- Email: [email protected]
Optimum technique for CT imaging of pleural disease: a comparison of two contrast infusion protocols
Posters, 6th Annual BTOG Meeting, 2008 Cardiff and Vale), suggesting the vast majority of patients are being referred for review. In Cardiff and Vale there was an increase in recorded cases from 13 to 21. The quality of data collected also improved with performance status (PS) recorded in 71% of patients compared to 54% before the mMDT. More patients with poor PS (WHO 2) (33% Vs 0%) were discussed. The identification of histological subtype increased (61.9% vs. 46.1%). Importantly, there was a reduction in time from referral to treatment (median 30 vs. 60 days), and a suggested increase in the use of systemic chemotherapy (14.3% vs. 7.7%). Conclusions: Our early data indicate that the development of an mMDT is a worthwhile exercise, leading to a demonstrable improvement in quality of care received by patients with mesothelioma in South East Wales. We believe there is sufficient evidence to support widespread implementation. 20 Optimum technique for CT imaging of pleural disease: a comparison of two contrast infusion protocols R. Kirke, J.V. Raj, J. Entwisle. Leicester Thoracic Oncology Team, Glenfield Hospital, Leicester, UK Purpose: Pleural thickening and abnormal enhancement are essential in the diagnosis of malignant pleural disease. In past, delayed scans were performed to assess pleural enhancement. In our centre we have devised a new scan protocol, which negates the use of delayed scans. Aim of our study was to compare two different scan protocols and assess their efficacy in demonstrating pleural enhancement on CT. Methods: 20 patients, with pleural disease identified on chest x-ray were examined by CT using our existing protocol (100 mls Iopamidol 61.2% wt/vol injected at 2 mls/sec with a 60 second delay before scanning from lung apices to inferior liver margin). The next 20 patients were imaged with a modified infusion technique (150 mls of the same contrast agent injected at 3 mls/sec with the same image acquisition parameters after a 60 second delay). Mean attenuation values (Hounsfield Units) for the main pulmonary artery (PA), aorta (AO), portal vein (PV), superior mesenteric artery (SMA) and enhanced pleura (PL) were calculated and compared. Results: Mean attenuation values with the new technique vs. old technique were: PA 200HU vs. 160HU, AO 226 HU vs. 150 HU, PV 164 HU vs. 112 HU, SMA 200 HU vs. 140HU. Abnormal pleural enhancement was present in 11 of the 20 in the new technique vs. 14 out of 20 in the old technique. Average was 94HU vs. 57 HU with a range of 70 127 HU vs. 40 81HU. Conclusion: Our modified technique not only improves conspicuity of pleural enhancement but also provides adequate enhancement of other anatomical structures aiding in detection of incidental abnormalities like pulmonary emboli, pericarditis and liver metastases. Based on this we propose every patient with suspected pleural disease has a single block of CT scan covering thorax and the upper abdomen after instillation of 150mls of contrast at 3 mls/sec with a 60 sec delay. This would reduce the radiation dose (avoiding repeat delayed scan), save time and improve diagnostic confidence. Modification of CT protocol is required for suspected malignant effusions and clinicians should be encouraged to request ‘Pleural’ CT. 21 Positive trends in diagonosis of maligant pleural mesothelioma: a six year experience in Leicestershire A. Bajaj, D.T.B. Barnes, L. Darlison, J.A. Bennett, J.J. Entwisle. University Hospitals of Leicester NHS Trust, Leicester, UK Purpose: To ascertain whether diagnosis of malignant pleural mesothelioma (MPM) is becoming quicker. To determine the trend in the median survival time and possible influential factors. To review the shifting trends in the mode and number of interventions for diagnosis.
