Table 1. Comparison of Colonic Phantoms for CT Colonography Previously Reported in the Literature.
| Phantom Design, Casing | Polyps | Insufflation | Reproducibility | Advantages | Disadvantages |
|---|---|---|---|---|---|
| Simulation | |||||
| Digital synthesis from CTC data (3) | Digital synthesis | - | - | Polyps of any size, shape and density, genuine colon anatomy | Requires special software, cannot be used for low-dose testing |
| Ex vivo | |||||
| Porcine colon (4) | Wax | Yes | Poor | Readily available, polyps in different shapes can be easily created | Needs insufflation, deteriorates rapidly, low density of wax polyps (-16 HU) |
| Porcine colon (5-7) | Puckering the mucosa with securing suture | Yes | Poor | Readily available, appropriate density of polyps | Needs insufflation, deteriorates rapidly, draping of adjacent mucosa |
| Colonic polyposis colectomy specimen (8) | Natural | Yes | Poor | Colon with natural polyps | Size of polyps cannot be controlled, deteriorates rapidly, very limited availability |
| Flexible materials | |||||
| Latex balloon (9) | Ham (meat) | Yes | Poor | Easy construction | Poor reproducibility, needs insufflation |
| Stereolithography (silicone) (10) | Silicone | Yes | Average | Genuine anatomy of the colon with large and small structures | Soft-walled model, needs insufflation |
| Thermoreversible flexible plastic material (Dubliplast) (11, 12) | Thermoreversible flexible plastic material (Dubliplast) | No | Excellent | Molding of various shapes including haustral folds and polyps, correct attenuation (45 HU) | Elastic material needs supporting structure, straight without bends |
| Silastic (silicone rubber) (13, 14) | Unknown material, low density on image | No | Excellent | Reproducible | High density of the wall (200 HU), low density of polyps, needs supporting structure |
| Rigid tubing | |||||
| Plexiglass (15, 16) | Plexiglass | No | Excellent | Several diameters of tubes | No bends ± haustral folds, high density (150HU), thick wall (2, 8, and 11 mm) |
| Acrylic tube (17, 18) | Acrylic, plasticine | No | Excellent | Three diameters of tubes | No bends or haustral folds, thick wall (5 mm) |
| Glass (borosilicate) (19, 20) | Solid water, epoxy resin | No | Excellent | Excellent reproducibility, various shapes of the colon and polyps in different shapes can be easily created | Thick dense wall of the colon, fragile material, polyps made of solid water have low density |
| Commissioned, undisclosed material (21) | Undisclosed material with density of 10 HU | No | Excellent | Reproducible | No polyps on haustral folds, minimum polyp size 8 mm, low density of walls and polyps |
| PVC pipe (22) | Glass beads | No | Excellent | Reproducible | High density of the wall |
| Corrugated plastic tubing (23, 24) | Wood | No | Excellent | Easy construction | Corrugation is too fine to mimic haustral folds, low density of polyps (-370 HU) and tubing |
| PP pipe (this study) | Silicone | No | Excellent | Reproducible, soft-tissue attenuation, easy shaping of polyps | Opaque |
Abbreviations: PVC, polyvinylchloride; PP, polypropylene