Hau E.K.C.,St George Cancer Care Center |
Oborn B.M.,Wollongong Hospital |
Oborn B.M.,University of Wollongong |
Bucci J.,St George Cancer Care Center
Brachytherapy | Year: 2011
Purpose: We report a case of prostate brachytherapy seed migration to the vertebral venous plexus and subsequently to the renal artery with corresponding dosimetry analysis describing nerve doses. Methods and Materials: A 52-year-old male with low-risk prostate carcinoma (clinical stage T1c; Gleason score. =6; prostate-specific antigen level of 5.5) underwent transperineal permanent prostate seed implant. Postimplantation routine imaging had failed to locate the missing seed, but he subsequently presented with back pain and parathesia with radiation down the leg. Results: CT with bony windows and MRI had located the seed in the left L5 vertebral venous plexus. Neurosurgical intervention failed to locate and remove the migrated seed. Postsurgery, the left lower limb parathesia persisted but had normal nerve conduction studies. Dose to the spinal nerve roots and nearby structures were estimated using a GEANT4 Monte Carlo simulation. Serial X-ray imaging and CT had found that the seed had further migrated to left renal hilum. Conclusions: Seed migration to vertebral venous plexus is uncommon and to our knowledge this is the third reported case. Its subsequent migration to the renal hilum is most unusual. CT with bony windows or MRI are required if this is suspected. There is risk of spinal or nerve root damage and dose to these structures has to be estimated using GEANT4, although the tissue tolerance in the setting of low-dose rates are unknown and long-term followup of this patient is required. © 2011.
Pope D.J.,University of Wollongong |
Cutajar D.L.,University of Wollongong |
George S.P.,University of Wollongong |
Guatelli S.,University of Wollongong |
And 5 more authors.
Physics in Medicine and Biology | Year: 2015
Low dose rate brachytherapy is a widely used modality for the treatment of prostate cancer. Most clinical treatment planning systems currently in use approximate all tissue to water, neglecting the existence of inhomogeneities, such as calcifications. The presence of prostatic calcifications may perturb the dose due to the higher photoelectric effect cross section in comparison to water. This study quantitatively evaluates the effect of prostatic calcifications on the dosimetric outcome of brachytherapy treatments by means of Monte Carlo simulations and its potential clinical consequences. Four pathological calcification samples were characterised with micro-particle induced x-ray emission (μ-PIXE) to determine their heavy elemental composition. Calcium, phosphorus and zinc were found to be the predominant heavy elements in the calcification composition. Four clinical patient brachytherapy treatments were modelled using Geant4 based Monte Carlo simulations, in terms of the distribution of brachytherapy seeds and calcifications in the prostate. Dose reductions were observed to be up to 30% locally to the calcification boundary, calcification size dependent. Single large calcifications and closely placed calculi caused local dose reductions of between 30-60%. Individual calculi smaller than 0.5 mm in diameter showed minimal dosimetric impact, however, the effects of small or diffuse calcifications within the prostatic tissue could not be determined using the methods employed in the study. The simulation study showed a varying reduction on common dosimetric parameters. D90 showed a reduction of 2-5%, regardless of calcification surface area and volume. The parameters V100, V150 and V200 were also reduced by as much as 3% and on average by 1%. These reductions were also found to relate to the surface area and volume of calcifications, which may have a significant dosimetric impact on brachytherapy treatment, however, such impacts depend strongly on specific factors in the patient's individual treatment. These factors include the number, size, composition and spatial distribution of calcifications in the prostate as well as the distribution of brachytherapy seeds. © 2015 Institute of Physics and Engineering in Medicine.
Tenconi C.,Fondazione IRCCS Instituto Nazionale dei Tumori |
Tenconi C.,University of Milan |
Carrara M.,Fondazione IRCCS Instituto Nazionale dei Tumori |
Borroni M.,Fondazione IRCCS Instituto Nazionale dei Tumori |
And 8 more authors.
