Pulsed cavitation ultrasound (PCU) can be used to remotely soften human degenerative calcified biosprosthetic valves and may significantly improve the valve opening function, according to a study.
Olivier Villemain, MD, et al., examined the effects of PCU on human bioprosthetic heart valves that were removed from patients because they were heavily calcified and were non-functional. PCU, also called histotripsy, uses short-pulses of focused high pressure ultrasound to soften biological tissue. The ultrasound is delivered by a transducer that can be placed outside of the body and directed in a focused manner to the area of interest.
The removed valves were surgically implanted in sheep or were studied in an experimental bath apparatus in order to examine the longer-term effects of PCU. The researchers found that the PCU was able to soften the stiff calcified valves and improve the function of the valves. The amount of stenosis of the calcified aortic valves decreased by about two-fold on average in both the animal model and the experimental apparatus. The researchers believe that this new non-invasive approach has the potential to improve the outcome of patients with severe calcified bioprosthesis stenosis by avoiding risky surgical or transcatheter reintervention.
This study was designed as a proof of concept study and did not evaluate the potential risk of PCU causing pieces of the calcified aortic valve breaking off and causing an embolic stroke.
"The results of this experimental study must be regarded as provisional because neither the safety nor efficacy of this technique have been evaluated in humans," commented Douglas L. Mann, MD, FACC, editor-in-chief of JACC: Basic to Translational Science. "However, the concept of using high energy ultrasound to restore the function of calcified artificial tissue valves, analogous to the manner in which nephrologists use ultrasound to break up kidney stones, is both provocative and exciting. The ultrasound devices to perform this type of therapy exist today, so the ability to translate these concepts to patients can move very quickly."

American College of Cardiology www.acc.org/latest-in-cardiology/articles/2017/06/16/10/40/can-pulsed-cultivation-ultrasound-improve-valve-function?w_nav=LC

The 2017 edition of KIMES brought together a record number of exhibiting companies and visitors from Korea and 92 other countries. A total of 1292 exhibitors – a 12% increase over 2016 – from 41 countries presented over 30,000 products covering the full range of medical equipment, from radiology and medical imaging systems to emergency equipment, from surgical instruments to dental appliances, from medical information systems to disposables, as well as cosmetic and dermatology products. In addition, there was a growing medical device component section that numbered 198 manufacturing and service companies.

Korea’s vibrant medical industry sector was well represented with 579 exhibitors, followed by China (154), the United States (125), Germany (88) and Japan (62).

As last year, the show was held concurrently with Global Bio & Medical Plaza, hosted by KOTRA and acting as the principal global platform for facilitating cooperation and trading between Korean and foreign companies in the bio and medical industries. The event is designed to develop concrete business relationships and pursue potential contract opportunities between guests from abroad and Korean companies. This year it attracted 226 companies from 61 countries, including for the first time a strong delegation from the European Union Buyer’s Group.

Conference
A total of 180 sessions took place in the COEX Conference Centre during the show and covered a variety of topics, including the latest advances in medical device technology as well as government policies on the medical device market. The seminar programme was kicked off by keynote speaker Andrew Nordon of the World-first cancer detection programme.
www.kimes.kr

An advanced form of image-guided radiation therapy, known as intensity modulated proton therapy (IMPT), has shown early promise for the treatment of recurrent lung cancer, according to new research from The University of Texas MD Anderson Cancer Center. Researchers found that after re-irradiation with IMPT, the majority of patients were free from local recurrence one year following treatment and few experienced severe side effects.

The data, presented at the 2017 Multidisciplinary Thoracic Cancers Symposium, is the first to analyse re-irradiation of thoracic cancers with IMPT and offers hope for a patient population with few curative treatment options.

Lung cancer is the leading cause of cancer death in the U.S. According to the American Cancer Society, more than 222,500 people will be diagnosed and 155,870 will die from the disease in 2017, with recurrence the primary cause of death in these patients.

As many recurrent lung cancer patients are not candidates for surgery, and response rates to second-line chemotherapy are poor, there’s been growing interest in the repeat use of radiation, explained Jennifer Ho, M.D., resident, Radiation Oncology.

‘Historically, repeat radiation at a higher, curative dose was not possible with older, less precise radiation techniques because the cumulative radiation dose necessary to treat the cancer would cause too much toxicity,’ said Ho, the study’s lead author. ‘In lung cancer, tumours are close to the oesophagus, aorta and spinal cord, and all of these critical structures are vital for the body to function. The proton beam – and pencil beam in particular — provides much more conformal radiation, which means higher doses to tumours and lower dosages to critical structures nearby.’

IMPT, one of the most advanced forms of proton therapy, is based on scanning beam technology that can simultaneously optimize intensities and energies of all pencil beams to deliver a precise dose of protons to tumours, explained Joe Y. Chang, M.D., Ph.D., professor, Radiation Oncology.

‘The technology has the ability to destroy cancer cells while sparing surrounding healthy tissue from damage. Therefore, important quality of life outcomes can be preserved and severe toxicities have shown to be reduced,’ said Chang, the study’s corresponding author.

