Blockchain-based organ matching system

Abstract

Proposed in the present invention is a blockchain-based organ matching system (Blockchain-enabled Organ Matching System (BOMS)) designed to manage a process of matching, storing, and sharing information. An organ matching method carried out by the blockchain-based organ matching system of the present invention comprises the steps of: registering donor or recipient information in a system; determining whether matching between a donor and a recipient is necessary; when, through the determination, it is determined that matching is not necessary, storing surgery-related information in a blockchain smart contract; and when, through the determination, it is determined that matching is necessary, carrying out organ matching between a donor and a recipient to match with a final recipient and storing the surgery-related information in the blockchain smart contract. The blockchain-based organ matching system of the present invention has effects wherein biological factors are integrated into matching, a cross-matching process is implemented in smart contracts, privacy is ensured by using patient-related blockchain addresses without transmitting or using personal patient records during a matching process, and a matching algorithm implemented as a smart contract can be verified by all parties.

Description

Blockchain-based long-term matching system

[0001] The present invention relates to a blockchain-based organ matching system, and more specifically, to a blockchain-enabled organ matching system (BOMS) designed to manage the process of matching, storing, and sharing information.

[0002]

[0003] In the United States and some European countries, organizations such as the United Network for Organ Sharing (UNOS) and Eurotransplant (ET) respectively oversee organ allocation and distribution.

[0004] They regulate organ transplantation in cooperation with hospitals, transplant centers, and organ procurement organizations (OPOs).

[0005] UNOS utilizes a secure internet-based transplant information database system called 'UNet' to manage organ allocation and transplant data, including waiting lists and donor lists.

[0006] Both UNOS and ET use a point-scoring rule for organ allocation and donor management that assigns points based on patient factors such as blood, waiting time, and distance from the donor.

[0007] Since 2014, U.S. kidney procurement agencies have been implementing the UNet allocation system to match donated grafts with recipients.

[0008] This allocation system optimizes organ availability using the kidney donor profile index (KDPI) and the estimated post-transplant survival score (EPTS).

[0009] KDPI assigns a quantified score to a donor's organ based on various factors, while EPTS evaluates the recipient's survival probability after transplantation based on specific recipient factors.

[0010] Schult et al. explored the applicability of these scores in the ET domain and evaluated the effectiveness of the ET lengthening allocation algorithm in enhancing long-term utility.

[0011] According to the study results, only the donor age of KDPI and the recipient age of EPTS were found to significantly predict graft and recipient survival after transplantation, and the ET kidney allocation algorithm has limitations in matching transplanters and recipients due to a low age correlation.

[0012] Major agencies such as the Uniform Anatomical Gift Act (UAGA) and the Organ Procurement and Transplantation Network (OPTN) are involved in the regulatory framework for organ donation and transplantation.

[0013] The UAGA, enacted in 1968, serves as the legal basis for organ and tissue donation by individuals aged 18 and older. To complement this framework, OPTN manages organ procurement and distribution through Organ Procurement Organizations (OPOs), which act as intermediaries between hospitals and UNOS associations in the organ and tissue distribution process.

[0014] For example, in Italy, the process of allocating deceased kidney donors begins at the local level, and matching is carried out by considering factors such as waiting time, age, HLA match, and panel reactive antibody (PRA) ratios.

[0015] The regional or national kidney emergency system also allocates resources by taking transplant and pediatric priorities into account.

[0016]

[0017] The internet is also an important source for organ donation, and one of the representative internet-based organ allocation systems is MatchingDonors.com.

[0018] Since its establishment in 2004, Matching Donors.com has supported thousands of transplants, and as of 2023, more than 15,000 altruistic living donors are registered.

[0019] Through this platform, many patients can receive a transplant within six months of registering on the website, and the waiting time is significantly shorter compared to donation networks managed by other organ procurement agencies.

[0020] Initially, the use of such platforms was limited due to unfamiliarity with the internet and perceptions of risks, but now MatchingDonors.com is visited by more than 1.5 million people every month.

[0021] According to Henderson, the internet, particularly social media, is also widely used for organ donation and transplantation of the deceased.

[0022] Several solutions have been proposed to prevent illegal organ transplants using a decentralized ledger.

[0023]

[0024] Despite the widespread application of various allocation systems, some countries are still facing difficulties due to the lack of connection platforms between donors, beneficiaries, hospitals, or procurement agencies.

[0025] These disparities can lead to illegal practices or illicit allocation methods, such as waiting list manipulation, patient data manipulation, and even human trafficking.

[0026]

[0027] Blockchain technology has significantly improved data sharing by guaranteeing maximum security to data owners through encryption, immutability, and decentralization.

[0028] Recently, several blockchain-based mobile applications for organ donation have been developed, becoming private Ethereum-based solutions that enable decentralized, secure, traceable, auditable, private, and trusted organ donation and transplant management.

[0029] In other web-based applications, matching was performed using the First-In, First-Out method.

[0030] However, patients in critical condition skipped the queue, and each patient had to go through an online registration process, providing medical ID, organ type, and blood type, and describing their overall health status.

[0031] This invention highlighted the role of blockchain and distributed ledger technology in the field of organ transplantation, and the manipulation of waiting lists was mitigated by introducing decentralized technology.

[0032]

[0033] The purpose of the present invention is to provide a blockchain-based organ matching system that considers tissue compatibility, medical urgency, and geographical proximity in the field of organ transplantation to solve the aforementioned problems, and provides anti-tampering, confidentiality of personal information, decentralization, transparency of the matching process, and organ cross-matching functions.

[0034]

[0035] The organ matching method of the blockchain-based organ matching system of the present invention for the above-mentioned problem to be solved is characterized by comprising the steps of: registering donor or recipient information in the system; determining whether matching between the donor and the recipient is necessary; storing surgery-related information in a blockchain smart contract if it is determined that matching is not necessary; performing organ matching between the donor and the recipient to match the final recipient if it is determined that matching is necessary; and storing surgery-related information in a blockchain smart contract.

