What is CD-Recordable?
CD-R stands for compact disc recordable. It
is at technology through which a blank compact disc, a CD-R, is converted into an audio CD
or a conventional CD-ROM which can be read in the CD drive of your computer.
CD-R is governed by the Orange Book standard. This means that all CD-Rs, regardless of the
manufacturer, must conform to a specific set of standards.
The DICOM standard
The DICOM (Digital Imaging and
Communications in medicine) Standard is a set of rules that allow medical images and
associated information to be exchanged between imaging equipment, computers, and
hospitals. The standard establishes a commonlanguage that permits medical images and
information produced on one vendor's machine to be available for use on the digital system
of another vendor. The DICOM Standard evolvedthrough meetings between medical imaging
companies (represented through the National Electrical Manufacturers Association, NEMA)
and representatives from major medical societies including the American College of
Cardiology, American College of Echocardiography, European Society of Cardiology, and
American Society oif Nuclear Cardiology.
CD-R and the DICOM standard
Since 1992, cardiologists have been
researching a replacement for cine film which would store information in digital format
and offer worldwide compatiblity for archival and exchange media for digital x-ray
angiographic, echocardiography, and nuclear cardiac images.
How is data recorder to a CD-R?
The blank CD-R is placed in a CD writer or
recorder which uses a laser to write to the disc. The laser creates a series of holes in
the disc's dye layer called "pits". The spaces between the pits are called
"lands". The pattern of pits and lands on the disc encodes the information and
allows it ti be retrieved on an audio or computer based CD player.
How long does it take to write to a
CD-R?
It depends upon how much information you
are writing. To completely fill a 74min/650mb disc using a 1X writer takes 74 minutes. If
you use a 2X writer, the same job would take about 37 minutes. A 4X writer would do the
job in about 19 minutes.
Why switch from cine film to CD-R
archiving?
In the current hospital environment, there
must be compelling economic and clinical motivations for investing in new technology.
Electronic archiving in general, and CD-R archiving specifically, offer compelling
advantages:
Economic Advantages
- Reduced procedure costs
- Increased throughput of cath lab
- Increased productivityu of facility
- Accelerated reimbursement through physician and technician time savings
- Potential for consolidation of computing resources
- Reduces staffing requirements of cath lab
- Reduces storage space requirements
- Eliminates use of expensive and toxic chemicals
Clinical Advantages
- Superior image quality through electronic enhascement
- Saves phycician time for rapid diagnosis & treatment
- Increased access to patient study - Archive and exchange media are the same
- Allows for easy duplication, hardcopy, and trasmittal
- Significantly reduces noise during procedure by eliminating cine film camera
- Significantly reduces noise during review by eliminating cine film projector
How are CD-R discs different from
CD-ROM discs
CD-R discs are quite different from
conventional CD-ROM discs. CD-ROM discs are mass produced using specialized equipment and
are projected to last for about 20 years. CD-R discs can be written at your desktop using
an inexpensive CD recorder and, in the case of Mitsui Gold media, are projected to last
for well over 100 years. The layering structure of a CD-ROM is shown below: 
The polycarbonate serves as
the base of the disc and is physically stamped with the appropiate pits and lands to
convery the required information. A layer of aluminium is added for reflectivity.
The lacquer coating is applied as a protectant. In comparison, CD-R discs are more
sophisticated and robustly constructed. The information on a Mitsui Gold disd is projected
to last for well over 100 years. The layering structure of a Mittsui Gold CD-R is
diagrammed below:
As in a conventional
CD-ROM, polycarbonate is used as the fundation. However, CD-R uses a special dye which is
etched by laser to create the pits and lands. This dye will be covered in the next
section. A layer of lacquer is then applied, followed by Mitsui's patented Data Shield
Surface which provides additional protection against environmental hazards and rough
handling.
Does it matter what
dye is used to make the CD-R?
The dye formulation used in a CD-R is
perhaps the most critical factor in the disc's performance. Mitsui Gold discs utilize a
patented Phthalocyanine dye (thal-o-sy-a-nene) which offers substantial performance
advantages. You can recognize a Mitsui disc by turning it over and looking at the color of
the writable surface. A Phthalocyannine disc is gold colored with a slight greenish tint.
Other manufacturer's discs come in a variety of shades ranging from blue-green. Both
varieties of discs will be gold colored on the top, or non-writable surface.
Mitsui Gold Phthalocyanine-based discs offer substantial performance advantages over other
discs in two key areas; longevity and compatibility with high speed CD recorders.
Longevity on the order of 100 or more years is derived from the inherent stability of
Phthalocyanine dye. Phthalocyanine-based discs can withstand environmental conditions that
could render other discs useless. This is because Phthalocyanine resists ambient heat,
light, and humidity better than other dye formulations even after the disc has been
written to.
Phthalocyaine is aslo more compatible with high speed writers. Mitsui was the first
manufacturer to be certified by Yamaha to work with their 4X writers and is also certified
for use with the Kodak 6X system. This accuracy is due to the precision with which laser
light is able to create pits in the Phthalocyanine dye.
Advantages of the Mitsui Gold
CD-R
1. Because Mitsui makes all of its own
discs, and in fact makes most of the component materials which go into its discs, Mitsui
Gold media benefits from a consistency and process control which no other manufacturer can
equal. Since we don't rely on third-parties to provide our technology, production
facilities, or raw materials, Mitsui Gold customers know that each component and each step
in the manufacturing process has been subjected to the most rigorous quality controls in
the industry.
2. Every Mitsui Gold disc is warranted for life. No other CD-R media manufacturer offers a
warranty of this strength.
3. Every Mitsui Gold disc is certified for use with all high speed recorders whether they
be 4X or 6X. There are two reasons for this; First, Mitsui's stamping process results in
discs that are flatter than the competition's. While all discs are slightly warped, if
they are warped beyond a certain tolerance they cannot be used for high speed recording.
The second reason for Mitsui Gold's superb performance in high speed recorders stems from
the unique characteristics of the Phthalocyanine dye. Phthalocyanine simply works better
in high speed writers than other dyes.
4. Mitsui Gold discs last longer than competing media. The information recorded on a
Mitsui Gold disc will last for well over 100 years with some accelerated aging tests show
longevity of over 200 years.
Image Compression and the DICOM
standard
Several compression schemes are defined in
DICOM. JPEG (Joint Photographic Experts Group) lossless compression, which allows perfect
reconstruction of the original image is mandated by the standard for cardiac angiography.
JPEG lossy compression, which is not fully reversible, is an option only for
echocardiography interchange; echocardiography also allows lossless compressed data. The
use of lossy compression with angiography will be evaluated by the x-ray angiographic
working group. Nuclear files are generally much smaller than angiographic or
echocardiographic files, are stored without compression. The FDA has announced that it
will leave it up to the market to determine the appropriate compression standards.
Equipment using lossless or lossy can now receive the 510k certification.
CD-R as an archival and exchange media
CD-R discs are able to serve as a long term
data repository as well as a convenient means of exchanging data due to their longevity
and universality
Archival
role:
Once recorded, data on a CD-R cannot be altered or erased. CD-R will permit
additional recording upon a partially recorded disc but no existing data may be changed or
deleted. Furthermore, studies indicate that discs manufactured with Mitsui's patented
Phthalocyanine dye will last more than 100 years. Discs using conventional Cyanine dyes
will last for approximately 20 years.
Exchange
role:
Once a CD-R disc has been written to, it is essentially no different than any
CD-ROM disc. This means that the data can be accessed with equipment widely available at
modest cost. CD-R is also quite small, light weight, and easily transportable without
undue concern for fragility. |
Mitsui Medical