Abstract
The need of radiation therapy in cancer treatment is increasing, however, the dose of radiation is limited by its late effects on normal tissues. Hyperfractionated radiotherapy was applied to patients with various kinds of carcinomas in the 1980s, expecting to improve tumor control rates. Some reports showed that the total radiation dose could be increased without increasing late radiation damage by using hyperfractionated radiotherapy. We calculated the early and late biologically effective doses (BED)for conventional and hyperfractionated radiotherapy to predict the early and late radiation damage based on the linear-quadratic model (L-Q model). Setting the values of the α/β ratio and t1/2 (half time repaire) in the L-Q model is still controversial, and few reports deal with t1/2. Assuming t1/2 = 0.5hour, the total radiation dose can be up to 71Gy by hyperfractionated schedule (1.2Gy/fr. 2 times/day) without increasing the late BED of conventional schedule (2Gy/day, total 60Gy). However, the late BED should be increased in tissues with a larger t1/2 value, even if applying the same hyperfractionated schedule. Thus, it is not recommended to apply the same hyperfractionated protocol to all organs.
| Original language | English |
|---|---|
| Pages (from-to) | 599-604 |
| Number of pages | 6 |
| Journal | Nippon Acta Radiologica |
| Volume | 56 |
| Issue number | 8 |
| Publication status | Published - 1996 Jul |
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Keywords
- Dose rate
- Hyperfractionation
- Linear-quadratic model
- Radiotherapy
ASJC Scopus subject areas
- Medicine(all)
Cite this
Pitfalls of Hyperfractionation : Theoretical considerations of effect of repair time on late radiation damage. / Shigematsu, Naoyuki; Ito, Hisao; Kubo, Atsushi; Dokiya, Takushi.
In: Nippon Acta Radiologica, Vol. 56, No. 8, 07.1996, p. 599-604.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pitfalls of Hyperfractionation
T2 - Theoretical considerations of effect of repair time on late radiation damage
AU - Shigematsu, Naoyuki
AU - Ito, Hisao
AU - Kubo, Atsushi
AU - Dokiya, Takushi
PY - 1996/7
Y1 - 1996/7
N2 - The need of radiation therapy in cancer treatment is increasing, however, the dose of radiation is limited by its late effects on normal tissues. Hyperfractionated radiotherapy was applied to patients with various kinds of carcinomas in the 1980s, expecting to improve tumor control rates. Some reports showed that the total radiation dose could be increased without increasing late radiation damage by using hyperfractionated radiotherapy. We calculated the early and late biologically effective doses (BED)for conventional and hyperfractionated radiotherapy to predict the early and late radiation damage based on the linear-quadratic model (L-Q model). Setting the values of the α/β ratio and t1/2 (half time repaire) in the L-Q model is still controversial, and few reports deal with t1/2. Assuming t1/2 = 0.5hour, the total radiation dose can be up to 71Gy by hyperfractionated schedule (1.2Gy/fr. 2 times/day) without increasing the late BED of conventional schedule (2Gy/day, total 60Gy). However, the late BED should be increased in tissues with a larger t1/2 value, even if applying the same hyperfractionated schedule. Thus, it is not recommended to apply the same hyperfractionated protocol to all organs.
AB - The need of radiation therapy in cancer treatment is increasing, however, the dose of radiation is limited by its late effects on normal tissues. Hyperfractionated radiotherapy was applied to patients with various kinds of carcinomas in the 1980s, expecting to improve tumor control rates. Some reports showed that the total radiation dose could be increased without increasing late radiation damage by using hyperfractionated radiotherapy. We calculated the early and late biologically effective doses (BED)for conventional and hyperfractionated radiotherapy to predict the early and late radiation damage based on the linear-quadratic model (L-Q model). Setting the values of the α/β ratio and t1/2 (half time repaire) in the L-Q model is still controversial, and few reports deal with t1/2. Assuming t1/2 = 0.5hour, the total radiation dose can be up to 71Gy by hyperfractionated schedule (1.2Gy/fr. 2 times/day) without increasing the late BED of conventional schedule (2Gy/day, total 60Gy). However, the late BED should be increased in tissues with a larger t1/2 value, even if applying the same hyperfractionated schedule. Thus, it is not recommended to apply the same hyperfractionated protocol to all organs.
KW - Dose rate
KW - Hyperfractionation
KW - Linear-quadratic model
KW - Radiotherapy
UR - http://www.scopus.com/inward/record.url?scp=2742602556&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=2742602556&partnerID=8YFLogxK
M3 - Article
C2 - 8797353
AN - SCOPUS:2742602556
VL - 56
SP - 599
EP - 604
JO - Nippon Acta Radiologica
JF - Nippon Acta Radiologica
SN - 0048-0428
IS - 8
ER -