6 results
Dosimetric evaluation of SBRT treatment plans of non-central lung tumours: clinical experience
- Ernest Osei, Johnson Darko, Steph Swanson, Katrina Fleming, Ronald Snelgrove, Anmol Bhangu, Darin Gopaul
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- Journal:
- Journal of Radiotherapy in Practice / Volume 21 / Issue 2 / June 2022
- Published online by Cambridge University Press:
- 09 December 2020, pp. 179-199
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Objectives:
Lung cancer is the most commonly diagnosed cancer in Canada and the leading cause of cancer-related mortality in both men and women in North America. Surgery is usually the primary treatment option for early-stage non-small cell lung cancer (NSCLC). However, for patients who may not be suitable candidates for surgery, stereotactic body radiation therapy (SBRT) is an alternative method of treatment. SBRT has proven to be an effective technique for treating NSCLC patients by focally administering high radiation dose to the tumour with acceptable risk of toxicity to surrounding healthy tissues. The goal of this comprehensive retrospective dosimetric study is to compare the dosimetric parameters between three-dimensional conformal radiation therapy (3DCRT) and volumetric-modulated arc therapy (VMAT) lung SBRT treatment plans for two prescription doses.
Methods:We retrospectively analysed and compared lung SBRT treatment plans of 263 patients treated with either a 3DCRT non-coplanar or with 2–3 VMAT arcs technique at 48 Gy in 4 fractions (48 Gy/4) or 50 Gy in 5 fractions (50 Gy/5) prescribed to the planning target volume (PTV), typically encompassing the 80% isodose volume. All patients were treated on either a Varian 21EX or TrueBeam linear accelerator using 6-MV or 10-MV photon beams.
Results:The mean PTV V95% and V100% for treatment plans at 48 Gy/4 are 99·4 ± 0·6% and 96·0 ± 1·0%, respectively, for 3DCRT and 99·7 ± 0·4% and 96·4 ± 3·4%, respectively, for VMAT. The corresponding mean PTV V95% and V100% at 50 Gy/5 are 99·0 ± 1·4% and 95·5 ± 2·5% for 3DCRT and 99·5 ± 0·8% and 96·1 ± 1·6% for VMAT. The CIRI and HI5/95 for the PTV at 48 Gy/4 are 1·1 ± 0·1 and 1·2 ± 0·0 for 3DCRT and 1·0 ± 0·1 and 1·2 ± 0·0 for VMAT. The corresponding CIRI and HI5/95 at 50 Gy/5 are 1·1 ± 0·1 and 1·3 ± 0·1 for 3DCRT and 1·0 ± 0·1 and 1·2 ± 0·0 for VMAT. The mean R50% and D2cm at 48 Gy/4 are 5·0 ± 0·8 and 61·2 ± 7·0% for 3DCRT and 4·9 ± 0·8 and 57·8 ± 7·9% for VMAT. The corresponding R50% and D2cm at 50 Gy/5 are 4·7 ± 0·5 and 65·5 ± 9·4% for 3DCRT and 4·7 ± 0·7 and 60·0 ± 7·2% for VMAT.
Conclusion:The use of 3DCRT or VMAT technique for lung SBRT is an efficient and reliable method for achieving dose conformity, rapid dose fall-off and minimising doses to the organs at risk. The VMAT technique resulted in improved dose conformity, rapid dose fall-off from the PTV compared to 3DCRT, although the magnitude may not be clinically significant.
Dosimetric evaluation of 3 and/or 4 field radiation therapy of breast cancers: clinical experience
- Ernest Osei, Susan Dang, Johnson Darko, Katrina Fleming, Ramana Rachakonda
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- Journal:
- Journal of Radiotherapy in Practice / Volume 20 / Issue 4 / December 2021
- Published online by Cambridge University Press:
- 09 July 2020, pp. 380-394
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Background:
Breast cancer is the most commonly diagnosed cancer among women and the second leading cause of cancer-related death in Canadian women. Surgery is often the first line of treatment for low-risk early stage patients, followed by adjuvant radiation therapy to reduce the risk of local recurrence and prevent metastasis after lumpectomy or mastectomy. For high-risk patients with node positive disease or are at greater risk of nodal metastasis, radiation therapy will involve treatment of the intact breast or chest-wall as well as the regional lymph nodes.
Materials and methods:We retrospectively evaluated the treatment plans of 354 patients with breast cancer with nodes positive or were at high risk of nodal involvement treated at our cancer centre. All patients were treated with a prescription dose of 50 Gy in 25 fractions to the intact breast or chest-wall and 50 Gy in 25 fractions to the supraclavicular region and, based on patient suitability and tolerance, were treated either using the deep inspiration breath hold (DIBH) or free-breathing (FB) techniques.
