Device for securing samples during μCT scanning

Abstract

A device is described herein comprising a cylindrical structure including a lower base, an upper cap, and walls, wherein the walls longitudinally extend from the lower base to the upper cap, wherein the walls radially extend from a central axis of the cylindrical structure, a plurality of platforms longitudinally spaced along the central axis, wherein the plurality of platforms radially extend from the central axis, the walls and the plurality of platforms forming receiving slots, wherein each receiving slot comprises a receptacle upwardly extending from a corresponding platform, wherein the receptacle is configured to receive and position a bone sample.

Description

[0001] Docket No.: 2932719-000264-W01 Filed: September 19, 2025

[0002] DEVICE FOR SECURING SAMPLES DURING uCT SCANNING

[0003] Inventor:

[0004] Matthew Scott, Elizabeth Floyd

[0005] RELATED APPLICATION

[0006] This application claims the benefit of US Application No. 63 / 697,164, filed September 20, 2024.

[0007] TECHNICAL FIELD

[0008] Embodiments are described herein relating to pCT scanning and analysis of bone samples.

[0009] INCORPORATION BY REFERENCE

[0010] Each patent, patent application, and / or publication mentioned in this specification is herein incorporated by reference in its entirety to the same extent as if each individual patent, patent application, and / or publication was specifically and individually indicated to be incorporated by reference.

[0011] SUMMARY OF THE INVENTION

[0012] A device is described herein comprising a cylindrical structure comprising a lower base, an upper cap, and walls, wherein the walls longitudinally extend from the lower base to the upper cap, wherein the walls radially extend from a central axis of the cylindrical structure, a plurality of platforms longitudinally spaced along the central axis, wherein the plurality of platforms radially extend from the central axis, the walls and the plurality of platforms forming receiving slots, wherein each receiving slot comprises a receptacle upwardly extending from a corresponding platform, wherein the receptacle is configured to receive and position a bone sample.

[0013] In embodiments, the cylindrical structure is dimensioned to slide into a sample holder for scanning. Docket No.: 2932719-000264-W01 Filed: September 19, 2025

[0014] In embodiments, the sample holder comprises a height of 70mm and a diameter of 10 mm sample holder.

[0015] In embodiments, a lower surface of the upper cap comprises an attachment slot, wherein the attachment slot is configured to receive an upper rim of the sample holder in a press fit.

[0016] In embodiments, the receiving and securing comprises positioning the distal end of the bone sample into the receptacle.

[0017] In embodiments, the bone sample comprises a mouse tibia.

[0018] In embodiments, the positioning comprises orienting the mouse tibia with anterior surface facing outward.

[0019] In embodiments, the device includes at least one wedge, wherein the at least one wedge comprises a thick proximal end tapering to a distal thin edge.

[0020] In embodiments, the at least one wedge comprises a rectangular prism.

[0021] In embodiments, the insertion of the at least one wedge biases the distal end of the corresponding bone sample toward the central axis of the cylindrical structure.

[0022] In embodiments, the cylindrical structure comprises an acrylonitrile-styrene- acrylate plastic.

[0023] In embodiments, the upper cap comprises roman numerals, wherein each roman numeral corresponds to a column of receiving slots.

[0024] BRIEF DESCRIPTION OF THE FIGURES

[0025] Figure 1 shows a process of pCT scanning and analysis, under an embodiment.

[0026] Figure 2 shows a device (Tibia Tower) for securing samples during pCT analysis, under an embodiment.

[0027] Figure 3 shows a device (Tibia Tower) for securing samples during pCT analysis, under an embodiment.

[0028] Figure 4 shows a device (Tibia Tower) for securing samples during pCT analysis entirely secured within a sample holder, under an embodiment. Docket No.: 2932719-000264-W01 Filed: September 19, 2025

[0029] Figure 5 shows a specimen holder (Tibia Tower) for pCT analysis partially secured within a sample holder, under an embodiment.

[0030] Figure 6 shows an image of Osmium stained bones after uCT scanning using a Tibia Tower, under an embodiment.

[0031] Figure 7 provides a scout view of tibias in the Tibia Tower, under an embodiment.

[0032] Figure 8 shows a pCT scan of tibias, under an embodiment.

[0033] Figure 9 shows a pCT scan of tibias, under an embodiment.

[0034] Figure 10 shows a pCT scan of tibias, under an embodiment.

[0035] Figure 11 shows a device (Tibia Tower) for securing samples during pCT analysis, under an embodiment.

[0036] Figure 12 shows a device (Tibia Tower) for securing samples during pCT analysis, under an embodiment.

[0037] Figure 13 shows a device (Tibia Tower) for securing samples during pCT analysis, under an embodiment.