Radiation Measurements | Year: 2014
The increasing complexity and high amount of dose per fraction delivered in prostate high dose rate (HDR) brachytherapy treatments call for the implementation of accurate and effective methods for the systematic and independent quality control of the overall treatment procedure. In this study, MOSkin detectors were placed on a trans-rectal ultrasound (TRUS) probe with the aim of performing both imaging and real time rectal wall in vivo dosimetry with the use of just one single instrument. After an adequate calibration of the detectors, which was carried out in a solid water phantom, the use of MOSkins integrated to the TRUS probe was studied in a gel phantom with a typical (simplified) prostate implant. Measured and calculated doses from the treatment planning system were compared, with a resulting very low average discrepancy of -0.6 ± 2.6%. The results are very promising and of particular clinical importance, however, further in vivo investigation is planned to validate the proposed method. © 2014 Elsevier Ltd. All rights reserved.
Chen F.Q.,Westmead Cancer Care Center |
Gupta R.,St George Cancer Care Center |
Metcalfe P.,University of Wollongong
Australasian Physical and Engineering Sciences in Medicine | Year: 2010
A new PTW advanced Markus ionization chamber has been implemented in IMRT fields, to measure surface dose at ICRU and ICRP reference depth of 0.07 mm [ICRU Report 39, Determination of dose equivalents resulting from external radiation sources, 1985; ICRP Publication 60, 1990 recommendations of the International Commission on Radiological Protection, 1991]. This chamber has a small radius with a revised guard ring design, therefore less prone to surface over-response effects. The over response correction for advanced Markus chamber is 3.3%, which is significantly smaller than 10.1% which was the original Markus chamber over response. After over response correction, the surface dose can be accurately measured by either data extrapolation or by adding one layer of plastic sheet protector to the top of Markus chamber. The surface dose measurements for small fields, e.g 3 × 3 cm, the polarity effect of advanced Markus chamber is 12%, which is significantly higher than the 5% polarity effect of the original Markus. For a 12 × 12 cm field size, surface dose (at 0.07 mm) measured by advanced Markus chamber is 19.8% for open field and 19.2% for an unmodulated step-and-shoot IMRT field. The variation in surface dose due to intensity modulated IMRT fields has also been investigated. For an intensity modulated, step-wedge IMRT field, surface dose varies from 15.7 ±1% for the highest intensity segment to 26.9 ±1% for the lowest intensity segment. The results of chamber measurements have been compared against EBT type GAFCHROMIC® film results. © Australasian College of Physical Scientists and Engineers in Medicine 2010.
Wong J.H.D.,University of Wollongong |
Wong J.H.D.,University of Malaya |
Carolan M.,University of Wollongong |
Carolan M.,Wollongong Hospital |
And 6 more authors.
Medical Physics | Year: 2010
Purpose: Intensity modulated radiation therapy (IMRT) allows the delivery of escalated radiation dose to tumor while sparing adjacent critical organs. In doing so, IMRT plans tend to incorporate steep dose gradients at interfaces between the target and the organs at risk. Current quality assurance (QA) verification tools such as 2D diode arrays, are limited by their spatial resolution and conventional films are nonreal time. In this article, the authors describe a novel silicon strip detector (CMRP DMG) of high spatial resolution (200 μm) suitable for measuring the high dose gradients in an IMRT delivery. Methods: A full characterization of the detector was performed, including dose per pulse effect, percent depth dose comparison with Farmer ion chamber measurements, stem effect, dose linearity, uniformity, energy response, angular response, and penumbra measurements. They also present the application of the CMRP DMG in the dosimetric verification of a clinical IMRT plan. Results: The detector response changed by 23% for a 390-fold change in the dose per pulse. A correction function is derived to correct for this effect. The strip detector depth dose curve agrees with the Farmer ion chamber within 0.8%. The stem effect was negligible (0.2%). The dose linearity was excellent for the dose range of 3-300 cGy. A uniformity correction method is described to correct for variations in the individual detector pixel responses. The detector showed an over-response relative to tissue dose at lower photon energies with the maximum dose response at 75 kVp nominal photon energy. Penumbra studies using a Varian Clinac 21EX at 1.5 and 10.0 cm depths were measured to be 2.77 and 3.94 mm for the secondary collimators, 3.52 and 5.60 mm for the multileaf collimator rounded leaf ends, respectively. Point doses measured with the strip detector were compared to doses measured with EBT film and doses predicted by the Philips Pinnacle treatment planning system. The differences were 1.1%±1.8% and 1.0%±1.6%, respectively. They demonstrated the high temporal resolution capability of the detector readout system, which will allow one to investigate the temporal dose pattern of IMRT and volumetric modulated arc therapy (VMAT) deliveries. Conclusions: The CMRP silicon strip detector dose magnifying glass interfaced to a TERA ASIC DAQ system has high spatial and temporal resolution. It is a novel and valuable tool for QA in IMRT dose delivery and for VMAT dose delivery. © 2010 American Association of Physicists in Medicine.