Results:Based on patient suitability and tolerance, 130 (36·7%) patients were treated with DIBH and 224 (63·3%) with FB techniques. There were 169 (47·7%) patients treated with intact breast, whereas 185 (52·3%) were treated for post-mastectomy chest-wall. The mean PTV_eval V92%, V95%, V100% and V105% for all patients are 99·4 ± 0·7, 97·6 ± 1·6, 74·8 ± 7·9 and 1·5 ± 3·2%, respectively. The mean ipsilateral lung V10Gy, V20Gy and V30Gy are 30·0 ± 5·3, 22·4 ± 4·7 and 18·4 ± 4·3% for intact breast and 30·9 ± 5·8, 23·5 ± 5·4 and 19·4 ± 5·0% for post-mastectomy patients with FB, respectively. The corresponding values for patients treated using DIBH are 26·3 ± 5·9, 18·9 ± 5·0 and 15·6 ± 4·7% for intact breast and 27·5 ± 6·5, 20·6 ± 5·7 and 17·1 ± 5·2% for post-mastectomy patients, respectively. The mean heart V10Gy, V20Gy, is 1·8 ± 1·7, 0·9 ± 1·0 for intact breast and 3·1 ± 2·2, 1·7 ± 1·6 for post-mastectomy patients with FB, respectively. The corresponding values with the DIBH are 0·5 ± 0·7, 0·1 ± 0·4 for intact breast and 1·1 ± 1·4, 0·4 ± 0·7 for post-mastectomy patients, respectively.
Conclusion:The use of 3 and/or 4 field hybrid intensity-modulated radiation therapy technique for radiation therapy of high-risk node positive breast cancer patients provides an efficient and reliable method for achieving superior dose uniformity, conformity and homogeneity in the breast or post-mastectomy chest-wall volume with minimal doses to the organs at risk. The development and implementation of a consistent treatment plan acceptability criteria in radiotherapy programmes would establish an evaluation process to define a consistent, standardised and transparent treatment path for all patients that would reduce significant variations in the acceptability of treatment plans.
Dosimetric evaluation of whole-pelvis radiation therapy of prostate cancers: clinical experience
- Ernest Osei, Hafsa Mansoor, Johnson Darko, Beverley Osei, Katrina Fleming, Ramana Rachakonda
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- Journal:
- Journal of Radiotherapy in Practice / Volume 20 / Issue 4 / December 2021
- Published online by Cambridge University Press:
- 18 June 2020, pp. 433-447
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Background:
The standard treatment modalities for prostate cancer include surgery, chemotherapy, hormonal therapy and radiation therapy or any combination depending on the stage of the tumour. Radiation therapy is a common and effective treatment modality for low-intermediate-risk patients with localised prostate cancer, to treat the intact prostate and seminal vesicles or prostate bed post prostatectomy. However, for high-risk patients with lymph node involvement, treatment with radiation will usually include treatment of the whole pelvis to cover the prostate and seminal vesicles or prostate bed and the pelvic lymph nodes followed by a boost delivery dose to the prostate and seminal vesicles or prostate bed.
Materials and Methods:We retrospectively analysed the treatment plans for 179 prostate cancer patients treated at the cancer centre with the volumetric-modulated arc therapy (VMAT) technique via RapidArc using 6 MV photon beam. Patients were either treated with a total prescription dose of 78 Gy in 39 fractions for patients with intact prostate or 66 Gy in 33 fractions for post prostatectomy patients.
Results:There were 114 (64%) patients treated with 78 Gy/39 and 65 (36%) treated with 66 Gy/34. The mean homogeneity index (HI), conformity index (CI) and uniformity index (UI) for the PTV-primary of patients treated with 78 Gy are 0.06 ± 0.01, 1.04 ± 0.01 and 0.99 ± 0.01, respectively, and the corresponding mean values for patients treated with 66 Gy are 0.06 ± 0.02, 1.05 ± 0.01 and 0.99 ± 0.01, respectively. The mean PTV-primary V95%, V100% and V105% are 99.5 ± 0.5%, 78.8 ± 12.2% and 0.1 ± 0.5%, respectively, for patients treated with 78 Gy and 99.3 ± 0.9%, 78.1 ± 10.6% and 0.1 ± 0.4%, respectively, for patients treated with 66 Gy. The rectal V50Gy, V65Gy, V66.6Gy, V70Gy, V75Gy and V80Gy are 26.8 ± 9.1%, 14.2 ± 5.3%, 13.1 ± 5.0%, 10.8 ± 4.3%, 6.9 ± 3.1% and 0.1 ± 0.1%, respectively, for patients treated with 78 Gy and 33.7 ± 8.4%, 14.1 ± 4.5%, 6.7 ± 4.5%, 0.0 ± 0.2%, 0.0% and 0.0%, respectively, for patients treated with 66 Gy.
Conclusion:The use of VMAT technique for radiation therapy of high-risk prostate cancer patients is an efficient and reliable method for achieving superior dose conformity, uniformity and homogeneity to the PTV and minimal doses to the organs at risk. Results from this study provide the basis for the development and implementation of consistent treatment criteria in radiotherapy programs, have the potential to establish an evaluation process to define a consistent, standardised and transparent treatment path for all patients that reduces significant variations in the acceptability of treatment plans and potentially improve patient standard of care.
