Analysis of ion beam teletherapy patient-specific quality assurance

The objective of this study was to evaluate the procedures for patient-specific quality assurance measurements using modulated scanned and energy stacked beams for proton and carbon ion teletherapy. Delivery records from 1734 portal measurements were analyzed using a 3-point pass criteria: more than 22 of 24 chambers in a water phantom (WP) had to have a measured dose difference from the planned portal doses less than or equal to 3%, or the distance from the measurement point location to a point location in the plan having the same dose had to be less than or equal to 3?mm (distance to agreement [DTA]), and the mean dose deviation of all chambers had to be less than 3%. Stratification of results showed some associations between measurement parameters and pass rates. For proton portals, pass rates were high at all measurement depths, but for carbon ion portals, pass rates decreased as a function of increasing measurement depth. Pass rates of both proton and carbon ion portals with 1 WP were slightly lower than those with a second WP. The total pass rates were 97.7% and 91.9% for proton and carbon ion patient portals, respectively. In general, the measured doses exhibited good agreement with the treatment planning system (TPS) calculated doses. When the chamber position was deeper than 150?mm in carbon ion beams, a lower pass rate was observed, which may have been caused by ion chamber array setup uncertainty (lateral and depth) in highly modulated portals or incorrect modeling of scatter by the TPS. These deviations need further investigation.     

Clinical study on the correlation between psychogenic dental prosthesis incompatibility, oral stereognosis, and the psychologic diagnostic tools SCL-90-R and CES-D

PURPOSE: The objective of this study was to use an oral stereognosis test to evaluate possible intraoral/sensorimotor causes in patients with a psychologic diagnosis of psychogenic prosthesis incompatibility, and to evaluate possible correlations between oral stereognosis and the psychologic diagnostic tools Symptom Checklist-90-R (SCL-90-R) and Center of Epidemiological Studies Depression Scale (CES-D). MATERIALS AND METHODS: The study cohort comprised 83 patients with complete dentures fabricated according to a standardized protocol. Twelve patients diagnosed with psychogenic prosthesis incompatibility (11 women, 1 man) using the SCL-90-R and CES-D scales in a previous study and a group of 24 randomly selected control subjects (14 women, 10 men) underwent an oral stereognosis test with 10 neutral-tasting plastic test specimens with a maximum edge length of 8 mm in 2 test cycles. RESULTS: The results revealed no significant differences in oral stereognostic ability between patients with diagnosed psychogenic dental prosthesis incompatibility and the control patients. The patients in the test group expressed clear dissatisfaction with their dentures. No correlation was found between oral stereognostic ability and the SCL-90-R or CES-D values. CONCLUSIONS: This study is the first to use oral stereognosis tests for patients with psychologically diagnosed psychogenic dental prosthesis incompatibility. The diagnosis of psychogenic prosthesis incompatibility by the SCL-90-R and CES-D scales is affirmed by the lack of correlations between the functional/anatomic aspects of oral stereognostic ability, psychologic diagnostic tools, and the clinical picture of psychogenic prosthesis incompatibility. Thus, psychogenic prosthesis incompatibility can be classified more explicitly as a psychosomatic disorder.     

Concomitant overexpression of the EGFR and erbB-2 genes in renal cell carcinoma (RCC) is correlated with dedifferentiation and metastasis

Gene amplification or structural alteration of different erbB genes exerts a transforming effect in a variety of human neoplasms. Overexpression of the EGF receptor is associated with tumor initiation and progression of renal cell carcinoma (RCC). However, the role of erbB-2 in these processes remains unknown. We investigated 34 renal cell carcinomas for gene amplification and expression of the EGFR and erbB-2 genes at the mRNA and protein level and their relationship to pathological and clinical parameters. No amplification of both genes has been observed. However, high expression of the EGF receptor protein and p185erbB2 was frequent in RCC and statistically significantly related to higher tumor grades. We could demonstrate a close correlation of p185erbB2 overexpression with high EGF receptor levels. Co-overexpression of both receptor types was significantly associated with metastatic disease. Our results suggest a synergistic involvement of both EGF receptor and p185erbB2 in the progression of RCC. © 1996 Wiley-Liss, Inc.     

Complete response to therapy: why do primary central nervous system lymphoma patients not return to work?

Journal of Neuro-Oncology - Evidence supporting routine postoperative antiepileptic drug (AED) prophylaxis following oncologic neurosurgery is limited, and actual practice patterns are largely...     

Computerized optimization of 125I implants in brain tumors

A computer program for treatment planning for the interstitial radiotherapy of brain tumors with 125I stereotactic implants is presented. To minimize brain traumatization only 1-3 catheters loaded with several seeds are implanted. It is possible to position the catheters very accurately due to CT guided stereotactic techniques. Precise treatment planning is necessary because of the high dose gradient of the radiation field. Two planning methods are available: conventional planning with interactive optimization of source configurations and an automatic optimization procedure. The goal of optimization is to identify source parameters (catheter positions and seed activities) for which a prescribed dose at the target surface is approximated as closely as possible.