 |
Description  |
|
|
TECHNICAL FIELD
This invention relates to the imposition of coordinate marks on
fluoroscopic or film images produced during patient scanning procedures.
More particularly, this invention relates to a marker device adapted for
placement over the part of a patient's body to be examined by
non-intrusive wave-imaging, which produces visual indexing marks on the
body parts of clinical interest. Specifically, this invention relates to a
tape comprising a flexible substrate coated with a pressure sensitive
adhesive on one side thereof which contains indexing marks, advantageously
substantially opaque to the scanning waves employed in the scanning
procedure, which marks produce visible reference points superimposed on
the image of the patient's body produced by the procedure.
BACKGROUND OF THE INVENTION
In recent years, advances in wave technology and detecting devices
associated therewith have allowed physicians to examine organs and other
internal body features of patients without resort to invasive procedures
which unavoidably involve the risk of infection and trauma attendant to
all surgery, even that of the simple diagnostic variety. By use of such
technology, including magnetic resonance, positron emission, ultra-sound,
and similar techniques, in conjunction with wave detectors and data
processing equipment, cross sections of the entire body are now readily
obtainable. The advantages of the new diagnostic tools are so pronounced
that most of the larger hospitals and similar facilities now have this
equipment available for their staffs. Computerized axial tomography, for
example, commonly known as CAT scan, once relatively exotic has now become
common place, and such equipment is available for use throughout the
country. Among the advantages of total body scanning may be mentioned the
fact that the injection of radioisotopes is not required to produce a
record of findings; it being possible to obtain images of tissue density
across a complete cross section of the body being scanned without resort
to such materials. The technique is particularly useful in visualizing the
retroperitoneal space, for example, the pancreas, liver, spleen, and
ovaries, as well as the abdominal section of the aeorta.
While such equipment has allowed physicians to view internal portions of
the body previously inaccessible in the absence of surgery, one of the
disadvantages of the equipment is the tendancy to over-expose patients to
excessive amounts of wave energy during the scanning procedure. For
example, in employing in such techniques, it is frequently necessary to
provide a reference point relative to which internal features of the
patient may be located, fluroscopically or on film, for subsequent biopsy,
or for other purposes. Commonly such a reference point is established by
placing a small piece of metal as a marker on the area of interest prior
to exposing the patient to, for example, X-ray radiation. Quite often,
however, after such placement and subsequent X-ray exposure, it is
necessary to reposition the marker to make it more useful as a reference
point. Such repositioning necessitates additional X-ray exposure, with
still further adjustment and more X-ray exposures sometimes being found
necessary. While small amounts of exposure to radiation are normally
justified on a risk/benefit basis, X-ray exposures are cumulative and
capable of producing adverse cellular changes, including malignancies, in
tissue with which it comes in contact. Consequently, it is highly
desirable to reduce exposure to such waves to the absolute minimum
necessary to achieve the result desired.
DISCLOSURE OF THE INVENTION
In view of the preceding, therefore, it is a first aspect of this invention
to provide a reference marker for use in the medical imaging procedures.
A second aspect of this invention is to provide an indexing reference
useful in patient imaging diagnostic procedures which results in reduction
of patient exposure time to the imaging scanning waves.
Another aspect of this invention is to provide an indexing tape which is
attachable to a patient, and which superimposes reference marks on the
internal image of the patient obtained during the scanning procedure.
A further aspect of this invention is to provide an imaging reference
marking device that cannot be accidentally shifted or dislodged from the
patient's skin over the area being scanned. An additional aspect of this
invention is the provision of an imaging marker device which permits
simultaneous indexing over a substantial portion of a patient's internal
features.
Another aspect of this invention is to furnish an inexpensive, medical
imaging reference marker that is easy to use and which is disposable.
The foregoing and still additional aspects of the invention are provided by
a marker device for indexing internal features of medical patients during
image-scanning procedures comprising a flexible tape adapted for
attachment to the skin of a patient, said tape including a rectangular
substrate with a plurality of index markings thereon, said markings and
said substrate having detectably different affects on scanning waves
striking the tape during the image-scanning of a patient.
The foregoing and other aspects of the invention are provided by a marker
device for indexing internal features of medical patients during
image-scanning procedures comprising a flexible plastic tape adapted for
attachment to patients by means of a pressure sensitive adhesive disposed
thereon, which includes a rectangular substrate with a plurality of index
marking lines equidistant from each other and positioned at right angles
to the longitudinal axis of said substrate, wherein said substrate is
substantially permeable to scanning waves striking said tape, while said
marking lines are substantially impermeable thereto.
BRIEF DESCRIPTION OF DRAWINGS
The invention will be better understood when reference had to the following
drawings of the invention, in which like numbers refer to like parts and
in which:
FIG. 1 is a plan view of the marker device of the invention.
FIG. 1A is an end view of the marker device of FIG. 1.
FIG. 2 shows a patient lying on a stretcher wearing a marker device of the
invention over an area of the body of clinical interest, preparatory to
being scanned.
FIG. 3 is a representation of a patient about to be inserted into an
image-generating scanning device.
FIG. 4 illustrates a transverse cross section of a patient's body to which
a marker device of the invention has been attached.
DESCRIPTION OF THE PREFERRED MODE OF THE INVENTION
FIG. 1 is a plan view of the marker device of the invention, generally 10.
The device comprises a substrate 12 containing thereon scanning wave
blocking strips 14. The substrate may also be provided with biopsy access
holes 16, located between the blocking strips, the spacing between strips
depending upon the amount of imaging detail anticipated, as well as the
accuracy required in locating such detail. In most instance, however, the
blocking strips will be positioned from about 11/2 centimeters to 21/2
centimeters apart, a distance of about 2 centimeters apart being
satisfactory in most cases.
