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Koetsier KS, Oud M, de Klerck E, Hensen EF, van Vulpen M, van Linge A, Paul van Benthem P, Slagter C, Habraken SJ, Hoogeman MS, Méndez Romero A. Cochlear-optimized treatment planning in photon and proton radiosurgery for vestibular schwannoma patients. Clin Transl Radiat Oncol 2023; 43:100689. [PMID: 37867612 PMCID: PMC10585330 DOI: 10.1016/j.ctro.2023.100689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/05/2023] [Accepted: 10/05/2023] [Indexed: 10/24/2023] Open
Abstract
Objective To investigate the potential to reduce the cochlear dose with robotic photon radiosurgery or intensity-modulated proton therapy planning for vestibular schwannomas. Materials and Methods Clinically delivered photon radiosurgery treatment plans were compared to five cochlear-optimized plans: one photon and four proton plans (total of 120). A 1x12 Gy dose was prescribed. Photon plans were generated with Precision (Cyberknife, Accuray) with no PTV margin for set-up errors. Proton plans were generated using an in-house automated multi-criterial planning system with three or nine-beam arrangements, and applying 0 or 3 mm robustness for set-up errors during plan optimization and evaluation (and 3 % range robustness). The sample size was calculated based on a reduction of cochlear Dmean > 1.5 Gy(RBE) from the clinical plans, and resulted in 24 patients. Results Compared to the clinical photon plans, a reduction of cochlear Dmean > 1.5 Gy(RBE) could be achieved in 11/24 cochlear-optimized photon plans, 4/24 and 6/24 cochlear-optimized proton plans without set-up robustness for three and nine-beam arrangement, respectively, and in 0/24 proton plans with set-up robustness. The cochlea could best be spared in cases with a distance between tumor and cochlea. Using nine proton beams resulted in a reduced dose to most organs at risk. Conclusion Cochlear dose reduction is possible in vestibular schwannoma radiosurgery while maintaining tumor coverage, especially when the tumor is not adjacent to the cochlea. With current set-up robustness, proton therapy is capable of providing lower dose to organs at risk located distant to the tumor, but not for organs adjacent to it. Consequently, photon plans provided better cochlear sparing than proton plans.
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Affiliation(s)
- Kimberley S. Koetsier
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Albinusdreef 2, Leiden, the Netherlands
| | - Michelle Oud
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, the Netherlands
| | - Erik de Klerck
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, the Netherlands
| | - Erik F Hensen
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Albinusdreef 2, Leiden, the Netherlands
| | | | - Anne van Linge
- Department of Otorhinolaryngology and Head & Neck Surgery, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Peter Paul van Benthem
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Albinusdreef 2, Leiden, the Netherlands
| | - Cleo Slagter
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Steven J.M. Habraken
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Mischa S. Hoogeman
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - A. Méndez Romero
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, the Netherlands
- HollandPTC, Delft, the Netherlands
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Rossi L, Breedveld S, Heijmen B. Per-fraction planning to enhance optimization degrees of freedom compared to the conventional single-plan approach. Phys Med Biol 2023; 68:175014. [PMID: 37524087 DOI: 10.1088/1361-6560/acec27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 07/31/2023] [Indexed: 08/02/2023]
Abstract
Objective. In conventional radiotherapy, a single treatment plan is generated pre-treatment, and delivered in daily fractions. In this study, we propose to generate different treatment plans for all fractions ('Per-fraction' planning) to reduce cumulative organs at risk (OAR) doses. Per-fraction planning was compared to the 'Conventional' single-plan approach for non-coplanar 4 × 9.5 Gy prostate stereotactic body radiation therapy (SBRT).Approach. An in-house application for fully automated, non-coplanar multi-criterial treatment planning with integrated beam angle and fluence optimization was used for plan generations. For the Conventional approach, a single 12-beam non-coplanar IMRT plan with individualized beam angles was generated for each of the 20 included patients. In Per-fraction planning, four fraction plans were generated for each patient. For each fraction, a different set of patient-specific 12-beam configurations could be automatically selected. Per-fraction plans were sequentially generated by adding dose to already generated fraction plan(s). For each fraction, the cumulative- and fraction dose were simultaneously optimized, allowing some minor constraint violations in fraction doses, but not in cumulative.Main