Thesis (Ph. D.)--University of Wisconsin--Madison, 1941. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 12).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1943. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [34-35]).

Thesis--University of California, Berkeley, 1958. / "Physics and Mathematics" -t.p. Includes bibliographical references (p. 101-102).

Thesis supervisor: Onel Yasar. Includes bibliographic references (p. 73-74).

Presented as Plain's Thesis (Ph. D.)--University of Wisconsin--Madison, 1940. / Reprinted from Physical review, vol. 57, no. 3 (1 Feb. 1940). Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1950. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

In proton therapy systems with pencil-beam scanning, output of Halo effect is not necessarily included in Treatment Planning System (TPS). Halo effect (low-intensity tail) can significantly affect a patient’s dose distribution. The output of this dose depends on the field size being irradiated. Although much research has been made to investigate such relation to the field size, the number of reports on dose calculations including the halo effect is small. In this work we have investigated the Halo effect, including field size factor, target depth factor, and air gaps with a range shifter for a Varian ProBeam. Dose calculations created on the Eclipse Treatment Planning System (vs15.6 TPS) are compared with plane-parallel ionization chambers (PTW Octavius 1500) measurements using PCS and AcurosPT MC model in different isocenters: 5cm, 10cm, and 20cm. We find that in AcurosPT algorithm deviations range between -7.53% (for 2cm field in 25cm air gap with range shifter) up to +7.40% (for 20cm field in 15cm air gap with range shifter). Whereas, in PCS algorithm the deviations are -2.07% (for 20x20cm field in open conditions) to -6.29% (for 20x20cm field in 25cm air gap with range shifter). / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

Cancer therapy with high-energy particles has proved to be beneficial over the last 10 years. Protons are regarded as being more advantageous because of their distinctive physical depth dose distribution that allows dose conformation to the tumor while sparing normal tissue. In this study, the relative biological effectiveness (RBE) values for the 200-MeV clinical proton beam at iThemba LABS were measured at strategic positions along a 5 cm Spread-Out-Bragg-Peak (SOBP). RBE values were evaluated at the initial plateau of the virgin beam (24.2 mm in Perspex), and at the middle part, distal part and distal edge (12.4% max. dose) along the SOBP (depth in Perspex= 161.4, 181.3 and 207.7 mm respectively). Biological systems used were Chinese hamster ovary cells (CHO-Kl) for both cell survival and micronuclei frequencies as well as human T-lymphocytes for micronuclei frequency analysis. (60)^Co y-irradiation served as a reference. Cell survival measurements yielded RBE values of 1.17 at the distal part and 1.62 at the distal edge (12.4 max. dose). For micronuclei analysis, a limiting RBEap+ay value of 1.3 at the distal part was observed. Using T-lymphocytes, RBEap+/ay values calculated were 2.1, 2.7 and 3.2 at the middle part, distal part and distal edge, respectively. These results show an increase in RBE with depth of penetration and are explained by an increase in ionization density at the end of the SOBP. This is influenced by a high fraction of low-energy protons at that position. Protons were found to be most potent per unit dose towards the end as they slow down to a complete stop. It is recommended that an RBE value slightly greater than the current 1.1 be applied in therapy. Also, that the less steep biological effective depth dose curve be taken into account when dose planning. / Thesis (MSc. ARST) North-West University, Mafikeng Campus, 2003

Thesis (M.S. in Physics)--United States Naval Postgraduate School, 1959. / "Physics and Mathematics" -t.p. Includes bibliographical references (p. 39).

Thesis (MSc)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.