instruction: what was the top three most common procedures that followed during the same hospital encounter for patients who were given head ct scan - without contrast the last year?
response: SELECT t3.treatmentname FROM (SELECT t2.treatmentname, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM (SELECT patient.uniquepid, treatment.treatmenttime, patient.patienthealthsystemstayid FROM treatment JOIN patient ON treatment.patientunitstayid = patient.patientunitstayid WHERE treatment.treatmentname = 'head ct scan - without contrast' AND DATETIME(treatment.treatmenttime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-1 year')) AS t1 JOIN (SELECT patient.uniquepid, treatment.treatmentname, treatment.treatmenttime, patient.patienthealthsystemstayid FROM treatment JOIN patient ON treatment.patientunitstayid = patient.patientunitstayid WHERE DATETIME(treatment.treatmenttime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-1 year')) AS t2 ON t1.uniquepid = t2.uniquepid WHERE t1.treatmenttime < t2.treatmenttime AND t1.patienthealthsystemstayid = t2.patienthealthsystemstayid GROUP BY t2.treatmentname) AS t3 WHERE t3.c1 <= 3