Table 1.
Investigations of genetic damage using clinically relevant scanners or pulse sequences
| Schreiber et al.17 | Schwenzer et al.18 | Simi et al.9 | Lee et al.19 | Yildiz et al.20 | Fiechter et al.8 | Szerencsi et al.21 | Lancellotti et al.7 | Brand et al.22 | Reddig et al.23 | |
|---|---|---|---|---|---|---|---|---|---|---|
| Assay | Mutation (Ames test) | DSB (γH2AX: FC and foci) | MN | CA, MN, and SSB (alkaline comet) | SSB (alkaline comet) | DSB (γH2AX: FC and foci) | SSB (alkaline comet); MN | DSB (γH2AX: FC) | DSB (γH2AX: foci) | DSB (γH2AX: FC and foci) |
| Study | In vitro | In vitro | In vitro and in vivo | In vitro | In vivo | In vivo | In vitro | In vivo | In vivo | In vitro |
| Flux | 1.5 T and 7.2 T | 3 T | 1.5 T | 3 T | 1.5 T | 1.5 T | 3 T | 1.5 T | 1.5 T | 7 T |
| Scan protocol | Static only; static (1.5 T) + time-varying bipolar GMF; static (1.5 T) + pulsed RF | Static only; Static + turbo spin-echo (TSE); Static + gradient-echo (GE) | Cardiac | Brain: range of pulse sequences | Hypophysial | Cardiac | Brain: range of pulse sequences | Cardiac: range of pulse sequences | Cardiac: range of pulse sequences | Static only; Static with varying GMF and pulsed RF |
| Scan duration | 1.5 sT: 1 h and 24 h 7.2 T: 1 h |
TSE: 2 min 20s or 2 h | In vitro: 686, 1186, 1618, 2188s | 22, 45, 67, 89 min | ∼16 min | 68 ± 22 min | 22, 45, 67, 89 min | 35–40 min | 30–60 min | 1 h |
| Contrast agent | – | – | No contrast agent | – | With and without gadolinium | Gadolinium | – | No contrast agent | Gadolinium | – |
| Cells | Salmonella typhimurium bacteria | Human cancer cells (HL-60 and KG-1a) | Human blood lymphocytes | Human blood lymphocytes | Human blood lymphocytes | Human blood lymphocytes | Human blood lymphocytes | Human blood (T lymphocytes and NK cells) | Human blood lymphocytes | Human blood lymphocytes |
| Expts/Donors | ≥2 expts | – |
In vitro: 8 healthy donors In vivo: 8 patients and volunteers |
Single healthy donor | 28 patients | 20 patients | 2 healthy donors/3 repeats | 20 healthy donors | 45 patients | 16 healthy donors |
| Temp | 1.5 T: 32–37°C 7.2 T: 37°C |
37°C |
In vitro: Room temp In vivo: body temp |
25°C | Body temp | Body temp | 20°C | Body temp | Body temp | – |
| Assay time points | Colonies counted after 48 h | 0, 1, and 24 h post imaging | PHA stimulation: In vitro at 0 h and 24 h post scan; In vivo at 0, 24, 72, 96, 120 h post scan |
PHA stimulation prior to exposure. SSB: 0 h post exposure MN: 0 h CA: 0 h |
0 h post non-contrast scan; 0 h post subsequent contrast-enhanced scan |
0 h post imaging | SSB: 0 h post exposure; MN: 0 h PHA stimulation (following 20 min transport) |
1 h, 2 h, 2 days, 1 month and 1 year post imaging | 5 min post imaging | 0, 1, 20 h post imaging |
| Positive control | Chemical mutagens | 4 Gy 6MV x-rays | – | SSB: cisplatin MN, CA: bleomycin |
– | – | 4 Gy γ-ray | – | – | 120 kV CT scan and 0.2 Gy γ-rays |
| Results | No mutagenic or co-mutagenic effect observed | No significant increase observed |
In vitro: Significant increase at 0 h, frequency increasing with exposure time. Reduced after 24 h (2 highest exposures still significant) In vivo: Significant increase after 0 h and 24 h but not later times |
SSB, MN, CA: significant increase with increasing exposure times of 45 min and above | No significant increase after non-contrast-enhanced MRI; Significant increase following subsequent contrast-enhanced MRI |
DSB (FC, foci): Significant increase observed | SSB, MN: No significant increase observed | T lymphocytes: 1 h, 2 h, 1year—no significant effect; 2 days, 1 month—significant increase; NK cells: a slight increase was observed at 2 h and day 2 |
No significant increase observed | No significant increase observed |
SSB, assessed using the alkaline comet assay; DSB, assessed using γH2AX measured using either flow cytometry (FC) or immunofluorescent microscopy and counting resultant foci (foci); MN assay, following stimulation with phytohaemagglutinin (PHA), cells incubated for 72 h, with cytochalasin-B added after 44 h; CA assay, following stimulation with PHA, cells incubated for 48 h, with colcemid added after 45 h.