Abstract
We studied the dosimetry of single-isocenter treatment plans generated to treat a solitary intracranial lesion using linac-based stereotactic radiosurgery (SRS). A common metric for evaluating SRS plan quality is the volume of normal brain tissue irradiated by a dose of at least 12 Gy (V12), which is important because multiple studies have shown a strong correlation between V12 and incidence of radiation necrosis. Unrealistic expectations for values of V12 can lead to wasted planning time. We present a model that estimates V12 without having to construct a full treatment plan. This model was derived by retrospectively analyzing 50 SRS treatment plans, each clinically approved for delivery using circular collimator cone arc therapy (CAT). Each case was re-planned for delivery via dynamic conformal arc therapy (DCAT), and then scaling arguments were used to extend dosimetric data to account for different prescription dose (PD) values (15, 18, 21, or 24 Gy). We determined a phenomenological expression for the total volume receiving at least 12 Gy (TV12) as a function of both planning target volume (PTV) and PD: (Formula presented.), where {a, c, n, d} are fit parameters, and a separate set of values is determined for each plan type. In addition, we generated a sequence of plots to clarify how the relationship between conformity index (CI) and TV12 depends on plan type (CAT vs DCAT), PTV, and PD. These results can be used to suggest realistic plan parameters and planning goals before the start of treatment planning. In the absence of access to more sophisticated pre-planning tools, this model can be locally generated and implemented at relatively low cost with respect to time, money, and expertise.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 97-108 |
| Number of pages | 12 |
| Journal | Journal of Applied Clinical Medical Physics |
| Volume | 20 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 1 2019 |
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Keywords
- circular arc therapy (CAT)
- conformity index (CI)
- dynamic conformal arc therapy (DCAT)
- modeling
- stereotactic radiosurgery (SRS)
- V12
ASJC Scopus subject areas
- Radiation
- Instrumentation
- Radiology Nuclear Medicine and imaging
Cite this
A simple knowledge-based tool for stereotactic radiosurgery pre-planning. / Goldbaum, Daniel S.; Hurley, Justin D.; Hamilton, Russell J.
In: Journal of Applied Clinical Medical Physics, Vol. 20, No. 12, 01.12.2019, p. 97-108.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A simple knowledge-based tool for stereotactic radiosurgery pre-planning
AU - Goldbaum, Daniel S.
AU - Hurley, Justin D.
AU - Hamilton, Russell J.
PY - 2019/12/1
Y1 - 2019/12/1
N2 - We studied the dosimetry of single-isocenter treatment plans generated to treat a solitary intracranial lesion using linac-based stereotactic radiosurgery (SRS). A common metric for evaluating SRS plan quality is the volume of normal brain tissue irradiated by a dose of at least 12 Gy (V12), which is important because multiple studies have shown a strong correlation between V12 and incidence of radiation necrosis. Unrealistic expectations for values of V12 can lead to wasted planning time. We present a model that estimates V12 without having to construct a full treatment plan. This model was derived by retrospectively analyzing 50 SRS treatment plans, each clinically approved for delivery using circular collimator cone arc therapy (CAT). Each case was re-planned for delivery via dynamic conformal arc therapy (DCAT), and then scaling arguments were used to extend dosimetric data to account for different prescription dose (PD) values (15, 18, 21, or 24 Gy). We determined a phenomenological expression for the total volume receiving at least 12 Gy (TV12) as a function of both planning target volume (PTV) and PD: (Formula presented.), where {a, c, n, d} are fit parameters, and a separate set of values is determined for each plan type. In addition, we generated a sequence of plots to clarify how the relationship between conformity index (CI) and TV12 depends on plan type (CAT vs DCAT), PTV, and PD. These results can be used to suggest realistic plan parameters and planning goals before the start of treatment planning. In the absence of access to more sophisticated pre-planning tools, this model can be locally generated and implemented at relatively low cost with respect to time, money, and expertise.
AB - We studied the dosimetry of single-isocenter treatment plans generated to treat a solitary intracranial lesion using linac-based stereotactic radiosurgery (SRS). A common metric for evaluating SRS plan quality is the volume of normal brain tissue irradiated by a dose of at least 12 Gy (V12), which is important because multiple studies have shown a strong correlation between V12 and incidence of radiation necrosis. Unrealistic expectations for values of V12 can lead to wasted planning time. We present a model that estimates V12 without having to construct a full treatment plan. This model was derived by retrospectively analyzing 50 SRS treatment plans, each clinically approved for delivery using circular collimator cone arc therapy (CAT). Each case was re-planned for delivery via dynamic conformal arc therapy (DCAT), and then scaling arguments were used to extend dosimetric data to account for different prescription dose (PD) values (15, 18, 21, or 24 Gy). We determined a phenomenological expression for the total volume receiving at least 12 Gy (TV12) as a function of both planning target volume (PTV) and PD: (Formula presented.), where {a, c, n, d} are fit parameters, and a separate set of values is determined for each plan type. In addition, we generated a sequence of plots to clarify how the relationship between conformity index (CI) and TV12 depends on plan type (CAT vs DCAT), PTV, and PD. These results can be used to suggest realistic plan parameters and planning goals before the start of treatment planning. In the absence of access to more sophisticated pre-planning tools, this model can be locally generated and implemented at relatively low cost with respect to time, money, and expertise.
KW - circular arc therapy (CAT)
KW - conformity index (CI)
KW - dynamic conformal arc therapy (DCAT)
KW - modeling
KW - stereotactic radiosurgery (SRS)
KW - V12
UR - http://www.scopus.com/inward/record.url?scp=85075313129&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85075313129&partnerID=8YFLogxK
U2 - 10.1002/acm2.12770
DO - 10.1002/acm2.12770
M3 - Article
C2 - 31743563
AN - SCOPUS:85075313129
VL - 20
SP - 97
EP - 108
JO - Journal of Applied Clinical Medical Physics
JF - Journal of Applied Clinical Medical Physics
SN - 1526-9914
IS - 12
ER -