Stroboscope Visual Inspection of Medical Devices

Digital stroboscopes greatly facilitate visual inspections of cardiovascular medical devices as they undergo accelerated fatigue. The strobe light is a very useful tool in detecting device failures and tracking motion during testing.

加速疲劳是许多心血管医疗器械（如支架、心脏瓣膜和刺激器导线）的常用测试方法。心血管设备加速疲劳试验的行业标准包括ASTM F2477、ISO 5840-3和ISO 25539-1。在加速疲劳试验期间，样品通常运行4亿或6亿个周期，以模拟10或15个设备生命周期年。

Visual inspections during testing

作为试验方案的一部分，在不同阶段（包括试验前、试验中和试验后）进行常规检查。测试期间进行的检查分为两类：测试仪上的检查和测试仪下的检查。非测试人员的检查包括暂停测试、取出样品并在显微镜下检查，然后再将其返回测试人员。测试仪上的检查可以在测试运行时执行，也可以在设备保持在测试系统上时暂停测试后执行。

If the test is paused, visual inspections can be made with the aid of a backlight, handheld microscope or an endoscope. However, it is sometimes difficult to detect failures and small fractures when the device is stationary. Two popular inspection methods used while a test is running are stroboscope and high-speed video. In this article, we will highlight the benefits of using a stroboscope for high-frequency, on-tester inspections.

How the stroboscope works

A stroboscope, also called a strobe light, stroboscopic lamp or strobe tachometer, is a device used to produce regular flashes of light. The flashes of light can stop or adjust the appearance of motion during testing, which allows users to inspect devices moving at high frequencies visually. When the frequency of strobe light flash is adjusted to be in-phase with test frequency, the subject will appear still. The more out of phase the strobe light frequency is with the test frequency, the faster the motion will appear.

如果动作太慢或太快，则很难识别设备中的变化并检测故障。频闪灯的使用是最有效的，当频率调整，使外观的运动大致符合生理频率，通常在1和2赫兹之间。关闭室内灯光可以减少灯光干扰，并可以进一步提高能见度。FDA发表了一份reference documentguiding the use of stroboscopes for visual inspection.

Inspecting stents, heart valves and stimulator leads with strobe light

Our cardiovascular device testing lab commonly performs stroboscope visual inspections for the following tests and devices:

• S/N fatigue testing of stents and stent coupons
• Dynamic bend tests for stents and leads
• Largestent/graft testing
• Heart valve repair component testing

许多这样的测试在高频率下运行，通常在40到70赫兹的范围内，而频闪灯对于30赫兹以上的测试频率是最有用的。

A strobe light is a relatively inexpensive tool used during accelerated fatigue testing to detect the following:

• Failures
• 骨折
• Stent migration and loss of apposition
• Fretting marks
• Loose crimps
• Fixture and device motion

骨折create space in the device that can be more easily detected when the device is in motion; in fact, these fractures would take much longer to see when the system is stopped.

In addition to fractures and failures, strobe light inspections are often used for motion verification. Uniform device motion can be assessed and monitored over time to ensure that no undesirable motion is occurring. For example, during axial fatigue testing of a mitral valve tether, tether attachment to the commissure motion can be tracked and verified.

测试波形形状的变化或负载测量值的减少可能会触发闪光灯检查，以确定可能与设备、夹具或仪器有关的问题的来源。频闪灯检查需要非常少的准备，可以很容易地每天或每周进行。

The Element Advantage

Our Engaged Experts excel atcardiovascular device testingand have worked with many challenging device designs and test setups over the last several decades.Contact usto discuss how we can help with your test project.

Element has one of the most expansive medical device testing scopes in the world, ranging from orthopedics and cardiovascular implants testing to EMC/EMI/product safety testing, and biological and packaging evaluations. We strive to meet all your medical device testing needs in the most expedient, efficient and responsive way.