S16
Poster Presentations
in 10 fractions (range, 2500–4000). Retreatment was completed to a median dose of 2500 cGy in 5 fractions, (range, 800 cGy in 1 fraction to 3000 cGy in 10 fractions). The median sum dose to the spinal cord was 4400 cGy (range, 3300–5500). The median volume of spinal cord or cauda equina getting greater than 5000 cGy was 0 cm3 (range, 0– 1.3 cm3). The median % GTV receiving 95% of the prescription dose was 96% (range, 82-98%). Seven patients (70%) were noted to have improvement in pain symptoms following treatment, 95% CI (35%93%). Of the four patients who reported neurologic symptoms, all showed improvement. Conclusions: The use of IMRT allows patients to be retreated to metastatic disease in the vertebral bodies while protecting the spinal cord. There appears to be a therapeutic benefit based on physician reported outcomes, although limited follow-up makes more definitive conclusions difficult. Author Disclosure Block: V. Chowdhry: None. M.A. Cummings: None. S.S. Hahn: None. A.K. Chowdhry: None. K. Stellingwerf: None. A. Shapiro: None.
136 Verification of Respiratory Position Reproducibility With a Respiration Self-Monitoring Device: Results for 12 Patients With Lung Tumors S. Kawashiro, T. Nomiya, Y. Hagiwara, I. Ota, M. Ichikawa, Y. Kuroda, M. Murakami, K. Nemoto, Department of Radiation Oncology, Yamagata University, Yamagata, Japan Purpose/Objectives: Respiratory movement of the tumors occurs during radiation therapy for patients with lung tumors. There are some techniques for decreasing intrafractional target motion derived from a patient's respiratory movement. A respiration self-monitoring device called Abches (APEX Medical, Inc., Tokyo, Japan) was developed for the purpose of decreasing respiratory target motion. Abches has two arms: one senses respiratory motion of the chest and the other senses that of the abdomen. When Abches is set on a patient, the indicator moves in accordance with the patient's respiration. Patients can adjust their respiration by looking at the indicator and can theoretically hold their breath at the same respiratory position every time. Abches is expected to be useful, but its accuracy has not been sufficiently determined. The aim of this study was to confirm its accuracy by obtaining radiation therapy planning computed tomography (RTP-CT) images with the use of Abches. Materials/Methods: A total of 12 patients with primary or metastatic lung tumors underwent RTP-CT scans. First, they were asked to practice breath-holding at the same respiratory position with the use of Abches for 5 to 10 minutes prior to RTP-CT. Next, RTP-CT images were obtained while the patients were holding their breath at the same position as that in the practice session, which was indicated on Abches. This procedure was repeated 5 times continuously for each patient to obtain images to measure the movements of tumors. The 5 RTP-CT images for each patient were transferred to a radiation therapy planning system, Xio (Elekta) or Eclipse (Varian). The tumors of each image were contoured as gross tumor volumes (GTVs). Each edge of the tumors was recorded in every direction, i.e., anterior/posterior, left/right, and superior/inferior. The distance between the actual and the average of each edge was measured. As the indicator of the tumor shifts, the standard deviations (S.D.) of all measured data were calculated and analyzed. Results: All values of 1.96 × S.D., which statistically include 95% of all data, were included within 3 mm in each direction. In other words, tumor shifts were included in a 3 mm margin with the use of Abches. This result can be applied to the determination of internal target volume (ITV) margins under respiration control with Abches. Conclusions: Abches is useful for decreasing target motion with reproducible accuracy and for reducing ITV margins in radiation therapy for patients with lung tumors.
Practical Radiation Oncology: April-June Supplement 2013 Author Disclosure Block: S. Kawashiro: None. T. Nomiya: None. Y. Hagiwara: None. I. Ota: None. M. Ichikawa: None. Y. Kuroda: None. M. Murakami: None. K. Nemoto: None.
137 Advanced Radiation Techniques: Stereotactic Body Radiation Therapy (SBRT) in Early Stage Inoperable Lung Cancer Disease S. Kosmidis, D. Katsochi, DTCA Hygeia, Athens, Greece Purpose/Objectives: To present stereotactic body radiation therapy as a highly conformal treatment, in compare to conventional radiation therapy, that allows dose escalation and reduced treatment volumes, as a noninvasive alternative to operation in early lung cancer disease. Preliminary data of Clinical experience in Radiation Oncology Department of DTCA HYGEIA. Materials/Methods: Between May 2009 and June 2012, 15 patients with pulmonary tumors, medically inoperable, were treated with SBRT using daily image guidance (cone beam CT) for patient positioning and target localization. Computed tomography (CT scan) and PET computed tomography (FDG/PET) were used for target delineation and planning. Median prescription dose was 36 Gy in 3 fractions in 9 pts or 30Gy in 5 fractions for 3 pts with poor pulmonary function. Results: All patients completed treatment. Median follow up was 13 months (range 3–20). All patients achieved tumor local control, 12pts with complete tumor regression and 3pts with minimal residual tumor in which remains stable at follow up. None patient presented blood toxicity or pulmonary toxicity (pneumonitis) except for two patients who were treated with corticosteroids. Conclusions: Image guided SBRT in selected patients is a feasible, safe, and effective treatment for medically inoperable early stage lung cancer. Author Disclosure Block: S. Kosmidis: None. D. Katsochi: None.
