Cerebral radiation surgery using moving field irradiation at a linear accelerator facility

Hartmann, Günther H.; Schlegel, Wolfgang; Sturm, Volker; Kober, B; Pastyr, O.; Lorenz, Walter J.

doi:10.1016/0360-3016(85)90068-9

Cited by 281 publications

(61 citation statements)

References 8 publications

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“…Stereotactic radiosurgery (SRS), by definition, is the delivery of a large therapeutic dose of radiation to an accurately localized target 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 . This results in an ablative dose of radiation at the target with a steep dose gradient to minimize damage to tissues outside of the target 9 , 10 , 11 , 12 .…”

Section: Introductionmentioning

confidence: 99%

Quantifying isocenter measurements to establish clinically meaningful thresholds

Denton

Shields

Howe

et al. 2015

J Applied Clin Med Phys

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A dataset range of isocenter congruency verification tests have been examined from a statistical perspective for the purpose of establishing tolerance levels that are meaningful, based on the fundamental limitation of linear accelerator isocentricity and the demands of a high‐precision stereotactic radiosurgery program. Using a laser‐defined isocenter, a total of 149 individual isocenter congruency tests were examined with recorded values for ideal spatial corrections to the isocenter test tool. These spatial corrections were determined from radiation exposures recorded on an electronic portal imaging device (EPID) at various gantry, collimator, and treatment couch combinations. The limitations of establishing an ideal isocenter were quantified from each variable which contributed to uncertainty in isocenter definition. Individual contributors to uncertainty, specifically, daily positioning setup errors, gantry sag, multileaf collimator (MLC) offset, and couch walkout, were isolated from isocenter congruency measurements to determine a clinically meaningful isocenter measurement. Variations in positioning of the test tool constituted, on average, 0.38 mm magnitude of correction. Gantry sag and MLC offset contributed 0.4 and 0.16 mm, respectively. Couch walkout had an average degrading effect to isocenter of 0.72 mm. Considering the magnitude of uncertainty contributed by each uncertainty variable and the nature of their combination, an appropriate schedule action and immediate action level were determined for use in analyzing daily isocenter congruency test results in a stereotactic radiosurgery (SRS) program. The recommendations of this study for this linear accelerator include a schedule action level of 1.25 mm and an immediate action level of 1.50 mm, requiring prompt correction response from clinical medical physicists before SRS or stereotactic body radiosurgery (SBRT) is administered. These absolute values were derived from considering relative data from a specific linear accelerator and, therefore, represent a means by which a numerical quantity can be used as a test threshold with relative specificity to a particular linear accelerator.PACS number: 87.53Ly, 29.20.Ej, 87.56.Fc

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Section: Introductionmentioning

confidence: 99%

Quantifying isocenter measurements to establish clinically meaningful thresholds

Denton

Shields

Howe

et al. 2015

J Applied Clin Med Phys

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“…Berkeley Laboratory (LBL) [10], the Gamma Knife in Sweden [3], and the LINAC technique used at Heidelberg [5]. A range of targets were chosen to explore the impact of lesion size, shape and position on the distribution of radiation to the target volume and to regions of normal tissue.…”

Section: In:troductionmentioning

confidence: 99%

“…Another set of targets was used in order to have an easily reproducible stan- Two photon irradiation geometries were used-that of the Gamma Knife with 179 beams [3], and that of the isocentrically-mounted Linac as used in Heidelberg [5].…”

Section: In:troductionmentioning

confidence: 99%

Comparison of different radiation types and irradiation geometries in stereotactic radiosurgery

Phillips¹,

Frankel²,

Lyman³

et al. 1990

International Journal of Radiation Oncology*Biology*Physics

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“…Hallmarks of stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) include the accurate, conformal delivery of high‐dose radiation to targets while minimizing normal tissue irradiation via precise target localization (1) and steep dose gradients through multiple beam directions 2 , 3 . Most SRS/SBRT delivery systems today incorporate complex target localization and motion compensation strategies 4 , 5 and allow for nearly limitless possibilities for beam shapes, orientations, motion, and intensities, making it cumbersome, if not impossible, to create forward‐planned treatment plans in routine practice.…”

Section: Introductionmentioning

confidence: 99%

Inverse treatment planning for spinal robotic radiosurgery: an international multi‐institutional benchmark trial

Blanck

Wang

Baus

et al. 2016

J Applied Clin Med Phys

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Stereotactic radiosurgery (SRS) is the accurate, conformal delivery of high‐dose radiation to well‐defined targets while minimizing normal structure doses via steep dose gradients. While inverse treatment planning (ITP) with computerized optimization algorithms are routine, many aspects of the planning process remain user‐dependent. We performed an international, multi‐institutional benchmark trial to study planning variability and to analyze preferable ITP practice for spinal robotic radiosurgery. 10 SRS treatment plans were generated for a complex‐shaped spinal metastasis with 21 Gy in 3 fractions and tight constraints for spinal cord (normalV14Gy<2 cc, normalV18Gy<0.1 cc) and target (coverage >95%). The resulting plans were rated on a scale from 1 to 4 (excellent‐poor) in five categories (constraint compliance, optimization goals, low‐dose regions, ITP complexity, and clinical acceptability) by a blinded review panel. Additionally, the plans were mathematically rated based on plan indices (critical structure and target doses, conformity, monitor units, normal tissue complication probability, and treatment time) and compared to the human rankings. The treatment plans and the reviewers' rankings varied substantially among the participating centers. The average mean overall rank was 2.4 (1.2‐4.0) and 8/10 plans were rated excellent in at least one category by at least one reviewer. The mathematical rankings agreed with the mean overall human rankings in 9/10 cases pointing toward the possibility for sole mathematical plan quality comparison. The final rankings revealed that a plan with a well‐balanced trade‐off among all planning objectives was preferred for treatment by most participants, reviewers, and the mathematical ranking system. Furthermore, this plan was generated with simple planning techniques. Our multi‐institutional planning study found wide variability in ITP approaches for spinal robotic radiosurgery. The participants', reviewers', and mathematical match on preferable treatment plans and ITP techniques indicate that agreement on treatment planning and plan quality can be reached for spinal robotic radiosurgery.PACS number(s): 87.55.de

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Cerebral radiation surgery using moving field irradiation at a linear accelerator facility

Cited by 281 publications

References 8 publications

Quantifying isocenter measurements to establish clinically meaningful thresholds

Quantifying isocenter measurements to establish clinically meaningful thresholds

Comparison of different radiation types and irradiation geometries in stereotactic radiosurgery

Inverse treatment planning for spinal robotic radiosurgery: an international multi‐institutional benchmark trial

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