Perspective Therapeutics holder sells 247,932 shares

Perspective Therapeutics, Inc. (CATX) reported that Lantheus Alpha Therapy, LLC, a ten percent owner, sold shares of its common stock in open-market transactions on September 3 and September 4, 2026.

Rhea-AI Filing Summary

Perspective Therapeutics, Inc. (CATX) reported that Lantheus Alpha Therapy, LLC, a ten percent owner, sold shares of its common stock in open-market transactions on September 3 and September 4, 2026. The sales totaled 247,932 shares of common stock at weighted average prices around $3.11–$3.15 per share.

The shares are directly held by Lantheus Alpha Therapy, LLC, which is an indirect wholly owned subsidiary of Lantheus Holdings, Inc. Under SEC rules, Lantheus Holdings, Inc. may be deemed to have indirect beneficial ownership of these shares through Lantheus Alpha Therapy, LLC.

Insider Trade Summary

Net Seller: 247,932 shares

Net Sell 2 txns

Insider Lantheus Alpha Therapy, LLC, Lantheus Holdings, Inc.

Role 10% Owner | 10% Owner

Sold 247,932 shs ($777K)

Type	Security	Shares	Price	Value
Sale	Common Stock F3, F2	167,149	$3.1472	$526K
Sale	Common Stock F1, F2	80,783	$3.1058	$251K

Holdings After Transaction: Common Stock — 11,273,364 shares (Direct)

Footnotes (3)

1. F1. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.05 to $3.13, inclusive. The reporting person undertakes to provide to Perspective Therapeutics, Inc. ("CATX"), any security holder of CATX or the staff of the Securities and Exchange Commission ("SEC"), upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (1) to this Form 4.
2. F2. Represents securities directly held by Lantheus Alpha Therapy, LLC ("Lantheus"), a wholly owned indirect subsidiary of Lantheus Holdings, Inc. ("Lantheus Holdings"). Under SEC rules and regulations, Lantheus Holdings may be deemed to have indirect beneficial ownership of the shares held by Lantheus, which has direct beneficial ownership.
3. F3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.0448 to $3.1775, inclusive. The reporting person undertakes to provide to CATX, any security holder of CATX or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (3) to this Form 4.

Key Figures

Shares sold September 3, 2026: 80,783 shares Weighted average price September 3, 2026: $3.1058 per share Shares sold September 4, 2026: 167,149 shares +2 more

5 metrics

Shares sold September 3, 2026 80,783 shares Open-market sale of CATX common stock by Lantheus Alpha Therapy, LLC

Weighted average price September 3, 2026 $3.1058 per share Sale prices ranged from $3.05 to $3.13 per share

Shares sold September 4, 2026 167,149 shares Open-market sale of CATX common stock by Lantheus Alpha Therapy, LLC

Weighted average price September 4, 2026 $3.1472 per share Sale prices ranged from $3.0448 to $3.1775 per share

Total shares sold across both days 247,932 shares Combined CATX common stock sales on September 3 and 4, 2026

Key Terms

weighted average price, indirect beneficial ownership, ten percent owner, open market or private transaction

4 terms

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

indirect beneficial ownership financial

"Lantheus Holdings may be deemed to have indirect beneficial ownership of the shares"

ten percent owner regulatory

"reporting persons are listed as a ten percent owner of the issuer"

open market or private transaction financial

"Sale in open market or private transaction"

FAQ

What insider transaction did CATX disclose in this Form 4?

CATX disclosed that Lantheus Alpha Therapy, LLC, a ten percent owner, sold 247,932 shares of Perspective Therapeutics common stock in open-market transactions on September 3 and 4, 2026, at weighted average prices slightly above $3.10 per share.

How many CATX shares were sold on September 3, 2026?

On September 3, 2026, Lantheus Alpha Therapy, LLC sold 80,783 shares of CATX common stock at a weighted average price of $3.1058 per share, with individual trade prices ranging from $3.05 to $3.13.

How many CATX shares were sold on September 4, 2026?

On September 4, 2026, Lantheus Alpha Therapy, LLC sold 167,149 shares of CATX common stock at a weighted average price of $3.1472 per share, with individual trade prices ranging from $3.0448 to $3.1775.

Who is the reporting owner in this CATX Form 4 filing?

The directly holding reporting owner is Lantheus Alpha Therapy, LLC. It is a wholly owned indirect subsidiary of Lantheus Holdings, Inc., which may be deemed to have indirect beneficial ownership of the CATX shares held by Lantheus Alpha Therapy, LLC under SEC rules.

Were the CATX insider sales made under a Rule 10b5-1 trading plan?

No Rule 10b5-1 trading plan is indicated. The document-level checkbox for transactions under a Rule 10b5-1 plan is not checked, and the footnotes describe pricing details and ownership structure but do not reference any trading plan.

Does the Form 4 state how many CATX shares the insider holds after these sales?

The non-derivative transaction rows do not report a total shares following transaction figure, so the filing lists the shares sold and prices but does not state the remaining CATX common stock holdings after these sales.

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Available on EDGAR 09/08/2026 - 04:51 PM Accepted by SEC EDGAR 09/08/2026 - 04:51 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Lantheus Alpha Therapy, LLC

(Last) (First) (Middle)

C/O LANTHEUS HOLDINGS, INC.

201 BURLINGTON ROAD, SOUTH BUILDING

(Street)

BEDFORD MASSACHUSETTS 01730

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Perspective Therapeutics, Inc. [ CATX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/03/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/03/2026		S		80,783	D	$3.1058(1)	11,440,513	D(2)
Common Stock	09/04/2026		S		167,149	D	$3.1472(3)	11,273,364	D(2)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person^*

Lantheus Alpha Therapy, LLC

(Last) (First) (Middle)

C/O LANTHEUS HOLDINGS, INC.

201 BURLINGTON ROAD, SOUTH BUILDING

(Street)

BEDFORD MASSACHUSETTS 01730

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Lantheus Holdings, Inc.

(Last) (First) (Middle)

201 BURLINGTON ROAD, SOUTH BUILDING

(Street)

BEDFORD MASSACHUSETTS 01730

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.05 to $3.13, inclusive. The reporting person undertakes to provide to Perspective Therapeutics, Inc. ("CATX"), any security holder of CATX or the staff of the Securities and Exchange Commission ("SEC"), upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (1) to this Form 4.

2. Represents securities directly held by Lantheus Alpha Therapy, LLC ("Lantheus"), a wholly owned indirect subsidiary of Lantheus Holdings, Inc. ("Lantheus Holdings"). Under SEC rules and regulations, Lantheus Holdings may be deemed to have indirect beneficial ownership of the shares held by Lantheus, which has direct beneficial ownership.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.0448 to $3.1775, inclusive. The reporting person undertakes to provide to CATX, any security holder of CATX or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (3) to this Form 4.

	/s/ Eric M. Green, Assistant Corporate Secretary of Lantheus Holdings	09/08/2026
	/s/ Eric M. Green, Assistant Corporate Secretary of Lantheus	09/08/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)