S7 Methods and Materials: 101 patients were diagnosed with MPM from 2001 2006. The radiology information system and MDT database were used to obtain the method and date of diagnosis and death, trigger x-ray details, coding and occupational history. Results: The number of patients diagnosed in 2001 were 11 increasing to 22 in 2006. The average time of diagnosis (in months) fell from 8 in 2002 to 1.7 in 2006. 91% had pleural effusion. The median survival (in days) rose from 80 in 2001 to 300 in 2006. The coding on the trigger x-ray rose from 9% in 2001 to 40% in 2006. The number of needling procedures in 2001 were 1.5, 1.3 in 2002 and 1.1 in 2006 with CT guided biopsy being the commonest and most sensitive. Median age at diagnosis was 71 yrs. Conclusion: In our study the time to diagnosis and increase in median survival is likely multifactorial with raised awareness of unexplained pleural effusion, better occupational history documentation and increased coding for specialist referral. The apparent increase in median survival may be partially explained by a lead time bias due to more rapid diagnosis. The number of needling procedures for diagnosis has dropped in the last six years with CT guided biopsy having a higher diagnostic rate. The introduction of thoracoscopy in 2006 should improve this further. 22 Intensity modulated radiotherapy (IMRT) in right sided malignant mesothelioma following extrapleural pneumonectomy C. Eswar, Z. Malik, J. Kirk, A. Nahum, H. Mayles, J. Littler, J. Maguire. Clatterbridge Centre for Oncology, Wirral, UK Introduction: Malignant Mesothelioma is an aggressive disease with a poor median survival. In selected patients with good performance status chemotherapy with cisplatin and alimta followed by extrapleural pneumonectomy (EPP) and postoperative chest wall radiotherapy has produced good results. The delivery of radiotherapy encompassing the entire ipsilateral chest wall cavity is challenging due to the close presence of a number of critical organs. On the right side the scenario is worse due to the dose constraints to the liver, which are almost impossible to meet with conventional conformal radiotherapy. For our first right sided patient following EPP we devised our IMRT plan for post operative radiotherapy based on the literature from the MD Anderson cancer centre. Methods: The Patient was immobilised on a lung board with scars and drainage sites marked with wire and covered with 5 mm of wax. The respiratory motion was found to be minimal due to immobility of the prosthetic diaphragm and the CTV was delineated as all surgically violated space and extended from the apex of thorax to inferior pole of the right kidney. The PTV margin was 6 mm which Included margin for motion (2 mm) and setup uncertainty (SD of 4 mm in all directions). The planning was done using Pinnacle planning software. Results: The isocentre was in the centre of PTV and seven beams were used. The beams were split into 2 or 3 fields due to leaf over travel limitations on varian linac and each field was split into a number of segments. The total dose delivered was 45 gy in 25 fractions at 1.8 gy per fraction. The mean dose to the PTV was 47.36 gy (max 56.9, min 39.2). The V20 to the left lung was <5%, the V30 to the liver was 32% and V35 was 28%. The heart V30 was 32% and V40 10%. The maximum dose to the spinal cord was 47.5 gy. The V15 to the left kidney was <5%. Conclusion: In right sided mesothelioma post EPP radiotherapy can be successfully delivered by the use of IMRT. In our first case the dose constraints to the liver was the most challenging to meet but still the V35 was within limits. We have now treated two further patients successfully with this technique.
S7 Methods and Materials: 101 patients were diagnosed with MPM from 2001 2006. The radiology information system and MDT database were used to obtain the method and date of diagnosis and death, trigger x-ray details, coding and occupational history. Results: The number of patients diagnosed in 2001 were 11 increasing to 22 in 2006. The average time of diagnosis (in months) fell from 8 in 2002 to 1.7 in 2006. 91% had pleural effusion. The median survival (in days) rose from 80 in 2001 to 300 in 2006. The coding on the trigger x-ray rose from 9% in 2001 to 40% in 2006. The number of needling procedures in 2001 were 1.5, 1.3 in 2002 and 1.1 in 2006 with CT guided biopsy being the commonest and most sensitive. Median age at diagnosis was 71 yrs. Conclusion: In our study the time to diagnosis and increase in median survival is likely multifactorial with raised awareness of unexplained pleural effusion, better occupational history documentation and increased coding for specialist referral. The apparent increase in median survival may be partially explained by a lead time bias due to more rapid diagnosis. The number of needling procedures for diagnosis has dropped in the last six years with CT guided biopsy having a higher diagnostic rate. The introduction of thoracoscopy in 2006 should improve this further. 22 Intensity modulated radiotherapy (IMRT) in right sided malignant mesothelioma following extrapleural pneumonectomy C. Eswar, Z. Malik, J. Kirk, A. Nahum, H. Mayles, J. Littler, J. Maguire. Clatterbridge Centre for Oncology, Wirral, UK Introduction: Malignant Mesothelioma is an aggressive disease with a poor median survival. In selected patients with good performance status chemotherapy with cisplatin and alimta followed by extrapleural pneumonectomy (EPP) and postoperative chest wall radiotherapy has produced good results. The delivery of radiotherapy encompassing the entire ipsilateral chest wall cavity is challenging due to the close presence of a number of critical organs. On the right side the scenario is worse due to the dose constraints to the liver, which are almost impossible to meet with conventional conformal radiotherapy. For our first right sided patient following EPP we devised our IMRT plan for post operative radiotherapy based on the literature from the MD Anderson cancer centre. Methods: The Patient was immobilised on a lung board with scars and drainage sites marked with wire and covered with 5 mm of wax. The respiratory motion was found to be minimal due to immobility of the prosthetic diaphragm and the CTV was delineated as all surgically violated space and extended from the apex of thorax to inferior pole of the right kidney. The PTV margin was 6 mm which Included margin for motion (2 mm) and setup uncertainty (SD of 4 mm in all directions). The planning was done using Pinnacle planning software. Results: The isocentre was in the centre of PTV and seven beams were used. The beams were split into 2 or 3 fields due to leaf over travel limitations on varian linac and each field was split into a number of segments. The total dose delivered was 45 gy in 25 fractions at 1.8 gy per fraction. The mean dose to the PTV was 47.36 gy (max 56.9, min 39.2). The V20 to the left lung was <5%, the V30 to the liver was 32% and V35 was 28%. The heart V30 was 32% and V40 10%. The maximum dose to the spinal cord was 47.5 gy. The V15 to the left kidney was <5%. Conclusion: In right sided mesothelioma post EPP radiotherapy can be successfully delivered by the use of IMRT. In our first case the dose constraints to the liver was the most challenging to meet but still the V35 was within limits. We have now treated two further patients successfully with this technique.