results. In the Per-fraction approach, on average 32.9 ± 3.1 [29;39] unique beams per patient were used. PTV doses in the separate Per-fraction plans were acceptable and highly similar to those in Conventional plans, while also fulfilling all OAR hard constraints. When comparing total cumulative doses, Per-fraction planning showed improved bladder sparing for all patients with reductions in Dmean of 22.6% (p= 0.0001) and in D1cc of 2.0% (p= 0.0001), reductions in patient volumes receiving 30% and 50% of the prescribed dose of 54.7% and 6.3%, respectively, and a 3.1% lower rectum Dmean (p= 0.007). Rectum D1cc was 4.1% higher (p= 0.0001) and Urethra dose was similar.Significance. In this proof-of-concept paper, Per-fraction planning resulted in several dose improvements in healthy tissues compared to the Conventional single-plan approach, for similar PTV dose. By keeping the number of beams per fraction the same as in Conventional planning, reported dosimetric improvements could be obtained without increase in fraction durations. Further research is needed to explore the full potential of the Per-fraction planning approach.
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Affiliation(s)
- Linda Rossi
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Sebastiaan Breedveld
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Ben Heijmen
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
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Enhancing Radiotherapy for Locally Advanced Non-Small Cell Lung Cancer Patients with iCE, a Novel System for Automated Multi-Criterial Treatment Planning Including Beam Angle Optimization. Cancers (Basel) 2021; 13:cancers13225683. [PMID: 34830838 PMCID: PMC8616198 DOI: 10.3390/cancers13225683] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/25/2022] Open
Abstract
In this study, the novel iCE radiotherapy treatment planning system (TPS) for automated multi-criterial planning with integrated beam angle optimization (BAO) was developed, and applied to optimize organ at risk (OAR) sparing and systematically investigate the impact of beam angles on radiotherapy dose in locally advanced non-small cell lung cancer (LA-NSCLC). iCE consists of an in-house, sophisticated multi-criterial optimizer with integrated BAO, coupled to a broadly used commercial TPS. The in-house optimizer performs fluence map optimization to automatically generate an intensity-modulated radiotherapy (IMRT) plan with optimal beam angles for each patient. The obtained angles and dose-volume histograms are then used to automatically generate the final deliverable plan with the commercial TPS. For the majority of 26 LA-NSCLC patients, iCE achieved improved heart and esophagus sparing compared to the manually created clinical plans, with significant reductions in the median heart Dmean (8.1 vs. 9.0 Gy, p = 0.02) and esophagus Dmean (18.5 vs. 20.3 Gy, p = 0.02), and reductions of up to 6.7 Gy and 5.8 Gy for individual patients. iCE was superior to automated planning using manually selected beam angles. Differences in the OAR doses of iCE plans with 6 beams compared to 4 and 8 beams were statistically significant overall, but highly patient-specific. In conclusion, automated planning with integrated BAO can further enhance and individualize radiotherapy for LA-NSCLC.
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Desai DD, Johnson EL, Cordrey IL. An analytical expression for R50% dependent on PTV surface area and volume: A cranial SRS comparison. J Appl Clin Med Phys 2021; 22:203-210. [PMID: 33493385 PMCID: PMC7882107 DOI: 10.1002/acm2.13168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 12/19/2020] [Accepted: 12/22/2020] [Indexed: 11/09/2022] Open
Abstract
The intermediate dose spill for a stereotactic radiosurgery (SRS) plan can be quantified with the metric R50%, defined as the 50% isodose cloud volume (VIDC50% ) divided by the volume of the planning target volume (PTV). By coupling sound physical principles with the basic definition of R50%, we derive an analytical expression for R50% for a spherical PTV. Our analytical expression depends on three quantities: the surface area of PTV (SAPTV ), the volume of PTV (VPTV ), and the distance of dose drop-off to 50% (Δr). The value of ∆r was obtained from a simple set of cranial phantom plan calculations. We generate values from our analytical expression for R50% (R50%Analytic ) and compare the values to clinical R50% values (R50%Clinical ) extracted from a previously published SRS data set that spans the VPTV range from 0.15 to 50.1 cm3 . R50%Analytic is smaller than R50%Clinical in all cases by an average of 15% ± 7%, and the general trend of R50%Clinical vs VPTV is reflected in the same trend of R50%Analytic . This comparison suggests that R50%Analytic could represent a theoretical lower limit for the clinical SRS data; further investigation is required to confirm this. R50%Analytic could provide useful guidance for what might be achievable in SRS planning.
