FORM OF INSTRUCTIONS AS TO USE OF SUBSCRIPTION RIGHTS CERTIFICATES ACTINIUM PHARMACEUTICALS, INC. Please consult Broadridge Corporate Issuer Solutions, Inc., as to any questions. The following instructions relate to a ri

INSTRUCTIONS AS TO USE OF SUBSCRIPTION

ACTINIUM PHARMACEUTICALS, INC.

Please consult Broadridge Corporate Issuer

Solutions, Inc., as to any questions.

The following instructions relate to a

rights offering (the "Rights Offering") by Actinium Pharmaceuticals, Inc., a Delaware corporation ("Actinium"),

to the holders of record of its common stock, $0.001 par value (the "Common Stock') and certain participating warrants,

as described in Actinium's prospectus supplement dated February 15, 2018 (as it may be amended from time to time, the "Prospectus

Supplement"). Capitalized terms used but not defined herein shall have the meanings ascribed to them in the Prospectus Supplement.

Each holder of record of Common Stock or participating warrants at the close of business on February 14, 2018 (the "Record

Date") will receive, at no charge, a non-transferable subscription right (the "Subscription Right") for every

share of Common Stock held or underlying the participating warrants held at the Record Date.

Subscription Rights exercisable into an

aggregate maximum of 35,714,285 Units of Actinium ("Units"), subject to increase as described in the Prospectus Supplement,

are being distributed in connection with the Rights Offering. Each Unit is comprised of one share of Common Stock, 0.25 Series

A Warrants, and 0.75 Series B Warrants. Each whole Series A Warrant and each whole Series B Warrant will be exercisable for

one share of Common Stock. Each whole Subscription Right is exercisable, upon payment of $0.70 in cash (the "Subscription

Price"), to purchase one Unit (the "Basic Subscription Right"). In addition, each Subscription Right also carries

the right to subscribe at the Subscription Price for additional Units that are not purchased by other holders pursuant to their

Basic Subscription Right (to the extent available, and subject to proration and ownership limitations) (the "Over-Subscription

Privilege"). A holder is entitled to exercise an Over-Subscription Privilege only if the holder fully exercises the Basic

Subscription Right. See "The Rights Offering" in the Prospectus Supplement.

No fractional Subscription Rights or cash

in lieu thereof will be issued or paid. Fractional Subscription Rights will be rounded down to the nearest whole number.

The Subscription Rights will expire at

5:00 p.m., Eastern Time, on March 2, 2018, unless extended ("the "Expiration Date"). If you do not exercise your

Subscription Rights before that time, your Subscription Rights will expire and will no longer be exercisable. Actinium will not

be required to issue shares to you if the Subscription Agent receives your Subscription Rights Certificate or your subscription

payment after that time. Actinium has the option to extend the Rights Offering in its sole discretion, although it does not presently

intend to do so. Actinium may extend the Rights Offering by giving oral or written notice to the Subscription Agent before the

Expiration Date. If Actinium elects to extend the Rights Offering, Actinium will issue a press release announcing the extension

no later than 9:00 a.m., Eastern Time, on the next business day after the most recently announced Expiration Date of the Rights

The number of Subscription Rights to which

you are entitled is printed on the face of your Subscription Rights Certificate. You should indicate your wishes with regard to

the exercise of your Subscription Rights by completing the appropriate section on the back of your Subscription Rights Certificate

and returning the Subscription Rights Certificate with your payment to the Subscription Agent in the envelope provided.

Series A Warrants and Series B Warrants

that are issued as a component of the Unit pursuant to the exercise of the Basic Subscription Rights and Over-Subscription Privilege

entitle the holder to purchase one share of Common Stock at an exercise price (subject to adjustment) of $0.90 and $1.10, respectively

per share. The Warrants are exercisable for cash, or solely during any period when a registration statement for the exercise of

the Warrants is not in effect, on a cashless basis. The Series A Warrants and Series B Warrants may be redeemed for $0.001 per

Warrant if Actinium's Common Stock closes above $1.80 and $3.30 per share, respectively, for 10 consecutive trading days.

See "The Rights Offering" in the Prospectus.

YOUR SUBSCRIPTION RIGHTS CERTIFICATE

MUST BE RECEIVED BY THE SUBSCRIPTION AGENT ON OR BEFORE THE EXPIRATION DATE. PAYMENT OF THE SUBSCRIPTION PRICE OF ALL SUBSCRIPTION

RIGHTS EXERCISED, INCLUDING SUBSCRIPTION RIGHTS PURSUANT TO THE OVER-SUBSCRIPTION PRIVILEGE, INCLUDING FINAL CLEARANCE OF ANY CHECKS,

MUST BE RECEIVED BY THE SUBSCRIPTION AGENT ON OR BEFORE THE EXPIRATION DATE.

