Objective: To evaluate the influence of respiration on the radiation dose distribution in radiotherapy with matlab simulation and film dosimetry. Methods: Radiation of 50MU was delivered in a square, round, ellipse, dumb bell, or female shaped field to the films within a moving or static Respiration Motion Phantom respectively, the dose distributions for the two motion status were measured and compared. In order to further verify the impact of amplitude of respiration movement, the matlab simulation with movement amplitude of 0 cm, 0.5 cm, 1.0 cm, 1.5 cm, 2.0 cm, and 2.5cm were done respectively. The dose distributions in different status were measured and compared with film dosimetry. Iso-dose line comparison, NAT (Normalized Agreement Tests) and γ comparison were used for the comparison of dose distributions. Fs was used as an index to evaluate the differences of the areas that surrounded by iso-dose lines in different situations (FS90, FS50, FS25 delegates the ratio of the areas that surrounded by 90%, 50%, 25% iso-dose line in different situation respectively). Results: (1) For round field, the matlab simulation showed that S90 decreased as the increase of the movement. S90 was almost 0 when the amplitude became to half of the diameter of the field. S25 varied inversely. (2) The experiment showed that in horizontal movement situation compared with in static situation, the FS90 became smaller and the FS25 became larger. The more the displacement became larger, the more the FS90 and the FS25 deviate remarkable. In vertical movement situation, Fs changed significantly in square field and dumb bell shaped field while changed a little in the others. (3) γ and NAT comparison: In the horizontal movement situation, compared with in the static phantom, the Pγ was <60% and the PNAT was <75% in every radiation field. In vertical movement situation, the Pγ was less than 85% for all the square, round, dumb bell and female shaped fields. Conclusions: The respiration can impact on the dose distribution within the target volume in radiotherapy, leading to a smaller area of higher dose level and an expanded area of lower dose level. The influence will become more significant with larger movement of the target.
Dose Distribution Static Situation Shaped Field High Dose Region Film Dosimetry
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access.
Shirato, H., Shimizu, S., Kunieda, T.: Physical aspects of a real-time tumor-tracking system for gated radiotherapy. Int. J. Radiat. Oncol. Biol. Phys. 48, 1187–1195 (2000)CrossRefGoogle Scholar
Shimizu, S., Shirato, H., Kagei, K.: Impact of respiratory movement on the computed tomographic images of small lung tumors in three-dimensional (3D) radiotherapy. Int. J. Radiat. Oncol. Biol. Phys. 46, 1127–1133 (2000)CrossRefGoogle Scholar
Maxim, P.G., Loo Jr., B.W.: Quantification of motion of different thoracic locations using four-dimensional computed tomography: implications for radiotherapy plannings. Int. J. Radiat. Oncol. Biol. Phys. 69, 1395–1401 (2007)CrossRefGoogle Scholar
Liu, H.H., Balter, P., Tutt, T.: Assessing respiration-induced tumor motion and internal target volume using four-dimensional computed tomography for radiotherapy of lung cancer. Int. J. Radiat. Oncol. Biol. Phys. 68, 531–540 (2007)CrossRefGoogle Scholar
van Sornsen de Koste, J.R., Lagerwaard, F.J., Nijssen-Visser, M.R.: Tumor location cannot predict the mobility of lung tumors: A 3D analysis of data generated from multiple CT scans. Int. J. Radiat. Oncol. Biol. Phys. 56, 348–354 (2003)CrossRefGoogle Scholar
Seppenwoolde, Y., Shirato, H., Kitamura, K.: Precise and real-time measurement of 3D tumor notion in lung due to breathing and heartbeat, measured during radiotherapy. Int. J. Radiat. Oncol. Biol. Phys. 53, 822–834 (2002)CrossRefGoogle Scholar
Low, D.A., Harms, W.B., Mutic, S.: A technique for the quantitative evaluation of dose distributions. Med. Phys. 25, 656–661 (1998)CrossRefGoogle Scholar
Balter, J.M., Ten-haken, R.H., Lawarence, T.S.: Uncertainties in CT-based radiation therapy treatment planning association with patient breathing. Int. J. Radiat. Oncol. Biol. Phys. 36, 167–174 (1996)Google Scholar
Rosenzweig, K.E., Hanley, J., Mah, D.: The deep inspiration breath-hold technique in the treatment of inoperable non-small-cell lung cancer. Int. J. Radiat. Oncol. Biol. Phys. 48, 81–87 (2000)CrossRefGoogle Scholar
Shirato, H., Shimzu, S., Kunieda, T.: Physical aspects of a real-time tumor-tracking system for gated radiotherapy. Int. J. Radiat. Oncol. Biol. Phys. 48, 1187–1195 (2000)CrossRefGoogle Scholar
Shirato, H., Shimizu, S., Kitamura, K.: Four-dimensional treatment planning and fluoroscopic real-time tumor tracking radiotherapy for moving tumor. Int. J. Radiat. Oncol. Biol. Phys. 48, 435–442 (2000)CrossRefGoogle Scholar
Kim, D.J.W., Murray, B.R., Halperin, R.: Held-breath self-gating technique for radiotherapy of non-small-cell lung cancer: a feasibility study. Int. J. Radiat. Oncol. Biol. Phys. 49, 43–49 (2001)CrossRefGoogle Scholar
Sixel, K.E., Aznar, M.C., Ung, Y.C.: Deep inspiration breath hold to reduce irradiated heart volume in breast cancer patients. Int. J. Radiat. Oncol. Biol. Phys. 49, 199–204 (2001)CrossRefGoogle Scholar
Rijkhorst, E.J., van Herk, M., Lebesque, J.V.: Strategy for online correction of rotational organ motion for intensity-modulated radiotherapy of prostate cancer. Int. J. Radiat. Oncol. Biol. Phys. 69, 1608–1617 (2007)CrossRefGoogle Scholar