[0036] In addition, the organ matching method of the blockchain-based organ matching system of the present invention is characterized by registering donor or recipient information in the system and storing biological and non-biological information regarding the donor or recipient in a smart contract, wherein the biological information is one or more of the weight and height, age, organ condition, blood type, and medical history information of the donor or recipient, and the non-biological information is one or more of the geographical location, degree of urgency, and waiting list of the donor or recipient.

[0037] In the long-term matching method of the blockchain-based long-term matching system of the present invention, the determination of whether matching is necessary is characterized by determining that matching is not necessary if there is a compatible beneficiary already predetermined for the donor, and determining that matching is necessary otherwise.

[0038] In the organ matching method of the blockchain-based organ matching system of the present invention, the step of matching a final recipient by performing organ matching comprises: a step of generating an organ transplant ranking list by performing organ matching between a donor and a recipient; a step of selecting a final recipient through cross-matching between a recipient and a donor in the order of the organ transplant ranking list; and a step of selecting a final recipient through cross-matching between a recipient and a donor in the order of the organ transplant ranking list.

[0039] The method of long-term matching in the blockchain-based long-term matching system of the present invention is characterized in that the case where it is determined that matching is not necessary is when the donor is anonymous or when it is found that the recipient designated by the donor is not long-term compatible with each other.

[0040] In addition, in the organ matching method of the blockchain-based organ matching system of the present invention, the organ transplant ranking list is characterized by the recipients being sorted in order of highest score by assigning scores by a recipient score calculation algorithm.

[0041]

[0042] Managing organ donation systems is an important process that requires transparency, but many organ donation systems are not transparent.

[0043] An organ donation system utilizing blockchain is being proposed to ensure transparency in the matching process.

[0044] According to the long-term matching method of the blockchain-based long-term matching system of the present invention, an optimal match is selected based on biological and geographical compatibility using the patient's electronic medical records.

[0045] In addition, according to the organ matching method of the blockchain-based organ matching system of the present invention, the role of cross-matching in the organ donation process is considered and integrated into a blockchain smart contract system.

[0046]

[0047] Furthermore, the long-term matching method of the blockchain-based long-term matching system according to the present invention ensures usability in actual scenarios through a practical design, has been implemented as a front-end decentralized (distributed) application, and has been successfully deployed and tested on public, private, and consortium networks.

[0048] The smart contract implemented as part of the system was tested using SolidCheck, Aderin, and Slither security checkers and achieved a score of 100 out of 100, confirming that there are no known vulnerabilities.

[0049] The blockchain-based long-term matching system according to the present invention demonstrated superior performance compared to other blockchain solutions, passing all security checks in terms of considered functions.

[0050]

[0051] Figure 1 illustrates the entire proposal matching process showing the blockchain matching process, priority list generation, cross-matching, and surgery process.

[0052] Figure 2 illustrates an interaction diagram between the institutions involved in the matching process from patient registration to organ transplantation.

[0053] Figure 3 is a flowchart of the biological process in the proposed BOMS.

[0054] Figure 4 is an analysis of gas costs according to the increase in the number of patients in the system.

[0055] The blue bar indicates the amount of gas required for the matching process when there is a specific number of recipients in the smart contract waiting list (gas for matching).

[0056] The orange bar represents the additional gas required for matching when one recipient is added to the current waiting list.

[0057] Figure 5 is a log showing the successful matching of a donor and a suitable recipient.

[0058] Figure 6 shows that the proposed system can interact through a customized user interface or an automatically generated user interface.

[0059] (A) is a custom design of a user interface for patient registration, and (B) is a user interface automatically generated in Remix IDE to test a smart contract.

[0060] Figure 7 shows the results of a smart contract vulnerability check that showed no vulnerabilities on three platforms.

[0061] (A) is the inspection result using SolidCheck, (B) is the inspection result using Aderin, and (C) is the inspection result using Slider.

[0062] Figure 8 shows the matching algorithm in the proposed BOMS.

[0063]

[0064] ① Application (External blockchain process) - Donor or beneficiary application

[0065] ② Donor / Recipient Registration

[0066] ③ Cases where matching is needed (Matching is needed - No): Matching is not required if the donor already has a pre-determined compatible recipient.

[0067] a. Deceased donor matched with recipient

[0068] b. Alive with a matching recipient

[0069] ④ When matching is needed (Matching is needed - Yes)

[0070] a. Deceased anonymous donor

[0071] b. Alive anonymous donor

[0072] c. Deceased with non-matching recipient

[0073] d. Alive with a non-matching recipient

[0074] ⑤ Proceed with the donor retrieval surgery process that does not require matching.

[0075] ⑥ Ranked list; if matching is required, listed on the organ transplant recipient ranking list

[0076] ⑦ Cross-matching between the donor's organ and the recipient on the priority list

[0077] ⑧ Best Match Selection (Best Match) - The best match recipient is selected by a donor-recipient matching algorithm.

[0078] ⑨ Organ removal surgery performed by a donor surgeon

[0079] 10. Organ Transport

[0080] 11 Organ Transplant Surgeon (Transplant)

[0081] ⑫ Organ transplant surgery (Surgery), transplant surgery performed on a recipient by a surgeon

[0082]

[0083] Specific structural or functional descriptions of embodiments according to the concept of the present invention disclosed herein are provided merely for the purpose of explaining embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms and are not limited to the embodiments described herein.

[0084] Embodiments according to the concept of the present invention may be subject to various modifications and may take various forms; therefore, embodiments are illustrated in the drawings and described in detail in this specification. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes all modifications, equivalents, or substitutions that fall within the spirit and scope of the present invention.

[0085]

[0086] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings.

[0087]

[0088] 1. Introduction

[0089] For patients with advanced organ failure, organ transplantation is an important life-saving treatment.

[0090] However, the demand for organ donation often outweighs the supply, leading to long waiting times and frequently resulting in preventable deaths.

