Browsing by Author "Paino, JR"

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Characterisation and evaluation of a PNP strip detector for synchrotron microbeam radiation therapy
    (IOP Publishing, 2018-06-21) Davis, JA; Paino, JR; Dipuglia, A; Cameron, M; Siegele, R; Pastuovic, Z; Petasecca, M; Perevertaylo, VL; Rosenfeld, AB; Lerch, MLF
    The Quality Assurance requirements of detectors for Synchrotron Micro-beam Radiation Therapy are such that there are limited commercial systems available. The high intensity and spatial fractionation of synchrotron microbeams requires detectors be radiation hard and capable of measuring high dose gradients with high spatial resolution sensitivity. Silicon single strip detectors are a promising candidate for such applications. The PNP strip detector is an alternative design of an already proven technology and is assessed on its contextual viability. In this study, the electrical and charge collection efficiency properties of the device are characterised. In addition, a dedicated TCAD model is used to support ion beam induced charge measurements to determine the spatial resolution of the detector. Lastly, the detector was used to measure the full width half maximum and peak to valley dose ratio for microbeams with only a slight over response. With the exception of radiation hardness the PNP detector is a promising candidate for quality assurance in microbeam radiation therapy. Copyright 2024 IOP Publishing
  • No Thumbnail Available
    Item
    IBIC microscopy – the powerful tool for testing micron – sized sensitive volumes in segmented radiation detectors used in synchrotron microbeam radiation and hadron therapies
    (Elsevier B. V., 2019-11-01) Pastuovic, Z; Davis, J; Tran, LT; Paino, JR; Dipuglia, A; James, B; Povoli, M; Kok, A; Perevertaylo, VL; Siegele, R; Prokopovich, DA; Lerch, MLF; Petasecca, M; Rosenfeld, AB; Cohen, DD
    Ion Beam Induced Charge (IBIC) microscopy performed using highly tuned microbeams of accelerated ions with energies in the MeV range is the powerful tool for analysis of charge carrier transport properties in semiconductor devices based on semiconductor hetero-junction, metal-on-semiconductor and semiconductor-on-insulator configurations. Here we present two cases of recent applications of the IBIC microscopy in the field of medical radiation physics. The reduced-rate ion microbeams with energies in the MeV range and sub-micrometer spot-sizes have been used for the investigations of the charge collection efficiency (CCE) in sensitive volumes of segmented radiation detectors in order to measure the spatial distribution and uniformity of CCE in different polarization conditions. This information allows the determination of the charge carrier transport properties in selected substructures of a particular device and to quantify its ability to accurately determine the energy deposited by incident ionizing radiation - two fundamental requirements of any microdosimeter or detector of ionizing radiation. © 2019 Elsevier B.V.
  • Thumbnail Image
    Item
    Incorporating clinical imaging into the delivery of microbeam radiation therapy
    (MDPI, 2021-09-30) Paino, JR; Barnes, M; Engels, E; Davis, JA; Guatelli, S; de Veer, M; Hall, CJ; Häusermann, D; Tehei, M; Corde, S; Rosenfeld, AB; Lerch, MLF
    Synchrotron microbeam radiation therapy is a promising pre-clinical radiation treatment modality; however, it comes with many technical challenges. This study describes the image guidance protocol used for Australia’s first long-term pre-clinical MRT treatment of rats bearing 9L gliosarcoma tumours. The protocol utilises existing infrastructure available at the Australian Synchrotron and the adjoining Monash Biomedical Imaging facility. The protocol is designed and optimised to treat small animals utilising high-resolution clinical CT for patient specific tumour identification, coupled with conventional radiography, using the recently developed SyncMRT program for image guidance. Dosimetry performed in small animal phantoms shows patient dose is comparable to standard clinical doses, with a CT associated dose of less than 1.39cGy and a planar radiograh dose of less than 0.03cGy. Experimental validation of alignment accuracy with radiographic film demonstrates end to end accuracy of less than ±0.34mm in anatomical phantoms. Histological analysis of tumour-bearing rats treated with microbeam radiation therapy verifies that tumours are targeted well within applied treatment margins. To date, this technique has been used to treat 35 tumour-bearing rats. © 2021 by the Authors. Licensee MDPI, Basel, Switzerland.
  • Thumbnail Image
    Item
    A novel anthropomorphic phantom composed of tissue-equivalent materials for use in experimental radiotherapy: design, dosimetry and biological pilot study
    (MDPI, 2023-04-26) Breslin, T; Paino, JR; Wegner, M; Engels, E; Fiedler, S; Forrester, HB; Rennau, H; Bustillo, J; Cameron, M; Häusermann, D; Hall, CJ; Krause, D; Hildebrandt, G; Lerch, MLF; Schültke, E
    The production of anthropomorphic phantoms generated from tissue-equivalent materials is challenging but offers an excellent copy of the typical environment encountered in typical patients. High-quality dosimetry measurements and the correlation of the measured dose with the biological effects elicited by it are a prerequisite in preparation of clinical trials with novel radiotherapy approaches. We designed and produced a partial upper arm phantom from tissue-equivalent materials for use in experimental high-dose-rate radiotherapy. The phantom was compared to original patient data using density values and Hounsfield units obtained from CT scans. Dose simulations were conducted for broad-beam irradiation and microbeam radiotherapy (MRT) and compared to values measured in a synchrotron radiation experiment. Finally, we validated the phantom in a pilot experiment with human primary melanoma cells. © 2023 The Authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) licence.
  • Thumbnail Image
    Item
    The spinal cord as organ of risk: assessment for acute and subacute neurological adverse effects after microbeam radiotherapy in a rodent model
    (MDPI, 2023-04-26) Jaekel, F; Paino, JR; Engels, E; Klein, M; Barnes, M; Häusermann, D; Hall, CJ; Zheng, G; Wang, HX; Hildebrandt, G; Lerch, MLF; Schültke, E
    Microbeam radiotherapy (MRT), a high dose rate radiotherapy technique using spatial dose fractionation at the micrometre range, has shown a high therapeutic efficacy in vivo in different tumour entities, including lung cancer. We have conducted a toxicity study for the spinal cord as organ of risk during irradiation of a target in the thoracic cavity. In young adult rats, the lower thoracic spinal cord was irradiated over a length of 2 cm with an array of quasi-parallel microbeams of 50 µm width, spaced at a centre-to-centre distance of 400 µm, with MRT peak doses up to 800 Gy. No acute or subacute adverse effects were observed within the first week after irradiation up to MRT peak doses of 400 Gy. No significant differences were seen between irradiated animals and non-irradiated controls in motor function and sensitivity, open field test and somatosensory evoked potentials (SSEP). After irradiation with MRT peak doses of 450–800 Gy, dose-dependent neurologic signs occurred. Provided that long-term studies do not reveal significant morbidity due to late toxicity, an MRT dose of 400 Gy can be considered safe for the spinal cord in the tested beam geometry and field size. © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.