preparation and heating of the phantom material mixture

안정적이고 생물학적으로 유의미한 팬텀 물질의 제조

Establishing the precision and accuracy of novel optical imaging biomarkers through technical validation1,2 is paramount to ensuring their successful implementation in clinical practice. To achieve this, technical validation studies frequently employ durable physical phantoms, which facilitate inter-instrument performance assessment and routine quality control. For widespread use of a phantom material in research and clinical translation, a simple, highly reproducible fabrication protocol is required. An ideal biophotonic phantom material should include the following properties3: (1) independently tunable properties within biologically relevant ranges; (2) mechanical robustness; (3) long-term stability; (4) flexibility in geometry and architecture; (5) safe handling; (6) widely available ingredients that can be purchased from standard scientific suppliers; and (7) low cost. At present, biophotonic applications lack a standardized protocol for a widely accepted phantom material that fulfils the outlined requirements and also includes tunable acoustic properties for hybrid applications, such as photoacoustic imaging (PAI).
Biologically relevant phantom materials targeted for combined optical and acoustic applications include hydrogels4,5, polyvinyl alcohol (PVA)6,7,8,9, and polyvinyl chloride plastisol (PVCP)10,11,12,13,14,15,16. However, these materials are characterized by certain limitations that restrict their application as a stable phantom material. Hydrogels, for example, are prone to dehydration, mechanical damage, and bacterial ingrowth, limiting their shelf life17,18,19. The addition of chemicals can increase the longevity, but common preservatives, such as formaldehyde20 or benzalkonium chloride21, are hazardous and require cautionary measures during handling. Additionally, targets containing water-soluble dyes can diffuse within the base material if not encapsulated. PVA cryogels are characterized by a higher longevity and structural robustness, but their preparation process involves long freeze-thaw cycles22. This can limit the independent tunability of acoustic and optical parameters23 and-if slightly varied-can lead to inhomogeneities6, thereby compromising reproducibility. Moreover, the diffusion of dyes from inclusions has been observed after 1 year13. PVCP has a complex fabrication process that includes high temperatures of up to 180-220 &#176;C13,14,24,25. PVCP also suffers from a lack of a supply chain with scientific suppliers26 and can contain plasticizers based on phthalates, which may cause reproductive and developmental harm27, making them controlled substances in some countries.
Copolymer-in-oil compositions, such as gel wax28,29,30,31 or blends based on thermoplastic styrenic elastomers32,33,34,35,36, exhibit good longitudinal stability and feature tissue-like acoustic and optical properties31,35,36,37, thereby having high potential as a durable phantom candidate in multimodal applications. Additionally, this class of material is cost-effective, non-water absorbing, non-toxic, and biologically inert35,38. The speed of sound c(f) and acoustic attenuation coefficient &#945;(f) can be tuned in a biologically relevant range (Table 1) by variation of the polymer concentration33,35,39, whilst optical absorption &#181;a(&#955;) and reduced scattering &#181;s&#39;(&#955;) coefficients can be primarily varied by the addition of oil-soluble dyes or titanium dioxide (TiO2)39, respectively.
Here, a simple, easy-to-follow protocol is presented for the creation of durable copolymer-in-oil phantoms suitable for use in optical, ultrasound, or photoacoustic device calibration. All ingredients have defined Chemical Abstract Service (CAS) numbers and are readily available from standard scientific suppliers. Potential difficulties in the fabrication procedure are highlighted and ways to overcome them are presented. Whilst the protocol allows the fabrication of materials with a range of acoustic and optical properties, the presented protocol yields a material with a speed of sound of ~1,481 m&#183;s-1, aligning with the speed of sound of water at room temperature (20 &#176;C)40. This value was selected as a neutral standard for representing the wide range of existing tissue properties (Table 1), allowing the establishment of a consistent and reliable reference point for comparison. By providing this detailed protocol, we aim to broaden the uptake and manufacturing reproducibility of this promising phantom material type, thereby facilitating biophotonic, acoustic, and photoacoustic validation studies and supporting routine quality control in preclinical and clinical imaging applications.

