The Impact of Dose Rate on the Accuracy of Step-and-Shoot Intensity-modulated Radiation Therapy Quality Assurance Using Varian 2300CD.

Introduction: Intensity-modulated radiation therapy (IMRT) delivery using "step-and-shoot" technique on Varian C-Series linear accelerator (linac) is influenced by the communication frequency between the multileaf collimator and linac controllers. Hence, the dose delivery accuracy is affected by the dose rate.

Aim: Our aim was to quantify the impact of using two dose rates on plan quality assurance (QA).

Vascular development in mouse lung metastases.

Dissemination of cancer cells is strongly associated with reduction in quality of life, worsening of prognosis, and remains the primary cause of therapeutic failure and high mortality in cancer. A crucial factor in the progression of metastases is the ability to establish a functioning blood vessel network. Consequently therapeutic strategies which selectively target tumor vasculature may hold promise for the treatment of metastatic disease.

Monitoring the treatment efficacy of the vascular disrupting agent CA4P.

The purpose of this study was to investigate two non-invasive methods for determining the treatment efficacy of the vascular disrupting agent (VDA) CA4P: gadolinium enhanced dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) for perfusion analysis and enzyme-linked immunosorbent assay (ELISA) of blood samples. Candidate proteins were identified by multi-analyte profile analysis of plasma from KHT sarcoma-bearing C3H/HeJ mice after CA4P administration. Candidate proteins were further analysed by ELISA of plasma from treated C3H/HeJ, BALBc and C57BL6 mice.

Effect of heterogeneous vasculature on interstitial transport within a solid tumor.

Novel strategies for cancer treatment involving macromolecular therapeutic agents have been recently developed and show promising results. Inadequate and heterogeneous uptake in tumor tissue has been shown to be a major obstacle for these compounds in clinical cancer therapy. Such distributions have been difficult to account for in predictive models.

Evaluations of vascular disrupting agents CA4P and OXi4503 in renal cell carcinoma (Caki-1) using a silicon based microvascular casting technique.

The present study evaluated the treatment efficacy of the vascular disrupting agents CA4P and OXi4503 in an orthotopically transplanted human renal cell carcinoma xenograft model (Caki-1). Experiments used vascular casting, vessel density assessments as well as tumour necrosis measurements to evaluate the efficacy of these agents. After treatment with either agent, assessment of the vascular casts showed an almost total eradication of tumour blood vessels.

Effect of the second-generation vascular disrupting agent OXi4503 on tumor vascularity.

Purpose: As first-generation small-molecule vascular disrupting agents (VDA) have begun to enter clinical trials, second-generation agents are under active development. One such agent is the combretastatin A4 disodium phosphate (CA4P) analogue OXi4503 (CA1P).

Experimental Design: C3H/HeJ mice bearing KHT sarcomas were treated with CA4P and OXi4503 and the effect on tumor vasculature was determined by evaluating the extent of vascular shutdown (Hoechst-33342 vessel staining) and tumor perfusion inhibition (dynamic contrast-enhanced magnetic resonance imaging).

Utility of 19F MRS detection of the hypoxic cell marker EF5 to assess cellular hypoxia in solid tumors.

Background And Purpose: The present studies were undertaken to determine whether 19F MRS could be used to quantify the binding of the pentafluorinated derivative of etanidazole (EF5) in hypoxic cells of solid tumors.

Materials And Methods: A 4.7 T imaging magnet was used for the in situ and in vitro evaluation of EF5 signals.