SPIRIT Instructions For Use

Foreword

These instructions for use contain all the information necessary to operate the SPIRIT phantom in accordance with its specifications. This information includes explanations of the functions of the controls, displays and signals, the sequence of operation, and connection and disconnection of the parts and accessories you can remove.

You must regard these instructions as a part of the equipment. It is important that these instructions are read thoroughly.

Disclaimer

Gold Standard Phantoms considers itself responsible for the effects on safety, reliability, and performance of the equipment only if:

• Assembly operations, re-adjustments, modification or repairs are carried out by persons authorised by ourselves, and

• The electrical installation of the room where the device is used meets the requirements of the standards in force, and

• The device is used in accordance with this instruction manual.

Glossary and Abbreviations

Introduction

About this Instruction Manual

The purpose of this instruction manual is to promote the safe use of a SPIRIT phantom during its expected service life.
It describes the use of the device as intended by the manufacturer.

Identification

Product Name: SPIRIT

Manufacturer and Contact Information

Intended Use

The SPIRIT phantom is designed for Quality Assurance measurements of Magnetic Resonance Imaging (MRI). Phantoms (also known as Quality Assurance Devices) are used in lieu of a human being inside an MRI scanner to assess its performance. The user should refer to the MRI device’s instructions for use to set up the correct pulse sequence for a given outcome. Equivalent acquisition techniques need to be used on the phantom as in the humans / patients.

Intended User

The SPIRIT phantom is intended for use by qualified MRI system operating personnel. The phantom must be used by competent personnel who have the applicable education and experience. This includes but is not limited to:

• Radiographer/MRI Technologist

• Clinical Scientist/Hospital Physicist

• MRI Physicist

• Radiologist

• Student/Researcher

• Other trained Medical Professional.

As for any phantom, this device must be used by a skilled person who has the applicable education and experience to enable them to perceive risks and to avoid hazards which operation or maintenance of the device can create.

Warnings and Cautions Used

Essential safety descriptions are provided in the instruction manual in the form of either a Warning or a Caution, as described below:

All users must familiarise themselves with all the warnings and cautions contained in the instructions before using this device.

Device Description

About the SPIRIT

SPIRIT

The SPIRIT is a 191 mm spherical phantom designed for use in an MRI scanner. The SPIRIT holds a total of sixteen 4ml Nalgene vials and four 10 mm Polypropylene vials. These vials contain a set of solutions with known reference quantities. It additionally contains an array of physical features which can be used for assessing the performance of MRI scanners. Further, the Phantom contains a pair of ethylene glycol filled NMR tubes which can be used to determine the temperature via MR thermometry.

It addresses the need for a standardised neuroimaging test object for multisite validation of advanced MRI techniques.

Applications include:

• Quantitative T₁/T₂ relaxometry

• Quantitative Diffusion imaging

• Mapping of geometric distortions due to gradient field non-linearities

• Measurement of effective slice thickness

• Assessment of effective resolution

Materials

About the Vials

The phantom contains a set of Prefilled Vials. These plastic vials are filled with reference materials for Quality Assurance measurements in Magnetic Resonance Imaging. The vials contained in the SPIRIT come in two sizes:

Traceability

Each vial is labelled with a unique identification code which is traceable to the batch of liquid within the vial. Records are made during manufacture of this liquid identifying the components, the quantities added of each component, and their batch numbers which are traceable to their suppliers. In addition, this traceability extends to any characterisation performed on batches of materials.

SI Traceable Characterisation

Relaxometry (MNCL-XXXX) and Diffusion (PVP-XXXX) materials come from batches characterised by a National Metrological Institute (either the National Institute of Standard - USA, or the National Physical Laboratory - UK):

• Relaxometry: characterised for proton relaxation times (T₁, T₂) at 3.0 T and specified temperatures, in accordance with NIST SP 250-97 ^[1]

• Diffusion: characterised for proton relaxation times (T₁, T₂) and the diffusivity of water (D) at 3.0 T and specified temperatures, in accordance with NIST SP 250-100 ^[2]

Composition

The MR Reference Materials have the following compositions:

About the NMR Thermometers

Overview

Many MR observable quantities, including T₁, T₂, and diffusivity exhibit temperature dependence. In order to compare phantom measurements with the supplied reference values, it is important to factor in this temperature dependence and estimate the temperature of the phantom during the MR acquisitions.

