P01.048 A novel transducer array layout for delivering Tumor Treating Fields to the infratentorial brain at therapeutic levels
Bibliographic record
Abstract
Tumor Treating Fields (TTFields) is an antimitotic cancer treatment that utilizes low intensity (1–3 V/cm) alternating electric fields in the intermediate frequency (100–300 kHz), approvedfor the treatment of Glioblastoma Multiforme (GBM) located in the supratentorial regions of the brain. A clinical trial testing the efficacy of TTFields for treating brain metastases is currently underway (METIS, NCT02831959). TTFields are delivered via two pairs of transducer arrays placed on the patient’s skin in proximity to the tumor. The standard array layouts used to deliver TTFields involve placement of the arrays on the supratentorial regions of the head. Using these layouts, therapeutic field intensities above 1 V/cm are achieved within the surpatentorial brain. However, field intensities in the infratenorium fall to sub-therapeutic levels. . Brain metastases commonly occur in the infratentorium. In addition, infratentorial tumors are common in the pediatric population. Hence, there is a need to for array layouts that can be used to deliver TTFields effectively to the infratentorial brain. Here we present a new array layout designed to deliver high field intensities to the infratentorial brain. To simulate delivery of TTFields to the brain, realistic computerized head models of an adult human female and an adult human male were used. Virtual transducer arrays were placed on the models, and boundary conditions were set to simulate delivery of TTFields at 200 kHz. Various array layouts were tested, and field distributions resulting from the layouts were evaluated. In both models, TTfields was delivered to the infratentorium most effectively with a layout, in which each array of one pair was laterally placed superficially to the lower region of the occipital lobe, and the two arrays of the second pair were placed on the calvarium and the superior aspect of the neck. In both models, the pair of arrays in which one array was placed on the calvarium and one array on the superior aspect of the neck delivered field intensities above 1.1 V/cm to over 95% of the volume of the infratentorial brain, and the pair of arrays placed on the lateral aspects of the occipital lobe delivered field intensities above 1 V/cm to over 95% of the infratentorial brain. Both pairs of arrays delivered field intensities above 1 V/cm to significant portions of the supratentorial brain. This work suggests a practical approach for delivering TTFields to the cerebellum, brain-stem and surrounding regions which are located inferior to the tentorium.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.011 | 0.003 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".