Quantitative evaluation of acute mucosal reaction to interstitial brachytherapy using color histograms.
OBJECTIVE
Color histograms of tongue photographs were used to make a quantitative evaluation of acute mucosal reaction to high-dose-rate fractionated interstitial brachytherapy.


METHODS
Six patients with oral cavity cancer were analyzed with two methods (color histogram and vinyl plate). Using a photograph of the tongue, we calculated the histogram of each pixel of 1mm(2) of the tongue surface. The results were compared with the physician's inspection and the radiation dose.


RESULTS
The histogram showed a difference between the reactive area (erythema and pseudomembranous mucositis [PM]) and the nonreactive area. The relationship between inspection and the histogram showed a good correlation, although the histogram tended to change earlier than the subjective judgment. The peak time was 12-13 days after delivery of the final fraction of brachytherapy. The minimum dose required to cause PM was 3.3-3.6Gy per fraction (total: 29.7-32.4Gy).


CONCLUSIONS
Our new method of using color histograms for quantitative evaluation is helpful in the analysis of the relationship between mucosal reaction and radiation dose. The minimum dose causing PM was considered to be about 30Gy per nine fractions.
Yoshida
Ken
K
Department of Radiology, Osaka National Hospital, Osaka, Japan. kyoshida@onh.go.jp
Nose
Takayuki
T
Watanabe
Yoshiyuki
Y
Tokuda
Yukiko
Y
Choi
Soomi
S
Hosoki
Takuya
T
Mitomo
Masanori
M
Inaba
Osamu
O
Iida
Takeshi
T
Okada
Hisakazu
H
D000208:Acute Disease; D001918:Brachytherapy / Q000009:adverse effects*; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D004890:Erythema / Q000209:etiology / Q000473:pathology; D005720:Gamma Rays / Q000009:adverse effects; D006801:Humans; D009060:Mouth Floor / Q000473:pathology / Q000528:radiation effects; D009061:Mouth Mucosa / Q000473:pathology* / Q000528:radiation effects*; D009092:Mucous Membrane / Q000473:pathology / Q000528:radiation effects; D015588:Observer Variation; D010781:Photography; D013280:Stomatitis / Q000209:etiology* / Q000473:pathology*; D014062:Tongue Neoplasms / Q000532:radiotherapy