[0091] Connecting existing country-specific donation systems into a single decentralized system will help reduce the inefficiency of matching donors and recipients and decrease the number of deaths.

[0092] The core of the organ donation system is the organ matching algorithm, which plays a key role in increasing the success rate of organ transplants by considering various factors such as tissue compatibility, immunological indicators, medical urgency, and geographical proximity.

[0093] Long-term matching algorithms must preserve data from all relevant parties and provide a certain level of tamper-proofing, especially when handling personal medical information.

[0094] To protect patients' personal information and ensure confidentiality, it is important to comply with strict privacy standards.

[0095] The aforementioned requirements can be resolved using encryption technology and distributed ledger technology.

[0096]

[0097] Using blockchain technology allows sensitive medical data to be shared and stored transparently and securely.

[0098] The blockchain-based long-term matching system of the present invention stores the encrypted hash of a record on the blockchain to prevent falsification or alteration of the record.

[0099] The blockchain-based long-term matching system of the present invention uses smart contracts to automate and track changes in viewing rights or the creation of new records in the system.

[0100] Smart contracts are used to improve security and reduce reliance on central servers in the context of institution matching.

[0101] In particular, because blockchain is decentralized and immutable, once a matching algorithm is adopted and stored on the blockchain, it cannot be changed or manipulated.

[0102] Using open source smart contracts ensures the transparency and immutability of the matching process, which promotes equity and trust among all involved parties.

[0103] In addition, automated notifications and updates can be provided throughout the long-term matching process through smart contract event emission properties.

[0104] For example, when a suitable match is found, messages can be automatically sent to appropriate stakeholders, such as medical staff, transplant teams, and potential recipients.

[0105] While blockchain and smart contracts guarantee that algorithms remain unchanged, the biggest drawback is that the data processed by the algorithms must be in plain text.

[0106] Therefore, due to the difficulty in protecting personal information, donor matching must be performed on medical records accessible to everyone.

[0107] To reduce the possibility of patient identity exposure, blockchain addresses are used to represent process participants.

[0108] This provides a certain degree of privacy protection while maintaining transparency.

[0109] The blockchain-based organ matching system of the present invention focuses on the practical aspects of integrating blockchain and smart contract technologies into an organ donation system.

[0110] The blockchain-based long-term matching system of the present invention considers regulatory issues, addresses subtle differences in implementation, and investigates biological processes related to the matching process.

[0111] The blockchain-based long-term matching system of the present invention contributes to (1) the implementation of a blockchain-supported matching algorithm and (2) the integration of various biological factors into the long-term matching process.

[0112] The Development Background and Design Considerations section explains the background of blockchain technology and biological considerations regarding organ donation; the System Model section presents the blockchain-based organ matching system of the present invention, focusing on the implementation design of blockchain smart contracts; the Evaluation and Results section presents the performance evaluation of the blockchain-based organ matching system of the present invention and a comparison with existing systems; and the Conclusion section explains the conclusions and the effects of the blockchain-based organ matching system of the present invention.

[0113]

[0114] 2. Development Background and Design Considerations (Background)

[0115] This section explains the background of blockchain technology and biological considerations regarding organ donation.

[0116] 2.1 Smart Contracts

[0117] A smart contract is a programmable account on a blockchain network.

[0118] A smart contract has a set of instructions predefined before deployment, and once deployed, the commands cannot be changed.

[0119] The smart contract according to the blockchain-based organ matching system of the present invention is equipped with functions such as registering participants including hospitals, donors, recipients, procurement agencies, doctors, and transporters, tracking organ progress, matching donors and recipients, and generating a waiting list.

[0120] If the match is successful, the smart contract removes the matched donor and beneficiary from the list, and the entire process after registration is managed by the smart contract.

[0121] The system according to the blockchain-based long-term matching system of the present invention is highly secure when deployed on a public blockchain network, and personal information protection is enhanced by representing patients using blockchain addresses.

[0122] This address is used to manage the items that each participant in the network can access, so only authorized participants can perform operations.

[0123] Smart contracts serve as the backend for decentralized applications (DApps).

[0124]

[0125] 2.2 Biological Factors

[0126] As of September 3, 2023, there are more than 103,000 potential recipients on the U.S. National Organ Transplant Waiting List, with kidneys accounting for 86% of them. (www.organdonor.com)

[0127] Therefore, a powerful matching method is needed to connect donors and recipients more efficiently.

[0128] When matching donors and recipients for transplantation, various factors are considered, and tests are conducted to verify tissue and organ compatibility.

[0129] The type of blood or antigen is determined based on biological match, and the ABO blood types of the donor and recipient must be compatible for transplantation.

[0130] Human leukocyte antigen (HLA) matching is important to avoid immunological incompatibility and increase the likelihood of a successful transplant.

[0131] While HLA matching is generally required for kidney transplants, there has been controversy regarding HLA-matched heart donation, particularly in the case of deceased donors, due to cold ischemia and clinical urgency.

[0132] Graft size is also considered in organ transplantation, and it has been found that the smaller the organ size relative to the recipient, the lower the transplant survival rate.

[0133] Since the size of the body is often unknown at the time of donation, the body surface area can be calculated using the generally known height and weight of the donor and recipient, and this is correlated with the size of the body.

[0134] The age of the donor and recipient also affects matching and transplant survival rates.

[0135] Although older recipients have a shorter survival period even with a normal organ transplant, special considerations for transplantation are generally given to pediatric recipients compared to adults.

[0136] Regarding the impact of age and graft size on survival, previous studies have revealed that age can attenuate the effect of donor-recipient size mismatch, and that the negative impact of donor-recipient size mismatch on transplant survival is greater than that of the donor's age.

[0137] Another issue to consider during organ transplantation is the possibility of infection being transmitted to the recipient, as it is difficult to eliminate donor-derived infections.

[0138] Therefore, methods to minimize transmission are generally adopted through clinical tests such as viral load tests, as well as medical history and social history examinations.

[0139] Other factors considered in long-term matching include the donor's geographical location relative to the recipient's residence, the length of time the potential recipient has been on the waiting list, and medical emergencies.

