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- Petersson, Kristoffer, et al.
(författare)
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Beam commissioning and measurements validating the beam model in a new TPS that converts helical tomotherapy plans to step-and-shoot IMRT plans.
- 2011
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Ingår i: Medical Physics. - : Wiley. - 0094-2405. ; 38:1, s. 40-46
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Tidskriftsartikel (refereegranskat)abstract
- A new type of treatment planning system called SHAREPLAN has been studied, which enables the transfer of treatment plans generated for helical tomotherapy delivery to plans that can be delivered on C-arm linacs. The purpose is to ensure continuous patient treatment during periods of unscheduled downtime for the TomoTherapy unit, particularly in clinics without a backup unit. The purpose of this work was to verify that the plans generated in this novel planning system are deliverable and accurate. The work consists primarily of beam commissioning, verification of the beam model, and measurements verifying that generated plans are deliverable with sufficient accuracy.
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| 2. |
- Petersson, Kristoffer, et al.
(författare)
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Conversion of helical tomotherapy plans to step-and-shoot IMRT plans-Pareto front evaluation of plans from a new treatment planning system
- 2011
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Ingår i: Medical Physics. - : Wiley. - 0094-2405. ; 38:6, s. 3130-3138
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The resulting plans from a new type of treatment planning system called SharePlan (TM) have been studied. This software allows for the conversion of treatment plans generated in a TomoTherapy system for helical delivery, into plans deliverable on C-arm linear accelerators (linacs), which is of particular interest for clinics with a single TomoTherapy unit. The purpose of this work was to evaluate and compare the plans generated in the SharePlan system with the original TomoTherapy plans and with plans produced in our clinical treatment planning system for intensity-modulated radiation therapy (IMRT) on C-arm linacs. In addition, we have analyzed how the agreement between SharePlan and TomoTherapy plans depends on the number of beams and the total number of segments used in the optimization. Methods: Optimized plans were generated for three prostate and three head-and-neck (H&N) cases in the TomoTherapy system, and in our clinical treatment planning systems (TPS) used for IMRT planning with step-and-shoot delivery. The TomoTherapy plans were converted into step-and-shoot IMRT plans in SharePlan. For each case, a large number of Pareto optimal plans were created to compare plans generated in SharePlan with plans generated in the Tomotherapy system and in the clinical TPS. In addition, plans were generated in SharePlan for the three head-and-neck cases to evaluate how the plan quality varied with the number of beams used. Plans were also generated with different number of beams and segments for other patient cases. This allowed for an evaluation of how to minimize the number of required segments in the converted IMRT plans without compromising the agreement between them and the original TomoTherapy plans. Results: The plans made in SharePlan were as good as or better than plans from our clinical system, but they were not as good as the original TomoTherapy plans. This was true for both the head-and-neck and the prostate cases, although the differences between the plans for the latter were small. The evaluation of the head-and-neck cases also showed that the plans generated in SharePlan were improved when more beams were used. The SharePlan Pareto front came close to the front for the TomoTherapy system when a sufficient number of beams were added. The results for plans generated with varied number of beams and segments demonstrated that the number of segments could be minimized with maintained agreement between SharePlan and TomoTherapy plans when 10-19 beams were used. Conclusions: This study showed (using Pareto front evaluation) that the plans generated in SharePlan are comparable to plans generated in other TPSs. The evaluation also showed that the plans generated in SharePlan could be improved with the use of more beams. To minimize the number of segments needed in a plan with maintained agreement between the converted IMRT plans and the original TomoTherapy plans, 10-19 beams should be used, depending on target complexity. SharePlan has proved to be useful and should thereby be a time-saving complement as a backup system for clinics with a single TomoTherapy system installed alongside conventional C-arm linacs. (C) 2011 American Association of Physicists in Medicine. [DOI: 10.1118/1.3592934]
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| 3. |
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| 4. |
- Petersson, Kristoffer
(författare)
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Optimising the clinical use of tomotherapy
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Radiotherapy is one of the major tools for treating cancer. Through research and technical development radiotherapy is becoming more advanced with new treatment techniques emerging. In the work presented in this thesis, well-known methods have been used, or modified for use, and new methods have been introduced in order to optimise the clinical use of an advanced radiotherapy treatment technique, specifically tomotherapy. In the presented work, tools used for fallback planning are evaluated. Methods are developed for the commissioning of them, evaluating the quality of the treatment plans (describes how patients are to be treated) they produce, and measurements are performed to ensure that the resulting treatments can be accurately delivered to the patients. These could assure an uninterrupted patient treatment with specialised treatment techniques. The results show that fallback planning is useful as it in many cases prevents a prolongation of the treatment which can have clinically significant impact. It should be an important time-saving complement, especially for clinics with a single specialised treatment unit such as tomotherapy, as they are more affected by its downtime. A method called clinical grading analysis (CGA) is presented as a way of comparing radiotherapy treatment plans. A CGA study takes advantage of the radiation oncologists’ clinical assessments to identify the clinical relevant differences between treatment plans. These subjective assessments are quantified in a CGA study, and used to decide which patients have a clinical benefit from treatment with one or the other of the advanced treatment techniques available to them. The results indicate that a CGA study provides a supporting framework for decision making regarding treatment techniques which helps to ensure a more optimal use of the clinic’s advanced treatment resources. Beam commissioning, plan quality assessment, and treatment deliverability measurements are important when introducing new techniques into the clinic. However, the work presented in this thesis shows that despite performing such investigations thoroughly, unexpected treatment side effects might occur. Hence, patient follow-up is of utmost importance when introducing new treatment techniques as it enables treatment adjustment to optimise the treatment outcome.
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| 5. |
- Petersson, Kristoffer, et al.
(författare)
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Treatment plan comparison using grading analysis based on clinical judgment.
- 2013
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Ingår i: Acta Oncologica. - 1651-226X. ; 52:3, s. 645-651
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. In this work we explore a method named clinical grading analysis (CGA) which is based on clinical assessments performed by radiation oncologists (ROs). The purpose is to investigate how useful the method is for treatment plan comparisons, and how the CGA results correlate with dosimetric evaluation parameters, traditionally used for treatment plan comparisons. Material and methods. Helical tomotherapy (HTT) and seven-beam step-and-shoot intensity modulated radiation therapy (SS-IMRT) plans were compared and assessed by 10 experienced ROs for 23 patient cases. A CGA was performed where the plans were graded based on how the ROs thought they compared to each other. The resulting grades from the CGA were analyzed and compared to dose-volume statistics and equivalent uniform dose (EUD) data. Results. For eight of the 23 cases the CGA revealed a significant difference between the HTT and the SS-IMRT plans, five cases were in favor of HTT, and three in favor of SS-IMRT. Comparing the dose-volume statistics and EUD-data with the result from the CGA showed that CGA results correlated well with dose-volume statistics for cases regarding difference in target coverage or doses to organs at risk. The CGA results also correlated well with EUD-data for cases with difference in clinical target volume (CTV) coverage but the correlation for cases with difference in planning target volume (PTV) coverage was not as clear. Conclusions. This study presents CGA as a useful method of comparing radiotherapy treatment plans. The proposed method offers a formalized way of introducing and evaluating the implementation of new radiotherapy techniques in a clinical setting. The CGA identify patients that have a clinical benefit of one or the other of the advanced treatment techniques available to them, i.e. in this study HTT and SS-IMRT, which facilitates a more optimal use of a clinics' advanced treatment resources.
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