RESUMEN
BACKGROUND: Tumour seeking characteristics of TL-201 have been underutilized. The study was undertaken to evaluate the role of TL-201 scintigraphy in tumour imaging. METHODS: A total of 50 cases were studied over a period of 18 months (13 lymphomas, 11 breast carcinoma, 10 lung cancer, 6 of soft tissue sarcoma, 2 bone tumours and 4 cases each of thyroid and brain tumours). Thallium-201 chloride was injected IV in the dose range of 3-5 mCi. Imaging was done using Siemen's ECAM dual headed gamma camera. Mean tumour to background ratio (T/B ratio) was calculated for all the positive cases. Descriptive statistical analysis was carried out. RESULTS: Findings revealed a sensitivity of 94.12%, specificity 87.5%, PPV 94.12%, NPV 87.50% and accuracy of 92% for TL-201 tumour imaging. The mean T/B ratio for the true positive cases at 10 min and at 3 h was 1.81 and 1.99 respectively, the difference being 0.18 (P value <0.001). Amongst them, the mean T/B ratios for low-grade tumours were 1.45 ± 0.32 at 10 min and 1.63 ± 0.38 after 3 h with difference of 0.176 (P < 0.001). For the high-grade tumours the ratios were 2.08 ± 0.35 and 2.26 ± 0.41 respectively with a difference of 0.186 (P < 0.001). CONCLUSION: Thallium-201 scintigraphy is a useful tumour imaging modality in cases of thyroid, breast, brain, lung, soft tissue and bone tumours and lymphomas. A T/B ratio of 1.63 ± 0.38 in 3 h-delayed imaging is suggestive of low-grade tumours. For high-grade tumours a ratio of 2.26 ± 0.41 should be considered significant.
RESUMEN
Radiation therapy (RT) is a clinical modality dealing with the use of ionizing radiations to treat malignant neoplasias (and occasionally benign diseases). Since its inception, the goal of RT has been to cure cancer locally without excessive side effects. The most important factors affecting the results of RT are the tumor type, its location and regional extent, the anatomic area of involvement and the geometric accuracy with which a calculated radiation dose is delivered. Although higher doses of radiation can produce better tumor control, the dosage which can be given is limited by the possibility of normal tissue damage. Approximately 60-65% of all cancer patients require RT as the sole treatment modality and / or in combination with surgery or chemotherapeutic drugs. There is a huge gap between demand and supply of radiotherapy facilities and infrastructure. Most of the oncocentres are located in urban areas in private sector and are beyond the reach of the common man.