How to enhance non-thermal effects of ultrasound

December 29, 2008,

In recent years HIFU has been widely used for the treatment of solid tumors, such as liver tumor, bone tumor, and breast cancer. The mechanism for therapeutic actions of HIFU includes thermal effects and non-thermal effects with the latter dominated by cavitational effects. Adjusting acoustic parameters of pulsed high intensity focused ultrasound (PHIFU) can control thermal effects and non-thermal effects; short duty cycle and high intensity favors the occurrence of cavitation. Ultrasound contrast agent (UCA) can enhance cavitational effects. Lesions caused by non-thermal effects have characteristic pathological changes quite different from those of thermal lesions.

A research article to be published on November 21, 2008 in the World Journal of Gastroenterology addresses this question. The research group led by Professor Zhi-Biao Wang from Department of Biomedical Engineering of Chongqing Medical University used PHIFU with short duty cycle and high intensity combined with UCA to damage rabbit liver VX2 tumour by non-thermal effect, and the non-thermal damage was evaluated by histopathology.

Liver VX2 tumor model were established in 20 rabbits, which were then divided randomly into PHIFU combined with UCA group (PHIFU+UCA group) and sham group, with 10 rabbits in each group. In the PHIFU+UCA group, 0.2 mL of SonoVue was injected intravenously, followed by rapid injection of 1 mL normal saline. Fifteen seconds after the injection, the tumours were exposed to HIFU with ISP 5900W/cm2 for 90 seconds. Rabbits were sacrificed one day after HIFU exposure. Specimens of the exposed tumor tissues were obtained and observed pathologically under light microscope and transmission electron microscope.

The remaining exposed tumor tissues were sent for TTC staining. Before TTC staining, tumor tissues in both the sham and the PHIFU+UCA group resembled gray fish meat; after TTC staining, the tumour tissues were uniformly stained red, with a clear boundary between tumor tissue and normal tissue. For PHIFU + UCA group, light microscopy displayed abundant vacuoles of various sizes in the cytoplasm and in some cells, chromatin margination and karyopyknosis were present. Electron microscopic examination revealed presence of karyopyknosis and chromatin margination in some cells, intercellular space widening, the presence of high electron-density apoptotic bodies and many vacuoles of various sizes in the cytoplasm.

This study found that PHIFU combination with UCA can enhance non-thermal effects of ultrasound, and the pathological characteristics of the non-thermal damage is different from those of thermal damage. Immunohistochemical detection found that PHIFU combined with UCA can promote tumor cell apoptosis and inhibit tumor cell proliferation, which will be reported in another article.

Source: World Journal of Gastroenterology

Explore further: Metformin could one day be used to treat malignant tumors

Related Stories

Metformin could one day be used to treat malignant tumors

January 16, 2018
A*STAR researchers have provided strong evidence, using patient tumor grafts, that metformin, a common diabetes drug, might help fight colorectal cancer in humans.

FDA approves first drug for tumors tied to breast cancer genes

January 12, 2018
(HealthDay)—The U.S. Food and Drug Administration on Friday approved the first drug aimed at treating metastatic breast cancers linked to the BRCA gene mutation.

Rare melanoma type highly responsive to immunotherapy

January 11, 2018
Desmoplastic melanoma is a rare subtype of melanoma that is commonly found on sun-exposed areas, such as the head and neck, and usually seen in older patients. Treatment is difficult because these tumors are often resistant ...

Biomarkers may help predict outcomes in gastric cancer patients who abuse alcohol

January 10, 2018
Alcohol consumption has been identified as a modifiable risk factor for cancers such as gastric cancer. A new report in the The American Journal of Pathology sheds light on how specific proteins interact with alcohol, and ...

Removing the immunotherapy blindfold

January 11, 2018
Immunotherapies are promising in theory, but often not in practice. In fact according to experts, they actually only work 10 percent of the time in the treatment of cancer – at best. Yet, while immunotherapy drugs may only ...

Scientists curb growth of cancer cells by blocking access to key nutrients

January 10, 2018
Salk researchers have discovered how to curb the growth of cancer cells by blocking the cells' access to certain nutrients. The approach, detailed in a new paper published today in Nature, took advantage of knowledge on how ...

Recommended for you

New study offers insights on genetic indicators of COPD risk

January 16, 2018
Researchers have discovered that genetic variations in the anatomy of the lungs could serve as indicators to help identify people who have low, but stable, lung function early in life, and those who are particularly at risk ...

Previous influenza virus exposures enhance susceptibility in another influenza pandemic

January 16, 2018
While past exposure to influenza A viruses often builds immunity to similar, and sometimes different, strains of the virus, Canadian researchers are calling for more attention to exceptions to that rule.

Don't hold your nose and close your mouth when you sneeze, doctors warn

January 15, 2018
Pinching your nose while clamping your mouth shut to contain a forceful sneeze isn't a good idea, warn doctors in the journal BMJ Case Reports.

New antifungal provides hope in fight against superbugs

January 12, 2018
Microscopic yeast have been wreaking havoc in hospitals around the world—creeping into catheters, ventilator tubes, and IV lines—and causing deadly invasive infection. One culprit species, Candida auris, is resistant ...

Dengue takes low and slow approach to replication

January 11, 2018
A new study reveals how dengue virus manages to reproduce itself in an infected person without triggering the body's normal defenses. Duke researchers report that dengue pulls off this hoax by co-opting a specialized structure ...

Different strains of same bacteria trigger widely varying immune responses

January 11, 2018
Genetic differences between different strains of the same pathogenic bacterial species appear to result in widely varying immune system responses, according to new research published in PLOS Pathogens.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

E_L_Earnhardt
not rated yet Dec 29, 2008
Right on track! X-ray increases tumor growth! Can you REDUCE cell temperature by ultra-sound? If so, you have a CURE!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.