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PurposeStereotactic radiosurgery (SRS) can be delivered with a standard linear accelerator (linac). At institutions having more than one linac, beam matching is common practice. In the literature, there are indications that machine... more
PurposeStereotactic radiosurgery (SRS) can be delivered with a standard linear accelerator (linac). At institutions having more than one linac, beam matching is common practice. In the literature, there are indications that machine central axis (CAX) matching for broad fields does not guarantee matching of small fields with side ≤2 cm. There is no indication on how matching for broad fields on axis translates to matching small fields off axis. These are of interest to multitarget single‐isocenter (MTSI) SRS planning and the present work addresses that gap in the literature.MethodsWe used 6 MV flattening filter free (FFF) beams from four Elekta VersaHD® linacs equipped with an Agility™ multileaf collimator (MLC). The linacs were strictly matched for broad fields on CAX. We compared output factors (OPFs) and effective field size, measured concurrently using a novel 2D solid‐state dosimeter “Duo” with a spatial resolution of 0.2 mm, in square and rectangular static fields with sides fr...
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PURPOSE The purpose of this study was to examine the effect of departmental planning techniques on appropriate in-vivo source tracking error thresholds for high dose rate (HDR) prostate brachytherapy (BT) treatments, and to determine if a... more
PURPOSE The purpose of this study was to examine the effect of departmental planning techniques on appropriate in-vivo source tracking error thresholds for high dose rate (HDR) prostate brachytherapy (BT) treatments, and to determine if a single in-vivo source tracking error threshold would be appropriate for the same patient anatomy. METHOD The prostate, rectum, and urethra, was contoured on a single patient trans-rectal ultrasound (TRUS) dataset. Anonymised DICOM files were disseminated to 16 departments who created an HDR prostate BT treatment plan on the dataset with a prescription dose of 15 Gy in a single fraction. Departments were asked to follow their own local treatment planning guidelines. Source positioning errors were then simulated in the 16 treatment plans and the effect on dose-volume histogram (DVH) indices calculated. Change in DVH indices were used to determine appropriate in-vivo source tracking error thresholds. Plans were considered to require intervention if the following DVH conditions occurred: prostate V100% < 90%, urethra D0.1cc > 118%, and rectum Dmax > 80%. RESULTS There was wide variation in appropriate in-vivo source tracking error thresholds amongst the 16 participating departments, ranging from 1 - 6 mm. Appropriate in-vivo source tracking error thresholds were also found to depend on the direction of the source positioning error and the end-point. A robustness parameter was derived, and found to correlate with the sensitivity of plans to source positioning errors. CONCLUSION A single HDR prostate BT in-vivo source tracking error threshold cannot be applied across multiple departments, even for the same patient anatomy. The burden on in-vivo source tracking devices may be eased through improving HDR prostate BT plan robustness during the plan optimisation phase. This article is protected by copyright. All rights reserved.
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Diffusing alpha-emitters radiation therapy (DaRT) is a revolutionary brachytherapy technique used to treat solid tumours. Implant seeds are coated with 224Ra which, along its shortlived daughter atoms, emits alpha particles of high linear... more
Diffusing alpha-emitters radiation therapy (DaRT) is a revolutionary brachytherapy technique used to treat solid tumours. Implant seeds are coated with 224Ra which, along its shortlived daughter atoms, emits alpha particles of high linear energy transfer (LET) and of high relative biological efficiency (RBE), creating a tumour-killing dose distribution a few mm wide. Those alpha particles are of energy between 5.67 and 8.78 MeV. DaRT is under investigation in clinical trials, but there currently is no obvious solution for dosimetry aimed at quality assurance of treatment. This study introduces alpha-RAD, a dosimeter based on a metal-oxide-semiconductor (MOS) sensor technology. Alpha-RAD was characterized with 241Am, which emits alpha particles of energy 5.49 MeV. The results showed that alpha-RAD had good linearity with dose, with the signal increasing linearly in the range from 0 to 6.84 Gy. Also, an external bias in the range between 15 and 60 V, applied on the gate of alpha-RAD d...
