Image guided respiratory gated hypofractionated Stereotactic Body Radiation Therapy (H-SBRT) for liver and lung tumors: Initial experience.

To evaluate our initial experience with image guided respiratory gated H-SBRT for liver and lung tumors. The system combines a stereoscopic x-ray imaging system (ExacTrac X-Ray 6D) with a dedicated conformal stereotactic radiosurgery and radiotherapy linear accelerator (Novalis) and ExacTrac Adaptive Gating for dynamic adaptive treatment. Moving targets are located and tracked by x-ray imaging of implanted fiducial markers defined in the treatment planning computed tomography (CT). The marker position is compared with the position in verification stereoscopic x-ray images, using fully automated marker detection software. The required shift for a correct, gated set-up is calculated and automatically applied. We present our acceptance testing and initial experience in patients with liver and lung tumors. For treatment planning CT and Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) as well as magnetic resonance imaging (MRI) taken at free breathing and expiration breath hold with internal and external fiducials present were used. Patients were treated with 8-11 consecutive fractions to a dose of 74.8-79.2 Gy. Phantom tests demonstrated targeting accuracy with a moving target to within +/-1 mm. Inter- and intrafractional patient set-up displacements, as corrected by the gated set-up and not detectable by a conventional set-up, were up to 30 mm. Verification imaging to determine target location during treatment showed an average marker position deviation from the expected position of up to 4 mm on real patients. This initial evaluation shows the accuracy of the system and feasibility of image guided real-time respiratory gated H-SBRT for liver and lung tumors.

Virtual simulation in patients with breast cancer.

BACKGROUND: Investigation of the feasibility and effectiveness of virtual simulation in patients receiving radiotherapy of the breast. METHODS: Twenty-three patients were included in the study. All of them underwent a course of postoperative tangential breast irradiation. The patients were prospectively randomised into two groups. Group A patients (n=11) received a conventional computed tomography -based treatment planning, group B patients (n=12) a virtual simulation. The results of both treatment planning procedures were compared. RESULTS: The treatment planning was feasible in all patients. The time expenditure could be reduced from a median of 45.0 to 16.5 min and from 55.0 to 32.0 min for the technician and physician, respectively, using virtual simulation. Furthermore the treatment planning for the patient could be reduced from a median of 45.0 min in two sessions to 16.5 min in one session. The image quality of the digital reconstructed radiographs was satisfying compared to the simulation films. The incidence and extension of set-up corrections for the patients at the first treatment were comparable in both groups. The time interval between the planning CT and the first treatment could be reduced by 31% using virtual simulation due to the omission of the conventional simulation. CONCLUSION: The virtual simulation is a feasible tool for the treatment planning of patients undergoing tangential irradiation of the breast. Compared with the conventional simulation procedure virtual simulation is superior regarding to the precision of patients marking, the quality of the reference images and, the time expenditure for the patients and medical staff.

Prognostically orientated multimodality treatment including surgery for selected patients of small-cell lung cancer patients stages IB to IIIB: long-term results of a phase II trial.

Following mediastinoscopy, a prognostically orientated multimodality approach was chosen in selected small-cell lung cancer (SCLC) patients with hyperfractionated accelerated chemoradiotherapy (Hf-RTx) and definitive surgery (S). Stage IB/IIA patients had four cycles of cisplatin/etoposide (PE) and surgery. Stage IIB/IIIA patients had three cycles PE followed by one cycle concurrent chemoradiation including Hf-RTx and surgery. Most stage IIIB patients were not planned for surgery and had CTx followed by sequential RTx or one cycle concurrent CTx/RTx. Of 46 consecutive patients (stage IB six, IIA two, IIB/IIIA 22, IIIB 16) 43 (94%) showed an objective response. Twenty-three of patients (72%) planned for inclusion of S were completely resected (R0) (IB 6/6, IIA 2/2, IIB/IIIA 13/22, IIIB 2/2). Overall toxicity was acceptable--one patient died of septicaemia, no perioperative deaths occurred. Median follow-up of patients alive (n = 21) is 52 months (30+ - 75+). Median survival and 5-year survival rate of all patients are 36 months and 46%, in R0 patients 68 months and 63% (R0-IIB/IIIA/IIIB: not yet reached and 67%). This multimodality treatment including surgery proved highly effective with 100% local control and remarkable long-term survival after complete resection, even in locally advanced SCLC stages IIB/IIIA patients.

Impact of the filling status of the bladder and rectum on their integral dose distribution and the movement of the uterus in the treatment planning of gynaecological cancer.

