Investigation on using high‐energy proton beam for total body irradiation (TBI)

Abstract

This work investigated the possibility of using proton beam for total body irradiation (TBI). We hypothesized the broad‐slow‐rising entrance dose from a monoenergetic proton beam can deliver a uniform dose to patient with varied thickness. Comparing to photon‐based TBI, it would not require any patient‐specific compensator or beam spoiler. The hypothesis was first tested by simulating 250 MeV, 275 MeV, and 300 MeV protons irradiating a wedge‐shaped water phantom in a paired opposing arrangement using Monte Carlo (MC) method. To allow ±7.5% dose variation, the maximum water equivalent thickness (WET) of a treatable patient separation was 29 cm for 250 MeV proton, and >40 cm for 275 MeV and 300 MeV proton. The compared 6 MV photon can only treat patients with up to 15.5 cm water‐equivalent separation. In the second step, we simulated the dose deposition from the same beams on a patient's whole‐body CT scan. The maximum patient separation in WET was 23 cm. The calculated whole‐body dose variations were ±8.9%,±9.0%, ±9.6%, and ±14% for 250 MeV proton, 275 MeV proton, 300 MeV proton, and 6 MV photon. At last, we tested the current machine capability to deliver a monoenergetic proton beam with a large uniform field. Experiments were performed on a compact double scattering single‐gantry proton system. With its C‐shaped gantry design, the source‐to‐surface distance (SSD) reached 7 m. The measured dose deposition curve had 22 cm relatively flat entrance region. The full width half maximum field size was measured 105 cm. The current scatter filter had to be redesigned to produce a uniform intensity at such treatment distance. In conclusion, this work demonstrated the possibility of using proton beam for TBI. The current commercially available proton machines would soon be ready for such task.PACS number(s): 87.53.Bn, 87.55.K‐, 87.55.‐x, 87.56.‐v

Natural Baicalein-Rich Fraction as Radiosensitizer in Combination with Bismuth Oxide Nanoparticles and Cisplatin for Clinical Radiotherapy

“…Therefore, only the theoretical DEF for two sources, the HDR brachytherapy with an average energy of 0.38 MeV and the 6 MV photon beam with an effective photon energy of 2.0 MeV, was examined in this work concerning each treatment component. [55][56][57][58]…”

Effects of Bismuth Oxide Nanoparticles, Cisplatin and Baicalein-rich Fraction on ROS Generation in Proton Beam irradiated Human Colon Carcinoma Cells

“…2 Proton beam radiotherapy has a broad-slow-rising entrance area before the sharp-rising Bragg peak, which is useful to treat deep-seated tumors without harming the normal healthy tissues. 3 The potential of proton beam therapy have led to more research and clinical endeavor in cancer treatment using ion beams. [3][4][5] Apart from that, the application of radiosensitizers in radiotherapy is also widely explored to target the effect of ionizing radiation on cancer cells while lowering side effects onto normal cells.…”

“…3 The potential of proton beam therapy have led to more research and clinical endeavor in cancer treatment using ion beams. [3][4][5] Apart from that, the application of radiosensitizers in radiotherapy is also widely explored to target the effect of ionizing radiation on cancer cells while lowering side effects onto normal cells. Many types of radiosensitizers are being explored, such as chemicals or drugs, metal-based nanoparticles (NPs), and natural compounds.…”