Bladder dose-surface maps and urinary toxicity

F. Palorini, A. Botti, Viviana Carillo, Stefano Gianolini, Ilaria Improta, C. Iotti, T. Rancati, C. Cozzarini, C. Fiorino

Research output: Contribution to journalArticle

Abstract

The purpose of this study was to quantify the impact of inter-fraction modifications of bladder during RT of prostate cancer on bladder dose surface maps (DSM).Eighteen patients treated with daily image-guided Tomotherapy and moderate hypofractionation (70-72.8. Gy at 2.5-2.6. Gy/fr in 28 fractions and full bladder) were considered. Bladder contours were delineated on co-registered daily Megavoltage CT (MVCT) by a single observer and copied on the planning CT to generate dose-volume/surface histograms (DVH/DSH) and bladder DSMs. Discrepancies between planned and daily absorbed doses were analyzed through the average of individual systematic errors, the population systematic errors and the population random errors for the DVH/DSHs and DSMs.In total, 477 DVH/DSH and 472 DSM were available. DSH and DVH showed small population systematic errors of absolute surfaces (2) and volumes (3) at the highest doses.The dose to the posterior bladder base assessed on DSMs showed a mean systematic error below 1. Gy, with population systematic and random errors within 4 and 3. Gy, respectively. The region surrounding this area shows higher mean systematic errors (1-3. Gy), population systematic (8-11. Gy) and random (5-7. Gy) errors.In conclusion, DVH/DSH and DSMs are quite stable with respect to inter-fraction variations in the high-dose region, within about 2. cm from bladder base. Larger systematic variations occur in the anterior portion and cranially 2.5-3.5. cm from the base.Results suggest that dose predictors related to the high dose area (including the trigone dose) are likely to be sufficiently reliable with respect to the expected variations due to variable bladder filling.
Original languageEnglish
JournalPhysica Medica
DOIs
Publication statusPublished - Mar 1 2016

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bladder
toxicity
Urinary Bladder
dosage
systematic errors
Population
random errors
Urinary Bladder Neoplasms
Prostatic Neoplasms
histograms
planning
cancer

Keywords

  • Bladder
  • Dose-surface maps
  • Inter-fraction motion

Cite this

Bladder dose-surface maps and urinary toxicity. / Palorini, F.; Botti, A.; Carillo, Viviana; Gianolini, Stefano; Improta, Ilaria; Iotti, C.; Rancati, T.; Cozzarini, C.; Fiorino, C.

In: Physica Medica, 01.03.2016.

Research output: Contribution to journalArticle

Palorini F, Botti A, Carillo V, Gianolini S, Improta I, Iotti C et al. Bladder dose-surface maps and urinary toxicity. Physica Medica. 2016 Mar 1. https://doi.org/10.1016/j.ejmp.2016.03.006
Palorini, F. ; Botti, A. ; Carillo, Viviana ; Gianolini, Stefano ; Improta, Ilaria ; Iotti, C. ; Rancati, T. ; Cozzarini, C. ; Fiorino, C. / Bladder dose-surface maps and urinary toxicity. In: Physica Medica. 2016.
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AU - Iotti, C.

AU - Rancati, T.

AU - Cozzarini, C.

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