- Email: [email protected]
656 poster Tumor maps derived from voxel-by-voxel magnetic resonance spectroscopy imaging
S286
Posters
perfusion, the difference between these two should reflect perfusion (ADCpe~=ADCIow-ADChi~h).
prognostic information will determine allocation to treatment groups.
Results: One and 6 hours posttreatment, k and the initial slope as well as ADCpe, decreased significantly, while the ADChigh remained unchanged. Histology showed still viable tumor tissue at this time. At 2 days, no significant changes were found in the perfusion indicators (k, initial slope and ADCpe,) compared to the previous time point, but a significant increase in ADChigh was noted, histologically corresponding to increase of the necrotic area in the tumor. At 9 days, all perfusion indicators increased significantly, while the ADChigh showed a significant decrease. This was paralleled by an increase in viable rim of the tumor on histology. Regression analysis showed correlation of the changes in ADCperf with k (R*=0.76) and with the initial slope (R*--0.75).
1. Hainsworth, J.D. and F.A. Greco, Management of patients with cancer of unknown primary site. Oncology 2000. 14(4): p. 563-74
Conclusion: The ADCpe~ from the DW-MRI correlates with the findings from the DCE-MRI in visualizing early and later perfusion changes induced by CA-4-P. Additionally, the ADChigh from the same DW-MRI measurement provides information on cell viability and necrosis induction due to the treatment.
~University of Wisconsin Medical School, Human Oncology and Medical Physics, Madison, U.S.A. 2University of Wisconsin Medical School, Medical Physics, Madison, U.S.A Magnetic Resonance Spectroscopy Imaging (MRSI) has proven to be a valuable tool in the identification of worrisome regions of pathology. Chemical Shift Imaging (CSl) a technique based on MRSl and provides voxel-by-voxel metabolic information about these regions. Single-voxel MRS has been useful in discriminating solid tumors, necrosis and normal brain tissues based on the ratio of choline level to Nacetyl Aspartate (NAA). Maps of the Choline NAA Index (CNI) overlaid onto the MRI and the planning CT seem to be more beneficial in determining the pathology than overlaid contours of this index. With the CNI map overlaid onto the planning CT and MRI, oncologists have a good visual tool to correlate individual voxels to anatomy rather than having to correlate the contour to the anatomy. A minimum CNI value of 2 has been used to identify a voxel containing tumor. In our CNI maps, voxels that have a CNI value of larger or equal to 2, i.e. voxels containing tumor are shown in white, whereas voxels with CNI values of less than 2 are shown in black indicating non-pathological voxels.
655 poster FDG-PET in the initial investigation of patients with unknown primary tumours (UPTS)
T. Eade ~, R. Simcock ~, M. Fulham 2 ~Royal Prince Alfred Hospital, Department of Radiation Oncology, Sydney, Australia 2Royal Prince Alfred Hospital, Department of PET and Nuclear Medicine, Sydney, Australia Aim: To retrospectively examine the role of FDG-PET in the management of patients presenting with an unknown primary tumours (UPTs). Methods: 86 patients were referred between July 1994 and January 2004 for FDG-PET for the investigation of an UPT. All patients had undergone prior investigation with a minimum of clinical examination, biopsy and CT. At referral, medical history, ECOG status and previous investigations were recorded and written consent to record clinical progress for research was obtained from each subject. Patients with well recognised clinical subsets of metastatic squamous cell carcinoma in cervical lymph nodes (n=13) and axillary nodes in women (n=13) were excluded leaving 60 patients in total. Clinical and surgical follow up and Cancer Registry data were used to assess accuracy of the FDG-PET findings. Median follow up was 10 months. Most patients were scanned with whole body tomography; 5 patients were scanned on a PETCT device. Results: FDG-PET was able to identify the primary site in 15/60 cases (25% True Positives, TP). In 31 patients where FDG-PET did not identify a primary site, 8 eventually became clinically evident (13% False Negatives FN). PET suggested primary sites in another 14 but none of these were confirmed by biopsy or during follow up (False Positives, FP). Based on previously published prognostic models, PET added prognostic information in 6 FP scans, 8 TN scans and 3 TP scans. According to the site of metastases at presentation the PPV of PET scanning was 60% for CNS metastases (n=10), 66.7% for hepatic metastases (n=8) and 25% for malignant adenopathy (n=22). Conclusions: For patients with an UPT, not within well defined clinical subsets for treatment, FDG-PET scanning provided additional information in 29 of 60 patients. The sensitivity of FDG-PET for identification of the primary tumour was 65.2%, specificity 62.2% and PPV=51.7%. FDG-PET may thus be justified in patients with an UPT where