PURPOSE: Determination of the impact of the filling status of the organs at risk (bladder and rectum) on the uterus mobility and on their integral dose distribution in radiotherapy of gynaecological cancer. METHODS: In 29 women suffering from cervical or endometrial cancer two CT scans were carried out for treatment planning, one with an empty bladder and rectum, the second one with bladder and rectum filled. The volumes of the organs at risk were calculated and in 14 patients, receiving a definitive radiotherapy, the position of the uterus within the pelvis was shown using multiplanar reconstructions. After generation of a 3D treatment plan the dose volume histograms were compared for empty and filled organs at risk. RESULTS: The mobility for the corpus uteri with/without bladder and rectum filling was in median 7 mm (95%-confidence interval: 3-15 mm) in cranial/caudal direction and 4 mm (0-9 mm) in posterior/anterior direction. Likewise, cervical mobility was observed to be 4 mm (-1-6 mm) mm in cranial/caudal direction. A full bladder led to a mean reduction in organ dose in median from 94-87% calculated for 50% of the bladder volume (P < 0.05, Wilcoxon's matched-pairs signed-ranks test). For 66% of the bladder volume the dose could be reduced in median from 78 to 61% (P < 0.005) and for the whole bladder from 42 to 39% (P < 0.005), respectively. No significant contribution of the filling status of the rectum to its integral dose burden was noticed. CONCLUSIONS: Due to the mobility of the uterus increased margins between CTV and PTV superiorly, inferiorly, anteriorly and posteriorly of 15, 6 and 9 mm each, respectively, should be used. A full bladder is the prerequisite for an integral dose reduction.

[Palliative radiotherapy of bone metastases. A retrospective analysis of 176 patients]. / Palliative Strahlentherapie von Knochenmetastasen. Eine retrospective Analyse von 176 Patienten.

BACKGROUND: The effect of the palliative irradiation of bone metastases was explored in this retrospective analysis. The spectrum of primary tumor sites, the localization of the bone metastases and the fractionation schedules were analyzed with regard to palliation discriminating total, partial and complete pain response. PATIENTS AND METHODS: One hundred seventy-six patients are included in this retrospective quantitative study from April 1992 to November 1993. Two hundred fifty-eight localizations of painful bone metastases were irradiated. The percentage of bone metastases of the total irradiated localizations in our department of radiotherapy in the Charité-Hospital, the primary tumor sites, the localizations and the different fractionation schedules were explored. The total, partial and complete pain response was analyzed in the most often used fractionation schedules and by primary tumor sites. RESULTS: Eight per cent of all irradiated localizations in the observation period were bone metastases. There were irradiated bone metastases of 21 different tumor sites. Most of the primary tumor sites were breast cancer (49%), lung cancer (6%) and kidney cancer (6%). The most frequent site of metastases was the vertebral column (52%). The most often used fractionation schedules were: 4 x 5 Gy (32%), 10 x 3 Gy (18%), 6 x 5 Gy (9%), 7 x 3 Gy (7%), 10 x 2 Gy (5%) and 2 x 8 Gy. The total response rates in this fractionation schedules were 72%, 79%, 74%, 76%, 75% and 72%, the complete response rates were 35%, 32%, 30%, 35%, 33% and 33%. There were no significant differences between the most often irradiated primary tumor sites, the most frequent localizations and the palliation with regard to total, partial and complete pain response. CONCLUSION: There are no differences between the different fractionation schedules with regard to the pain effect of bone metastases. A palliation is ensured in 75% of all cases with a partial response of 42% and complete response of 33%. With regard to pain response these results do not justify a recommendation for a standard fractionation schedule. Current fractionation schedules such as 10 x 3 Gy for 2 weeks or 5 x 4 Gy for 1 week should be used. Another point is the recalcification in the palliative treatment of bone metastases in patients with better prognosis. The recalcification is the basis for stabilization and prevention of fractures. This aspect should be explored in prospective studies.

[Comparison of different 3-dimensional irradiation techniques in local radiotherapy of prostatic carcinoma]. / Vergleich unterschiedlicher dreidimensionaler Bestrahlungstechniken bei der lokalen Strahlentherapie des Prostatakarzinoms.

