嗅神經母細胞瘤(olfactory neuroblastoma;ONB)是一種來自於嗅黏膜的惡性腫瘤，也是在鼻腔中少見的腫瘤，傳統的治療方式是以手術進行切除，然而常伴隨著高復發率及高致死率。本案例是以強度調控式放射治療技術(Intensity Modulated Radiation Therapy;IMRT)治療ONB的報告。
　　一名67歲男性建築工人因右側臉頰及牙齒疼痛超過一個月，經牙科診所拔牙治療後右側臉頰疼痛並未改善，而且情況有持續加重的現象因而至本院求診。93年5月13日安排電腦斷層(computed tomography;CT)檢查發現在上頜竇右側有一腫塊，並造成右側額骨、篩骨及蝶竇被破壞。耳鼻喉科進行進一步的切片檢查，病理檢查報告腫塊為嗅神經母細胞瘤，神經元特異烯醇酶(neuron specific enolase stain; NSE)染色為陽性反應，於是轉介至放射腫瘤科進行IMRT治療。放射治療自93年6月30日至93年8月20日共治療6300 cGY，期間合併2次30mg/M2/週cisplatin 靜脈注射的化學治療。93年9月9日CT顯示在上頜竇右側仍然有殘留的腫瘤，93年10月1日針對殘存的腫瘤給予小範圍IMRT 3300 cGy 加強放射線劑量，病患完成治療後右側臉頰疼痛的問題已獲解決。95年12月CT追蹤檢查在額骨、上頜竇、篩骨及蝶竇的位置有發炎的現象並但是沒有腫瘤復發的跡象。治療的副作用包括鼻淚管狹窄、阻塞所造成的右眼疼痛。鼻淚管狹窄、阻塞以手術的方式解除症狀，治療結束15個月後病患雙眼視力有視力減退的情形。目前已追蹤29個月沒有發現復發及其他系統性的疾病。
　　對於ONB無法開刀的病患，IMRT合併每週cisplatin化學治療是另一種可以選擇的治療方式。因為IMRT可以給予腫瘤最的放射線劑量，並保護正常的組織，可以將副作用減至最低。然而;不幸的是在治療的過程中因視神經受到過高輻射劑量照射而對病患視力造成損傷。因此雖然IMRT的治療計畫可以減少正常組織接受的劑量，還是要注意所有可能引起的傷害以減輕正常器官的副作用。

Olfactory neuroblastoma(ONB) is a rare aggressive tumor of the olfactory mucosa that has been traditionally treated with radical surgical excision. Nevertheless, these rare tumors are still associated with high rates of tumor recurrence and mortality. A novel therapeutic approach using intensity modulated radiotherapy(IMRT) is presented in this report.
We would like to report a 67 years old construction worker who was referred to our department due to a chief complaint of progressive right cheek pain and right side toothache for 1 month. The patient has been previously seen by a dentist who performed a tooth extraction; however, this did not resolve this right cheek pain. A CT scan of the paranasal sinuses performed on May 13, 2004 revealed a large enhancing tumor in the right maxillary sinus with right frontal, ethmoid and sphenoed sinuses bone destruction. the patient was referred to the department of ENT for biopsy of the unresectable tumor. The pathologic finding was that of an olfactory neuroblastoma, with the tumor staining positive for neuron specific enolase. IMRT was given to the patient for a total dose of 6300 cGy (June 30, 2004 to August 20, 2004) concurrently with 2 course of cisplatin iv infusion at 30 mg/m2 per week. Arepeat CT scan on Sept. 9, 2004 revealed a residual enhancing tumor of right maxillary sinus with bone invasion. A very small field IMRT boost for 3300 cGy was then given from Oct. 1, 2004 to Nov. 4, 2004. The patient completed the whole course of radiotherapy smoothly with no treatment break. A CT scan of the sinus performed on Dec.31, 2006 revealed only frontal, maxillary, ethmoid and sphenoid sinusitis with no evidence of tumor recurrence. Radiation induced right nasolacrimal duct stenosis and obstruction, tearing of the right eye, and decreased vision of both eyes was noted 15 months after IMRT. The stenosis was successfully corrected by surgical intervention. The patient is still well and alive 29 months after IMRT with no evidence of local recurrence or systemic disease.
IMRT in conjunction with weekly cisplatin should be considered as a treatment option in patients with unresectable olfactory neuroblastoma since this technique can deliver an adequate tumorical dose; however, it is unfortunate that the patient developed significant vision impairment due to the high radiation dose to the optic nervs. Careful IMRT treatment planning is necessary to avoid or minimize untoward side effects.