Search results for "Radiotherapy Dosage"
showing 10 items of 73 documents
Brachytherapy organ dose estimation using Monte Carlo simulations of realistic patient models
2018
Radiation Therapy Planning Systems (RTPS) currently used in hospitals contain algorithms based on deterministic simplifications that do not properly consider electrons lateral transport in the areas where there are changes of density, and as a result, erroneous dose predictions could be produced. According to this, the present work proposes the use of Monte Carlo method in brachytherapy planning systems, which could affect positively on the radiotherapy treatment planning, since it provides results that are more accurate and takes into account the in homogeneities density variations. This paper presents a Monte Carlo (MC) simulation of a brachytherapy prostate treatment with I-125 seeds, us…
Chemoradioimmunotherapy with 5-fluorouracil, cisplatin and interferon-α in pancreatic and periampullary cancer: Results of a feasibility study
2008
Abstract Background Recent studies give rise to the hypothesis, that adjuvant chemoradioimmunotherapy with 5-fluorouracil (5-FU), cisplatin and interferon-α (IFN-α) might be a possible new treatment of pancreatic cancer in resected patients. We report the up-to-now experience at our institution. Patients and methods Eleven patients with histological diagnosis of localized carcinoma of the pancreas ( n = 7) or periampullary ( n = 4) were prospectively analyzed. Four patients were deemed unresectable because of local invasion of adjacent organs (neoadjuvant setting) and seven patients underwent curative resection (adjuvant setting). Eight patients were classified as T3 carcinomas and three …
Dose–volume-related dysphagia after constrictor muscles definition in head and neck cancer intensity-modulated radiation treatment
2014
Dysphagia remains a side effect influencing the quality of life of patients with head and neck cancer (HNC) after radiotherapy. We evaluated the relationship between planned dose involvement and acute and late dysphagia in patients with HNC treated with intensity-modulated radiation therapy (IMRT), after a recontouring of constrictor muscles (PCs) and the cricopharyngeal muscle (CM).Between December 2011 and December 2013, 56 patients with histologically proven HNC were treated with IMRT or volumetric-modulated arc therapy. The PCs and CM were recontoured. Correlations between acute and late toxicity and dosimetric parameters were evaluated. End points were analysed using univariate logisti…
Extent of Surgery in Rhabdomyosarcoma of Urogenital Structures
1989
After high inguinal semicastration in group-1 paratesticular rhabdomyosarcoma (RMS), the patient having undergone chemotherapy can be followed closely by CT scanning without retroperitoneal lymphadenectomy. In contrast, retroperitoneal RMS should be operated on as radically as possible after downstaging the tumor mass. In RMS of the female genitalia locally limited organ-preserving surgery is the method of choice. The prognosis is excellent with adjuvant chemotherapy. Only 20% of all bladder RMS arise from the bladder dome or the movable part of the bladder, where primary partial resection including a safety margin of 3 cm of healthy tissue is possible. The majority, however, arising from t…
Fibrosarcoma in pediatric patients: Results of the Italian Cooperative Group Studies (1979-1995)
2001
Background and Objectives Fibrosarcoma is a rare soft tissue sarcoma (STS) that has two peaks of incidence in pediatric patients: one in infants and young childern (infantile fibrosarcoma), another in older children (“adult type” fibrosarcoma). The purpose of this study was to describe the clinical features and the treatment results in patients affected by fibrosarcoma enrolled in two consecutive studies run by the STS-Italian Cooperative Group (ICG) between 1979 and 1995. Patients and Methods Twenty-five evaluable patients were grouped according the intergroup rhabdomyosarcoma staging (IRS) system: 12 Gr I, 5 Gr II, 8 Gr III. The cut-off point between the two forms was considered the age o…
Local and systemic risk factors influencing the long-term success of angular stable alloplastic reconstruction plates of the mandible
2013
Introduction: After ablative surgery of the mandible, angular stable alloplastic reconstruction plates are commonly employed. The aim of the study was a long-term evaluation of local anatomical, as looking at systemic factors influencing specific complications and the failure rate of such plates. Materials and methods: In a retrospective study covering an 11-year period, we reviewed the outcomes of angular stable plates of patients who had a segmental resection of the mandible and subsequent alloplastic reconstruction. Complications and failure rates were assessed and local (anatomical size and localization of resection) as well as systemic risk factors (age, sex, radiation therapy, smoking…
Is high dose rate brachytherapy reliable and effective treatment for prostate cancer patients? A review of the literature.
2014
The intrinsic physical and radiobiological characteristics of High Dose Rate Brachytherapy (HDR-BT) are well suited to the treatment of prostate cancer. HDR-BT was initially used as a boost to external beam brachytherapy, but has subsequently been employed as the sole treatment, which is termed HDR monotherapy. This review summarizes the clinical outcomes and toxicity results of the principal studies and discusses the radiobiological basis supporting its use.
Multiparametric MRI and post implant CT-based dosimetry after prostate brachytherapy with iodine seeds: The higher the dose to the dominant index les…
2015
Abstract Purpose To determine whether post-implant MRI-based dosimetry of the Dominant Intra-prostatic Lesion (DIL) could best predict the occurrence of PSA bounce after prostate brachytherapy. Methods and materials We selected 66 patients with a low risk prostate cancer treated with 125 I prostate brachytherapy as monotherapy. Post-implant dosimetry based on day 30 CT-scan and multiparametric MRI co-registration was generated: planned D 90, D 95, V 100, V 150 values were calculated for each DIL. Bounce was defined as a PSA elevation ⩾0.2ng/mL from the previous baseline value followed by a decrease to or below the prior nadir with no additional treatment. Results After a median follow-up of…
Prediction of Normal Organ Absorbed Doses for [177Lu]Lu-PSMA-617 Using [44Sc]Sc-PSMA-617 Pharmacokinetics in Patients With Metastatic Castration Resi…
2018
In vivo pharmacokinetic analysis of [Sc]Sc-PSMA-617 was used to determine the normal organ-absorbed doses that may result from therapeutic activity of [Lu]Lu-PSMA-617 and to predict the maximum permissible activity of [Lu]Lu-PSMA-617 for patients with metastatic castration-resistant prostate carcinoma. Methods Pharmacokinetics of [Sc]Sc-PSMA-617 was evaluated in 5 patients with metastatic castration-resistant prostate carcinoma using dynamic PET/CT, followed by 3 static PET/CT acquisitions and blood sample collection over 19.5 hours, as well as urine sample collection at 2 time points. Total activity measured in source organs by PET imaging, as well as counts per milliliter measured in bloo…
Interactive multiobjective optimization for anatomy-based three-dimensional HDR brachytherapy.
2010
In this paper, we present an anatomy-based three-dimensional dose optimization approach for HDR brachytherapy using interactive multiobjective optimization (IMOO). In brachytherapy, the goals are to irradiate a tumor without causing damage to healthy tissue. These goals are often conflicting, i.e. when one target is optimized the other will suffer, and the solution is a compromise between them. IMOO is capable of handling multiple and strongly conflicting objectives in a convenient way. With the IMOO approach, a treatment planner’s knowledge is used to direct the optimization process. Thus, the weaknesses of widely used optimization techniques (e.g. defining weights, computational burden an…