[0140] In addition, special consideration is given to cases where a previously living donor later becomes a potential recipient.

[0141]

[0142] 2.3 Factors Affecting Fair and Transparent Agency Matching and Allocation

[0143] There are several factors to consider to ensure fair and equal treatment for organ donors.

[0144] 2.3.1 Utility: The utility of all benefits provided by scarce resources.

[0145] This approach involves allocating resources to save or enable the saving of more lives.

[0146] In organ transplants, one organ is always used, which means one life to be saved.

[0147] Therefore, consider factors such as who can receive more benefits from the organ, and assign priorities based on the following criteria.

[0148] a. The patient with the highest likelihood of surviving the longest during the transplant process and after transplantation.

[0149] b. Patients with the highest compatibility rate to avoid long-term rejection.

[0150] c. Availability of alternative treatments (post-clinical intervention)

[0151] d. Transplant or organ survival period (the period during which the organ can function after transplantation).

[0152]

[0153] 2.3.2 Equity: In this case, institutions are assigned by random selection, either by lottery or on a first-come, first-served basis.

[0154] a. Random selection: A method in which the lucky winner is determined through a draw.

[0155] While this method appears to present a fair and unbiased selection procedure, it may be disadvantageous to patients in more critical condition because it may favor those in the early stages of the disease, those in good condition, or those who may have a longer survival period.

[0156] b. In addition, a first-come, first-served rule is applied, giving an advantage only to those who know early and request and register early.

[0157] Therefore, it is a decision disadvantageous to sicker patients because it does not consider the severity of disease that makes organ allocation and transplantation unsuitable and unfair.

[0158]

[0159] 2.3.3 Assignment based on priority or preference for the most vulnerable patients: This option considers patients with severe / deteriorated conditions without relying on the waiting list.

[0160] The downside of this option is that insufficient organs may be wasted because compatibility is not considered when selecting it.

[0161] This option assumes a temporary organ shortage and that organs may be provided to patients with low severity in the future, but this is not guaranteed.

[0162] Furthermore, it is argued that priority is given to young patients to prevent premature death, and that more value can be placed on allocating organs to younger patients than to older ones.

[0163]

[0164] 2.3.4 Principles of Transparency and Autonomy: This option allows individuals to decide whether to donate or receive donations as long as it does not cause harm to others.

[0165] This allows patients to decide whether to reject or accept specific organs based on their own beliefs or the donor's health history.

[0166] In addition, if the donor or the donor's family is eligible, they may decide to donate directly without going through the allocation waiting list.

[0167] The problem with this option is that patients encouraging direct donation exploit it by creating groups where members promise to donate their organs to others upon death, in return receiving the same benefits when organs are needed.

[0168]

[0169] 3. System Model

[0170] The blockchain-based long-term matching system of the present invention is a system model centered on the design of a blockchain smart contract implementation.

[0171] 3.1 Blockchain-based Long-term Matching System

[0172] The blockchain-based long-term matching system of the present invention is built on a blockchain using smart contracts.

[0173] Biological factors are used to determine the compatibility between the donor and the recipient.

[0174] Other factors, such as region, fairness, and whether the beneficiary came with the donor, are used to rank the list of beneficiaries.

[0175]

[0176] Figure 1 (the overall proposal matching process showing the blockchain matching process and priority list generation, cross-matching, and surgery process) briefly shows the flowchart of the donation system.

[0177] It is traceable and publicly accessible at every stage of the matching process.

[0178] ① Application (External blockchain process) - Donor or beneficiary application

[0179] ② Donor / Recipient Registration

[0180] ③ Cases where matching is needed (Matching is needed - No): Matching is not required if the donor already has a pre-determined compatible recipient.

[0181] a. Deceased donor matched with recipient

[0182] b. Alive with a matching recipient

[0183]

[0184] ④ When matching is needed (Matching is needed - Yes)

[0185] a. Deceased anonymous donor

[0186] b. Alive anonymous donor

[0187] c. Deceased with non-matching recipient

[0188] d. Alive with a non-matching recipient

[0189]

[0190] ⑤ Proceed with the donor retrieval surgery process that does not require matching.

[0191] ⑥ Ranked list; if matching is required, listed on the organ transplant recipient ranking list

[0192] ⑦ Cross-matching between the donor's organ and the recipient on the priority list

[0193] ⑧ Best Match Selection (Best Match) - The best match recipient is selected by a donor-recipient matching algorithm.

[0194] ⑨ Organ removal surgery performed by a donor surgeon

[0195] 10. Organ Transport

[0196] 11 Organ Transplant Surgeon (Transplant)

[0197] ⑫ Organ transplant surgery (Surgery), transplant surgery performed on a recipient by a surgeon

[0198]

[0199] Figure 2 shows an interaction diagram between the institutions involved in the matching process from patient registration to organ transplantation.

[0200] T1. Patient (Donor, Recipient) Registration Step

[0201] - The donor registers for organ donation at the hospital, and the hospital registers the donor in a smart contract.

[0202] - The beneficiary registers an organ transplant application at the hospital, and the hospital registers the organ transplant application in the smart contract.

[0203] T2. Long-term Matching and Priority List Generation Steps

[0204] T3. Transplant Preparation Phase

[0205] - The BOMS smart contract system sends events to the donor

[0206] - The BOMS smart contract system sends events to the beneficiary

[0207] - Cross-matching of donors and recipients

[0208] - The beneficiary accepts the matching

[0209] - The donor accepts the match

[0210] - Send event to donor doctor (organ removal surgeon)

[0211] - Send event to recipient doctor (organ transplant surgeon)

[0212] T4. Surgical stage

[0213]

[0214] A. Registration by hospital

[0215] Both the donor and the recipient are registered through the hospital, and the medical system initiates the organ donation process.

[0216] Inpatient hospitals must comply with the following requirements:

[0217] ⊙Medical Evaluation: The hospital has the capacity and resources to conduct medical evaluations of potential donors and recipients.