PubMed | University of New South Wales, Liverpool and Macarthur Cancer Therapy Centres and St George Cancer Care Center
Type: Journal Article | Journal: Asia-Pacific journal of clinical oncology | Year: 2016
Flurodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is routinely used in non-small-cell lung cancer. This study aims to assess the prognostic value of quantitative FDG-PET/CT parameters including standard uptake value (SUV), metabolic tumor volume (MTV) and total lesional glycolysis (TLG) in non-small-cell lung cancer.A retrospective review of 92 nonsurgical patients with pathologically confirmed stage I-III non-small-cell lung cancers treated with radical dose radiotherapy (50 Gy) was conducted. Metabolically active tumor regions on FDG-PET/CT scans were contoured manually. SUV, MTV and TLG were calculated for primary, nodal and whole-body disease. Univariate and multivariate (adjusting for age, sex, disease stage and primary tumor size in centimeters) Cox regression modeling were performed to assess the association between these parameters and both overall and progression-free survival (PFS).On univariate analysis, overall survival (OS) was significantly associated with primary MTV (P= 0.03), whole-body MTV (P = 0.02), whole-body maximum SUV (P = 0.05) and whole-body TLG (P = 0.03). PFS was significantly associated with primary MTV (P = 0.01), primary TLG (P = 0.04), whole-body MTV (P < 0.01) and whole-body TLG (P = 0.01). On multivariate analysis, OS was significantly associated with whole-body MTV (P = 0.05). PFS was significantly associated with whole-body MTV (P = 0.02) and whole-body TLG (P = 0.05).Whole-body MTV was significantly associated with overall and PFS, and whole-body TLG was significantly associated with PFS on multivariate analysis. These two parameters may be significant prognostic factors independent of other factors such as stage. SUV was not significantly associated with survival on multivariate analysis.
Pramana A.,St George Cancer Care Center |
Descallar J.,Liverpool Hospital |
Descallar J.,University of Sydney |
Vinod S.K.,Liverpool Hospital |
And 2 more authors.
Asia-Pacific Journal of Clinical Oncology | Year: 2016
Aim: Clinical trials have reported good outcomes for non-small cell lung cancer (NSCLC) patients treated with curative radiotherapy. These populations are highly selected and may not be representative of lung cancer population. We aim to evaluate the outcomes of NSCLC patients treated with radiotherapy ± chemotherapy in Australian community setting and to assess the effect of comorbidity on outcomes. Method: Oncology records at Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia, were queried to retrieve patient, tumor and treatment data for stage I–III NSCLC patients who were treated with radiotherapy (minimum dose 60 Gy) between 1 January 2000 and 31 December 2010. Simplified comorbidity score (SCS) was used to score comorbidity. Kaplan–Meier and Cox hazards models were used for survival analysis. Results: A total of 160 patients were identified with median follow-up of 22 months. Median age was 69 years (range 36–89); 76 patients received radiotherapy alone, 25 received sequential chemoradiation and 59 received concurrent chemoradiation. Median overall survivals for stages I, II and III were 29, 26 and 18 months, respectively. On multivariate analysis, stage II or III and weight loss > 5% were predictive of cancer-specific survival with hazard ratios of 4.47 (1.08–18.55, P = 0.04) and 2.23 (1.13–4.39, P = 0.02), respectively. Toxicities were grade ≥ 3 pneumonitis in 2% of patients, grade ≥ 3 esophagitis in 6% and grade ≥ 3 febrile neutropenia in 2%. There were no treatment-related deaths. SCS was neither prognostic nor predictive of toxicity or survival. Conclusion: Curative radiotherapy ± chemotherapy is a well-tolerated and effective treatment for inoperable or locally advanced NSCLC. Patients should not be excluded from radiotherapy on basis of comorbidity since higher SCS was not correlated with worse survival. © 2014 Wiley Publishing Asia Pty Ltd
PubMed | Liverpool Hospital and St George Cancer Care Center
Type: Journal Article | Journal: Asia-Pacific journal of clinical oncology | Year: 2016