[0038] DETAILED DESCRIPTION

[0039] A device is described herein that optimally positions specimens for Micro- Computed Tomography (pCT) scanning and analysis. pCT scanning is an x-ray imaging method capable of visualizing bone at the micro- structural scale, that is, 1-100 pm resolution. pCT is the gold-standard method for assessment of 3D bone morphology in studies of small animals. As applied to the small bones of mice or rats, pCT can efficiently and accurately assess bone structure (e.g., cortical bone area) and microstructure (e.g., trabecular bone volume fraction).

[0040] Figure 1 shows a process of pCT analysis in general. The process involves preparation of the sample (bone, tooth, etc.) 102 that is subject to analysis. The pCT apparatus then images 104 the sample by scanning a series of two-dimensional slices of the object. The process reconstructs 106 a three-dimensional image of the sample using the series of two dimensional slices. The reconstructed image is then available for Docket No.: 2932719-000264-W01 Filed: September 19, 2025 evaluation and visualization 108. A device (referred to herein as a Tibia Tower) is described below for positioning post-mortem mouse tibia specimens for pCT analysis but embodiments are not so limited.

[0041] The Tibia Tower is a 3D printed structure that is designed for use with pCT scanners including the Scanco Medical pCT 35 (but embodiments are not so limited). The device serves as an efficient and safe way to organize mouse tibiae within the pCT for analysis of bone morphology. The Tibia Tower comprises a cylindrical structure that provides slots for a consistent placement of the tibiae in an upright position, where the shape of the slot allows for tibiae to be easily oriented with their anterior surface outward.

[0042] Figure 2 shows a perspective view of the tibia tower. The cylindrical structure comprises a base 202 and cap 204 and three walls 206, 207 (third wall not shown) longitudinally disposed therebetween. The walls extend radially from the structure’s central axis 230. The cylindrical structure comprises three platforms 208, 210, 212 longitudinally spaced apart along the central axis. The platforms and walls define nine slots for receiving mouse tibia. Note that each slot features a receptacle 214, 216, 218 for securing a tibia 220 within a corresponding slot.

[0043] Under an embodiment, the height between platforms 208, 210, 212 comprises 21.5 mm.

[0044] As indicated, this embodiment features three platforms and corresponding receptables configured to receive mouse tibia (where platform 212 is part of the cylindrical structures base while platforms 208 and 210 are intermediate). Alternative embodiments implement a greater or fewer number of intermediate platforms with spacing therebetween configured to receive different bone samples or materials. The spacing therebetween may be uniform or varied. Additionally a greater or fewer number of walls may be used depending as needed to accommodate different bone samples or materials.

[0045] Figure 3 shows a perspective view of a tibia placed in a receptacle. The view illustrates a half sphere shape 304 that is integrally formed with the cap. The half sphere provides structural support for angular rotation of the cap when placing and removing the Docket No.: 2932719-000264-W01 Filed: September 19, 2025 tower from a sample holder. The cap features a receiving slot 302 on its lower end. The slot is then press fit onto the open-end rim of a sample holder (see Figures 4 and 5) during placement of the device.

[0046] The Tibia Tower shown in Figure 2 allows for the placement of 3 tibiae per tier and 3 tiers per Tibia Tower (9 tibiae per Tibia Tower). The top cap of the tibia tower also includes roman numerals for identifying tier sections. The device is configured to fit well within the Scanco pCT 35 70mm (height) by 10 mm (diameter) sample holder, providing easy sample identification and orientation within the scanner and post-scanning visualization. Figure 4 shows the Tibia Tower placed within the sample holder. Figure 5 shows the Tibia Tower partially placed within the sample holder. The Tibia Tower is a unique way to prepare samples for scanning and provides a unique solution over other common methods for sample preparation.

[0047] The long bones of mice are commonly examined for bone structure and marrow adiposity using pCT. A common instrument used is the scanco pCT 35 or 40, where samples are placed inside tubes designed specifically for the instrument. While various tube sizes are available, the 70mm (height) by 10mm (diameter) tube is commonly used for mouse bones due to resolution requirements for post-scanning analysis.

[0048] Standard procedure suggests placing mouse tibiae in gauze and tightly wrapping them before placing them in the tube. This allows for 1 tibia per z-area of interest, but the 10mm diameter could house 3 tibias comfortably within the same z-area. (Note that a z- area corresponds to a section along a z-axis parallel to the longitudinal central axis of the tower). This is useful because z-area is the major determinant of scan time outside of scanning parameters (resolution); this is also typically the main determinant of financial and time investment.

[0049] Researchers will sometimes use the plunger from a 3ml syringe to increase the number of tibiae per z-axis, as the plunger has 4 quadrants per z-area and allows for increased sample throughput. However, the plunger requires the user to wrap the samples with parafilm after the tibiae are placed, which is a tedious process that requires the user to hold samples onto the syringe while trying to parafilm wrap them and could lead to Docket No.: 2932719-000264-W01 Filed: September 19, 2025 dropping multiple samples that can no longer be distinguished to experimental groups or specific mice. Additionally, the exact placement of tibias within the plunger is difficult and commonly leads to a disparity in z-height and tibia orientation, which requires researchers to expand the scan window and pay additional attention to tibia identification in the scan reconstructions.