[0218] Donors must undergo testing to determine if they are eligible for organ transplantation, and recipients must be evaluated to verify medical eligibility and compatibility with the donor.

[0219] ⊙Legal and Ethical Principles: Organ donation is managed in accordance with legal and ethical principles in many countries.

[0220] Hospitals often have to establish procedures in accordance with the law to find potential donors, obtain consent, and ensure that the process is carried out ethically and legally.

[0221] ⊙Consent and Support: The hospital may provide appropriate counseling and support to the donor and recipient.

[0222] This allows patients and their families to make informed decisions regarding organ donation and transplantation, while also considering the emotional and ethical aspects of the procedure.

[0223] ⊙Coordination: Organ transplantation involves several stages, including donor identification, organ retrieval, transportation, and transplant surgery.

[0224] The hospital is fully prepared to systematically manage this complex logistics so that organ transplants can be carried out effectively and in a timely manner.

[0225] Raising public awareness: Hospitals can help educate the public about the need for organ donation and transplantation.

[0226] The hospital can inform patients and their families of the benefits of registering as future donors or recipients and resolve any misunderstandings or concerns.

[0227] ⊙Standardization and Documentation: Hospitals can maintain consistent documentation for both donors and recipients, which is important for tracking the organ donation process and determining accountability.

[0228] This paperwork contributes to enhancing the transparency and fairness of the long-term allocation process.

[0229] ⊙Responsibility and Supervision: The hospital is responsible for organ donation and transplant activities carried out within the facility.

[0230] The hospital's participation ensures that the entire process is carried out honestly, in compliance with regulations, and under supervision.

[0231]

[0232] B. Organ Donation Procedure

[0233] Matching is performed by considering the biological factors described in the background section to determine whether the transplanted organ is compatible with the recipient's body, that is, to reduce the risk of rejection and increase the likelihood of transplant success.

[0234] The proposed system encourages the recipient to come with the donor even if the pairs are incompatible, or vice versa.

[0235] Recipients and donors can register without a pair, but they cannot receive points associated with pair registration.

[0236] In the case of living donors, consent is generally obtained, but in the case of deceased donors, organ or tissue donation can only take place after the donor consented before death or after a close relative approved the donation.

[0237]

[0238] In the proposed system, two types of donors are distinguished:

[0239] i. Donors who do not require matching: As shown in Fig. 1, if the donor already has a predetermined compatible recipient, matching is not required.

[0240] If the donor and recipient are known to be compatible due to predetermined characteristics, such as being closely biologically related or passing extensive compatibility tests, matching is generally not required.

[0241] In many cases, compatibility between the donor and the recipient is thoroughly verified before surgery.

[0242] In situations where compatibility is well established, matching may not be necessary.

[0243] The proposed system stores information related to surgery in a blockchain smart contract according to steps ①, ②, ③, ⑤, ⑨, ⑩, ⑪, and ⑫ as shown in Fig. 1.

[0244] ii. Donors requiring matching: The proposed system has two main cases requiring matching, which are as follows:

[0245] ⊙ Cases where there is a recipient who does not match the donor: If the donor has a recipient but the recipient does not match, matching is required.

[0246] Organ donation is successfully completed for the highest-ranked matched recipient.

[0247] Donors and registered beneficiaries are set as priority whenever a matching donor is found, and all information related to this process is stored on the blockchain network.

[0248] This situation follows steps ①, ②, ④, ⑥, ⑦, ⑧, ⑨, ⑩, ⑪, and ⑫ shown in Fig. 1.

[0249] ⊙ Cases where the donor has no recipient (altruistic donation or non-directive donation): If the donor does not have a predetermined recipient, matching is required.

[0250] Matching is performed using extensive compatibility attributes that guarantee a high probability of success.

[0251] The matching process prioritizes beneficiaries who have registered with donors who were initially unmatched.

[0252] All information related to this process is stored on the blockchain network.

[0253] This situation follows the same procedure as ①, ②, ④, ⑥, ⑦, ⑧, ⑨, ⑩, ⑪, and ⑫ in Fig. 1, 'case where there is a beneficiary not matched with a donor', but the beneficiary does not receive points for bringing in a donor.

[0254]

[0255] Figure 8 is a donor-recipient matching algorithm.

[0256] For the convenience of explanation, the algorithm of Fig. 8 is summarized as follows.

[0257] Require: donor is registered

[0258] Require: donor has not been assigned to any recipient

[0259] Require: donor and recipient organ are the same

[0260] for all recipients do

[0261] score = 0;

[0262] if donor and recipient's blood type are compatible then

[0263] if donor is dead then

[0264] check recipient's location

[0265] end if

[0266] if recipient has a confirmed donor then

[0267] add donor / recipient pair score;

[0268] end if

[0269] if donor and recipient's size are compatible then

[0270] add compatible size score;

[0271] end if

[0272] if donor and recipient's age are compatible then

[0273] add compatible age score;

[0274] end if

[0275] add recipient's condition score; subtract the recipient's serial number;

[0276] end ifrecord recipient's score;

[0277] end forsort all recipients according to score; crossMatch = negative;

[0278] while cross-match is negative do

[0279] if cross-match of highest score recipient is positive then

[0280] crossMatch = positive;

[0281] else disqualify the highest recipient;

[0282] end if

[0283] end while

[0284] return best match;

[0285] If we look at the algorithm above,

[0286] The basic requirements are that the donor must be registered, the donor must not be assigned to another recipient, and the organs of the donor and the recipient must be identical.

[0287] The algorithm's procedure consists of a beneficiary score calculation process and a cross-checking process.

[0288] (Beneficiary Score Calculation Process)

[0289] Calculate the following score for all recipients.

[0290]

[0291] S1. (Score Initialization Step) Initialize the beneficiary score (set to 0).

[0292] S2. (Blood Type Compatibility Check Step) Determine whether the blood types of the donor and recipient are compatible. If incompatible, switch to the next recipient and proceed to the score reset step.