Clinical trials have reported good outcomes for non-small cell lung cancer (NSCLC) patients treated with curative radiotherapy. These populations are highly selected and may not be representative of lung cancer population. We aim to evaluate the outcomes of NSCLC patients treated with radiotherapychemotherapy in Australian community setting and to assess the effect of comorbidity on outcomes.Oncology records at Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia, were queried to retrieve patient, tumor and treatment data for stage I-III NSCLC patients who were treated with radiotherapy (minimum dose 60Gy) between 1 January 2000 and 31 December 2010. Simplified comorbidity score (SCS) was used to score comorbidity. Kaplan-Meier and Cox hazards models were used for survival analysis.A total of 160 patients were identified with median follow-up of 22 months. Median age was 69 years (range 36-89); 76 patients received radiotherapy alone, 25 received sequential chemoradiation and 59 received concurrent chemoradiation. Median overall survivals for stages I, II and III were 29, 26 and 18 months, respectively. On multivariate analysis, stage II or III and weight loss>5% were predictive of cancer-specific survival with hazard ratios of 4.47 (1.08-18.55, P=0.04) and 2.23 (1.13-4.39, P=0.02), respectively. Toxicities were grade3 pneumonitis in 2% of patients, grade3 esophagitis in 6% and grade3 febrile neutropenia in 2%. There were no treatment-related deaths. SCS was neither prognostic nor predictive of toxicity or survival.Curative radiotherapychemotherapy is a well-tolerated and effective treatment for inoperable or locally advanced NSCLC. Patients should not be excluded from radiotherapy on basis of comorbidity since higher SCS was not correlated with worse survival.
Pramana A.,St George Cancer Care Center |
Browne L.,St George Cancer Care Center |
Graham P.H.,St George Cancer Care Center |
Graham P.H.,University of New South Wales
Journal of Medical Imaging and Radiation Oncology | Year: 2012
Introduction: Information regarding the addition of tissue equivalent bolus to adjuvant radiotherapy (RT) for intra-parotid metastatic head and neck cutaneous squamous cell carcinoma is lacking. This study aimed to evaluate the effect of bolus versus no bolus on the patterns of regional and distant recurrence, regional control (RC), cancer-specific survival (CSS), overall survival, RT toxicity and RT interruption. Methods: A retrospective study was performed on consecutive patients diagnosed between 1994 and 2008 with metastatic head and neck cutaneous squamous cell carcinoma who were treated with parotidectomy ± selective neck dissection and adjuvant RT ± parotid bolus. Results: Seventy-five patients were identified: 64 males and 11 females, with median age of 79 years (range 40-96) of which 39 had bolus during RT. Median follow up was 48 months (range 4-177). There were 23 regional recurrences - 14 dermal, six dermal + nodal and three isolated nodal - and only two systemic recurrences. Nine patients had RT interruption >6 days due to acute skin toxicity. Bolus was associated with increased grade ≥3 radiation dermatitis (P = 0.02). RT interruption >6 days was significantly associated with inferior RC and hazard ratio, 2.83 (95% confidence interval: 1.04-7.71, P = 0.042). Lympho-vascular space invasion, positive margins and nodes >2 cm were adversely significant on CSS multivariate analysis. RC, CSS and overall survival at 5 years were 67, 66 and 52%, respectively. Conclusions: Dermal involvement dominated the pattern of regional recurrence. Bolus was associated with significantly worse skin reaction. Bolus use was not associated with a significant overall benefit on RC. This analysis does not support the use of bolus as applied in this cohort. © 2012 The Authors. Journal of Medical Imaging and Radiation Oncology © 2012 The Royal Australian and New Zealand College of Radiologists.
PubMed | St George Cancer Care Center
Type: Journal Article | Journal: Journal of cancer education : the official journal of the American Association for Cancer Education | Year: 2012
There is an urgent need for efficient cancer education programmes to promote safe practice in a comprehensive cancer centre. Educational practice has developed historically in an unplanned and inefficient way. Developments in educational theory and information technology provide an opportunity to develop systems with better educational methodology, better efficiency and potential for better impact on safety outcomes. We have developed such a programme at St. George Comprehensive Cancer Centre in Sydney, Australia, and describe here our experience in the first 2 years of implementing such a programme. In this article, we describe the programme, the obstacles and solutions we encountered and our reflections on the journey so far.