DE102009017071A1 - Phantom standard for e.g. examining tissue samples, has transparent substrate designed in form of plate made from glass ceramics or glass, and layer comprising barium sulfate, where barium sulfate is mixed with binder to form paste - Google Patents

Abstract

The phantom standard has a transparent substrate designed in the form of a plate that is made from glass ceramics or glass e.g. soda-lime glass or borosilicate glass, and a layer comprising barium sulfate, where the barium sulfate is mixed with a binder to form a paste that is applied on the substrate. The layer is made from silicone, polymethyl methacrylate or polyurethane, where the layer has thickness of 5 to 100 micrometer, and hardened to temperature of 140 to 160 degree Celsius. An independent claim is also included for a method for manufacturing a phantom standard.

Description

The The invention relates to a phantom standard, in particular for Imaging methods on organic samples, in particular for biomedical applications.

In Recently, many imaging methods and Diagnostics in biophotonics in investigations of tissue samples (human or animal origin) for the purpose of cancer detection and used to study the effect of pharmaceuticals. there is specifically the difference in refractive power of the marked and unmarked Tissue parts exploited. For the purpose of reproducibility and quantification the results are on the part of the competent authorities prescribed to use reference materials or standards. by virtue of These specifications have been different in the last 10 to 15 years Approaches to develop such standards.

• – Langzeitstabilität über mindestens zwei Jahre;
• – Färbung ähnlich der von Gewebe;
• – Streuzentren mit ähnlicher Geometrie des Gewebes (Größe 200 bis 250 nm, sphärisch);
• – Brechwertunterschied zu Wasser (stellt etwa 90% des Gewebeanteils dar) bei Applikationswellenlängen zwischen 300 und 1500 nm);
• – ebene (planparallele) und großflächige (> 20 × 20 cm) Geometrie zum Einsatz für bildgebende Verfahren.

The standards must fulfill the following characteristics:

• - long term stability over at least two years;
• - staining similar to tissue;
• - Scattering centers with similar geometry of the tissue (size 200 to 250 nm, spherical);
• - difference in refractive power to water (represents about 90% of the tissue content) at application wavelengths between 300 and 1500 nm);
• Plane (plane parallel) and large area (> 20 × 20 cm) geometry for use in imaging procedures.

In the prior art, there are various approaches based on polymers. The dyeing was realized by organic dyes, the scattering particles over TiO ₂ powder.

A large-scale and homogeneous distribution of the scattering centers is not possible.

From the US 2003/0086535 A1 For example, there is known a phantom standard for calibration in imaging processes that includes a first layer of a tissue-like material with a marker embedded therein and a second layer of a tissue-like material. In this case, the marker may consist of glass and the tissue-like material containing at least one fat component, which may be paraffin oil in particular. Furthermore, the fabric-like material may consist of an agar gel.

With Such organic materials can be no homogeneous and realize long-term stable layers, which is a prerequisite for a phantom standard for such an application is.

From the US 5,587,657 For a magneto-resonance device, a phantom standard is known, with water containing fat and copper sulfate as a non-magnetic material.

One Such standard is not long-term stable and is subject to variations in homogeneity.

Of the Invention is therefore based on the object of a phantom standard, in particular for imaging of organic samples, to create as long-term stability and homogeneity as possible, has a tissue-like coloration and scattering centers having similar geometry of the tissue. Also should at an application wavelength between 300 and 1500 nm, a sufficient refractive index difference to give water.

After all is intended to provide a method of making such a phantom standard be specified.

This object is achieved by a phantom standard, in particular for imaging methods on organic samples, in particular for biomedical applications, with a transparent substrate made of glass or glass ceramic, on which a layer is provided which contains BaSO ₄ .

It is known from the literature that BaSO ₄ crystals have a round shape and can also be produced with a diameter in the required range of 100 nm to 10 μm. In addition, BaSO _{4 has} a refractive index in the range of 1.54 and is thus in the range of the refractive index of melanins and lime deposits in the tissue. The phantom standard of the present invention has good homogeneity and long-term stability and has properties very similar to natural tissue.

In an advantageous embodiment of the invention, the layer contains a binder mixed BaSO ₄ in powder form.

On this way can be a good homogeneity of the Ensure phantom standards.

According to a further embodiment of the invention, the layer contains silicone, in which BaSO _{4 is} distributed.

With silicone as carrier or binding material, a very homogeneous distribution of the BaSO ₄ powder and a sufficient long-term stability can be ensured.

According to a further embodiment of the invention, the layer is a screen-printing layer in which BaSO _{4 is} distributed.

Also In this way a good homogeneity can be achieved and ensure long-term stability of the standard.

According to a further embodiment of the invention, the layer contains PMMA (polymethyl methacrylate) in which BaSO _{4 is} distributed.

Finally, the layer may also contain polyurethane, optionally in addition to silicone, in which BaSO _{4 is} distributed.

Also With such an embodiment can be good phantom standards realize.

The Thickness of the layer is preferably 5 to 100 μm.

Further, the layer may preferably contain 10 to 60 volume percent of BaSO ₄ .

ever according to the required application can so adapted the properties of the phantom standard in a suitable way become.

According to one Another embodiment of the invention, the layer is a cured by a temperature treatment sol-gel layer.

