Izvorni znanstveni članak
https://doi.org/10.55378/rv.50.2.2
Assessment of intrafractional displacements in surface-guided inspiration breath-hold stereotactic body radiation therapy
Domagoj Brkić
; Specialty Hospital Radiochirurgia Zagreb
*
Damir Vučinić
; Specialty Hospital Radiochirurgia Zagreb
Ivana Alerić
; Specialty Hospital Radiochirurgia Zagreb
Vanda Leipold
; Specialty Hospital Radiochirurgia Zagreb
Hrvoje Kaučić
; Specialty Hospital Radiochirurgia Zagreb
* Dopisni autor.
Sažetak
Background: Stereotactic Body Radiation Therapy (SBRT) delivers high radiation doses to tumours with steep dose gradients, minimising exposure to surrounding healthy tissues. Surface-guided Inspiration Breath-Hold (IBH) is particularly useful for thoracic and upper abdominal tumours, where respiratory motion can affect target position. Aim: This retrospective cohort study aimed to assess whether GTV or anatomical surrogate intrafractional displacement during surface-guided IBH remains ≤0.5 cm when surface guidance confirms reproducible breath-hold throughout treatment. The study also evaluated the accuracy and precision of an SBRT protocol using IBH monitored by Surface Guided Radiation Therapy (SGRT). Intrafractional displacement was compared between lung and liver cohorts. Materials and Methods: Offline reviews were performed for 86 lung SBRT patients (182 fractions) and 124 liver SBRT patients (159 fractions). Results: In the liver cohort, the greatest mean intrafractional displacement was observed in the vertical (VRT) direction (0.087 cm), while mean shifts in lateral (LAT) and longitudinal (LNG) directions were -0.031 cm and -0.042 cm, respectively. The highest SD was observed in LNG (±0.275 cm). Mean 3D displacement was 0.351 ± 0.181 cm. In the lung cohort, the greatest mean displacement was observed in the LNG direction (-0.092 cm), followed by LAT (-0.025 cm) and VRT (0.036 cm). The highest SD was also observed in LNG (±0.251 cm). Mean 3D displacement was 0.298 ± 0.186 cm. Significant differences between liver and lung cohorts were observed for VRT, LNG, and 3D displacement (p=0.0140, p=0.0331, and p=0.0032, respectively). Conclusion: The hypothesis that intrafractional displacement during surface-guided IBH is consistently ≤0.5 cm was not confirmed. Nevertheless, the protocol provided adequate geometric accuracy for most treatments, demonstrating high positional stability during SBRT. Significant differences between lung and liver cohorts suggest that region-specific considerations may be warranted when applying surface-guided IBH SBRT.
Ključne riječi
Hrčak ID:
352454
URI
Datum izdavanja:
26.10.2026.
Posjeta: 0 *