Single dose radiosurgical treatment of recurrent previously irradiated primary brain tumors and brain metastases: final report of RTOG protocol 90-05

Shaw, Edward G.; Scott, Charles; Souhami, Luís; Dinapoli, Robert P.; Kline, Robert W.; Loeffler, Jay S.; Farnan, Nancy

doi:10.1016/s0360-3016(99)00507-6

Cited by 1,395 publications

(930 citation statements)

References 12 publications

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“…In 1993, Radiation Therapy Oncology Group (RTOG) proposed routine evaluation of stereotactic radiotherapy treatment plans based on reference isodose value and reference isodose volume and target volume. ( 2 – 4 , 7 , 19 ) The RTOG proposed the conformity index as PITV ( 4 , 7 , 8 , 11 , 19 , 20 ) which is defined as:

P I T V = \frac{P I V}{T V}

…”

Section: Methodsmentioning

confidence: 99%

“…( 4 , 7 , 8 , 21 – 24 ) According to the PITV ratio, a PITV value equal to 1 corresponds to ideal conformation. A PITV greater than 1 indicates that the irradiated volume is greater than the target volume, which means it includes healthy tissues.…”

Section: Methodsmentioning

confidence: 99%

“…Conformity Index (CI) is the ratio of the prescription volume to the target volume, as defined in the Radiation Therapy Oncology Group (RTOG) radiosurgery guidelines in 1993. ( 2 – 4 ) CI is useful for evaluating competing plans for the same patient or comparing different modalities. Dose volume histograms (DVH) summarize the dose distribution information for a region of interest or anatomical structure and identify characteristics such as dose uniformity and hot or cold spots.…”

Section: Introductionmentioning

confidence: 99%

“…In the past, it has been reported that linear accelerator‐based SRS is less conformal than gamma knife SRS. ( 4 , 7 , 8 ) However, linear accelerator‐based SRS has become highly sophisticated, evolving from circular arc and multiple isocenters per target to dynamic conformal arcs (DCA) based on a single isocenter. The dynamic conformal arc is a method of linear accelerator‐based SRS that uses multiple arcs rotating about a single isocenter.…”

Section: Introductionmentioning

confidence: 99%

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Dosimetric performance of the new high‐definition multileaf collimator for intracranial stereotactic radiosurgery

Dhabaan

Elder

Schreibmann

et al. 2010

J Applied Clin Med Phys

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The objective was to evaluate the performance of a high‐definition multileaf collimator (MLC) of 2.5 mm leaf width (MLC2.5) and compare to standard 5 mm leaf width MLC (MLC5) for the treatment of intracranial lesions using dynamic conformal arcs (DCA) technique with a dedicated radiosurgery linear accelerator. Simulated cases of spherical targets were created to study solely the effect of target volume size on the performance of the two MLC systems independent of target shape complexity. In addition, 43 patients previously treated for intracranial lesions in our institution were retrospectively planned using DCA technique with MLC2.5 and MLC5 systems. The gross tumor volume ranged from 0.07 to 40.57 cm3 with an average volume of 5.9 cm3. All treatment parameters were kept the same for both MLC‐based plans. The plan evaluation was performed using figures of merits (FOM) for a rapid and objective assessment on the quality of the two treatment plans for MLC2.5 and MLC5. The prescription isodose surface was selected as the greatest isodose surface covering ≥95% of the target volume and delivering 95% of the prescription dose to 99% of target volume. A Conformity Index (CI) and conformity distance index (CDI) were used to quantifying the dose conformity to a target volume. To assess normal tissue sparing, a normal tissue difference (NTD) was defined as the difference between the volume of normal tissue receiving a certain dose utilizing MLC5 and the volume receiving the same dose using MLC2.5. The CI and normal tissue sparing for the simulated spherical targets were better with the MLC2.5 as compared to MLC5. For the clinical patients, the CI and CDI results indicated that the MLC2.5 provides better treatment conformity than MLC5 even at large target volumes. The CI's range was 1.15 to 2.44 with a median of 1.59 for MLC2.5 compared to 1.60–2.85 with a median of 1.71 for MLC5. Improved normal tissue sparing was also observed for MLC2.5 over MLC5, with the NTD always positive, indicating improvement, and ranging from 0.1 to 8.3 for normal tissue receiving 50% (NTV50), 70% (NTV70) and 90% (NTV90) of the prescription dose. The MLC2.5 has a dosimetric advantage over the MLC5 in Linac‐based radiosurgery using DCA method for intracranial lesions, both in treatment conformity and normal tissue sparing when target shape complexity increases.PACS number: 87.56J‐, 87.56 jk

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P I T V = \frac{P I V}{T V}

…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dosimetric performance of the new high‐definition multileaf collimator for intracranial stereotactic radiosurgery

Dhabaan

Elder

Schreibmann

et al. 2010

J Applied Clin Med Phys

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show abstract

“…While an earlier investigation suggested the dose heterogeneity generated by GammKnife radiosurgery may result in greater control of cranial tumors compared to linac‐based stereotactic radiosurgery, ( 23 ) the conclusion has been disputed. ( 24 ) Certainly those results cannot be generalized to apply to lung SBRT.…”

