Company: DRTSW
Filing Date: 2025-03-12
Form Type: 20-F
Source: 0001213900-25-023187
Chunk: 120

Company: Alpha Tau Medical Ltd.
Filing Date: 2025-03-12
Form: 20-F
Item: Item 4
Chunk 120
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and stereotactic body radiation therapy, have focused on improving the precision of gamma rays to concentrate more radiation in a tighter
area, but ultimately face similar limitations from the innate characteristics of gamma rays.

In brachytherapy, small capsules
containing a therapeutic dose of radiation, or seeds, are placed in or as close as possible to the tumor. By hewing closely to the tumor
and utilizing the sharp dose falloff beyond the seed, physicians may more ably navigate around the healthy surrounding tissue. Brachytherapy,
in being based on beta or gamma radiation, has similar concerns with respect to spillover damage in the surrounding healthy tissue.

A less common form of internal
radiotherapy is radioembolization, or selective internal radiation therapy, via tiny radioactive beads. The ability of these radioactive
beads to adhere to small blood vessels has led to their use in the treatment of liver cancer. Given the unique differential blood supply
of the liver, irradiating the tumor and concurrently blocking the blood supply may deprive the tumor of vital oxygen and nutrients.

In any instance of radiotherapy,
the total exposure must be carefully calibrated, as the human body has a fixed, maximum level of radiation tolerance before the onset
of irreversible toxicity and debilitating side effects, such as impaired brain, spinal cord, kidney and bone marrow function and immune
deficiency. With its higher relative biological efficiency enabling lower dose levels for anti-tumor activity, and very limited range,
we believe alpha radiotherapy may offer an attractive treatment modality against this backdrop.

Uses of alpha radiation in radiotherapy

We believe alpha radiation
has several significant advantages for use in cancer radiotherapy, including having a high relative biological efficiency (potentially
enabling it to destroy tumor cells with administration of lower levels of radiation); it is impervious to factors such as hypoxia, and
it has a very well-defined range of travel with limited collateral damage. Nonetheless, its use has also been limited precisely due to
alpha’s extremely short particle range of less than 100 μm in living tissue, well below the threshold of clinical utility.
For this reason, traditional attempts to deliver alpha radiation locally have failed to generate a clinically useful killing effect.

The limited use to date
of alpha radiation in radiotherapy has been in systemic therapies using radiopharmaceuticals. For example, Xofigo, a salt of radium
that naturally localizes to regions where cancer cells are infiltrating bone, has been approved by the FDA for the treatment of