저자 스포트라이트: 광학 및 음향 이미징을 위한 안정적인 팬텀 재료  

광학 및 음향 이미징을 위한 안정적인 팬텀 소재

Watch this Scientific Journal Video about Preparation and Heating of the Phantom Material Mixture at JoVE.com

Preparation and Heating of the Phantom Material Mixture   

팬텀 물질 혼합물의 준비 및 가열 

섭씨 90도에서 60분 동안 미네랄 오일 100밀리리터에 이산화티타늄 0.15g과 흡수제 염료 원액 1밀리리터의 초음파 처리를 시작합니다. 모든 구성 요소가 완전히 용해되도록하십시오. 적절한 유리 제품과 실리콘 오일을 사용하여 오일 수조를 만들고 핫 플레이트에 조심스럽게 고정합니다.균일한 열 분배를 위해 오일 수조 내부에 마그네틱 교반 막대를 놓습니다. 핫 플레이트를 켜고 가열 온도를 섭씨 160도로 설정하고 교반을 50RPM으로 조정합니다. 다음으로, 25.14 그램의 SEBS와 6.70 그램의 LDPE의 무게를 측정하고 초음파 처리 된 미네랄 오일이 들어있는 유리 비커로 옮깁니다.교반 막대를 비커에 놓고 오일 배스 중앙으로 옮겨 측정된 성분을 가열합니다. 첨가된 폴리머가 미네랄 오일 위에 떠 있을 때 금속 주걱을 사용하여 미네랄 오일 용액을 수동으로 저어주고 플로팅 폴리머를 미네랄 오일 내부에 분배합니다. 모든 폴리머가 용해되고 용액이 균일하게 혼합되고 매끄럽고 균질하게 나타날 때까지 혼합물을 섭씨 160도에서 1.5시간 동안 그대로 두십시오.

preparation-and-heating-of-the-phantom-material-mixture

Research

JoVE Journal

Medicine

Preparation and Heating of the Phantom Material Mixture

290 조회수. 섭씨 90도에서 60분 동안 미네랄 오일 100밀리리터에 이산화티타늄 0.15g과 흡수제 염료 원액 1밀리리터의 초음파 처리를 시작합니다. 모든 구성 요소가 완전히 용해되도록하십시오. 적절한 유리 제품과 실리콘 오일을 사용하여 오일 수조를 만들고 핫 플레이트에 조심스럽게 고정합니다.균일한 열 분배를 위해 오일 수조 내부에 마그네틱 교반 막대를 놓습니다. 핫 플레이?...

비디오: Preparation and Heating of the Phantom Material Mixture   

A Stable Phantom Material for Optical and Acoustic Imaging

Establishing tissue-mimicking biophotonic phantom materials that provide long-term stability are imperative to enable the comparison of biomedical imaging devices across vendors and institutions, support the development of internationally recognized standards, and assist the clinical translation of novel technologies. Here, a manufacturing process is presented that results in a stable, low-cost, tissue-mimicking copolymer-in-oil material for use in photoacoustic, optical, and ultrasound standardization efforts.
The base material consists of mineral oil and a copolymer with defined Chemical Abstract Service (CAS) numbers. The protocol presented here yields a representative material with a speed of sound c(f) = 1,481 &#177; 0.4 m&#183;s-1 at 5 MHz (corresponds to the speed of sound of water at 20 &#176;C), acoustic attenuation &#945;(f) = 6.1 &#177; 0.06 dB&#183;cm-1 at 5 MHz, optical absorption &#181;a(&#955;) = 0.05 &#177; 0.005 mm-1 at 800 nm, and optical scattering &#181;s&#39;(&#955;) = 1 &#177; 0.1 mm-1 at 800 nm. The material allows independent tuning of the acoustic and optical properties by respectively varying the polymer concentration or light scattering (titanium dioxide) and absorbing agents (oil-soluble dye). The fabrication of different phantom designs is displayed and the homogeneity of the resulting test objects is confirmed using photoacoustic imaging.
Due to its facile, repeatable fabrication process and durability, as well as its biologically relevant properties, the material recipe has high promise in multimodal acoustic-optical standardization initiatives.

This protocol describes the fabrication of a stable, biologically relevant phantom material for optical and acoustic biomedical imaging applications, featuring independently tunable acoustic and optical properties.

Establishing tissue-mimicking biophotonic phantom materials that provide long-term stability are imperative to enable the comparison of biomedical imaging ...