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Affiliation(s)
- Dharmin D Desai
- Department of Radiation Oncology, CHI Memorial Hospital, Chattanooga, TN, USA
| | - E L Johnson
- Department of Radiation Medicine, University of Kentucky Chandler Medical Center, Lexington, KY, USA
| | - Ivan L Cordrey
- Department of Radiation Oncology, CHI Memorial Hospital, Chattanooga, TN, USA
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Giżyńska MK, Rossi L, den Toom W, Milder MTW, de Vries KC, Nuyttens J, Heijmen BJM. Largely reduced OAR doses, and planning and delivery times for challenging robotic SBRT cases, obtained with a novel optimizer. J Appl Clin Med Phys 2021; 22:35-47. [PMID: 33475227 PMCID: PMC7984474 DOI: 10.1002/acm2.13172] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/21/2020] [Accepted: 12/25/2020] [Indexed: 11/12/2022] Open
Abstract
Recently, VOLO™ was introduced as a new optimizer for CyberKnife® planning. In this study, we investigated possibilities to improve treatment plans for MLC-based prostate SBRT with enhanced peripheral zone dose while sparing the urethra, and central lung tumors, compared to existing Sequential Optimization (SO). The primary focus was on reducing OAR doses. For 25 prostate and 25 lung patients treated with SO plans, replanning with VOLO™ was performed with the same planning constraints. For equal PTV coverage, almost all OAR plan parameters were improved with VOLO™. For prostate patients, mean rectum and bladder doses were reduced by 34.2% (P < 0.001) and 23.5% (P < 0.001), with reductions in D0.03cc of 3.9%, 11.0% and 3.1% for rectum, mucosa and bladder (all P ≤ 0.01). Urethra D5% and D10% were 3.8% and 3.0% lower (P ≤ 0.002). For lung patients, esophagus, main bronchus, trachea, and spinal cord D0.03cc was reduced by 18.9%, 11.1%, 16.1%, and 13.2%, respectively (all P ≤ 0.01). Apart from the dosimetric advantages of VOLO™ planning, average reductions in MU, numbers of beams and nodes for prostate/lung were 48.7/32.8%, 26.5/7.9% and 13.4/7.9%, respectively (P ≤ 0.003). VOLO™ also resulted in reduced delivery times with mean/max reductions of: 27/43% (prostate) and 15/41% (lung), P < 0.001. Planning times reduced from 6 h to 1.1 h and from 3 h to 1.7 h for prostate and lung, respectively. The new VOLO™ planning was highly superior to SO planning in terms of dosimetric plan quality, and planning and delivery times.
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Affiliation(s)
- Marta K Giżyńska
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Dr.Molewaterplein 40, Rotterdam, 3015 GD, The Netherlands
| | - Linda Rossi
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Dr.Molewaterplein 40, Rotterdam, 3015 GD, The Netherlands
| | - Wilhelm den Toom
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Dr.Molewaterplein 40, Rotterdam, 3015 GD, The Netherlands
| | - Maaike T W Milder
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Dr.Molewaterplein 40, Rotterdam, 3015 GD, The Netherlands
| | - Kim C de Vries
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Dr.Molewaterplein 40, Rotterdam, 3015 GD, The Netherlands
| | - Joost Nuyttens
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Dr.Molewaterplein 40, Rotterdam, 3015 GD, The Netherlands
| | - Ben J M Heijmen
- Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Dr.Molewaterplein 40, Rotterdam, 3015 GD, The Netherlands
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