A Qualitative Study on the Transition Support Needs of Indigenous Australians Following Traumatic Brain Injury
- Michelle S. Fitts, Katrina Bird, John Gilroy, Jennifer Fleming, Alan R. Clough, Adrian Esterman, Paul Maruff, Yaqoot Fatima, India Bohanna
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- Journal:
- Brain Impairment / Volume 20 / Issue 2 / September 2019
- Published online by Cambridge University Press:
- 22 August 2019, pp. 137-159
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Objective:
A growing body of qualitative literature globally describes post-hospital experiences during early recovery from a traumatic brain injury. For Indigenous Australians, however, little published information is available. This study aimed to understand the lived experiences of Indigenous Australians during the 6 months post-discharge, identify the help and supports accessed during transition and understand the gaps in service provision or difficulties experienced.
Methods and Procedure:Semi-structured interviews were conducted at 6 months after hospital discharge to gain an understanding of the needs and lived experiences of 11 Aboriginal and Torres Strait Islander Australians who had suffered traumatic brain injury in Queensland and Northern Territory, Australia. Data were analysed using thematic analysis.
Results:Five major themes were identified within the data. These were labelled ‘hospital experiences’, ‘engaging with medical and community-based supports’, ‘health and wellbeing impacts from the injury’, ‘everyday living’ and ‘family adjustments post-injury’.
Conclusions:While some of the transition experiences for Indigenous Australians were similar to those found in other populations, the transition period for Indigenous Australians is influenced by additional factors in hospital and during their recovery process. Lack of meaningful interaction with treating clinicians in hospital, challenges managing direct contact with multiple service providers and the injury-related psychological impacts are some of the factors that could prevent Indigenous Australians from receiving the supports they require to achieve their best possible health outcomes in the long term. A holistic approach to care, with an individualised, coordinated transition support, may reduce the risks for re-admission with further head injuries.
The Potential of a Narrative and Creative Arts Approach to Enhance Transition Outcomes for Indigenous Australians Following Traumatic Brain Injury
- India Bohanna, Michelle Fitts, Katrina Bird, Jennifer Fleming, John Gilroy, Alan Clough, Adrian Esterman, Paul Maruff, Martin Potter
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- Journal:
- Brain Impairment / Volume 20 / Issue 2 / September 2019
- Published online by Cambridge University Press:
- 31 July 2019, pp. 160-170
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Background:
Increasingly, narrative and creative arts approaches are being used to enhance recovery after traumatic brain injury (TBI). Narrative and arts-based approaches congruent with Indigenous storytelling may therefore provide benefit during the transition from hospital to home for some Indigenous TBI patients. This qualitative study explored the use and impact of this approach as part of a larger, longitudinal study of TBI transition with Indigenous Australians.
Method:A combined narrative and arts-based approach was used with one Indigenous Australian artist to describe his transition experiences following TBI. Together with the researchers and filmmaking team, the artist was involved in aspects of the process. The artist contributed two paintings, detailing the story of his life and TBI. Based on the artworks, a film was co-created. Following the viewing of the film, impacts of the narrative and arts-based process were examined through semi-structured interviews with the artist, a service provider and a family member. Multiple sources of data were used in the final thematic analysis including transcripts of the interviews and filming, paintings (including storylines) and researcher notes.
Results:Positive impacts from the process for the artist included positive challenge; healing and identity; understanding TBI and raising awareness.
Discussion:This approach may enable the individual to take ownership over their transition story and to make sense of their life following TBI at a critical point in their recovery. A combined narrative and arts-based approach has potential as a culturally responsive rehabilitation tool for use with Indigenous Australians during the transition period following TBI.
The Transition from Hospital to Home: Protocol for a Longitudinal Study of Australian Aboriginal and Torres Strait Islander Traumatic Brain Injury (TBI)
- India Bohanna, Michelle S. Fitts, Katrina Bird, Jennifer Fleming, John Gilroy, Adrian Esterman, Paul Maruff, Alan R. Clough
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- Journal:
- Brain Impairment / Volume 19 / Issue 3 / December 2018
- Published online by Cambridge University Press:
- 02 February 2018, pp. 246-257
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Background: Traumatic brain injury (TBI) is a leading cause of disability in Australia. Evidence shows that multidisciplinary rehabilitation and support in the six months following TBI is important for successful independent living and social re-integration. Despite this, access to services and supports during this period is often limited by environmental, socio-economic, geographic and cultural factors. Australian studies on outcomes after brain injury have reported primarily on non-Indigenous people. This study will investigate key sentinel events during the transition from hospital to home after a TBI in the first longitudinal study with Indigenous Australians.
Method: Indigenous Australians admitted to one of three major trauma hospitals in northern Australia with a TBI, and their care givers, will be recruited. Clinical and brain injury risk factor information, along with measures of cognitive function, transition events, mental health and community re-integration will be collected at three time points prior to hospital discharge, and at three and six months post-discharge. Qualitative interviews will also be conducted. Data will be analysed using regression methods for the quantitative component, and situational analysis for the qualitative component. Annual rates of brain injury will be calculated for patients admitted to tertiary hospital facilities in the study region with a diagnosis of TBI.
Discussion: Understanding the experience and events which shape the transition period is critical to determining the services and supports that may enhance transition outcomes, and ensure that such services are culturally appropriate and endorsed by Indigenous families and communities.