Radiation treatment planning system and method of radiation treatment planning
There is disclosed a radiation treatment planning system for preparing treatment planning information for carrying out radiation treatment. The apparatus includes an input unit with which an operator inputs a prescription dose and an irradiation angle; an arithmetic unit which prepares the treatment planning information by determining irradiation conditions in such a manner as to bring a dose distribution calculated based on the result of the input from the input unit closer to the prescription dose, and a display unit which displays the treatment planning information. The arithmetic unit sets, per point for radiation irradiation, an index representing the degree of demand for irradiation amount suppression, the degree of demand determined by the radiation irradiation point, and the arithmetic unit further determines the irradiation conditions using the index.
1. A radiation treatment planning system for preparing treatment planning information for carrying out radiation treatment, the radiation treatment planning system comprising:
an input unit with which an operator inputs a prescription dose and an irradiation angle;
an arithmetic unit which prepares the treatment planning information by determining irradiation conditions in such a manner as to bring a dose distribution calculated based on the inputs from the input unit closer to the prescription dose; and
a display unit which displays the treatment planning information,
wherein the arithmetic unit sets, per radiation irradiation point of the radiation treatment, an index representing a degree of demand for irradiation amount suppression, the degree of demand determined by the radiation irradiation point, and the arithmetic unit further determines the irradiation conditions using the index according to the following expression:
F
(
x
->
)
=
∑
i
=
1
m
w
i
(
1
)
(
d
i
(
1
)
-
p
)
2
+
∑
i
=
1
n
w
i
(
2
)
(
d
i
(
2
)
-
l
)
2
θ
(
d
i
(
2
)
-
l
)
+
K
0
∑
j
=
1
k
S
j
x
j
,
where “p” is a target dose set for “m” points corresponding to a target region, “w i (1) ” are weights corresponding to the “m” points, and “{right arrow over (d)} (1) ” are doses for the “m” points in the target region,
where “l” is a permissible dose set for “n” points corresponding to an organ at risk, “w i (2) ” are weights corresponding to the “n” points, “{right arrow over (d)} (2) ” are doses for the “n” points in the organ at risk, and “θ(d i (2) −l)” is a step function that is 0 when d i (2) <1 and is 1 otherwise, and
where “K 0 ” is a degree of importance greater than 0, “S j ” are scores representing a degree of demand for irradiation amount suppression, and “{right arrow over (x)}” are irradiation amounts for a total number “k” of spots.
2. The radiation treatment planning system according to claim 1 , wherein the arithmetic unit determines the index in accordance with density information for a patient, the density information being based on the result of the inputs from the input unit.
3. The radiation treatment planning system according to claim 2 , wherein the arithmetic unit sets the index with regard to the radiation irradiation points included in a desired region designated using the input unit.
4. The radiation treatment planning system according to claim 1 , wherein the arithmetic unit causes information about the set index to be displayed on the display unit.
5. The radiation treatment planning system according to claim 4 , wherein the arithmetic unit sets the index with regard to the radiation irradiation points included in a desired region designated using the input unit.
6. The radiation treatment planning system according to claim 1 , wherein the arithmetic unit sets the index with regard to the radiation irradiation points included in a desired region designated using the input unit.