Picture Archiving and Communication System
Picture Archiving and Communication System, or PACS, is a medical technology that has revolutionized the imaging aspect of the healthcare system. It is an integrated, computerized system that can capture, store, retrieve and distribute the digital medical images across an enterprise or cloud-based network. It provides short-term as well as long-term image storage in the form of “archives” that can be cataloged as per requirements. The technology was adopted in the United States, for the first time, in the early 1990s, and it has since then spread across the developed world and parts of the developing world.
Technologically, PACS is based on the principle of using a universal image format that can be stored, transferred and accessed across various platforms. This universal image format used by PACS was a standard format developed by the American College of Radiology (ACR) and National Electrical Manufacturers Association (NEMA) and is known as DICOM (Digital Imaging and Communication in Medicine). This enables the integration of medical imaging devices – like scanners, servers, workstations, printers, network hardware, and PACS. Apart from images, other reports and documents can also be archived and shared in formats like PDF (Portable Document Format) on the PACS, once they have been encapsulated in DICOM.
Structure And Components
Like all other IT systems, PACS is a combination of software and hardware, with the addition of imaging modalities and archiving system. There are four key parts or components of a PACS:
- Imaging modalities that include:
- Digital radiography including mammography.
- Computed Tomography (CT).
- Magnetic Resonance Imaging (MRI).
- Positron Emission Tomography (PET).
- Nuclear Medicine Imaging.
- Angiography and venography.
- A secure network for distribution of images.
- Workstations for interpretation and processing.
- Archives for image storage and retrieval.
Architecturally, a PACS contains a multitude of devices that are handled by various professional personnel. The major parts of the system include:
- A viewing station for radiologist or other physicians.
- A QA workstation for the technologist.
- A climate-controlled computer room for the PACS administrator.
- An optional Reporting software to assist the radiologists.
- Software for Image backup.
Uses of PACS
In western medicine, PACS has replaced the conventional film-based imaging, providing an advantage in terms of time, cost as well as space. It has proved useful in more than just that one way.
- It provides remote access, that is, off-site viewing and reporting of the images. Physicians and radiologists in a different location can have simultaneous access to the same information
- It has proved useful in the efficient management of the workflow of the patient by compiling the patient’s data and diagnoses by the physician/radiologist in one place.
- It provides a suitable platform for electronic integration of the image with Hospital Information System (HIS), Radiology Information System (RIS) and Electronic Medical Records (EMR) system so that all of the patient’s medical data is integrated.
In the market today are available a number of PACS along with the PACS Viewer ranging from the ones that meet the most basic needs of a small healthcare provider to the ones encompassing the complex needs of large hospital enterprises. All these systems have certain basic features and attributes while some also include advanced features. Let us enumerate some of these-
- Basic features–
- Storage Size- It is a key aspect of all PACS depending upon three factors- the study volume, image modality type and the duration for which the studies need to be kept accessible.
- DICOM Compatibility- Every PACS today is DICOM compatible, though it is advisable to confirm that the system is able to get the images from all modalities.
- DICOM Send- All PACS have this feature to share or “push” the studies to other DICOM destinations like workstations, CD Burners, backup, etc.
- DICOM Print- It allows the printing of the DICOM images on Digital DICOM film printers.
- CD Burning- Most preferred way of distributing studies is through CDs and, hence, almost all systems feature this.
- Query and Retrieve- All PACS Viewers and other PACS and modalities are equipped with this feature to query and get specific files from PACS to the destinations over the network.
- Patient, Study and Image Data Modification- This feature enables the user to edit patient information in case of errors, although its access should be provided to trusted users only.
- Web access- This aspect is becoming available in newer versions of PACS for easing the administration and maintenance of the images and software over other PACS.
- Advanced features-
- Web viewing- Advanced PACS are equipped with the web viewing feature to allow the images to be accessed over the web, though they are often encrypted to prevent misuse of the data over the interwebs.
- DICOM Auto-Routing- This feature allows the system to sort and forward particular preset information to specific Pacs destination.
- EMR or RIS integration
- Dictation, Transcription and Voice Recognition
- Study Lifecycle Management
To support the above-mentioned features, a PACS requires a set of configurations. As Cohen et al. mentioned in their study Planning for PACS, published in the American College of Radiology Journal (2005, April), “A complete picture archiving and communication system (PACS) installation is one of the largest projects a radiology department will undertake.” The basic requirements for any PACS software can be summarized as follows-
- Operating System, that the software is compatible with, as mentioned by the manufacturer
- Internet Browser, especially if using the Web View features
- Processor, usually more than 2.0 GHz for the smooth functioning of the system
- Memory (RAM) of at least 2 GB, and recommended 4 GB
- Media drive, i.e., CD/DVD drive for burning
- Graphics card of minimum 128 MB and recommended 256 MB
- Network Port that provides a good speed for distribution
- Secure Network, mostly Wide Area Network for access across the desired premises
Benefits of PACS
PACS has replaced the conventional film-based images with digital images. The advent of technology such as this is always a step towards advancement in the field of medical radiology. There are obvious advantages that it offers over the conventional imaging system. Some of them are enlisted as follows-
- The foremost advantage that PACS has, is the increase in the efficiency of the whole system owing to electronic data handling. That allows the hospital to save on films storage space, film processing equipment, supplies, and personnel.
