DVHs evaluation in brain metastases stereotactic radiotherapy treatment plans.
OBJECTIVE
The aim of this work is to report a retrospective study of radiobiological indicators based on Dose-Volume Histograms analysis obtained by stereotactic radiotherapy treatments.


METHODS
Fifty-five patients for a total of sixty-seven brain metastases with a mean target volume of 8.49 cc were treated by Dynamic Conformal Arc Therapy (DCAT) and Intensity-Modulated Stereotactic Radiotherapy (IMRST). The Delivered prescription dose was chosen on the basis of tumor size and location so as to ensure a 100% isodose coverage to the target volume.


RESULTS
The treatment plans reported a mean value of 10% and 2.19% for the inhomogeneity and conformal index, respectively. The F factor showed we overdosed sixty-three patients delivering an additional 7% dose more than calculated values. The radiobiological parameters: TCP and NTCP showed a complete tumor control limiting the organs at risk damage.


CONCLUSIONS
One goal of stereotactic radiotherapy is to design a treatment plan in which the steep dose gradient achievable minimizes the amount of radiation delivered outside the tumor region. This technique allows to deliver a much larger dose to the target without exceeding the radiation-related tolerance of normal tissues and improving patients' quality of life.
Pasciuti
Katia
K
Laboratory of Medical Physics and Expert Systems, Regina Elena National Cancer Institute, Rome, Italy. ka.pasciuti@libero.it
Iaccarino
Giuseppe
G
Soriani
Antonella
A
Bruzzaniti
Vicente
V
Marzi
Simona
S
Gomellini
Sara
S
Arcangeli
Stefano
S
Benassi
Marcello
M
Landoni
Valeria
V
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D005260:Female; D006801:Humans; D007103:Immobilization; D008297:Male; D008875:Middle Aged; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D013238:Stereotaxic Techniques; D016896:Treatment Outcome