Personalized 3D-printed anthropomorphic whole-body phantom irradiated by protons, photons, and neutrons

Abstract

The objective of this study was to confirm the feasibility of three-dimensionally-printed (3D-printed), personalized whole-body anthropomorphic phantoms for radiation dose measurements in a variety of charged and uncharged particle radiation fields. We 3D-printed a personalized whole-body phantom of an adult female with a height of 154.8 cm, mass of 90.7 kg, and body mass index of 37.8 kg/m2. The phantom comprised of a hollow plastic shell filled with water and included a watertight access conduit for positioning dosimeters. It is compatible with a wide variety of radiation dosimeters, including ionization chambers that are suitable for uncharged and charged particles. Its mass was 6.8 kg empty and 98 kg when filled with water. Watertightness and mechanical robustness were confirmed after multiple experiments and transportations between institutions. The phantom was irradiated to the cranium with therapeutic beams of 170-MeV protons, 6-MV photons, and fast neutrons. Radiation absorbed dose was measured from the cranium to the pelvis along the longitudinal central axis of the phantom. The dose measurements were made using established dosimetry protocols and well-characterized instruments. For the therapeutic environments considered in this study, stray radiation from intracranial treatment beams was the lowest for proton therapy, intermediate for photon therapy, and highest for neutron therapy. An illustrative example set of measurements at the location of the thyroid for a square field of 5.3 cm per side resulted in 0.09, 0.59, and 1.93 cGy/Gy from proton, photon, and neutron beams, respectively. In this study, we found that 3D-printed personalized phantoms are feasible, inherently reproducible, and well-suited for therapeutic radiation measurements. The measurement methodologies we developed enabled the direct comparison of radiation exposures from neutron, proton, and photon beam irradiations.

Dosimetric characteristics of 3D-printed and epoxy-based materials for particle therapy phantoms

“…To overcome this limitation, QA solutions for novel workflows are machined from slabs of well-characterized surrogate materials [12,13] or use conventional phantoms modified, for example, by drilling holes to access the nasal cavities and change their filling [14]. On the other hand, additive manufacturing (AM), more commonly known as 3D printing, has gained traction as a way to enable quick and economical production of phantom components [15][16][17]. In recent years, commercial solutions for individualized, 3D-printed phantoms for photon therapy have entered the market [18,19], but their transferability to particle application is limited [20].…”

A Compact Neutron Generator for the Niort® Treatment of Severe Solid Cancers

“…Differently from the Boron Neutron Capture Therapy (BNCT) exploiting thermal and epithermal neutrons to induce (n, a) reactions in boron carriers injected into patients 5,6,7 , the fast neutrons interact directly and efficiently with the hydrogen nuclei, producing recoil protons that ionize the tissues. Monte Carlo simulations have shown that the nIORT® delivers on the tumour bed a fast-neutron IR with a high linear energy transfer (LET) 8 and a relative biological effectiveness (RBE) 9 significantly higher than all other IRs such as X-rays, electrons and protons, thus resulting very efficient in producing DNA double strand breaks (DSBs) of the cancer cells. 10 It is known that around 50% of the absorbed dose imparted by neutron collisions (between 0.1 and 70 MeV) is due the ionizing effect of elastically scattered recoil protons, mainly from hydrogen atoms present in water contained in living cells.…”

Reproduction of a conventional anthropomorphic female chest phantom by 3D‐printing: Comparison of image contrasts and absorbed doses in CT

“…Although various studies addressing patientspecific printed phantoms have been published, 5,[11][12][13][14] only few studies have performed detailed comparisons to conventionally produced anthropomorphic phantoms. 1,2,15,16 In the latter studies, computed tomography (CT) values (given in Hounsfield units [HU]) of reference phantoms could be reproduced with sufficient accuracy.…”