Much of medical technology has now become digital. Medical devices integrate through special languages and formats that are understood by a wide variety of machines allowing data to be transmitted and used by multiple medical departments or practices.
Before the digital era began, medical personnel would take a measurement on a medical device and display or print out the results. For example, x-ray machines provided a method for scanning a patient and producing the resulting image on film. The film would then have to find its way, usually by human hands, to a reviewing radiologist in order to be interpreted. With the evolution of technology, devices are becoming less dependent on humans and more on electronic transmission. That is to say, the results from medical imaging devices are stored electronically and require less dependability of human input to accomplish a task. In the case of the x-ray, digital images of x-rays are transmitted across computer networks, stored remotely, and displayed for medical personnel.
At the heart of the digital world is the computer network. Digital equipment within an office or small geographic area is connected with a local area network, or LAN. For organizations that are spread out geographically, a wide area network, or WAN, may be used to connect LANs. Computers, medical devices, and information systems communicate via the network.
There are a wide variety of devices used for diagnostic purposes. They take measurements and/or images and transmit them, via computer network, to medical information systems. Most people are familiar with the common types of medical devices, such as CT, MRI, digital x-ray machines (x-ray machines which no longer use film) and other imaging devices.
Other types of information systems act as repositories for medical data. Some of the common types of systems include: HIS (Hospital Information System), RIS (Radiology information System), reporting systems, and PACS (Picture Archiving and Communications System). HIS and RIS provide a wide variety of capabilities that encompass both administrative and clinical functions, including scheduling, billing, and storage and viewing of results. RIS tend to be geared more towards radiology departments. PACS are typically used for storage of large numbers of images and support almost instant recall of any image for viewing.
So how do the medical devices and information systems integrate? The computer network provides the physical connection through which systems communicate. Beyond that there are two standards that allow devices to interact via a common language – HL7 and DICOM. HL7 is generally used to transmit textual information, such as patient data, exam data, and results. DICOM was devised largely for radiology and includes the ability to transmit images.
Let’s take a look at how the process works and how the various systems and technologies fit together. A typical situation is one where a primary care physician orders a test for a patient. The patient is referred to a specialist – say a radiologist – for an x-ray. The radiologist will then read the image and provide results in the form of a report.
The steps in the process might go like this:
1) An appointment is made with the medical specialist, typically by the patient or primary care physician’s staff.
2) If the primary care physician’s staff makes the appointment, they might create an “order” in the HIS/RIS for the appointment.
3) On the scheduled appointment date, the patient arrives. A technologist performs the x-ray and transmits the images to the PACS via DICOM. Newly received images will remain in a queue within the PACS. This queue is often referred to as a worklist.
4) The radiologist logs into the PACS. It is common for radiologists to utilize multiple computers and monitors when reviewing images. A special monitor connected to the PACS offers high fidelity images, allowing the radiologist to see details in the image. A second monitor typically runs standalone reporting software, such as a dictation package. The radiologist, while looking at the image on one monitor, will dictate results into the other.
5) When the review of images and patient data is complete, the radiologist saves the interpretation on the computer with the reporting software. To get the results to the primary care physicians, the radiologist transmits the report to the HIS/RIS where the primary care physician has access to the report.
6) The primary care physician logs in to the HIS/RIS and view the results. Note that primary care typically does not have access to the tools of the specialist. PACS and the reporting software are tools used by the specialists to create reports.
This scenario represents one way in which medical systems may be integrated. This is a common case and most other situations are variations of this.