Modeling correlation indices between bladder and Foley's catheter balloon dose with CT-based planning using limited CT slices in intracavitary brachytherapy for carcinoma of cervix.
J Cancer Res Ther
;
2008 Oct-Dec; 4(4): 156-63
Article
in English
| IMSEAR
| ID: sea-111566
ABSTRACT
PURPOSE:
To derive and validate an index to correlate the bladder dose with the catheter balloon dose using limited computed tomography (CT) slices. MATERIALS ANDMETHODS:
Applicator geometry reconstructed from orthogonal radiographs were back-projected on CT images of the same patients for anatomy-based dosimetric evaluation. The correlation indices derived using power function of the catheter balloon dose and the bladder volume dose were validated in 31 patients with cervical cancer.RESULTS:
There was significant correlation between International Commission on Radiation Units (ICRU)-38 balloon reference dose (Dr) and the dose received by 25% bladder volume (D(25)) (P< 0.0001). Significant correlation was also found between the reference dose of mid-balloon point (D(rm)) and the dose to D(25) (P < 0.0001). Average percentage difference [100 x (observed index - expected index)/ expected index] of observed value of I'25 (index for the dose to D25 bladder with respect to mid-balloon reference point) from that of expected value was 0.52%, when the index was modeled with reference dose alone. Similarly the average percentage difference for I'10cc (index for the dose to 10 cc volume of bladder with respect to mid balloon point) was 0.84%. When this index was modeled with absolute bladder volume and reference dose, standard deviation of the percentage difference between observed and expected index for D(rm) reduced by approximately 2% when compared to D(r).CONCLUSION:
For clinical applications, correlation index modeled with reference dose and volume predicts dose to absolute volume of bladder. Correlation index modeled with reference dose gives a good estimate of dose to relative bladder volume. From our study, we found D(rm) to be a better indicator of bladder dose than D(r).
Full text:
Available
Index:
IMSEAR (South-East Asia)
Main subject:
Radiometry
/
Radiotherapy Dosage
/
Scattering, Radiation
/
Biopsy
/
Urinary Bladder
/
Radiotherapy Planning, Computer-Assisted
/
Brachytherapy
/
Female
/
Humans
/
Catheterization
Type of study:
Diagnostic study
/
Observational study
/
Prognostic study
Language:
English
Journal:
J Cancer Res Ther
Journal subject:
Neoplasms
/
Therapeutics
Year:
2008
Type:
Article
Similar
MEDLINE
...
LILACS
LIS