Note 2 - Accounting Policies (Details Textual)		12 Months Ended
	Jun. 12, 2020 USD ($)	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Jan. 01, 2022 USD ($)
Advertising Expense		$ 165,000	$ 233,000
Net Income (Loss) Attributable to Parent		$ 610,000	$ 1,328,000
Earnings Per Share, Diluted (in dollars per share) | $ / shares		$ 0.1	$ 0.21
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization		$ 81,227,000
Gain (Loss) on Sale of Assets and Asset Impairment Charges		(940,000)	$ (0)
Asset Retirement Obligation		290,000
Asset Impairment Charges		$ 650,000
Lessee, Operating Lease, Term of Contract (Year)		10 years
Weighted Average Number of Shares Outstanding, Basic, Total (in shares) | shares		6,358,000	6,297,000
Number of Reportable Segments		2	2
Goodwill and Intangible Asset Impairment		$ 0	$ 0
Gamma Knife Center Ecuador S.A. (GKCE) [Member]
Goodwill, Acquired During Period	$ 1,265,000
Gamma Knife Center Ecuador S.A. (GKCE) [Member] | Trade Names [Member]
Indefinite-lived Intangible Assets Acquired	$ 78,000
Restricted Stock Units (RSUs) [Member]
Weighted Average Number of Shares Outstanding, Basic, Total (in shares) | shares		123,000	123,000
Share-Based Payment Arrangement, Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares		144,000	20,000
GKCE [Member]
Accounts Receivable, after Allowance for Credit Loss		$ 1,626,000	$ 1,119,000	$ 668,000
Gamma Knife Units [Member]
Asset Retirement Obligation		$ 650,000
Number of Customer with Intent to Terminate Contract		2
Other Gamma Knife Units [Member]
Asset Retirement Obligation		$ 0
Rental Income from Medical Services [Member]
Revenue from Contract with Customer, Including Assessed Tax		17,772,000	16,655,000
PBRT Services [Member]
Revenue from Contract with Customer, Including Assessed Tax		$ 10,133,000	$ 8,952,000
Revenue Sharing Arrangements [Member]
Percentage of Revenues		70.00%	67.00%
Patient Income [Member]
Revenue from Contract with Customer, Including Assessed Tax		$ 3,553,000	$ 3,091,000
Equipment Sales [Member]
Revenue from Contract with Customer, Including Assessed Tax		200,000
Salvage Value [Member]
Net Income (Loss) Attributable to Parent		$ (207,000)
Earnings Per Share, Diluted (in dollars per share) | $ / shares		$ 0.03
Minimum [Member]
Property, Plant, and Equipment, Salvage Value		$ 140,000	140,000
Maximum [Member]
Property, Plant, and Equipment, Salvage Value		$ 300,000	300,000
Office Equipment [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)		3 years
Office Equipment [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)		10 years
Building [Member]
Property, Plant and Equipment, Useful Life (Year)		20 years
Proton Beam Radiation Therapy PBRT [Member]
Property, Plant and Equipment, Useful Life (Year)		20 years
Gamma Knife And Radiation Therapy Equipment [Member]
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization		$ 70,635,000	69,306,000
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, Accumulated Depreciation and Amortization		$ 52,302,000	$ 47,992,000
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number of Major Customers		15	15
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | One Customer [Member]
Concentration Risk, Percentage		48.00%	45.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Number of Major Customers		2	4
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer One [Member]
Concentration Risk, Percentage		30.00%	12.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer Two [Member]
Concentration Risk, Percentage		31.00%	14.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer Three [Member]
Concentration Risk, Percentage			16.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer Four [Member]
Concentration Risk, Percentage			22.00%