcholine (DMPC) multilayers in excess water. It was observed that, with the increase of the absorbed dose, the peak associated with the pretransition disappeared gradually, while the peak associated with the main transition became wider and flatter. The enthalpy change associated with the pretransition was found to be 4.4 +/- 0.3 kJ/mol of DMPC before irradiation and that associated with the main transition was found to be 26.0 +/- 1.3 kJ/mol of DMPC before and after irradiation. Moreover from our measurements, it seems that the trapped water becomes stable free water, because of the effect of the gamma-radiation.