The SPIRIT Phantom Contains a pair of NMR Tubes containing Ethylene Glycol (see vial layout table). These NMR tubes allow for temperature measurement via the well-characterised temperature dependence of the chemical shift between methylene (CH₂) and hydroxyl (OH) groups in Ethylene Glycol (EG) which has been used in variable-temperature NMR for over 50 years ^[3][4].

The temperature dependence between the methylene and hydroxyl groups has been characterised as:

At 20 °C, the frequency is approximately:

• 72 Hz at 1.0 T

• 108.5 Hz at 1.5 T

• 217 Hz at 3.0 T

A multi-echo gradient echo (MGE) acquisition can be used to sample this signal, which can then be fit in the time-domain^[5] to:

Further information on acquisition sequences and processing methodology's can be found via the Gold Standard Phantoms website and application notes. For implementation assistance please contact Gold Standard Phantoms.

About the Slice Wedges

Overview

The general dimensions of the SPIRIT slice wedges are shown below in isolation. The SPIRIT Phantom contains features for determining slice thickness at the center of the phantom, referred to as the slice wedges. These features are designed in accordance with the NEMA MS 5-2018 standard ^[6].

Integrated Resolution Array

In addition, the slice wedges include a resolution array oriented orthogonally to the angled faces. This grid consists of 11 holes, linearly spaced, with diameters ranging from 3.00 mm ± 0.05 mm to 0.50 mm ± 0.05 mm.

Geometry

The slice wedges are positioned symmetrically at the centre of the phantom. Dimensional drawings (see figures) provide:

• wedge angles and taper geometry,

• reference coordinates relative to phantom datum surfaces,

• resolution-grid hole placement and tolerances.

The general dimensions of the SPIRIT slice wedges are shown below in isolation.

About the Resolution Grids

Overview

Additional resolution-quantification features are located on the central plate of the SPIRIT Phantom. These allow assessment of image sharpness, partial-volume effects, system focus, and reconstruction quality across multiple directions.

Grid Layout

The central plate of the phantom incorporates a set of resolution grids arranged along the +X, -X, +Y, -Y axis.

Each grid consists of a 3 × 6 array of holes ranging from 3.00 mm ± 0.05 mm to 0.50 mm ± 0.05 mm, linearly spaced. The figures below illustrate their principal dimensions and layout.

Dimensional Features

Engineering drawings include:

• grid origin and alignment relative to the phantom centre,

• hole-to-hole spacing,

• diameter tolerances,

• plate thickness and depth profiles.

About the Distortion Grid Fiducals

Overview

For geometric-distortion assessment, the SPIRIT Phantom contains a set of 52 fiducials arranged in a rectilinear 3D grid with a 34 mm center-to-center spacing.
This structure provides a precise framework for quantifying both in-plane and through-plane distortion in MR imaging systems.

Ball-and-Stick Assemblies - Upper and Lower Grids

The distortion grid consists of two identical ball-and-stick arrays (upper and lower), each containing 17 nodes.
The Grids include:

• a solid 8 mm diameter sphere,

• joined to adjacent nodes via 3 mm diameter rods.

When imaged using MRI, the nodes appear as signal voids, producing a high-contrast grid for geometric calibration.

Central-Plate Fiducials

The central plate includes eighteen (18) 6.00 mm diameter through-holes, which fill with phantom flood fill during use.
These appear as bright, high-signal features on MR images and provide cross-plate alignment markers.

Dimensional Features

Engineering drawings include:

• 3D grid layout,

• node coordinates,

• rod lengths and tolerances,

• plate-through-hole positioning relative to phantom center.

Storage Instructions

• Store In a dry and well-ventilated environment

• Between 15 °C and 30 °C

• Out of direct sunlight

If possible, store the phantom in the MRI magnet room. This will ensure that it is at thermal equilibrium with the room and provide the most reliable and reproducible results. Either store in the supplied box, or use the integrated legs to store on a flat surface such as a shelf.

Cleaning

If the SPIRIT phantom requires cleaning, they can be cleaned with soap, water, and a soft cloth or sponge to remove dirt and debris. Isopropanol may be used to remove sticky residue, however these may cause the labels to stop adhering to the surface.

Operating Instructions

Unpacking the equipment

The SPIRIT phantom is supplied in a protective cardboard packaging box. To unpack:

1. Inspect the outer packaging. If any damage is present, do not use the device. Please contact Gold Standard Phantoms.

2. Remove each component from the box.

3. Inspect each component for damage. If any damage is present, do not use the device. Please contact Gold Standard Phantoms.