[0293] S3. (Beneficiary Location Consideration Step) If the donor has passed away, consider the beneficiary's location.

[0294] S4. (Donor verification step for the recipient) If there is a verified donor for the recipient, add the donor / recipient pair score.

[0295] S5. (Body Size Compatibility Verification Step) Verify that the body sizes of the donor and recipient are appropriate and add points.

[0296] S6. (Age Compatibility Verification Step) Add a score based on the age compatibility between the donor and the recipient.

[0297] S7. (Beneficiary Health Status Verification Step) Add points based on the beneficiary's health condition.

[0298] S8. (Beneficiary waiting order verification step) Adjust (deduct) points according to the beneficiary's waiting order (serial number).

[0299] S9. (Sorting step after recording beneficiary scores) Sort all beneficiaries based on the calculated scores.

[0300] (Cross-checking process)

[0301] Recipients with higher scores are given higher priority. The cross-match process begins with cross-match = negative, and cross-matching is performed starting with the recipient with the highest score.

[0302] If the cross-test of the relevant beneficiary is positive, the match is successful. If it is negative, the relevant beneficiary is eliminated and the next-ranked beneficiary is selected.

[0303] This process is repeated to finally select and return the most suitable beneficiary who has passed the cross-check.

[0304]

[0305] C. Donor and Beneficiary Matching Process

[0306] When the recipient best matched with the donor accepts the match, the donor and recipient's surgeons are notified, and the smart contract changes the status to matched.

[0307] The interaction between entities in a blockchain-based long-term matching system is shown in Fig. 2.

[0308] The entire process, from the registration of donors and recipients to the surgery, is tracked using blockchain smart contracts.

[0309]

[0310] 3.2 Biological Models

[0311] Appropriate biological considerations increase the likelihood of organ transplant success.

[0312] Figure 3 shows the flow of biological and non-biological processes.

[0313] To increase the likelihood of a successful transplant, the blockchain-based organ matching system of the present invention performs two stages of biological testing in our model:

[0314] Pre-blockchain matching is a test performed before initial data is transmitted to the blockchain matching system.

[0315] In this stage, the patient's size, age, organ status, blood type, etc., are measured. The blockchain model uses this information and other non-biological data to perform patient matching, ranking all compatible patients to generate a ranked list.

[0316] A priority list is generated after blockchain matching. Cross-matching tests are conducted starting with the beneficiary with the highest priority.

[0317] The cross-matching process includes examining blood samples from donors and recipients in a controlled environment to determine whether the minute interactions of the cells can support organ transplantation.

[0318] The blockchain-based long-term matching system of the present invention considers matching before and after biological testing for the first time and integrates the process with blockchain technology.

[0319]

[0320] 4. Evaluation and Results

[0321] This section presents the performance evaluation of the proposed system and a comparison with existing systems.

[0322] The evaluation of this work focused on gas costs, security, comparison, user interface (UI), and the advantages and challenges of blockchain-based organ donation systems compared to non-blockchain-based systems.

[0323] [Table 1] below shows the gas costs for smart contracts and functions.

[0324] [Table 1: Smart Contract and Function Gas Costs]

[0325]

[0326]

[0327] 4.1 Gas Costs

[0328] There are fees associated with the computational activities performed when a smart contract is deployed on a blockchain and its functions are executed.

[0329] In this invention, to evaluate the computational cost of the solution as shown in [Table 1], a cost analysis was performed focusing on gas consumption during smart contract task execution.

[0330] In this study, we compared the gas costs associated with the various features used in our solution.

[0331] Gas costs are a measure of the computational complexity of the functions, processes, and tasks performed by the Ethereum Virtual Machine (EVM).

[0332] Since write operations update blockchain records, write operations consume more gas than read operations.

[0333] The gas cost for reading is lower than that for writing. When a full node reads a smart contract, the cost of the read operation is reduced to 0.

[0334] Figure 4 shows the analysis of gas costs as the number of patients increases in the system.

[0335] The blue bar represents the amount of gas required for the matching process when a specific number of subjects are in the smart contract waiting list (gas for matching), and the orange bar represents the additional gas required for matching when one patient is added to the current waiting list.

[0336] When one patient is added, the gas cost increases by an average of 104,180 gas in the same pattern.

[0337] Figure 5 shows a successful matching operation as a log of the successful matching of a donor and a suitable recipient.

[0338]

[0339] 4.2 User Interface

[0340] The decentralized user interface (UI) of this work facilitates communication between blockchain smart contracts and users.

[0341] This is an interactive interface for web-based applications.

[0342] FIG. 6A is a customized registration web page of the blockchain-based long-term matching system of the present invention, and FIG. 6B is an automatically generated Remix interface showing all public functions of the blockchain-based long-term matching system of the present invention.

[0343] Some functions are not exposed and therefore cannot be executed outside of the smart contract.

[0344] These functions can be called from other functions of the smart contract only when specific conditions are met.

[0345] This includes classification, blood type comparison, deactivation of successfully matched patients, and removal of recipients who refused to accept the donor's organ donation.

[0346]

[0347] 4.3 Security

[0348] Blockchain technology inherently possesses the security provided by decentralization.

[0349] However, some blockchain systems may have other forms of vulnerabilities.

[0350] Smart contract implementation is a common cause of security flaws.

[0351] As shown in FIGS. 7A-C respectively, the blockchain-based long-term matching system of the present invention was tested with the smart contract vulnerability scanners SolidCheck (https: / solidcheck.io / ), Slither (https: / github.com / crytic / slither / ), and Aderin (https: / github.com / Cyfrin / aderyn).

[0352] When tested by SolidCheck, the smart contract demonstrated perfect security results with a security score of 100%.

[0353] No issues were found in the Adelin vulnerability scanner.

[0354] Slither issued a complexity warning, which is not a vulnerability but the result of a complex process of comparing various patient characteristics to select suitable candidates and ranking them according to priority.

