Optimization of the prescription isodose line for Gamma Knife radiosurgery using the shot within shot technique
Abstract Background This work explores how the choice of prescription isodose line (IDL) affects the dose gradient, target coverage, and treatment time for Gamma Knife radiosurgery when a smaller shot is encompassed within a larger shot at the same stereotactic coordinates (shot within shot techniqu...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2017-11-01
|
| Series: | Radiation Oncology |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s13014-017-0919-4 |
| _version_ | 1818442464888881152 |
|---|---|
| author | Perry B. Johnson Maria I. Monterroso Fei Yang Eric Mellon |
| author_facet | Perry B. Johnson Maria I. Monterroso Fei Yang Eric Mellon |
| author_sort | Perry B. Johnson |
| collection | DOAJ |
| description | Abstract Background This work explores how the choice of prescription isodose line (IDL) affects the dose gradient, target coverage, and treatment time for Gamma Knife radiosurgery when a smaller shot is encompassed within a larger shot at the same stereotactic coordinates (shot within shot technique). Methods Beam profiles for the 4, 8, and 16 mm collimator settings were extracted from the treatment planning system and characterized using Gaussian fits. The characterized data were used to create over 10,000 shot within shot configurations by systematically changing collimator weighting and choice of prescription IDL. Each configuration was quantified in terms of the dose gradient, target coverage, and beam-on time. By analyzing these configurations, it was found that there are regions of overlap in target size where a higher prescription IDL provides equivalent dose fall-off to a plan prescribed at the 50% IDL. Furthermore, the data indicate that treatment times within these regions can be reduced by up to 40%. An optimization strategy was devised to realize these gains. The strategy was tested for seven patients treated for 1–4 brain metastases (20 lesions total). Results For a single collimator setting, the gradient in the axial plane was steepest when prescribed to the 56–63% (4 mm), 62–70% (8 mm), and 77–84% (16 mm) IDL, respectively. Through utilization of the optimization technique, beam-on time was reduced by more than 15% in 16/20 lesions. The volume of normal brain receiving 12 Gy or above also decreased in many cases, and in only one instance increased by more than 0.5 cm3. Conclusions This work demonstrates that IDL optimization using the shot within shot technique can reduce treatment times without degrading treatment plan quality. |
| first_indexed | 2024-12-14T18:44:34Z |
| format | Article |
| id | doaj.art-6421e05393b045e1a732580276dd92e8 |
| institution | Directory Open Access Journal |
| issn | 1748-717X |
| language | English |
| last_indexed | 2024-12-14T18:44:34Z |
| publishDate | 2017-11-01 |
| publisher | BMC |
| record_format | Article |
| series | Radiation Oncology |
| spelling | doaj.art-6421e05393b045e1a732580276dd92e82022-12-21T22:51:24ZengBMCRadiation Oncology1748-717X2017-11-011211910.1186/s13014-017-0919-4Optimization of the prescription isodose line for Gamma Knife radiosurgery using the shot within shot techniquePerry B. Johnson0Maria I. Monterroso1Fei Yang2Eric Mellon3Radiation Oncology / Biomedical Engineering, University of MiamiRadiation Oncology, University of MiamiRadiation Oncology, University of MiamiRadiation Oncology, University of MiamiAbstract Background This work explores how the choice of prescription isodose line (IDL) affects the dose gradient, target coverage, and treatment time for Gamma Knife radiosurgery when a smaller shot is encompassed within a larger shot at the same stereotactic coordinates (shot within shot technique). Methods Beam profiles for the 4, 8, and 16 mm collimator settings were extracted from the treatment planning system and characterized using Gaussian fits. The characterized data were used to create over 10,000 shot within shot configurations by systematically changing collimator weighting and choice of prescription IDL. Each configuration was quantified in terms of the dose gradient, target coverage, and beam-on time. By analyzing these configurations, it was found that there are regions of overlap in target size where a higher prescription IDL provides equivalent dose fall-off to a plan prescribed at the 50% IDL. Furthermore, the data indicate that treatment times within these regions can be reduced by up to 40%. An optimization strategy was devised to realize these gains. The strategy was tested for seven patients treated for 1–4 brain metastases (20 lesions total). Results For a single collimator setting, the gradient in the axial plane was steepest when prescribed to the 56–63% (4 mm), 62–70% (8 mm), and 77–84% (16 mm) IDL, respectively. Through utilization of the optimization technique, beam-on time was reduced by more than 15% in 16/20 lesions. The volume of normal brain receiving 12 Gy or above also decreased in many cases, and in only one instance increased by more than 0.5 cm3. Conclusions This work demonstrates that IDL optimization using the shot within shot technique can reduce treatment times without degrading treatment plan quality.http://link.springer.com/article/10.1186/s13014-017-0919-4RadiosurgeryGamma KnifeGradient indexOptimizationMetastases |
| spellingShingle | Perry B. Johnson Maria I. Monterroso Fei Yang Eric Mellon Optimization of the prescription isodose line for Gamma Knife radiosurgery using the shot within shot technique Radiation Oncology Radiosurgery Gamma Knife Gradient index Optimization Metastases |
| title | Optimization of the prescription isodose line for Gamma Knife radiosurgery using the shot within shot technique |
| title_full | Optimization of the prescription isodose line for Gamma Knife radiosurgery using the shot within shot technique |
| title_fullStr | Optimization of the prescription isodose line for Gamma Knife radiosurgery using the shot within shot technique |
| title_full_unstemmed | Optimization of the prescription isodose line for Gamma Knife radiosurgery using the shot within shot technique |
| title_short | Optimization of the prescription isodose line for Gamma Knife radiosurgery using the shot within shot technique |
| title_sort | optimization of the prescription isodose line for gamma knife radiosurgery using the shot within shot technique |
| topic | Radiosurgery Gamma Knife Gradient index Optimization Metastases |
| url | http://link.springer.com/article/10.1186/s13014-017-0919-4 |
| work_keys_str_mv | AT perrybjohnson optimizationoftheprescriptionisodoselineforgammakniferadiosurgeryusingtheshotwithinshottechnique AT mariaimonterroso optimizationoftheprescriptionisodoselineforgammakniferadiosurgeryusingtheshotwithinshottechnique AT feiyang optimizationoftheprescriptionisodoselineforgammakniferadiosurgeryusingtheshotwithinshottechnique AT ericmellon optimizationoftheprescriptionisodoselineforgammakniferadiosurgeryusingtheshotwithinshottechnique |