YOUR SUBSCRIPTION RIGHTS, YOU CANNOT REVOKE THE EXERCISE OF SUCH SUBSCRIPTION RIGHTS. SUBSCRIPTION RIGHTS NOT VALIDLY

EXERCISED PRIOR TO THE EXPIRATION DATE OF THE RIGHTS OFFERING WILL EXPIRE. HOLDERS WHO HOLD SUBSCRIPTION RIGHTS THROUGH A

BROKER OR OTHER NOMINEE SHOULD VERIFY WITH THE BROKER OR NOMINEE BY WHEN THE INSTRUCTION MUST BE DELIVERED.

1. Subscription Rights. To

exercise Subscription Rights, complete your Subscription Rights Certificate and send your properly completed and executed Subscription

Rights Certificate, together with payment in full of the Subscription Price for each Unit subscribed for pursuant to the Basic

Subscription Right and the Over-Subscription Privilege, to the Subscription Agent. PLEASE DO NOT SEND RIGHTS CERTIFICATES

OR PAYMENTS TO ACTINIUM. The method of delivery of the Subscription Rights Certificate and the payment of the Subscription

Price to the Subscription Agent is at your election and risk. Subscription Rights Certificates and payments must be received by

the Subscription Agent prior to the Expiration Date. If you send your Subscription Rights Certificate and payment by mail, then

they should be sent by registered mail, properly insured, to arrive before the Expiration Date. If more Units are subscribed for

pursuant to the Over-Subscription Privilege than are available for sale, additional Units will be allocated pro rata among holders

and subject to ownership limitations, as described in the Prospectus Supplement. The Subscription Rights are non-transferable,

and may not be sold, transferred, assigned or given away to anyone.

2. Acceptance of Payments.

Payments will be deemed to have been received by the Subscription Agent only upon the (i) clearance of an uncertified personal

check drawn against a U.S. bank payable to "Broadridge Corporate Issuer Solutions, Inc., as Subscription Agent for Actinium

Pharmaceuticals, Inc.," (ii) receipt of a certified check drawn against a U.S. bank payable to "Broadridge Corporate

Issuer Solutions, Inc., as Subscription Agent for Actinium Pharmaceuticals, Inc.," (iii) receipt of a U.S. Postal money order

payable to "Broadridge Corporate Issuer Solutions, Inc., as Subscription Agent for Actinium Pharmaceuticals, Inc.";

or (iv) receipt of a wire transfer of immediately available funds directly to the account maintained by Broadridge Corporate Issuer

Solutions, Inc., as Subscription Agent, for purposes of accepting subscriptions in this Rights Offering at

ABA/Routing number: 121000248

420 Montgomery Street

San Francisco, CA 94104 United States

Beneficiary Account Name: Broadridge Corporate Issuer

Account Number: 4124218686

FFC: Actinium Pharmaceuticals, Inc.

Account Number: 4399752260

Funds paid by uncertified personal check

may take several business days to clear. Accordingly, if you wish to pay the Subscription Price by uncertified personal check,

then you should make payment sufficiently in advance of the Expiration Date to ensure its receipt and clearance by that time. To

avoid disappointment caused by a failure of your subscription due to your payment not clearing prior to the expiration date, Actinium

urges you to consider payment by means of certified or cashier's check, money order or wire transfer. It is highly recommend

that if you intend to pay the Subscription Price by personal check, then your subscription payment should be received by the Subscription

Agent well before the Expiration Date. If your personal check does not clear before the Expiration Date, then you will not receive

any Units, and Actinium's only obligation will be to return your subscription payment, without interest or deduction.

3. Contacting the Subscription

Agent. The address and telephone number of the Subscription Agent are shown below. Delivery to an address other than shown

below does not constitute valid delivery.

4. Partial Exercises; Effect of

Over- and Under-Payments. If you exercise less than all of the Subscription Rights evidenced by your Subscription Rights Certificate,

the Subscription Agent will issue to you a new Subscription Rights Certificate evidencing the unexercised Subscription Rights.

However, if you choose to have a new Subscription Rights Certificate sent to you, you may not receive any such new Subscription

Rights Certificate in sufficient time to permit exercise of the Subscription Rights evidenced thereby. If you do not indicate

the number of Units to be subscribed for on your Subscription Rights Certificate, or if you indicate a number of Units that does

not correspond with the aggregate Subscription Price payment you delivered, you will be deemed to have subscribed for the maximum

number of Units that may be subscribed for, under both the Basic Subscription Right and the Over-Subscription Privilege, for the

aggregate Subscription Price you delivered. If the Subscription Agent does not apply your full Subscription Price payment to your

purchase of Units, then the Subscription Agent will return the excess amount to you by mail, without interest or deduction, within

10 business days after the Expiration Date. If you subscribe for fewer than all of the Units represented by your Subscription

Rights Certificate, then the unexercised Subscription Rights will become null and void on the Expiration Date.