2. Hess, K.R., et al., Classification and regression tree analysis of 1000 consecutive patients with unknown primary carcinoma. Clin CancerRes, 1999.5(11): p. 3403-10. 656 poster Tumor maps derived from voxel-by-voxel resonance spectroscopy imaging H.A. Jaradat 1, .W.A. Tom~ 1'2
magnetic
Geometric uncertainties in RT 657 poster Radiotherapy for stomach cancer: the dosimetric consequences of physiological movement of organs at risk D. Lim Joon 1, C, Mantle 1, C. Kai 2, T. C h o j , M. Lim Joon 1, A. Rolfo 1, K. Rykers 1, M. Feigen 1, G. Liu 1, V. Khoo 3
~Austin Health, Radiation Oncology Centre, Heidelberg West, Australia 2peter MacCaflum Cancer Institute, Radiation Oncology, East Melbourne, Australia 3Royal Marsden Hospital, Radiation Oncology, London, UK Purpose: To assess the impact of intra-fraction movement of the liver and kidneys (organs at risk) on the dose volume histograms and normal tissue tolerance constraints during adjuvant radiotherapy for stomach cancer. Method: Serial spiral CT non-contrast and contrast scans are routinely acquired for adjuvant stomach cancer radiotherapy at the centre. The acquisition time approximates that of a single radiotherapy fraction. Thus, the organ movement between the scans has been used as a surrogate for intrafraction motion in this study. In ten patients the liver and both kidneys were contoured on both sets of scans. A forward planned IMRT technique was used to deliver 45 Gy in 25 fractions. The maximal translational movement of the centre of mass in three planes and volume changes of each structure was measured. The maximum, minimum and mean
Posters
perfusion, the difference between these two should reflect perfusion (ADCpe~=ADCIow-ADChi~h).
prognostic information will determine allocation to treatment groups.
Results: One and 6 hours posttreatment, k and the initial slope as well as ADCpe, decreased significantly, while the ADChigh remained unchanged. Histology showed still viable tumor tissue at this time. At 2 days, no significant changes were found in the perfusion indicators (k, initial slope and ADCpe,) compared to the previous time point, but a significant increase in ADChigh was noted, histologically corresponding to increase of the necrotic area in the tumor. At 9 days, all perfusion indicators increased significantly, while the ADChigh showed a significant decrease. This was paralleled by an increase in viable rim of the tumor on histology. Regression analysis showed correlation of the changes in ADCperf with k (R*=0.76) and with the initial slope (R*--0.75).
1. Hainsworth, J.D. and F.A. Greco, Management of patients with cancer of unknown primary site. Oncology 2000. 14(4): p. 563-74
Conclusion: The ADCpe~ from the DW-MRI correlates with the findings from the DCE-MRI in visualizing early and later perfusion changes induced by CA-4-P. Additionally, the ADChigh from the same DW-MRI measurement provides information on cell viability and necrosis induction due to the treatment.
~University of Wisconsin Medical School, Human Oncology and Medical Physics, Madison, U.S.A. 2University of Wisconsin Medical School, Medical Physics, Madison, U.S.A Magnetic Resonance Spectroscopy Imaging (MRSI) has proven to be a valuable tool in the identification of worrisome regions of pathology. Chemical Shift Imaging (CSl) a technique based on MRSl and provides voxel-by-voxel metabolic information about these regions. Single-voxel MRS has been useful in discriminating solid tumors, necrosis and normal brain tissues based on the ratio of choline level to Nacetyl Aspartate (NAA). Maps of the Choline NAA Index (CNI) overlaid onto the MRI and the planning CT seem to be more beneficial in determining the pathology than overlaid contours of this index. With the CNI map overlaid onto the planning CT and MRI, oncologists have a good visual tool to correlate individual voxels to anatomy rather than having to correlate the contour to the anatomy. A minimum CNI value of 2 has been used to identify a voxel containing tumor. In our CNI maps, voxels that have a CNI value of larger or equal to 2, i.e. voxels containing tumor are shown in white, whereas voxels with CNI values of less than 2 are shown in black indicating non-pathological voxels.