[0050] The specimen holder described in this disclosure (Tibia Tower) was designed to increase throughput for pCT scanning of tibias by increasing the number of specimens within the same z-axis region of interest. Further, labels and slots on the Tibia Tower allow for secure and identifiable tibia placement within the Tibia Tower while providing a consistent z-height and orientation for samples.

[0051] In essence, the Tibia Tower transforms the process of pCT scanning mice bones from a time-consuming task, using gauze or a makeshift 3 ml syringe with some parafilm and no inherently systematic sampling system, to a time and cost-saving, higher throughput, standardized (with predefined sample orientation and labeling) tool that is designed to work with the industry standard Scanco Medical pCT 35 or 40.

[0052] Figure 6 provides an image of Osmium stained bones after uCT scanning using a Tibia Tower, under an embodiment.

[0053] Figure 7 provides a scout view of tibias in the Tibia Tower, under an embodiment.

[0054] Figure 8 shows a pCT scan of tibias, under an embodiment. The image shows that the orientation of the tibias (posterior tibia towards the center) is well controlled due to the slots on each z-plane.

[0055] Figure 9 shows a pCT scan of tibias, under an embodiment.

[0056] Figure 10 shows a pCT scan of tibias, under an embodiment.

[0057] Figures 9 and 10 show well controlled z-heights.

[0058] ASA (acrylonitrile-styrene-acrylate) plastic was used to print the Tibia Tower because it has low x-ray attenuation properties (<50 HU, Hounsfield Units) and prints well with consumer grade 3D printers using manufacturer suggested settings (Bambu PIS with hardened steel extruder and ,2mm nozzle). Note that support must be enabled (tree Docket No.: 2932719-000264-W01

[0059] Filed: September 19, 2025 support-automatic). The Bambu software automatically generates the necessary supports when such is enabled.

[0060] Figures 11-13 show wedges for using in position the tibia bones for scanning.

[0061] Each wedge comprises an acrylonitrile-styrene-acrylate plastic material having one thick proximal end tapering to a distal thin edge that is driven into tower receptacles to assist in securing tibiae. As just one example, a wedge comprises a triangular prism, but embodiments are not so limited. As already described above, tibias are placed in receptacles 214, 216, 218 in order to secure the position of the tibia during the scanning process. Again note that the receptacles orient the tibia with its anterior surface facing outward. Under an embodiment, the distal end of the wedge is inserted into a receptacle, in particular into a space between a distal end of the tibia and inwardly facing interior surface of the receptacle. The insertion of the wedge biases the distal end of the tibia towards the central longitudinal axis of the Tibia Tower. Figures 11 and 13 illustrate insertion of wedge 1102 into a receptable. Figure 12 shows nine wedges that correspond to the nine receptacles of the tibia tower.

Claims

Docket No.: 2932719-000264-W01Filed: September 19, 2025CLAIMS1. A device comprising, a cylindrical structure comprising a lower base, an upper cap, and walls, wherein the walls longitudinally extend from the lower base to the upper cap, wherein the walls radially extend from a central axis of the cylindrical structure; a plurality of platforms longitudinally spaced along the central axis, wherein the plurality of platforms radially extend from the central axis; the walls and the plurality of platforms forming receiving slots, wherein each receiving slot comprises a receptacle upwardly extending from a corresponding platform, wherein the receptacle is configured to receive and position a bone sample.

2. The device of claim 1, wherein the cylindrical structure is dimensioned to slide into a sample holder for scanning.

3. The device of claim 2, wherein the sample holder comprises a height of 70mm and a diameter of 10 mm sample holder.

4. The device of claim 1, wherein a lower surface of the upper cap comprises an attachment slot, wherein the attachment slot is configured to receive an upper rim of the sample holder in a press fit.5 The device of claim 1, wherein the receiving and securing comprises positioning the distal end of the bone sample into the receptacle.

6. The device of claim 5, wherein the bone sample comprises a mouse tibia.

7. The device of claim 6, wherein the positioning comprises orienting the mouse tibia with anterior surface facing outward.Docket No.: 2932719-000264-W01Filed: September 19, 20258. The device of claim 1, wherein the device includes at least one wedge, wherein the at least one wedge comprises a thick proximal end tapering to a distal thin edge.

9. The device of claim 8, wherein the at least one wedge comprises a rectangular prism.

10. The device of claim 9, wherein the insertion of the at least one wedge biases the distal end of the corresponding bone sample toward the central axis of the cylindrical structure.

11. The device of claim 1, wherein the cylindrical structure comprises an aery 1 onitril e-sty rene-acry 1 ate pl asti c .

12. The device of claim 1, wherein the upper cap comprises roman numerals, wherein each roman numeral corresponds to a column of receiving slots.

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