For the single-institution study, the researchers retrospectively analysed 27 patients who received IMPT for a lung cancer recurrence between 2011 and 2016. All patients had received a prior thoracic radiation course with curative intent. Of the cohort, 22 (81 percent) were treated for non-small cell lung cancer. The median time to re-irradiation after initial treatment was 29.5 months.

At a median follow-up for all patients of 11.2 months – and 25.9 months for those still alive – the median overall survival (OS) was 18 months, with one year OS at 54 percent. Four patients (15 percent) experienced a local failure (LF), recurrence within the re-irradiation field; 78 percent of patients did not experience a LF within the first two years of follow-up. At one year, 61 percent of patients were free from recurrence in the chest and lung, and progression-free survival was 51 percent.

Of particular interest to the researchers, patients who received a higher dose of radiation had fewer local recurrences and improved progression-free survival.

Re-irradiation was well-tolerated, with two patients experiencing grade three pulmonary toxicity and none with severe oesophageal toxicity. No patients experienced grade four or five toxicities. Historically, re-irradiation of the lung was associated with moderate to severe toxicity, even fatal, toxicities in 20 to 30 percent of patients.

‘With the advancement of IMPT, we knew that we were able to generate more precise radiation treatment plans that spared normal tissue, but we weren’t sure if this would translate into beneficial clinical outcomes until we analyzed this data,’ said Chang. ‘While the findings are early, we’re hopeful that we can offer more positive outcomes and low toxicity with IMPT for recurrent thoracic cancer patients who previously had few treatment options.’

Limitations of the study include its small size and retrospective data. Reirradiation with IMPT in other disease sites is an area of continued research interest; studies in head and neck cancer are ongoing at MD Anderson.

MD Anderson Cancer Institute www.mdanderson.org/newsroom/2017/03/advanced-form-of-proton-therapy-shows-promise-for-treating-lung-cancer.html

In an important step toward endoscopic diagnosis of cancer, researchers have developed a handheld fibre optic probe that can be used to perform multiple nonlinear imaging techniques without the need for tissue staining. The new multimodal imaging probe uses an ultrafast laser to create nonlinear optical effects in tissue that can reveal cancer and other diseases.

Today, cancer is typically diagnosed by removing a bit of tissue with a biopsy and then sending that tissue to a specially trained pathologist who stains the tissue and uses a microscope to look for cancerous cells. The ability for doctors to skip the biopsy and use a multimodal imaging endoscope to diagnose cancer on the spot would save valuable time and could also allow surgeons to more easily differentiate between cancerous and healthy tissue during surgery.

With the new probe, imaging techniques that previously required bulky table-top instruments can be performed with a handheld device measuring only 8 millimeters in diameter, about the same diameter as a ballpoint pen. If miniaturized further, the probe could easily be integrated into an endoscope for nonlinear multimodal imaging inside the body.

‘We hope that, one day, multimodal endoscopic imaging techniques could help doctors make quick decisions during surgery, without the need for taking biopsies, using staining treatments or performing complex histopathological procedures,’ said Jurgen Popp, from Leibniz Institute of Photonic Technology in Jena, Germany and the paper’s lead author.

It is the first miniaturized probe for multimodal biological imaging to incorporate a multicore imaging fibre, a type of optical fibre consisting of several thousand light-guiding elements. This special imaging fibre allowed the researchers to keep all moving parts and electric power outside of the probe head, making the probe easy and safe to use in the body.

The researchers have tested the probe with many types of tissue samples, but because it is currently designed for forward view mode, the primary applications of the probe would likely include skin, brain or head and neck surgery. They are working on implementing a side view mode that could be used to investigate hollow organs and arteries such as the colon, bladder or aorta.

‘The new probe serves as a miniaturized microscope that uses near-infrared lasers to investigate tissue,’ said Popp. ‘Different components of biological tissue react differently to the excitation lasers, and their unique response gives us information about the molecular composition and morphology within the tissue.’

The handheld multimodal imaging probe can simultaneously acquire several types of images: coherent anti-stokes Raman scattering, second harmonic generation and two-photon excited auto-fluorescence. These nonlinear imaging techniques have been shown to be useful for clinical diagnostics, including identifying cancerous cells, but it has been difficult to miniaturize the required instrumentation for use inside the body.

The probe’s reduced size comes from its use of gradient index, or GRIN, lenses to focus the laser light. Compared to traditional spherical lenses that use complicated shaped surfaces to focus light, GRIN lenses can be made very small because they focus light through continuous refractive index changes within the lens material. Popp’s research team collaborated with scientists from Grintech Gmbh who designed GRIN lenses only 1.8 millimetres in diameter and helped incorporate the robust lens assembly into a small aluminium housing.

The Optical Society
http://www.osa.org/en-us/about_osa/newsroom/news_releases/2017/new_fiber_optic_probe_brings_endoscopic_diagnosis/