Ultrasound-stimulated microbubbles enhancement of fractionated radiation for tumor treatment.

Background: Radiation therapy (XRT) causes numerous biological changes in tumor microenvironment. Radiation vascular response, due to endothelial disruption, can influence treatment outcomes in a dose-dependent manner. Ultrasound-stimulated microbubbles (USMB) have also been demonstrated to create a vascular response in the tumor microenvironment and enhance tumor response when used in combination with XRT.

Focused Ultrasound Stimulation of Microbubbles in Combination With Radiotherapy for Acute Damage of Breast Cancer Xenograft Model.

Several studies have focused on the use of ultrasound-stimulated microbubbles (USMB) to induce vascular damage in order to enhance tumor response to radiation. In this study, power Doppler imaging was used along with immunohistochemistry to investigate the effects of combining radiation therapy (XRT) and USMB using an ultrasound-guided focused ultrasound (FUS) therapy system in a breast cancer xenograft model. Specifically, MDA-MB-231 breast cancer xenograft tumors were induced in severe combined immuno-deficient female mice.

Effect of Ultrasound-Stimulated Microbubbles and Hyperthermia on Tumor Vasculature of Breast Cancer Xenograft.

Objective: The objective of the present study was to investigate the treatment effects of ultrasound-stimulated microbubbles (USMB) and hyperthermia (HT) on breast tumor vasculature.

Methods: Tumor-bearing mice with breast cancer xenografts (MDA-MB-231), were exposed to different treatment conditions consisting of control (no treatment), USMB alone, HT alone, USMB with HT exposures of 10 and 50 minutes. Quantitative 3D Doppler ultrasound and photoacoustic imaging were used to detect tumor blood flow and oxygen saturation, respectively.

Ultrasound-stimulated microbubble radiation enhancement of tumors: Single-dose and fractionated treatment evaluation.

The use of ultrasound-stimulated microbubble therapy has successfully been used to target tumor vasculature and enhance the effects of radiation therapy in tumor xenografts in mice. Here, we further investigate this treatment using larger, more clinically relevant tumor models. New Zealand white rabbits bearing prostate tumor (PC3) xenografts received a single treatment of either ultrasound-stimulated microbubbles (USMB), ionizing radiation (XRT; 8Gy), or a combination of both treatments (USMB+XRT).

Optimization of microbubble enhancement of hyperthermia for cancer therapy in an in vivo breast tumour model.

We have demonstrated that exposing human breast tumour xenografts to ultrasound-stimulated microbubbles enhances tumour cell death and vascular disruption resulting from hyperthermia treatment. The aim of this study was to investigate the effect of varying the hyperthermia and ultrasound-stimulated microbubbles treatment parameters in order to optimize treatment bioeffects. Human breast cancer (MDA-MB-231) tumour xenografts in severe combined immunodeficiency (SCID) mice were exposed to varying microbubble concentrations (0%, 0.

Role of Acid Sphingomyelinase and Ceramide in Mechano-Acoustic Enhancement of Tumor Radiation Responses.

Background: High-dose radiotherapy (>8-10 Gy) causes rapid endothelial cell death via acid sphingomyelinase (ASMase)-induced ceramide production, resulting in biologically significant enhancement of tumor responses. To further augment or solicit similar effects at low radiation doses, we used genetic and chemical approaches to evaluate mechano-acoustic activation of the ASMase-ceramide pathway by ultrasound-stimulated microbubbles (USMB).

Methods: Experiments were carried out in wild-type and acid sphingomyelinase (asmase) knockout mice implanted with fibrosarcoma xenografts.

Dosimetric impact of inter-observer catheter reconstruction variability in ultrasound-based high-dose-rate prostate brachytherapy.

Purpose: To investigate the dosimetric impact of interobserver catheter reconstruction variability in transrectal ultrasound-guided prostate high-dose-rate (HDR) brachytherapy.

Methods And Materials: Twenty consecutive patients with intermediate- or high-risk prostate cancer were treated with a single, 15-Gy HDR brachytherapy boost as part of this study. The treated plan was used as the study reference plan (P).

Intraoperative ultrasound-based planning can effectively replace postoperative CT-based planning for high-dose-rate brachytherapy for prostate cancer.

Purpose: Ultrasound (US)-based planning for high-dose-rate brachytherapy allows prostate patients to be implanted, imaged, planned, and treated without changing position. This is advantageous with respect to accuracy and efficiency of treatment but is only valuable if plan quality relative to CT is maintained. This study evaluates any dosimetric impact of changing from CT- to US-based planning.

Use of cone-beam imaging to correct for catheter displacement in high dose-rate prostate brachytherapy.

Purpose: To determine the magnitude of catheter displacement between time of planning and time of treatment delivery for patients undergoing high dose-rate (HDR) brachytherapy, the dosimetric impact of catheter displacement, and the ability to improve dosimetry by catheter readjustment.

Methods And Materials: Twenty consecutive patients receiving single fraction HDR brachytherapy underwent kilovoltage cone-beam CT in the treatment room before treatment. If catheter displacement was apparent, catheters were adjusted and imaging repeated.