In the current study, extra-guidance other than conventional fluoroscopy - will be integrated to improve the success of the transforaminal approach to the thoracic dorsal root ganglia (DRG). The investigators hypothesize that joining CT scan with fluoroscopy to guide RF ablation through the transforaminal route may enhance its efficacy and safety in relieving the intractable pain associated with chest malignancies. The current study aimed to compare the results of thermal radiofrequency ablation (TRFA) of the thoracic DRG under combined CT and fluoroscopy guidance with the classic standard fluoroscopy technique.

Thoracic pain represents about 3-5% of pain clinics' visitors worldwide .Post-thoracotomy pain occurs in 30%-50% of patients undergoing thoracotomy .Interventional therapies include epidural or intrathecal drug injection, intercostal nerve block, sympathectomy, rhizotomy, and percutaneous cervical cordotomy. Rhizotomy refers to the selective segmental destruction of the dorsal sensory rootlets to interrupt pain perception by the spinal cord. This could be accomplished either neurosurgically, chemically or using selective percutaneous procedures such as cryoanalgesia and radiofrequency (RF) ablation.There are many technical difficulties in approaching the deep-seated thoracic dorsal root ganglia (DRG) through the transforaminal route.The spine is kyphotic - with the tip at T6 - and slightly scoliotic to the right side even in normal subjects . Spinous processes are acute, especially at T5-T8 level. Besides, broad and wide laminae together with narrow intervertebral foramina are other obstacles .The intervertebral foramina are further masked by the facet joints and the crowdedness of the costovertebral and the costotransverse joints .For all these factors, more guidance - other than conventional fluoroscopy - may improve the success of the transforaminal approach to the thoracic DRG. The investigators hypothesize that joining CT scan with fluoroscopy to guide RF ablation through the transforaminal route can enhance its efficacy and safety in relieving the intractable pain of chest malignancies. The current study aimed to compare the results of thermal radiofrequency ablation (TRFA) of the thoracic DRG under combined CT and fluoroscopy guidance with the classic standard fluoroscopy technique.

Inclusion Criteria:

• patients aged 18 years or more
• suffering from chronic moderate-to-severe pain ( VAS score ≥ 40 mm)
• due to malignancy involving the chest and pain was refractory to the maximally tolerated dose of opioids for at least four weeks. Malignancies included : lung cancer, pleural mesothelioma, chest wall tumors and metastatic deposits of the chest.

Exclusion Criteria:

• sepsis, coagulopathy
• malignant epidural invasion
• distorted local anatomy
• severe cardiorespiratory compromise
• neuropsychiatric illness
• history of drug dependence and known allergy to contrast media or the used medications.

It will be a shared team work study during which all the investigators will have equally distributed roles.