138 Optimizing Options for Re-irradiation With Deformable Image Registration of Prior Plans N. Saeed 2, K. Latifi 1, S.E. Hoffe 1, A. Cruz 3, D.W. Opp 1, E.G. Moros 1, G.G. Zhang 1, M.M. Budzevich 1, R. Shridhar 1, T.J. Dilling 1, 1Moffitt Cancer Center, Tampa, FL, 2Brown University, Providence, RI, 3 University of South Florida, Tampa, FL Purpose/Objectives: Patients who present for radiation treatment with a history of prior radiation pose a difficult challenge if there is overlap between the treatment fields. In the era of conformal therapy, new options offer re-treatment to small volumes of previously irradiated tissue. Materials/Methods: Five patients who were considered for re-treatment were selected for this retrospective study. All previous treatment data were transferred to the Mirada system for deformable image registration (DIR) to the current treatment planning CT. The cases previously irradiated at our institution included: a patient treated preoperatively for esophageal cancer who now had an adrenal metastasis in a postoperative abdomen, a patient treated for gastroesophageal junction cancer with a liver metastasis in the upper abdomen, a patient treated postoperatively for pancreatic cancer who had subsequently developed an adjacent symptomatic abdominal recurrence, and a patient with metastatic breast cancer with prior radiation to the lumbosacral spine who now developed an iliac wing site of painful disease. The fifth patient had received definitive conformal radiation to his prostate elsewhere but now had developed an anal cancer. Initially, the physicians asked the dosimetry staff to meet constraints based on clinical estimates of normal tissue tolerances. Once the initial plan was approved by the patient's treating physician, it was then fused to the prior plan in Mirada and a composite dose was then generated.
Poster Presentations
in 10 fractions (range, 2500–4000). Retreatment was completed to a median dose of 2500 cGy in 5 fractions, (range, 800 cGy in 1 fraction to 3000 cGy in 10 fractions). The median sum dose to the spinal cord was 4400 cGy (range, 3300–5500). The median volume of spinal cord or cauda equina getting greater than 5000 cGy was 0 cm3 (range, 0– 1.3 cm3). The median % GTV receiving 95% of the prescription dose was 96% (range, 82-98%). Seven patients (70%) were noted to have improvement in pain symptoms following treatment, 95% CI (35%93%). Of the four patients who reported neurologic symptoms, all showed improvement. Conclusions: The use of IMRT allows patients to be retreated to metastatic disease in the vertebral bodies while protecting the spinal cord. There appears to be a therapeutic benefit based on physician reported outcomes, although limited follow-up makes more definitive conclusions difficult. Author Disclosure Block: V. Chowdhry: None. M.A. Cummings: None. S.S. Hahn: None. A.K. Chowdhry: None. K. Stellingwerf: None. A. Shapiro: None.
136 Verification of Respiratory Position Reproducibility With a Respiration Self-Monitoring Device: Results for 12 Patients With Lung Tumors S. Kawashiro, T. Nomiya, Y. Hagiwara, I. Ota, M. Ichikawa, Y. Kuroda, M. Murakami, K. Nemoto, Department of Radiation Oncology, Yamagata University, Yamagata, Japan Purpose/Objectives: Respiratory movement of the tumors occurs during radiation therapy for patients with lung tumors. There are some techniques for decreasing intrafractional target motion derived from a patient's respiratory movement. A respiration self-monitoring device called Abches (APEX Medical, Inc., Tokyo, Japan) was developed for the purpose of decreasing respiratory target motion. Abches has two arms: one senses respiratory motion of the chest and the other senses that of the abdomen. When Abches is set on a patient, the indicator moves in accordance with the patient's respiration. Patients can adjust their respiration by looking at the indicator and can theoretically hold their breath at the same respiratory position every time. Abches is expected to be useful, but its accuracy has not been sufficiently determined. The aim of this study was to confirm its accuracy by obtaining radiation therapy planning computed tomography (RTP-CT) images with the use of Abches. Materials/Methods: A total of 12 patients with primary or metastatic lung tumors underwent RTP-CT scans. First, they were asked to practice breath-holding at the same respiratory position with the use of Abches for 5 to 10 minutes prior to RTP-CT. Next, RTP-CT images were obtained while the patients were holding their breath at the same position as that in the practice session, which was indicated on Abches. This procedure was repeated 5 times continuously for each patient to obtain images to measure the movements of tumors. The 5 RTP-CT images for each patient were transferred to a radiation therapy planning system, Xio (Elekta) or Eclipse (Varian). The tumors of each image were contoured as gross tumor volumes (GTVs). Each edge of the tumors was recorded in every direction, i.e., anterior/posterior, left/right, and superior/inferior. The distance between the actual and the average of each edge was measured. As the indicator of the tumor shifts, the standard deviations (S.D.) of all measured data were calculated and analyzed. Results: All values of 1.96 × S.D., which statistically include 95% of all data, were included within 3 mm in each direction. In other words, tumor shifts were included in a 3 mm margin with the use of Abches. This result can be applied to the determination of internal target volume (ITV) margins under respiration control with Abches. Conclusions: Abches is useful for decreasing target motion with reproducible accuracy and for reducing ITV margins in radiation therapy for patients with lung tumors.