- PACS installation ensures that no image can ever be lost, stolen or misfiled, which is more common with conventional films. This, in turn, makes sure that all patient appointments are kept, and that there is no unnecessary delay in the diagnosis and treatment.
- Digitalization of the images on PACS has removed the constraints associated with the physical film, meaning the images can be accessed on numerous PACS terminals across the hospital for simultaneous, multi-location viewing of the same image. For instance, an ER doctor can consult a radiologist as well as a surgeon regarding an accident patient needing surgery.
- Along with images, PACS also stores other patient data and arranges them in a correct examination and chronological order, so that all the patient information can be retrieved at any time, using a number of criteria like name, hospital ID, date, etc. The synchronization of all modalities at one place allows for intermodality comparison of the data which is beneficial for both the physician and the patient, in terms of time and effort.
- An array of computer tools can be used to manipulate and process the image, for example, altering the contrast width and level to allow soft tissue and bony tissue to be better appreciated on a single exposure. This could be made possible because of the soft copies captured using PACS
- It has been studied that the photostimulable phosphor plates used for digital radiography require a lower dose of radiation exposure to obtain a good image.
- The interfacing between various systems gives a more reliable and consistent dataset, as well as improve the workflow patterns. For instance, once a study is reported by the radiologist, it can be marked “read” and thus avoid unnecessary double-reading.
In conclusion, the advantages of PACS can be summarized as a technology having real, tangible financial savings along with time and qualitative value of money.
Like all the technologies out there, PACS comes with its set of downside and certain insufficiencies. Though there are definite pros of the technology, certain disadvantages can be noted as follows-
- As mentioned earlier, PACS installation is one of the largest system installations, therefore, it is one of the most expensive one, and also one of the most complex ones for any vendor to take up.
- The DICOM standards used on various PACS are not usually interoperable and, therefore, cannot be distributed or shared by more than one enterprise without the correct software is available. In case of outside hospital referral, the sharing of image data becomes tedious.
- Once a PACS is installed, it has to be guarded against a complete system failure because a hospital will not be able to function with an imaging service. After the hospital goes “filmless”, it usually does not have a fall-back option because the medium for capture, store, and retrieval of images is no longer present.
- One of the many problems of PACS is that the medical personnel and staff may not have adequate computer knowledge and skills to endorse the system, and that might require special training sessions. Also, there needs to be constant monitoring of the system performance by a technologist to detect any glitches or errors that might come up.
- The utility of a system like PACS is limited to the image-sensitive practices of medical science like radiology, cardiology, ophthalmology. There is a lack of penetration of the PACS technology throughout the medical enterprise that is considered cost-ineffective.
It can be noted that the lack of harmonization, declining penetration, high installing and operating cost of the system are the main restraints preventing the growth of the global market for PACS.
In conclusion, It can be asserted that the Picture Archiving and Communication System is a medical technology that has brought about a turnaround in the medical imaging fields, especially radiology. And this technology is still moving forward to imbibe the plus points of the upcoming information technology as well as the use of the conventional interwebs.
The DICOM technology is evolving with the time to include better and more compatible standards for PACS. Web Access to DICOM Objects, or WADO, is a creation of new and necessary standards to put up images on the web through truly portable medium. WADO can be the answer to the problem of lack of interoperability of PACS. They can increase the distribution of images and reports across different platforms to the referring physician and patients, using the web.
There has been the advent of a new medical technology called Vendor Neutral Archive (VMA), that stores images and other documents in a standard format on a standard interface. These can be accessed in a vendor-neutral manner by other systems. This means that various enterprise can share their data in a standard format.
Certain healthcare institutes have started using Cloud-based PACS to archive and back up their medical imaging data in an offsite server, not within the premise. Users who have permission to access these images can do so at any time using loud PACS.
In conclusion, PACS as technology is paving the path towards “filmless” hospitals. If an institute decides to invest in the technology, PACS can recover the cost of installment within five years. And the pros have been found to outweigh the cons of the technology. It has promising aspects of making the medical imaging more efficient and streamlined, cost-effective, time effective and space effective. However, the implementation of a successful PACS is a huge undertaking and there are a lot of unanticipated situations surrounding it. But if done the right way, PACS can make a huge difference to the medical image Storage, Retrieval and Distribution.
- Choplin R (1992). “Picture archiving and communication systems: an overview”. Radiographics. 12: 127–129. doi:1148/radiographics.12.1.1734458
- Oosterwijk, Herman. PACS Fundamentals. Aubrey: OTech Inc, 2004. ISBN 978-0-9718867-3-5
- Strickland N. PACS (picture archiving and communication systems): filmless radiology. Archives of Disease in Childhood. 2000;83(1):82-86. doi:10.1136/adc.83.1.82.
- Hutchinson, C. (2013, March 13), PACS Systems: Features and Regulations. Retrieved from: http://blog.dicomsolutions.com/2013/03/pacs-systems-features-and-regulations/
- Cohen, M., Rumreich, L., Garriot, K. & Jennings, G. (2005), Planning for PACS, Journal of American College of Radiology, 2, 327-337.
- Rouse, M., (2005, June), PACS (picture archiving and communication system). Retrieved from: http://searchhealthit.techtarget.com/definition/picture-archiving-and-communication-system-PACS
- Images retrieved from:http://wiki.ihe.net/images/5/56/ARI-v4.jpg, http://cdn.patchcdn.com/users/863023/2012/05/T800x600/df5e2f7af7c2b004ce7fa0ab16138498.jpg