Dosimetric feasibility of lattice radiotherapy for bulky tumors: a paired VMAT vs. helical tomotherapy comparison - the STRYKE trial
9 affiliations
- 1Department of Radiation Oncology, Istituto Nazionale Tumori - IRCCS Fondazione “G. Pascale”
- 2Radiation Oncology Unit, Responsible Research Hospital
- 3Medical Physics Unit, Responsible Research Hospital
- 4Division of Anesthesia and Pain Medicine, Istituto Nazionale Tumori - IRCCS Fondazione “G. Pascale”
- 5Laboratory Medicine Unit, Istituto Nazionale Tumori - IRCCS Fondazione “G. Pascale”
- 6University of Perugia
- 7Radiation Oncology, IRCCS Azienda Ospedaliero-Universitaria di Bologna
- 8Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum University of Bologna
- 9Dipartimento di Diagnostica per Immagini, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, UOC di Radioterapia Oncologica ed Ematologia
Abstract
Background: Lattice Radiotherapy (LRT) delivers ablative doses to intratumoral vertices alternating with low-dose valleys to treat bulky tumors. While VMAT-LRT is widely adopted, Helical Tomotherapy (HT-LRT) may offer enhanced spatial dose modulation. This study provides the first paired dosimetric comparison of HT-LRT versus VMAT-LRT across scalar, directional, and DVH-based endpoints.
Methods: Paired HT-LRT and VMAT-LRT plans were evaluated in a cohort of 22 patients with bulky tumors using a staggered triangular lattice geometry (5.0 cm inter-vertex spacing, 1.0 cm diameter). Spatial dose modulation was characterized using three scalar Valley-to-Peak Dose Ratio (VPDR) computational methods (VPDR Wu , VPDR D90/D10 , VPDR median ) and a directionally resolved decomposition along principal and diagonal spatial axes. Target coverage, OAR sparing, and morphological correlations were systematically analyzed.
Results: HT-LRT demonstrated statistically significant superiority over VMAT-LRT across all scalar VPDR metrics ( p < 0.05). Directional analysis revealed that HT-LRT advantage is anisotropic, concentrating along intra-plane radial and principal axes, whereas oblique inter-plane diagonals showed comparable modulation between techniques. HT-LRT yielded significantly cooler valley doses and improved low-dose OAR sparing without compromising target coverage ( D 95% ). Target elongation positively correlated with radial VPDR in both modalities due to inter-plane dose summation, while compactness influenced radial VPDR exclusively in HT-LRT.
Conclusion: HT-LRT should provide superior, directionally selective spatial dose modulation compared with VMAT-LRT in bulky tumors. Directionally resolved VPDR analysis exposes technique-specific geometric strengths obscured by scalar summary metrics, supporting HT-LRT as a promising platform for LRT execution, while the relative contribution of delivery technique and planning strategy warrants further investigation.
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BibTeX
@article{mottareale2026dosimetric,
title = {{Dosimetric feasibility of lattice radiotherapy for bulky tumors: a paired VMAT vs. helical tomotherapy comparison - the STRYKE trial}},
author = {Mottareale R and Serra M and Pezzulla D and Cilla S and Borzillo V and Scipilliti E and Silvestro G and De Palma G and Ametrano G and Buonanno F and Arrichiello C and d’Alesio V and di Franco MA and Mercogliano S and Cuomo A and Cavalcanti E and Maranzano E and Donati C and Cellini F and Ravo V and Di Franco R},
journal = {Frontiers in Oncology},
year = {2026},
month = oct,
doi = {10.3389/fonc.2026.1986573},
url = {https://www.frontiersin.org/articles/10.3389/fonc.2026.1986573/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Dosimetric feasibility of lattice radiotherapy for bulky tumors: a paired VMAT vs. helical tomotherapy comparison - the STRYKE trial
AU - Mottareale R
AU - Serra M
AU - Pezzulla D
AU - Cilla S
AU - Borzillo V
AU - Scipilliti E
AU - Silvestro G
AU - De Palma G
AU - Ametrano G
AU - Buonanno F
AU - Arrichiello C
AU - d’Alesio V
AU - di Franco MA
AU - Mercogliano S
AU - Cuomo A
AU - Cavalcanti E
AU - Maranzano E
AU - Donati C
AU - Cellini F
AU - Ravo V
AU - Di Franco R
PY - 2026
DA - 2026/10/27
JO - Frontiers in Oncology
DO - 10.3389/fonc.2026.1986573
UR - https://www.frontiersin.org/articles/10.3389/fonc.2026.1986573/full
AB - Background: Lattice Radiotherapy (LRT) delivers ablative doses to intratumoral vertices alternating with low-dose valleys to treat bulky tumors. While VMAT-LRT is widely adopted, Helical Tomotherapy (HT-LRT) may offer enhanced spatial dose modulation. This study provides the first paired dosimetric comparison of HT-LRT versus VMAT-LRT across scalar, directional, and DVH-based endpoints. Methods: Paired HT-LRT and VMAT-LRT plans were evaluated in a cohort of 22 patients with bulky tumors using a staggered triangular lattice geometry (5.0 cm inter-vertex spacing, 1.0 cm diameter). Spatial dose modulation was characterized using three scalar Valley-to-Peak Dose Ratio (VPDR) computational methods (VPDR Wu , VPDR D90/D10 , VPDR median ) and a directionally resolved decomposition along principal and diagonal spatial axes. Target coverage, OAR sparing, and morphological correlations were systematically analyzed. Results: HT-LRT demonstrated statistically significant superiority over VMAT-LRT across all scalar VPDR metrics ( p < 0.05). Directional analysis revealed that HT-LRT advantage is anisotropic, concentrating along intra-plane radial and principal axes, whereas oblique inter-plane diagonals showed comparable modulation between techniques. HT-LRT yielded significantly cooler valley doses and improved low-dose OAR sparing without compromising target coverage ( D 95% ). Target elongation positively correlated with radial VPDR in both modalities due to inter-plane dose summation, while compactness influenced radial VPDR exclusively in HT-LRT. Conclusion: HT-LRT should provide superior, directionally selective spatial dose modulation compared with VMAT-LRT in bulky tumors. Directionally resolved VPDR analysis exposes technique-specific geometric strengths obscured by scalar summary metrics, supporting HT-LRT as a promising platform for LRT execution, while the relative contribution of delivery technique and planning strategy warrants further investigation.
SN - 2234-943X
ER -