Search results for "RADIATION"

In reply to Alber and Söhn.

2014

Postponed Is Not Canceled: Role of Craniospinal Radiation Therapy in the Management of Recurrent Infant Medulloblastoma—An Experience From the HIT-RE…

2013

Purpose To evaluate the efficacy of craniospinal irradiation (CSI) in the management of recurrent infant medulloblastoma after surgery and chemotherapy alone. Methods and Materials Seventeen pediatric medulloblastoma patients registered in the HIT-REZ 1997 and 2005 studies underwent CSI as salvage treatment at first recurrence. All patients had achieved complete remission after first-line treatment consisting of surgery and chemotherapy. Eleven patients showed metastatic disease at relapse. Five patients underwent surgery prior to radiation therapy, which resulted in complete resection in 1 case. In 1 patient, complete resection of the residual tumor was performed after CSI. Eleven patients…

Regional perfusion and oxygenation of tumors upon methylxanthine derivative administration

1998

Abstract Purpose: The use of methylxanthine derivatives has been postulated as a means of increasing tumor perfusion and thus ameliorating tumor hypoxia. The aim of this study was to quantify and compare the effects of three methylxanthine derivatives: pentoxifylline (PX), torbafylline (TB), and HWA 138 (HW) on tumor perfusion and oxygenation. Methods and Materials: Anesthetized Sprague Dawley rats with DS-sarcomas implanted subcutaneously onto the hind foot dorsum were used in this study. Mean arterial blood pressure (MABP) was measured throughout experiments. Regional red blood cell (RBC) flux was monitored using a multichannel laser Doppler device and tumor oxygenation on a more global l…

Leukemic ophthalmopathy: a report of 21 pediatric cases.

1994

A multicentric retrospective study on leukemic ophthalmopathy (LO) is reported. It includes 21 patients, 16 males and 5 females, with acute leukemia (AL) observed in 10 SIOP centers. LO developed in three patients at the time of diagnosis of AL; five patients were in first complete remission (three off therapy); four patients were in second or third remission; and nine were in combined relapse. Most frequent symptoms were blurred vision, photophobia, and ocular pain. Two patients with acute nonlymphoblastic leukemia died before treatment; another underwent bone marrow transplantation; one patient with B-cell acute lymphoblastic leukemia (B-ALL) treated with chemotherapy and radiotherapy die…

Late neointimal tissue growth behind the stent after intravascular gamma-radiation.

2003

To determine the nature of the changes of the vascular wall after intravascular brachytherapy in stented arteries leading to incomplete stent apposition.Stents were implanted in the infrarenal aortas of rabbits, and gamma-intravascular brachytherapy (18 Gy) or a sham radiation procedure was immediately implemented. The arteries were harvested at 6 months for histologic analyses.The external elastic lamina area, as well as the vascular wall area behind the stent, were significantly greater in irradiated vs. control arteries (8.94 +/- 0.68 mm2 vs. 6.87 +/- 0.40 mm2 [p0.001] and 1.56 +/- 0.13 mm2 vs. 0.72 +/- 0.07 mm2 [p0.001], respectively). The ratio of the intimal area behind the stent rela…

The outcome of Wilms' tumor in infants. Italy 1970-79.

1982

Thirty-four infants under 1 year of age with Wilms’ tumor were diagnosed and treated in 14 Italian pediatric oncology units during 1970-79. The 3-year survival rates decreased with higher group unilateral tumors: 95% in group I Wilms’ tumor, 75% in group II and 20% in group III. The survival rates for children with group I and II Wilms’ tumor were similar for those who were treated with surgery and chemotherapy and those who also received postoperative radiotherapy. During 1975-79 fewer patients with group I Wilms’ tumor received radiotherapy (1 of 11) than during 1970-74 (4 of 6, p < 0.05). All these children are alive at this writing.

Reduced-dose computed tomography is the most accurate method to measure ceramic hip resurfacing cup version

2020

Background: A precise assessment of cup version after hip resurfacing is generally requested, especially in clinical trials or in case of complications. Aims: To identify which diagnostic imaging modality, between AP pelvis X-rays, the AP Pelvis CT Scout image and reduced-dose axial CT scan, is the most precise to assess cup version of an all-ceramic hip resurfacing implant in a first-in-human clinical trial. Methods: We retrospectively assessed the cup version of the first 20 patients who underwent an experimental all-ceramic hip resurfacing on AP pelvis X-rays (0.8 mSv of radiation), AP pelvis CT scout images (0.016 mSv) and axial CT slices performed using a reduced dose protocol (0.3 mSv…

A simple analytical method for heterogeneity corrections in low dose rate prostate brachytherapy

2015

In low energy brachytherapy, the presence of tissue heterogeneities contributes significantly to the discrepancies observed between treatment plan and delivered dose. In this work, we present a simplified analytical dose calculation algorithm for heterogeneous tissue. We compare it with Monte Carlo computations and assess its suitability for integration in clinical treatment planning systems. The algorithm, named as RayStretch, is based on the classic equivalent path length method and TG-43 reference data. Analytical and Monte Carlo dose calculations using Penelope2008 are compared for a benchmark case: a prostate patient with calcifications. The results show a remarkable agreement between …

Reproducibility of CT Radiomic Features within the Same Patient: Influence of Radiation Dose and CT Reconstruction Settings.

2019

Background Results of recent phantom studies show that variation in CT acquisition parameters and reconstruction techniques may make radiomic features largely nonreproduceable and of limited use for prognostic clinical studies. Purpose To investigate the effect of CT radiation dose and reconstruction settings on the reproducibility of radiomic features, as well as to identify correction factors for mitigating these sources of variability. Materials and Methods This was a secondary analysis of a prospective study of metastatic liver lesions in patients who underwent staging with single-energy dual-source contrast material-enhanced staging CT between September 2011 and April 2012. Technique p…

Functional Rehabilitation of Mandibular Continuity Defects Using Autologous Bone and Dental Implants – Prognostic Value of Bone Origin, Radiation The…

2008

<i>Aim:</i> The aim of this retrospective study was to investigate prognostic parameters for the rehabilitation of mandibular continuity defects with free autologous bone and dental implants for patients after intraoral squamous cell carcinoma. <i>Methods:</i> Following potential prognostic factors for implant survival were analyzed: bony bed (local bone versus augmented iliac crest bone), radiation dose (no radiation, <50 Gy, ≥50 Gy) and implant dimensions. Kaplan-Meier survival estimates of the inserted implants were performed. <i>Results:</i> After 5 years, the cumulative survival rate of all investigated implants was 82.6%. Dental implantation into…