Biological and Mechanical Synergies to Deal With Proton Therapy Pitfalls: Minibeams, FLASH, Arcs, and Gantryless Rooms.

Proton therapy has advantages and pitfalls comparing with photon therapy in radiation therapy. Among the limitations of protons in clinical practice we can selectively mention: uncertainties in range, lateral penumbra, deposition of higher LET outside the target, entrance dose, dose in the beam path, dose constraints in critical organs close to the target volume, organ movements and cost. In this review, we combine proposals under study to mitigate those pitfalls by using individually or in combination: (a) biological approaches of beam management in time (very high dose rate "FLASH" irradiations in the order of 100 Gy/s) and (b) modulation in space (a combination of mini-beams of millimetric extent), together with mechanical approaches such as (c) rotational techniques (optimized in partial arcs) and, in an effort to reduce cost, (d) gantry-less delivery systems.

FLASH and minibeams in radiation therapy: the effect of microstructures on time and space and their potential application to protontherapy.

After years of lethargy, studies on two non-conventional microstructures in time and space of the beams used in radiation therapy are enjoying a huge revival. The first effect called "FLASH" is based on very high dose-rate irradiation (pulse amplitude ≥10 Gy/s), short beam-on times (≤100 ms) and large single doses (≥10 Gy) as experimental parameters established so far to give biological and potential clinical effects. The second effect relies on the use of arrays of minibeams ( 0.

Treatment with 5-fluorouracil enhances radiosensitivity of the human pancreatic cancer cell line MiaPaCa-2.

Background And Purpose: Several clinical studies have suggested that the combination of radiation therapy and 5-fluorouracil (5-FU) may improve outcome of patients with pancreatic cancer. However, there are few experimental studies supporting this treatment.

Aim Of The Study: To examine the radiosensitivity of human pancreatic cancer cells and its modulation by 5-FU.