[0355] This security assessment proves that it is suitable for secure data transmission throughout the intended blockchain ecosystem.

[0356] This feature includes access control capabilities, allowing only authorized users to execute specific functions.

[0357] The vulnerabilities checked by this smart contract vulnerability scanner include reentrant attacks, front running, integer overflow and underflow, simple logic errors, block gas limit vulnerabilities, default visibility, and timestamp dependencies.

[0358] By eliminating these vulnerabilities, smart contracts can be considered secure.

[0359] Testing of the blockchain-based long-term matching system of the present invention is performed on the PureChain public EVM network, the private Truffle Ethereum network, and the Hyperledger Vesu consortium network.

[0360] Security checks and system tests on all three types of blockchain network operations suggest that the blockchain-based long-term matching system of the present invention is ready for use in various environments.

[0361] These three Ethereum-based test environments were used because they represent typical public, private, and consortium blockchain environments.

[0362]

[0363] 4.4 Comparison with other works

[0364] A comparison of the blockchain-based long-term matching system of the present invention and some existing blockchain-based solutions is shown in Table 2.

[0365] The comparison was conducted based on the platform used, whether security was achieved through smart contracts, network operating principles, matching process tracking capabilities, implementation status, dApp implementation status, consideration of cross-matching, consideration of the possibility of living and deceased donors, whether security analysis was performed, and finally, whether the registration of unmatched donors and recipients was also considered.

[0366] The blockchain-based long-term matching system of the present invention was built on the Ethereum network and tested in public, private, and consortium operating modes; it was implemented only on the Ethereum private network and deployed to the public network, but detailed information regarding the exact network was not provided.

[0367] The blockchain-based long-term matching system of the present invention is based on smart contracts.

[0368] Some systems provided distributed front-end applications capable of interacting with the matching process, while others did not.

[0369] The blockchain-based organ matching system of the present invention considered both living and deceased donors, whereas other systems did not specify a target donor group.

[0370] The long-term matching method of the blockchain-based long-term matching system according to the present invention is unique in performing security inspection analysis and explaining cross-matching.

[0371] The smart contract implementation code can be found on GitHub.

[0372]

[0373] Figure 6 illustrates the interface of the blockchain-based long-term matching system of the present invention.

[0374] The blockchain-based long-term matching system of the present invention can interact through a customized user interface or an automatically generated user interface.

[0375] (A) is a custom design of a user interface for patient registration, and (B) is an automatically generated user interface for testing a smart contract.

[0376] Figure 7 shows the results of a smart contract vulnerability check that showed no vulnerabilities on three platforms.

[0377] (A) is the inspection result using SolidCheck, (B) is the inspection result using Aderin, and (C) is the inspection result using Slider.

[0378] [Table 2] below is the result of comparing the blockchain-based long-term matching system of the present invention with other blockchain-based matching systems.

[0379]

[0380] [Table 2] Comparison of the system of the present invention with other blockchain-based matching systems

[0381]

[0382]

[0383] 4.5 Benefits of a Blockchain-Based Organ Donation System

[0384] All steps of the organ donation process are recorded on the blockchain.

[0385] The blockchain-based long-term matching system of the present invention proposed through this has the following effects.

[0386] - Transparency: Blockchain provides the ability for everyone involved in organ transplant and donation procedures to access the same data and verify its accuracy.

[0387] This can eliminate the possibility of fraud, corruption, or manipulation in the long-term allocation process.

[0388] - Security: Blockchain uses encryption and consensus technologies to ensure that data stored on the network cannot be altered or hacked.

[0389] This protects the identities and personal information of donors and recipients and prevents unauthorized access to or modification of organ records.

[0390] - Automation: A smart contract is an automated execution program capable of performing predetermined tasks based on specific situations.

[0391] Blockchain makes this possible.

[0392] In addition to implementing guidelines for the organ donation and transplantation system, organ matching and delivery procedures can be automated.

[0393]

[0394] 4.6 Challenges of Blockchain-based Organ Donation Systems

[0395] The challenges and implications related to the introduction of blockchain in a long-term matching environment are as follows.

[0396] a. Scalability and Performance: Performance and scalability are significant technical barriers to blockchain adoption.

[0397] Using a Layer 2 solution can overcome these problems, but implementing it increases setup costs and network complexity.

[0398] b. Technology Costs: Using new technology requires an initial investment for both healthcare institutions and patients, including learning costs for becoming familiar with the system.

[0399] In addition, the cost of purchasing devices to act as nodes in the blockchain network and the energy costs required to maintain the network are also substantial.

[0400] c. Ecosystem Readiness: Ecosystem participants lack awareness and understanding of the advantages and utility of blockchain.

[0401] If decision-makers do not properly understand and accept blockchain, its adoption will be difficult.

[0402] Basic education is necessary for both medical professionals and patients to use the system efficiently.

[0403]

[0404] The long-term matching method of the blockchain-based long-term matching system of the present invention has been described. It can be summarized as follows.

[0405] (Step 1) Step of registering donor or recipient information in the system;

[0406] The above registration involves storing biological and non-biological information about the donor or recipient in a smart contract, and

[0407] The above biological information is characterized by being one or more of the donor or recipient's weight and height, age, organ condition, blood type, and medical history information.

[0408] The above non-biological information is characterized by one or more of the geographical location of the donor or recipient, the degree of urgency, and the waiting list.

[0409]

[0410] (Step 2) A step to determine whether donor and recipient matching is necessary;

[0411] The determination of whether the above is necessary is characterized by determining that matching is not necessary if the donor already has a pre-determined compatible recipient, and determining that matching is necessary otherwise (if the donor is anonymous or if it is found that the recipient designated by the donor is not long-term compatible with each other).