Practical Radiation Oncology: April-June Supplement 2013 Author Disclosure Block: S. Kawashiro: None. T. Nomiya: None. Y. Hagiwara: None. I. Ota: None. M. Ichikawa: None. Y. Kuroda: None. M. Murakami: None. K. Nemoto: None.
137 Advanced Radiation Techniques: Stereotactic Body Radiation Therapy (SBRT) in Early Stage Inoperable Lung Cancer Disease S. Kosmidis, D. Katsochi, DTCA Hygeia, Athens, Greece Purpose/Objectives: To present stereotactic body radiation therapy as a highly conformal treatment, in compare to conventional radiation therapy, that allows dose escalation and reduced treatment volumes, as a noninvasive alternative to operation in early lung cancer disease. Preliminary data of Clinical experience in Radiation Oncology Department of DTCA HYGEIA. Materials/Methods: Between May 2009 and June 2012, 15 patients with pulmonary tumors, medically inoperable, were treated with SBRT using daily image guidance (cone beam CT) for patient positioning and target localization. Computed tomography (CT scan) and PET computed tomography (FDG/PET) were used for target delineation and planning. Median prescription dose was 36 Gy in 3 fractions in 9 pts or 30Gy in 5 fractions for 3 pts with poor pulmonary function. Results: All patients completed treatment. Median follow up was 13 months (range 3–20). All patients achieved tumor local control, 12pts with complete tumor regression and 3pts with minimal residual tumor in which remains stable at follow up. None patient presented blood toxicity or pulmonary toxicity (pneumonitis) except for two patients who were treated with corticosteroids. Conclusions: Image guided SBRT in selected patients is a feasible, safe, and effective treatment for medically inoperable early stage lung cancer. Author Disclosure Block: S. Kosmidis: None. D. Katsochi: None.
138 Optimizing Options for Re-irradiation With Deformable Image Registration of Prior Plans N. Saeed 2, K. Latifi 1, S.E. Hoffe 1, A. Cruz 3, D.W. Opp 1, E.G. Moros 1, G.G. Zhang 1, M.M. Budzevich 1, R. Shridhar 1, T.J. Dilling 1, 1Moffitt Cancer Center, Tampa, FL, 2Brown University, Providence, RI, 3 University of South Florida, Tampa, FL Purpose/Objectives: Patients who present for radiation treatment with a history of prior radiation pose a difficult challenge if there is overlap between the treatment fields. In the era of conformal therapy, new options offer re-treatment to small volumes of previously irradiated tissue. Materials/Methods: Five patients who were considered for re-treatment were selected for this retrospective study. All previous treatment data were transferred to the Mirada system for deformable image registration (DIR) to the current treatment planning CT. The cases previously irradiated at our institution included: a patient treated preoperatively for esophageal cancer who now had an adrenal metastasis in a postoperative abdomen, a patient treated for gastroesophageal junction cancer with a liver metastasis in the upper abdomen, a patient treated postoperatively for pancreatic cancer who had subsequently developed an adjacent symptomatic abdominal recurrence, and a patient with metastatic breast cancer with prior radiation to the lumbosacral spine who now developed an iliac wing site of painful disease. The fifth patient had received definitive conformal radiation to his prostate elsewhere but now had developed an anal cancer. Initially, the physicians asked the dosimetry staff to meet constraints based on clinical estimates of normal tissue tolerances. Once the initial plan was approved by the patient's treating physician, it was then fused to the prior plan in Mirada and a composite dose was then generated.
