A journey to understand SFRT.

This article tells the story of a medical physicist's journey to understand SFRT which started by accident more than 15 years ago. For decades, clinical application and preclinical research have shown that spatially fractionated radiation therapy (SFRT) can achieve a magically high therapeutic index. However, only recently, SFRT received well-deserved attention from mainstream radiation oncology. Today, our understanding of SFRT remains limited, which significantly hinders the advancement of SFRT for patient care. In this article, the author intends to shed some light on several important but unanswered SFRT research questions, including what is the essence of SFRT, which dosimetric parameters have clinical relevance and which do not, how does SFRT spare normal tissue but not tumor, and why radiobiological models developed for conventional radiation therapy may not be suitable for SFRT.

Chang S 《-》

Overview and Recommendations for Prospective Multi-institutional Spatially Fractionated Radiation Therapy Clinical Trials.

Li H ，Mayr NA ，Griffin RJ ，Zhang H ，Pokhrel D ，Grams M ，Penagaricano J ，Chang S ，Spraker MB ，Kavanaugh J ，Lin L ，Sheikh K ，Mossahebi S ，Simone CB ，Roberge D ，Snider JW ，Sabouri P ，Molineu A ，Xiao Y ，Benedict SH ... -  《-》

Spatially fractionated radiation therapy: a critical review on current status of clinical and preclinical studies and knowledge gaps.

Spatially fractionated radiation therapy (SFRT) is a therapeutic approach with the potential to disrupt the classical paradigms of conventional radiation therapy. The high spatial dose modulation in SFRT activates distinct radiobiological mechanisms which lead to a remarkable increase in normal tissue tolerances. Several decades of clinical use and numerous preclinical experiments suggest that SFRT has the potential to increase the therapeutic index, especially in bulky and radioresistant tumors. To unleash the full potential of SFRT a deeper understanding of the underlying biology and its relationship with the complex dosimetry of SFRT is needed. This review provides a critical analysis of the field, discussing not only the main clinical and preclinical findings but also analyzing the main knowledge gaps in a holistic way.

Prezado Y ，Grams M ，Jouglar E ，Martínez-Rovira I ，Ortiz R ，Seco J ，Chang S ... -  《-》

Conventional dose rate spatially-fractionated radiation therapy (SFRT) treatment response and its association with dosimetric parameters-A preclinical study in a Fischer 344 rat model.

Rivera JN ，Kierski TM ，Kasoji SK ，Abrantes AS ，Dayton PA ，Chang SX ... -  《PLoS One》

Which Modality of SFRT Should be Considered First for Bulky Tumor Radiation Therapy, GRID or LATTICE?

Spatially fractionated radiation therapy (SFRT), also known as the GRID and LATTICE radiotherapy (GRT, LRT), the concept of treating tumors by delivering a spatially modulated dose with highly non-uniform dose distributions, is a treatment modality of growing interest in radiation oncology, physics, and radiation biology. Clinical experience in SFRT has suggested that GRID and LATTICE therapy can achieve a high response and low toxicity in the treatment of refractory and bulky tumors. Limited initially to GRID therapy using block collimators, advanced, and versatile multi-leaf collimators, volumetric modulated arc technologies and particle therapy have since increased the capabilities and individualization of SFRT and expanded the clinical investigation of SFRT to various dosing regimens, multiple malignancies, tumor types and sites. As a 3D modulation approach outgrown from traditional 2D GRID, LATTICE therapy aims to reconfigure the traditional SFRT as spatial modulation of the radiation is confined solely to the tumor volume. The distinctively different beam geometries used in LATTICE therapy have led to appreciable variations in dose-volume distributions, compared to GRID therapy. The clinical relevance of the variations in dose-volume distribution between LATTICE and traditional GRID therapies is a crucial factor in determining their adoption in clinical practice. In this Point-Counterpoint contribution, the authors debate the pros and cons of GRID and LATTICE therapy. Both modalities have been used in clinics and their applicability and optimal use have been discussed in this article.

Zhang H ，Wu X 《-》