The purpose of the tape 10 is to provide detectably different affects on
the scanning waves striking the tape during the scanning of a patient so
that the tape markings are distinguishable on the scanning image produced,
enabling the internal features of the patient's body over which the tape
is placed to be located relative to the image of the markings superimposed
thereover. This is best achieved by selecting substrates which are
relatively permeable to the scanning waves, and marker strips which are
relatively impermeable thereto, advantageously strips which substantially
block the waves.
Accordingly, the substrate will be selected from any permeable material,
particularly from those permeable to X-rays such as fabric, plastic, and
the like, reinforced fiber glass epoxy materials being especially
preferred since besides being permeable to X-rays, tapes made from such
materials are both strong and sufficiently flexible to be contoured over
the surface of the patient's skin. Other plastics could also be used,
however, such as PVC, polyethylene, polypropylene, polyesters, and others.
Substantial wave opacity, on the other hand, is desired for fabricating the
scanning wave blocking strips 14. Consequently, it is preferred that such
strips be made from thin metal, plastic, inks containing metal, or similar
materials. It has been found, however, that the use of copper strips
results in a sharply defined image, and the use of copper is, therefore,
preferred for use with the invention. Where the strips consist of metal,
they can be fastened on one or both sides of the substrate, for example,
with a suitable adhesive. In one process, sheets of thin copper are
adhesively fastened to both sides of a fiber glass reinforced epoxy film,
following which the portion of the sheets destined to form the blocking
strips are covered with a protective ink or film. The sheets are than
exposed to ammonia, and thereafter immersed in a treatment solution which
dissolves the ammonia exposed portions, leaving only the protected marker
strips behind fastened to the substrate. The sheet is than slit to form
tapes of the desired size in ways well known to the art.
The dimensions of the tape may be varied within wide limits; however,
typically, tapes of from about 8 to 14 inches long are convenient to use,
particularly when the width of the tape is from about 3/4 inch to 11/2
inches wide. The thickness of the substrate will depend upon the strength
of the material from which it is fabricated, as well as its permeability.
In the case of a fiber glass reinforced epoxy material, it has been found
that a substrate of from about 2 to 8 microns will result in tape of
adequate strength, flexible enough to follow the contours of the skin of
the patient on which it is placed, and will provide good X-ray
permeability characteristics.
The dimensions of the scanning wave blocking strips may also be varied
within fairly broad limits; however, in the case of copper, an over-all
thickness of from about 0.003 inch to 0.006 inch will provide sufficient
X-ray impermeability and sharp definition to allow precise indexing of the
patient. Such thickness may be provided with two strips, one positioned
over the other on either side of the substrate, or in a single strip on
one side of the substrate. The width of the strip will conveniently be
from about 1/16 inch to 1/8 inch.
FIG. 1A is an end view of the marker device 10 of FIG. 1 showing further
details of the substrate 12 on which a scanning wave blocking strip 14 is
located. The bottom of the tape laminate is coated with a pressure
sensitive adhesive film 18, protected by a backing strip 20 until used, at
which time the latter strip is peeled from the tape. A biopsy access hole
16 is provided, as shown.
While not required by the marker device, the provision of biopsy holes 16
between the blocking strips 14 allows biopsy needles to be precisely
inserted through the tape into the patient, and desired biopsy samples
removed, as required. While one round hole is shown in FIG. 1 between each
pair of adjacents strips, more holes can be provided if required, and
holes with other than round shapes may be used. Although larger or smaller
holes may be employed, the use of round holes having a diameter of about
1/8 inch will accommodate most biopsy needles.
FIG. 2 shows a patient 22 lying on a stretcher 24 wearing a marker device
10 of the invention over the area of the body of clinical interest,
preparatory to being scanned. The marker device 10 is fastened to the
patient's skin by means of a pressure sensitive adhesive coated over all,
or a portion of the skin-side of the device. The pressure sensitive
adhesive may be any of those known to the art including pressure sensitive
adhesives of the acrylate or elastomeric types. While the time of contact
with the patient's skin is relatively brief, it is desirable that the
adhesive be of a hypo-allergenic type so that irritation to the patient's
skin can be avoided.
FIG. 3 is a representation of a patient about to be inserted into an
image-generating scanning device. As illustrated, the patient 22, lying on
a stretcher 24 is about to be passed into a scanning device 26 in the
direction of the associated arrow. The patient has a marker device 10
attached to his body by means of the pressure sensitive adhesive, as
previously described in connection with FIG. 2. While the invention is of
particular usefulness in connection with computerized axial tomography, it
also has application to various other scanning techniques including
ultra-sound and similar techniques.
FIG. 4 illustrates a transverse cross section of a patient's body,
generally 28, to which a marker device of the invention has been attached.
The relative impermeability of the scanning wave blocking strips 14
produces discernable marks 30 on the scanning image obtained. The position
of the marks relative to the internal features, generally 32, allows the
position of such features to be ascertained simply by noting their
location with respect to a particular mark. With the location thus
ascertained, a biopsy needle can be inserted through an appropriate biopsy
hole 16, and a sample of the tissue of interest obtained. Commonly, as
shown in FIG. 1, the scanning wave blocking strips are located at equal
distances from each other. Other positioning may be choosen, however, and
markings other than lines may be employed such as dots or other shapes.
While in accordance with the patent statures the best mode and preferred
embodiment of the invention has been described, it is to be understood
that the invention is not limited thereto, but rather is to be measured by
the scope and spirit of the appended claims.
* * * * *
|
|
 |
|
 |
Description |
|