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High Dose Rate Brachytherapy (HDRB) boost is a well-established treatment for prostate cancer (PC). We describe the PROstate Multicentre External beam radioTHErapy Using Stereotactic boost (PROMETHEUS) study. Non-surgical stereotactic... more
High Dose Rate Brachytherapy (HDRB) boost is a well-established treatment for prostate cancer (PC). We describe the PROstate Multicentre External beam radioTHErapy Using Stereotactic boost (PROMETHEUS) study. Non-surgical stereotactic techniques are used to deliver similar doses to HDRB boost regimens with a dose escalation sub-study. Eligible patients have intermediate or high risk PC. PROMETHEUS explores the safety, efficacy and feasibility of multiple Australian centres cooperating in the delivery of Prostate Stereotactic Body Radiotherapy (SBRT) technology. A SBRT boost component Target Dose (TD) of 19Gy in two fractions is to be delivered, followed by a subsequent EBRT component of 46Gy in 23 fractions. Once accrual triggers have been met, SBRT doses can be escalated in 1 Gy increments to a maximum of 22Gy in two fractions. Patient safety will also be measured with the rate of both acute and late moderate to severe Gastro-Intestinal (GI) and Genito-Urinary (GU) Common Terminolo...
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This study aims to assess the accuracy of source position verification during high-dose rate (HDR) prostate brachytherapy using a novel, in-house developed two-dimensional (2D) diode array (the Magic Plate), embedded exactly below the... more
This study aims to assess the accuracy of source position verification during high-dose rate (HDR) prostate brachytherapy using a novel, in-house developed two-dimensional (2D) diode array (the Magic Plate), embedded exactly below the patient within a carbon fiber couch. The effect of tissue inhomogeneities on source localization accuracy is examined. Monte Carlo (MC) simulations of 12 source positions from a HDR prostate brachytherapy treatment were performed using the Geant4 toolkit. An Ir-192 Flexisource (Isodose Control, Veenendaal, the Netherlands) was simulated inside a voxelized patient geometry, and the dose deposited in each detector of the Magic Plate evaluated. The dose deposited in each detector was then used to localize the source position using a proprietary reconstruction algorithm. The accuracy of source position verification using the Magic Plate embedded in the patient couch was found to be affected by the tissue inhomogeneities within the patient, with an average ...
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With the increase in complexity of brachytherapy treatments, there has been a demand for the development of sophisticated devices for delivery verification. The Centre for Medical Radiation Physics (CMRP), University of Wollongong, has... more
With the increase in complexity of brachytherapy treatments, there has been a demand for the development of sophisticated devices for delivery verification. The Centre for Medical Radiation Physics (CMRP), University of Wollongong, has demonstrated the applicability of semiconductor devices to provide cost-effective real-time quality assurance for a wide range of brachytherapy treatment modalities. Semiconductor devices have shown great promise to the future of pretreatment and in vivo quality assurance in a wide range of brachytherapy treatments, from high-dose-rate (HDR) prostate procedures to eye plaque treatments. The aim of this article is to give an insight into several semiconductor-based dosimetry instruments developed by the CMRP. Applications of these instruments are provided for breast and rectal wall in vivo dosimetry in HDR brachytherapy, urethral in vivo dosimetry in prostate low-dose-rate (LDR) brachytherapy, quality assurance of HDR brachytherapy afterloaders, HDR pr...
Research Interests: Engineering, Semiconductors, Brachytherapy, Medical Physics, Medicine, and 14 moreQuality Assurance, Humans, Female, Male, Breast, Clinical Sciences, Dosimetry, Science and Technology Studies, In Vivo Dosimetry, Breast Neoplasms, quality assurance in health care, Prostatic neoplasms, Rectum, and Urethra
Radiotherapy is one of the most important treatment options for localized early-stage or advanced-stage prostate cancer (CaP). Radioresistance (relapse after radiotherapy) is a major challenge for the current radiotherapy. There is great... more
Radiotherapy is one of the most important treatment options for localized early-stage or advanced-stage prostate cancer (CaP). Radioresistance (relapse after radiotherapy) is a major challenge for the current radiotherapy. There is great interest in investigating mechanisms of radioresistance and developing novel treatment strategies to overcome radioresistance. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression at the post-transcriptional level, participating in numerous physiological and pathological processes including cancer invasion, progression, metastasis and therapeutic resistance. Emerging evidence indicates that miRNAs play a critical role in the modulation of key cellular pathways that mediate response to radiation, influencing the radiosensitivity of the cancer cells through interplaying with other biological processes such as cell cycle checkpoints, apoptosis, autophagy, epithelial-mesenchymal transition and cancer stem cells. Here, we summarize...
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BrachyView is a novel in-body imaging system utilising high-resolution pixelated silicon detectors (Timepix) and a pinhole collimator for brachytherapy source localisation. Recent studies have investigated various options for real-time... more
BrachyView is a novel in-body imaging system utilising high-resolution pixelated silicon detectors (Timepix) and a pinhole collimator for brachytherapy source localisation. Recent studies have investigated various options for real-time intraoperative dynamic dose treatment planning to increase the quality of implants. In a previous proof-of-concept study, the justification of the pinhole concept was shown, allowing for the next step whereby multiple active seeds are implanted into a PMMA phantom to simulate a more realistic clinical scenario. In this study, 20 seeds were implanted and imaged using a lead pinhole of 400 μ m diameter. BrachyView was able to resolve the seed positions within 1–2 mm of expected positions, which was verified by co-registering with a full clinical post-implant CT scan.