4. Carefully remove the outer packaging. Do not use a sharp knife in case this cuts or punctures the device.

On receipt of the phantom remove the outer packaging to reveal the gold box

Opening the gold box reveals the following compenents

The SPIRIT box contains:

1. SPIRIT Phantom

2. Vial location key card

3. Paperwork including the SDS

4. Fixed Torque Screwdriver

5. Stainless Steel Hex Bits (6mm)

6. Spare Fixings

7. Phantom holder (to be assembled)

8. 250 ml bottle of phantom flood fill liquid

Holder Assembly and Use

The phantom holder requires assembly - instructions for this can be found at https://help.goldstandardphantoms.com/phantoms/spirit-phantom-holder-assembly-instructions

Phantom Use

This phantom is vendor-agnostic and is primarily designed for use in head coils.

1. For optimum performance, the phantom should be fitted into one of the coil specific Phantom holders with the SPIRIT product label facing up
   

   

2. Place the phantom onto the MRI scanner couch inside the head coil
   

   

3. Using the rotational alignment jig ensure the phantom is aligned in the coil

4. Align the MRI system’s laser with the middle of the phantom.

5. Move the phantom to magnet iso-centre.

6. Begin the MR examination.

7. When finished, store the phantom and holder.

Maintenance

Flood-fill top-up

The outer shell of the SPIRIT phantom is made from polycarbonate, which is permeable to water vapour. Over the course of several months water may evaporate from the flood-fill liquid that fills the phantom, resulting in bubbles forming. A bottle of flood-fill liquid is provided with the phantom, and can be used to top-up the phantom.

To top up the phantom:

1. Fit the supplied 6mm hex bit to the torque screwdriver.

2. Place the phantom on a flat surface.

3. Using the torque screwdriver, unscrew the cap (anticlockwise) from the filling port on the top of the phantom.

4. Add flood-fill liquid to the phantom until full. A pipette or syringe (not supplied) may aid.

5. Once full, re-fit the cap and tighten by hand a few turns.

6. Using the torque screwdriver, tighten the cap until the torque screwdriver “clicks”.

7. Check that there are no bubbles remaining in the phantom.

Repeat these steps as required until the phantom is bubble-free.

Adverse Events

Any adverse events that occur during the use of this device should be reported both to Gold Standard Phantoms and the relevant Competent Authority of the member state.

Warranty

Standard Manufacturer’s Warranty (SMW)
The phantoms carry as 1 year manufacturer’s warranty. This covers assurance regarding quality / lifespan with a promise to repair or replace the SPIRIT under a standard RMA (return merchandise authorisation). Shipping and Duty charges may apply. This warranty shall be null and void in the event that the phantom sustains damage resulting from a fall or any other form of mishandling.

Disposal

Do not allow the contents of the phantom to enter drains, sewers, or watercourses. Dispose of this material and its container as hazardous waste. Disposal should be in accordance with local, state, or national legislation.

Citations

1. ^ M. A. Boss et al., “Magnetic resonance imaging biomarker calibration service: proton spin relaxation times,” National Institute of Standards and Technology, May 2018. doi: 10.6028/nist.sp.250-97.
2. ^ M. A. Boss et al., “Magnetic resonance imaging biomarker calibration service :,” National Institute of Standards and Technology (U.S.), Oct. 2022. doi: 10.6028/nist.sp.250-100.
3. ^ A. L. Van Geet, “Calibration of the methanol and glycol nuclear magnetic resonance thermometers with a static thermistor probe,” Anal. Chem., vol. 40, no. 14, pp. 2227–2229, Dec. 1968, doi: 10.1021/ac50158a064.
4. ^ D. S. Raiford, C. L. Fisk, and E. D. Becker, “Calibration of methanol and ethylene glycol nuclear magnetic resonance thermometers,” Anal. Chem., vol. 51, no. 12, pp. 2050–2051, Oct. 1979, doi: 10.1021/ac50048a040.
5. ^ S. M. Sprinkhuizen, C. J. G. Bakker, and L. W. Bartels, “Absolute MR thermometry using time‐domain analysis of multi‐gradient‐echo magnitude images,” Magnetic Resonance in Med, vol. 64, no. 1, pp. 239–248, Jun. 2010, doi: 10.1002/mrm.22429.
6. ^ National Electrical Manufacturers Association. (2018). Determination of slice thickness in diagnostic magnetic resonance imaging (NEMA MS 5-2018).