Activity of Goodwill by Reportable Operating Segment (Detail) (USD $)	12 Months Ended
	Sep. 28, 2012	Sep. 30, 2011
Goodwill [Line Items]
Balance, beginning	$ 212,452,000	$ 208,500,000
Acquisition of businesses	12,400,000	3,400,000
Payment and/or accrual of contingent consideration		2,100,000
Adjustment to deferred tax asset		(100,000)
Foreign currency translation adjustments	(2,700,000)	(1,400,000)
Balance, ending	222,242,000	212,452,000
Oncology Systems
Goodwill [Line Items]
Balance, beginning	130,500,000	126,700,000
Acquisition of businesses	1,500,000	3,400,000
Payment and/or accrual of contingent consideration		400,000
Adjustment to deferred tax asset		0
Foreign currency translation adjustments	0	0
Balance, ending	132,000,000	130,500,000
X-Ray Products
Goodwill [Line Items]
Balance, beginning	6,100,000	4,500,000
Acquisition of businesses	10,900,000	0
Payment and/or accrual of contingent consideration		1,700,000
Adjustment to deferred tax asset		(100,000)
Foreign currency translation adjustments	0	0
Balance, ending	17,000,000	6,100,000
Other
Goodwill [Line Items]
Balance, beginning	75,900,000	77,300,000
Acquisition of businesses	0	0
Payment and/or accrual of contingent consideration		0
Adjustment to deferred tax asset		0
Foreign currency translation adjustments	(2,700,000)	(1,400,000)
Balance, ending	$ 73,200,000	$ 75,900,000