[0412]

[0413] (Step 3) If it is determined that matching is not necessary, the step of storing surgery-related information in a blockchain smart contract;

[0414]

[0415] (Step 4) Cases where matching is determined to be necessary

[0416] (Step 4-1) A step of generating an organ transplant ranking list by performing organ matching between donors and recipients;

[0417] (Step 4-2) A step of selecting the final recipient through cross-matching of recipients and donors in the order of the organ transplant ranking list above;

[0418] (Step 4-3) A step of selecting the final recipient through cross-matching of recipients and donors in the order of the organ transplant ranking list above; and

[0419] (Step 4-4) A step of storing surgery-related information in a blockchain smart contract; characterized by including

[0420] (Step 4-3-1) The step of selecting the final beneficiary through the above cross-matching

[0421] It is characterized by selecting based on the results of examining blood samples from the donor and recipient in a controlled environment to determine whether the minute cellular interactions between the donor and recipient can support organ transplantation, and

[0422] (Step 4-1-1) The above list of organ transplant rankings consists of recipients sorted in order of highest score after being assigned points by a recipient scoring algorithm.

[0423] The above beneficiary score calculation algorithm applies to all beneficiaries

[0424] S1. Beneficiary score initialization step;

[0425] S2. Blood type compatibility check step;

[0426] - Determine if the blood types of the donor and recipient are compatible, and if not compatible, switch to the next recipient and proceed to the score initialization step (S1).

[0427] S3. Beneficiary location consideration stage;

[0428] - If the donor dies, considering the locations of the donor and recipient, if the organ-specific transfer time is not satisfied, the process is changed to the next recipient and proceeds to the score initialization step (S1).

[0429] S4. Step for assigning points based on the donor for the beneficiary;

[0430] - If there is a donor for the beneficiary, assign the pre-set donor-beneficiary pair score.

[0431] S5. Body size compatibility score assignment step;

[0432] - Assign a pre-set compatibility score based on the degree of match between the donor and recipient's physical sizes (height, weight).

[0433] S6. Age Compatibility Score Assignment Step;

[0434] - If the age difference between the donor and the recipient falls within a specific range, a pre-set age compatibility score is assigned.

[0435] S7. Step for assigning scores based on beneficiary health status;

[0436] - A pre-set score is assigned based on the beneficiary's health condition.

[0437] S8. Score adjustment step based on beneficiary waiting order;

[0438] - Deduct points based on the beneficiary's serial number.

[0439] It is characterized by including

[0440]

[0441] 5. Conclusion

[0442] Managing organ donation systems is an important process that requires transparency, but many organ donation systems are not transparent.

[0443] An organ donation system utilizing blockchain is being proposed to ensure transparency in the matching process.

[0444] The blockchain-based long-term matching system of the present invention handles matching management.

[0445] Using the patient's electronic medical records, the optimal match is selected based on biological and geographical compatibility.

[0446] The blockchain-based organ matching system of the present invention considers the role of cross-matching in the organ donation process and integrates it with a blockchain smart contract system.

[0447] The blockchain-based long-term matching system of the present invention is practically designed to ensure usability in real-world scenarios.

[0448] It was implemented as a frontend decentralized application and has been successfully deployed and tested on public, private, and consortium networks.

[0449] The smart contract implemented as part of the system was tested using SolidCheck, Aderin, and Slither security checkers and achieved a score of 100 out of 100, confirming that there are no known vulnerabilities.

[0450] In terms of the functions considered, the blockchain-based long-term matching system of the present invention demonstrated superior performance compared to all previously proposed blockchain solutions while passing all security checks.

[0451] In the future, we plan to introduce homomorphic encryption to ensure the privacy of medical records for both donors and recipients.

[0452] By doing this, all members of the network can read all information in the current blockchain network, so it is possible to prevent patients' medical records from being used in an unauthorized manner.

[0453] System scalability can be improved when cloud and blockchain networks are combined.

[0454] Resource-intensive computations can be offloaded to the cloud, and security-enhancing activities can be managed on the blockchain network.

[0455]

[0456] As described above, although the present invention has been described with reference to preferred embodiments with reference to the accompanying drawings, it is evident to those skilled in the art that many obvious variations are possible from this description without departing from the scope of the invention. Accordingly, the scope of the invention should be interpreted by the claims described to include examples of such many variations.

Claims

1. In the long-term matching method of a blockchain-based long-term matching system, Step of registering donor or recipient information in the system; A step to determine whether matching donors and beneficiaries is necessary; If it is determined through the above judgment that matching is not necessary, the step of storing surgery-related information in a blockchain smart contract; If it is determined through the above judgment that matching is necessary The method is characterized by including: a step of matching the final recipient by performing organ matching between the donor and the recipient; and a step of storing surgery-related information in a blockchain smart contract. Long-term matching method of a blockchain-based long-term matching system 2. In Paragraph 1, The above registration involves storing biological and non-biological information about the donor or recipient in a smart contract, and The above biological information is one or more of the donor or recipient's weight and height, age, organ condition, blood type, and medical history information, and The above non-biological information is characterized by being one or more of the geographical location of the donor or recipient, the degree of urgency, and the waiting list. Long-term matching method of a blockchain-based long-term matching system 3. In Paragraph 1, The above determination of necessity is characterized by determining that matching is not necessary if the donor already has a predetermined compatible beneficiary, and determining that matching is necessary otherwise. Long-term matching method of a blockchain-based long-term matching system 4. In Paragraph 1, The step of matching the final beneficiary by conducting the aforementioned long-term matching A step of generating an organ transplant ranking list by performing organ matching between donors and recipients; A step of selecting the final recipient through cross-matching of recipients and donors in the order of the above organ transplant ranking list; Characterized by including the step of selecting a final recipient through cross-matching of recipients and donors in the order of the organ transplant ranking list above. Long-term matching method of a blockchain-based long-term matching system 5. In Paragraph 2, The above cases where it is not the case are characterized by being an anonymous donor or a case where it is found that the recipient designated by the donor is not long-term compatible with each other. Long-term matching method of a blockchain-based long-term matching system 6. In Paragraph 4, The above organ transplant ranking list is characterized by recipients being sorted in order of highest score by assigning scores using a recipient score calculation algorithm, in an organ matching method of a blockchain-based organ matching system.

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