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The dosimetric quality of seed implants is a crucial part of the prostate brachytherapy treatment procedure. Incorrect seed placement during or after deployment leads to both short and long term complications, including urethral and... more
The dosimetric quality of seed implants is a crucial part of the prostate brachytherapy treatment procedure. Incorrect seed placement during or after deployment leads to both short and long term complications, including urethral and rectal toxicity. The BrachyView system is a fast intraoperative planning system, providing real-time dosimetric information by acting as an in-body gamma camera. It incorporates three tiled
Research Interests: Engineering, Computer Science, Ultrasound Imaging, Imaging, Body, and 14 moreBrachytherapy, Body Image, Ultrasound, Novel, Medicine, Biomedical Imaging, Image Reconstruction, Radiation Therapy Treatment Planning, System, Prostate, Real Time, Treatment planning, Three dimensional Reconstruction, and Pinhole Optics
INTRODUCTIONProstate cancer (CaP) is the second leading malignancy in older men in Western countries. The role of CD44 variant 6 (CD44v6) in CaP progression and therapeutic resistance is still uncertain. Here, we investigated the roles of... more
INTRODUCTIONProstate cancer (CaP) is the second leading malignancy in older men in Western countries. The role of CD44 variant 6 (CD44v6) in CaP progression and therapeutic resistance is still uncertain. Here, we investigated the roles of CD44v6 in CaP metastasis and chemo/radioresistance. Expression of CD44v6 in metastatic CaP cell lines, human primary CaP tissues and lymph node metastases was assessed using immunofluorescence and immunohistochemistry, respectively.METHODSKnock down (KD) of CD44v6 was performed in PC‐3M, DU145, and LNCaP cells using small interfering RNA (siRNA), and confirmed by confocal microscope, Western blot and quantitative real time polymerase chain reaction (qRT‐PCR). Cell growth was evaluated by proliferation and colony formation assays. The adhesive ability and invasive potential were assessed using a hyaluronic acid (HA) adhesion and a matrigel chamber assay, respectively. Tumorigenesis potential and chemo‐/radiosensitivity were measured by a sphere form...
Research Interests: Biology, Metastasis, Cancer Research, Medicine, Pancreatic Cancer, and 15 moreIdentification, Humans, Drug Resistance, Male, Expression, Phosphorylation, CD, Clinical Sciences, Du, Cell Proliferation, Chemoresistance, Biochemistry and cell biology, LNCaP, Docetaxel, and Paediatrics and reproductive medicine
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Brachytherapy, Volume 6, Issue 2, Pages 87, April 2007, Authors:Annie Ho, MBBS, FRACP; Joseph Bucci, MBBS, FRACP; David J. Malouf, MBBS, FRACS. Journal Home, ... Annie Ho, MBBS, FRACP, Joseph Bucci, MBBS, FRACP, David J. Malouf, MBBS,... more
Brachytherapy, Volume 6, Issue 2, Pages 87, April 2007, Authors:Annie Ho, MBBS, FRACP; Joseph Bucci, MBBS, FRACP; David J. Malouf, MBBS, FRACS. Journal Home, ... Annie Ho, MBBS, FRACP, Joseph Bucci, MBBS, FRACP, David J. Malouf, MBBS, FRACS. ...
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No abstract is available. To read the body of this article, please view the Full Text online. ... © 2008 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved. ... Visit SciVerse ScienceDirect to see if you have... more
No abstract is available. To read the body of this article, please view the Full Text online. ... © 2008 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved. ... Visit SciVerse ScienceDirect to see if you have access via your institution.
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Abstract Urethral Spectroscopic Alarm (USA) Probe for Prostate Implants 1A. B. Rosenfeld, 1D. L. Cutajar, 1M. LF Lerch, 1G. J. Takacs, 2J. A. Bucci, 2L. J. Duggan, 3M. Zaider, 4M. Zelefsky and 3G. N. Cohen 1Centre for Medical Radiation... more
Abstract Urethral Spectroscopic Alarm (USA) Probe for Prostate Implants 1A. B. Rosenfeld, 1D. L. Cutajar, 1M. LF Lerch, 1G. J. Takacs, 2J. A. Bucci, 2L. J. Duggan, 3M. Zaider, 4M. Zelefsky and 3G. N. Cohen 1Centre for Medical Radiation Physics, University of ...