655 poster FDG-PET in the initial investigation of patients with unknown primary tumours (UPTS)
T. Eade ~, R. Simcock ~, M. Fulham 2 ~Royal Prince Alfred Hospital, Department of Radiation Oncology, Sydney, Australia 2Royal Prince Alfred Hospital, Department of PET and Nuclear Medicine, Sydney, Australia Aim: To retrospectively examine the role of FDG-PET in the management of patients presenting with an unknown primary tumours (UPTs). Methods: 86 patients were referred between July 1994 and January 2004 for FDG-PET for the investigation of an UPT. All patients had undergone prior investigation with a minimum of clinical examination, biopsy and CT. At referral, medical history, ECOG status and previous investigations were recorded and written consent to record clinical progress for research was obtained from each subject. Patients with well recognised clinical subsets of metastatic squamous cell carcinoma in cervical lymph nodes (n=13) and axillary nodes in women (n=13) were excluded leaving 60 patients in total. Clinical and surgical follow up and Cancer Registry data were used to assess accuracy of the FDG-PET findings. Median follow up was 10 months. Most patients were scanned with whole body tomography; 5 patients were scanned on a PETCT device. Results: FDG-PET was able to identify the primary site in 15/60 cases (25% True Positives, TP). In 31 patients where FDG-PET did not identify a primary site, 8 eventually became clinically evident (13% False Negatives FN). PET suggested primary sites in another 14 but none of these were confirmed by biopsy or during follow up (False Positives, FP). Based on previously published prognostic models, PET added prognostic information in 6 FP scans, 8 TN scans and 3 TP scans. According to the site of metastases at presentation the PPV of PET scanning was 60% for CNS metastases (n=10), 66.7% for hepatic metastases (n=8) and 25% for malignant adenopathy (n=22). Conclusions: For patients with an UPT, not within well defined clinical subsets for treatment, FDG-PET scanning provided additional information in 29 of 60 patients. The sensitivity of FDG-PET for identification of the primary tumour was 65.2%, specificity 62.2% and PPV=51.7%. FDG-PET may thus be justified in patients with an UPT where
2. Hess, K.R., et al., Classification and regression tree analysis of 1000 consecutive patients with unknown primary carcinoma. Clin CancerRes, 1999.5(11): p. 3403-10. 656 poster Tumor maps derived from voxel-by-voxel resonance spectroscopy imaging H.A. Jaradat 1, .W.A. Tom~ 1'2
magnetic
Geometric uncertainties in RT 657 poster Radiotherapy for stomach cancer: the dosimetric consequences of physiological movement of organs at risk D. Lim Joon 1, C, Mantle 1, C. Kai 2, T. C h o j , M. Lim Joon 1, A. Rolfo 1, K. Rykers 1, M. Feigen 1, G. Liu 1, V. Khoo 3
~Austin Health, Radiation Oncology Centre, Heidelberg West, Australia 2peter MacCaflum Cancer Institute, Radiation Oncology, East Melbourne, Australia 3Royal Marsden Hospital, Radiation Oncology, London, UK Purpose: To assess the impact of intra-fraction movement of the liver and kidneys (organs at risk) on the dose volume histograms and normal tissue tolerance constraints during adjuvant radiotherapy for stomach cancer. Method: Serial spiral CT non-contrast and contrast scans are routinely acquired for adjuvant stomach cancer radiotherapy at the centre. The acquisition time approximates that of a single radiotherapy fraction. Thus, the organ movement between the scans has been used as a surrogate for intrafraction motion in this study. In ten patients the liver and both kidneys were contoured on both sets of scans. A forward planned IMRT technique was used to deliver 45 Gy in 25 fractions. The maximal translational movement of the centre of mass in three planes and volume changes of each structure was measured. The maximum, minimum and mean