PURPOSE: Four different three-dimensional planning techniques for localized radiotherapy of prostate cancer were compared with regard to dose homogeneity within the target volume and dose to organs at risk, dependent upon tumor stage. PATIENTS AND METHODS: Six patients with stage T1, 7 patients with stage T2 and 4 patients with stage T3 were included in this study. Four different 3D treatment plans (rotation, 4-field, 5-field and 6-field technique) were calculated for each patient. Dose was calculated with the reference point at the isocenter (100%). The planning target volume was encompassed within the 95% isodose surface. All the techniques used different shaped portal for each beam. Dose volume histograms were created and compared for the planning target volume and the organs at risk (33%, 50%, 66% volume level) in all techniques. RESULTS: The 4 different three-dimensional planning techniques revealed no differences concerning dose homogeneity within the planning target volume. The dose volume distribution at organs at risk show differences between the calculated techniques. In our study the best protection for bladder and rectum in stage T1 and T2 was achieved by the 6-field technique. A significant difference was achieved between 6-field and 4-field technique only in the 50% volume of the bladder (p = 0.034), between the 6-field and rotation technique (all volume levels) and between 5-field and rotation technique (all volume levels). In stage T1, T2 6-field and 4-field technique in 50% (p = 0.033) and 66% (p = 0.011) of the rectum volume. In stage T3 a significant difference was not observed between the 4 techniques. The best protection of head of the femur was achieved by the rotation technique. CONCLUSION: In the localized radiotherapy of prostate cancer in stage T1 or T2 the best protection for bladder and rectum was achieved by a 3D-planned conformal 6-field technique. If the seminal vesicles have been included in the target volume and in the case of large planning target volume other techniques should be taken for a better protection for organs at risk e. g. a 3D-planned 4-field technique box technique.

Comparison of conventional and virtual simulation for radiation treatment planning of malignant lymphoma.

PURPOSE: The exact coverage of the lymph nodes and optimal shielding of the organs at risk are necessary for patients with Hodgkin's disease or malignant lymphoma to guarantee a high cure rate and a low rate of late effects for normal tissue. The purpose of this study was to compare conventional simulation and blocking with virtual simulation in terms of coverage of the target volume and shielding of the organs at risk in this highly curative patient group. PATIENTS AND METHODS: In 10 patients diagnosed with Hodgkin's disease and 5 patients with a Non-Hodgkin lymphoma radiation treatment planning for a mantle field or para-aortic field with inclusion of the spleen was performed in a conventional manner and with virtual simulation. With conventional technique, irradiation portals were defined during fluoroscopy and shielding of the organs at risk was drawn onto the simulation films, based on the information from previous X-ray films, CT or MRI scans. For virtual simulation, contouring of the target volumes and organs at risk (e.g. the kidneys) and the definition of the irradiation portals were performed with the AcQSim software package on a VoxelQ workstation (Picker Inc.) This was done in a beam's eye view environment on a currently driven CT scan in the treatment position. Both irradiation portals were compared in terms of coverage of the target volume and shielding of the organs at risk. RESULTS: Planning of a mantle field in the conventional way resulted in an incomplete coverage of the right hilus in 4/15 cases and of the left in 1/15 cases, respectively. The spleen and the spleen hilus were not covered completely in 5/15 and 6/15 cases, respectively. The left kidney was adequately shielded in only two thirds (10/15) of the conventionally planned fields. The planning time required for virtual simulation was reduced for the patient, but was increased for the physician because of the more time consuming contouring procedure compared to conventional simulation. CONCLUSIONS: Virtual simulation based on CT scans for radiation treatment planning of malignant lymphoma gives more information about soft tissue structures than conventional treatment planning. Therefore, it allows a more precise coverage of the target volumes and better shielding of the organs at risk. However, the time required for the whole procedure is increased. This is justified because of the often highly curative intention when treating this group of patients.

[Virtual simulation. First clinical results in patients with prostate cancer]. / Virtuelle Simulation. Erst klinische Ergebnisse bei Patienten mit Prostatakarzinom.

AIM: Investigation of options of virtual simulation in patients with localized prostate cancer. PATIENTS AND METHODS: Twenty-four patients suffering from prostate cancer were virtual simulated. The clinical target volume was contoured and the planning target volume was defined after CT scan. The isocenter of the planning target volume was determined and marked at patient's skin. The precision of patients marking was controlled with conventional simulation after physical radiation treatment planning. RESULTS: Mean differences of the patient's mark revealed between the 2 simulations in all room axes around 1 mm. The organs at risk were visualized in the digital reconstructed radiographs. CONCLUSIONS: The precise patient's mark of the isocentre by virtual simulation allows to skip the conventional simulation. The visualisation of organs at risk leeds to an unnecessarily of an application of contrast medium and to a further relieve of the patient. The personal requirement is not higher in virtual simulation than in conventional CT based radiation treatment planning.

Preoperative and postoperative radiotherapy in rectal carcinoma.

Surgery is the initial treatment of choice for most patients with rectal neoplasms. The objectives are to remove of tumor and drain the primary nodes. In stage I disease the surgical approach is though to be sufficiently effective. However, at least in the case of abdominoperineal resection, this causes considerable morbidity. Therefore, at the present time, there are efforts to reduce the extent of the resection by applying other treatment modalities in stage I disease. After curative resection in stage II/III disease a considerable number of patients suffer from local recurrence or distant metastases. In these patients adjuvant therapy is currently recommended. In locally advanced disease, primary resection is not feasible. Different treatment settings which apply combinations of all treatment modalities are possible. The article reviews the literature and shows future directions.