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Miniature Motors for biopsy systems, radiation treatment and cancer management

February 15, 2016

Miniature Motors for Biopsy Systems and Radiation Treatment

Precision electric motors are spinning the way to improved developments in cancer management.

“Oncology” is the field of study and treatment of tumors. By advancing treatments in biopsy, imaging, and radiation, miniature electric motors are helping to improve the detection and treatment of cancer. As oncology techniques continue to become less invasive, more accurate and effective, the use of miniature electric motors by medical OEMs will remain a driving force in evolution of cancer management.


Thousands of women undergo breast biopsy procedures every year. In the past, a biopsy was an anesthesia based invasive procedure that often resulted in long recovery times, visible incisions, and scarring. However, recent improvements in ways that breast biopsies are performed have helped advance the efficiency of the procedure and minimize discomfort and stress to the patient.

By using a powered device, a physician is able to collect and analyze multiple tissue samples from a single, small, and typically suture less incision at biopsy site. New powered biopsy procedures have shown to minimize biopsy incision size by up to 85% and shorten overall procedure time up to 75% compared to the more traditional scalpel method. By minimizing the incision site, physicians are also able to minimize scarring, eliminate sutures, and effectively reduce physical recovery time. Using a fully powered device also allows physicians to sort and organize multiple samples from single biopsy site more efficiently by using remote positioned pre-labeled sample compartments. By capturing and organizing samples more effectively, physicians can improve the accuracy and reliability of sample analysis.


A Biopsy Handheld Device



Slotted brushless DC gear motors are used to achieve performance requirements needed by powered biopsy devices. This motor provides extremely high torque in a small package which enables design engineers to minimize the package size and make the handheld device as small and light as possible. Additionally, these motors for biopsy systems also offer exceptional efficiency which further shrinks the end device size by allowing design engineers to use smaller batteries.

Miniature electric motors have also helped to make imaging more precise and accurate during biopsy and radiation procedures. During radiology procedures, injectors are used to add contrast agents into a patient’s vascular system to improve the readability of scanner images. Improved readability helps radiologists minimize the total amount of radiation delivered to the patient.

As an example, radiologists use control agents to help provide computer aided images to guide biopsy procedures. Depending on a patient’s target body area, age, weight and chemical absorption rate, radiologists fine-tune contrast agent injection patterns and scanner parameters to achieve the best image possible while simultaneously minimizing the amount of radiation received by a patient. As an example, a young patient with good absorption capacity will receive a strong injection concentration in order to allow a minimum radiation dose during scanner exposure. In order to customize each patient’s agent injection, the injector module must be able to accommodate different injection flow rates and processes. The fact that contrast agents are typically very viscous, even when preheated to the body temperature, makes the choice of an injector drive very narrow

Frequently, ironless brush DC motors are a good choice for an injector drive because they achieve higher power density than iron core motors. This helps to inject the viscous contrast agent into the body properly. Higher power density also helps reduce motor size to allow for a more compact design envelope. Ironless brush DC motors for radiation treatment are typically more efficient and responsive compared to iron core motors. Improved efficiency helps such motors optimize battery operation and life to help improve the performance of mobile injection devices. These motors also usually have lower rotor inertia and no detent torque which helps improve the control of agent delivery.

Some applications feature enough available room to use stepping motors. The technical advantage of a stepping motor is that it provides precise positioning and can be driven in open loop to achieve torque at low speeds (1000rpm and below). In comparison, a brush DC solution will need an encoder attachment and a gearbox to provide precision positioning and low speed torque for the same application. Another advantage is that a stepping motor solution is typically less expensive than a brush DC solution.



Portescap offers one of the largest selections of motor technology among all miniature motor design and manufacturing companies in the market. Matching some of the applications previously mentioned are the following motor options:


Ironless Brush DC motors: With both precious metal and graphite commutations, Portescap’s ironless motors typically offer up to 3 times more torque than similar sized conventional iron core motors. This is possible because there is no iron armature in Portescap’s brush DC options, so the rotor generates no iron losses while rotating. Additionally, having no armature opens up room inside the motor to be utilized by the permanent magnet in order to reduce the overall motor diameter and increase motor torque density. 

Brushless motors: Portescap’s brushless motors can be optimized for motor operating speeds up to and in excess of 80,000 rpms and long life applications. Slotted designs are typically used in high torque applications to power both autoclavable and non-autoclavable surgical hand tools. Slotless motors are frequently used in high speed lower torque applications where long life, high performance and efficiency are vital. Portescap also offers a full range of customizable gearbox options for both brush and brushless technologies.

Stepper motors: Portescap offers can stack, hybrid and disc magnet stepping motors that are often used for precise positioning applications. Can stacks are used for their simple construction and wide application. Hybrid motors are often used for higher torque density applications, and disc magnet motors are used for advanced positioning and response. Typical applications for stepping motors vary widely. Some frequent applications are fluid handling, diagnostics and infusion systems. Portescap’s global manufacturing sites are supported by local regional sales and application engineering groups that are in direct contact with end device OEMs.