Also with such an embodiment can be a high quality phantom standard.

According to one Another embodiment of the invention, the substrate consists of a Soda-lime glass or borosilicate glass.

Both Glasses stand as little scattered and transparent platelets with high plane parallelism available.

Of the inventive phantom standard leaves not only for optical imaging, but also as standard in magneto-resonance and X-ray methods and use other imaging methods advantageous.

• – Bereitstellen eines Substrats in Form einer transparenten Platte aus Glas oder Glaskeramik;
• – Bereitstellen von BaSO₄ in Pulverform;
• – Mischen des BaSO₄ mit einem Binder und Herstellen einer Paste;
• – Auftragen der Paste auf dem Substrat und
• – Aushärten der Paste.

The object of the invention is further achieved by a method for producing a phantom standard, in particular for imaging methods on organic samples, in particular for biomedical applications, with the following steps:

• - Providing a substrate in the form of a transparent plate made of glass or glass ceramic;
• - Providing BaSO ₄ in powder form;
• Mixing the BaSO ₄ with a binder and making a paste;
• - Apply the paste on the substrate and
• - curing the paste.

When Binder here z. As a silicone with a hardener used, with the curing of the silicone layer at preferably at 120 to 180 ° C, preferably at 140 to 160 ° C takes place.

It it is understood that other manufacturing processes, such as screen printing, Embedding in PMMA, etc. are possible.

It It should also be understood that the foregoing and the following to be explained features of the invention not only in the specified combination, but also in other combinations or used alone, without the scope of the invention to leave.

Further Features and advantages of the invention will become apparent from the following Description of preferred embodiments.

example 1

First, a paste of silicone, Harter and BaSO ₄ powder is applied. The silicone / hardener ratio is about 10: 1. To this is added 1% by weight of BaSO ₄ powder. This mixture is homogenized by hand with a glass rod. It turns out that mixing is most uniform when first mixing only the BaSO ₄ powder with the silicone until a homogeneous paste is formed. Immediately before processing, the hardener is added and stirred. Glass plates made of soda-lime glass with a size of 40 mm × 40 mm × 1 mm are used as the substrate. Before coating, it is cleaned with acetone to remove grease and other impurities. This step is important as it would otherwise lead to wetting disorders, which would result in an inhomogeneous surface.

The required amount of silicone paste is above the glass panel applied and evenly with a squeegee Distributed trains. The coated glass panel is for rest for a few minutes to vent the layer. Subsequently, the layer is at 150 ° C for 10 minutes networked in a drying oven.

The result is a very high quality standard with a uniform surface and homogeneous distribution of BaSO ₄ powder in the active layer.

Example 2

There are 250 mg BaSO ₄ powder, 18 mg Al ₂ O ₃ -C (nanoparticulate Al ₂ O ₃ , available from Degussa AG) and 0.75 ml verd. Qpac (binder for phosphors available from Osram AG) in a mortar mixed until a paste-like consistency is achieved is. This paste is applied to the substrate material with a squeegee and fired at 500 ° C for one hour. In this case, the oven is heated very slowly (for example, about 2 K / min) to avoid blistering.

Also This results in a high quality standard with a lot homogeneous, plane-parallel active layer.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 2003/0086535 A1 [0006]
• US 5587657 [0008]

Claims (14)

Phantom standard, in particular for imaging methods on organic samples, in particular for biomedical applications, with a transparent substrate made of glass or glass ceramic, on which a layer is provided which contains BaSO ₄ . A phantom standard according to claim 1 wherein said layer comprises a binder mixed with BaSO ₄ in powder form. A phantom standard according to claim 1 or 2, wherein the layer contains silicone in which BaSO _{4 is} distributed. A phantom standard according to claim 1 or 2, wherein the layer is a screen-printed layer in which BaSO _{4 is} distributed. A phantom standard according to any one of claims 1 to 2, wherein the layer contains PMMA in which BaSO _{4 is} distributed. A phantom standard according to any one of claims 1 to 3, wherein the layer contains polyurethane in which BaSO _{4 is} distributed. Phantom standard according to one of the preceding claims, wherein the layer has a thickness of 5 to 100 microns having. A phantom standard according to any one of the preceding claims, wherein the layer contains 10 to 60% by volume of BaSO ₄ . Phantom standard according to one of the preceding claims, wherein the layer is a cured by a temperature treatment sol-gel layer is. Phantom standard according to one of the preceding claims, in which the substrate is made of a soda-lime glass or a borosilicate glass consists. Use of the phantom standard of any one of the preceding Claims as standard for tissue, in particular in the study of tissue samples for the purpose of cancer detection and the effect of pharmaceuticals, or as a standard in magneto-resonance and X-ray method. Method for producing a phantom standard, in particular for imaging methods on organic samples, in particular for biomedical applications, comprising the following steps: - providing a substrate in the form of a transparent plate made of glass or glass ceramic; - Providing BaSO ₄ in powder form; Mixing the BaSO ₄ with a binder and making a paste; - Applying the paste to the substrate and - curing the paste. The method of claim 12, wherein as a binder Silicone is used with a hardener. The method of claim 13, wherein the silicone layer at 120 to 180 ° C, preferably at 140 to 160 ° C. is cured.