Section: Resultsmentioning

confidence: 99%

A dosimetric comparison of stereotactic body radiation therapy techniques for lung cancer: robotic versus conventional linac‐based systems

Ding

Chang

Haslam

et al. 2010

J Applied Clin Med Phys

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The aim of this study is to compare the dosimetric characteristics of robotic and conventional linac‐based SBRT techniques for lung cancer, and to provide planning guidance for each modality. Eight patients who received linac‐based SBRT were retrospectively included in this study. A dose of 60 Gy given in three fractions was prescribed to each target. The Synchrony Respiratory Tracking System and a 4D dose calculation methodology were used for CyberKnife and linac‐based SBRT, respectively, to minimize respiratory impact on dose calculation. Identical image and contour sets were used for both modalities. While both modalities can provide satisfactory target dose coverage, the dose to GTV was more heterogeneous for CyberKnife than for linac planning/delivery in all cases. The dose to 1000 cc lung was well below institutional constraints for both modalities. In the high dose region, the lung dose depended on tumor size, and was similar between both modalities. In the low dose region, however, the quality of CyberKnife plans was dependent on tumor location. With anteriorly‐located tumors, the CyberKnife may deliver less dose to normal lung than linac techniques. Conversely, for posteriorly‐located tumors, CyberKnife delivery may result in higher doses to normal lung. In all cases studied, more monitor units were required for CyberKnife delivery for given prescription. Both conventional linacs and CyberKnife provide acceptable target dose coverage while sparing normal tissues. The results of this study provide a general guideline for patient and treatment modality selection based on dosimetric, tumor and normal tissue sparing considerations.PACS numbers: 87.53.Ly, 87.55.dk.

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The Emerging Paradigm of Preoperative Stereotactic Radiosurgery for Resectable Brain Metastases

McClelland

Yeboa

2023

JAMA Oncol

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In the treatment of metastatic brain disease, the efficacy of stereotactic radiosurgery (SRS) as an effective cognition-sparing alternative to whole-brain radiotherapy (WBRT) has been well-established, largely in part to the level 1 evidence provided by Chang et al 1 that supports the initial treatment of brain metastases with the combination of SRS and close monitoring rather than with WBRT. For metastatic brain disease that is amenable to operative resection (1-4 brain metastases total with at least 1 lesion producing a significant mass effect and/or ≥2 cm in maximum diameter), Mahajan et al 2 provided level 1 evidence that SRS (performed in this trial as singlefraction gamma knife SRS) is associated with reduced 1-year resection cavity local recurrence from 57% to 28% for patients with 1 to 3 resected brain metastases. Brown et al 3 provided level 1 evidence that suggested that for patients with 1 resected brain metastasis and a resection cavity less than 5 cm, SRS is significantly less toxic than WBRT to cognition, with this reduced toxic effect not compromising overall survival.Because operative resection may carry the risk of leptomeningeal seeding of disease, preoperative sterilization of the lesion with SRS has increased in popularity with the goal of improving on the 28% risk of leptomeningeal disease (LMD) at 12 months post-SRS (as established by Mahajan et al), 2 as it allows for radiation delivery before potential dissemination of the tumor by operative resection. Data on the comparative risk of radionecrosis and local control are also areas of particular interest for investigating the future role of preoperative SRS.The article in this issue of JAMA Oncology by Prabhu et al 4 retrospectively combined the data from 8 centers to create a 416-lesion cohort study (from 404 patients) to evaluate the risk factors for progression and morbidity following preoperative SRS for brain metastases. Stereotactic radiosurgery was performed via either gamma knife or linear accelerator and administered to a single-fraction range of 14 to 17 Gy (median, 15 Gy) or a 3-fraction range of 24 to 26 Gy (median, 24 Gy) to a median gross tumor volume of 10 cc (approximately equivalent to a maximum diameter of 2.7 cm), with a median interval of 2 days between preoperative SRS and resection. The 1-year incidence of resection cavity local recurrence was 11.9%, 2 with an encouragingly low 13.7% 2-year cavity local recurrence rate.The authors found that single-fraction SRS provided worse local control than multifraction SRS, although the tumor size criteria between patients receiving single-fraction vs multifraction SRS was not clearly stated. For single-fraction preoperative SRS, it is likely that the 15-Gy dose the authors used was simply not sufficient to optimally sterilize lesions smaller than 3 cm. For instance, RTOG 90-05 recommendations indicated

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Single dose radiosurgical treatment of recurrent previously irradiated primary brain tumors and brain metastases: final report of RTOG protocol 90-05

Cited by 1,395 publications

References 12 publications

Dosimetric performance of the new high‐definition multileaf collimator for intracranial stereotactic radiosurgery

Dosimetric performance of the new high‐definition multileaf collimator for intracranial stereotactic radiosurgery

A dosimetric comparison of stereotactic body radiation therapy techniques for lung cancer: robotic versus conventional linac‐based systems

The Emerging Paradigm of Preoperative Stereotactic Radiosurgery for Resectable Brain Metastases

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